Beyond Set Theory: the Relationship Between Logic and Taxonomy from the Early 1930 to 1960

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Beyond Set Theory: The relationship between logic and taxonomy from the early 1930 to 1960.

Charissa Sujata Varma

A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Institute for the History and Philosophy of Science and Technology University of Toronto

Beyond Set Theory: The relationship between logic and taxonomy from the early 1930s to 1960.

Charissa Sujata Varma

Doctor of Philosophy

Institute for the History and Philosophy of Science and Technology University of Toronto

2013 Abstract

In this dissertation I look at the relationship between logic and taxonomy as taxonomists responded to double attack: an attack on their methodology from the biological community during the 1930s and at the start of a methodological civil war that erupted in late 1950s.

According to the usual story, the relationship between logic and taxonomy could not have been worse. Taxonomists were thought to be either mired in Aristotelian essences or lost in some dubious set-theoretic wasteland. This story, however, is now recognized as being a political tool rather than an accurate history and the time is ripe for something new. I examine four cases:

British botanist John Gilmour, American paleontologist George Gaylord Simpson, German entomologist Willi Hennig, and American philosopher Morton Beckner that help illustrate the richness of this relationship. These cases will show how different branches of logic successfully played roles in taxonomy’s methodological reform, rather than set-theory playing the dominant and ultimately failing role as the old paradigm. In addition, it will become clear that one reason why this could be done was because many of these taxonomists were part of transient interdisciplinary groups willing to relax the standards of authority within interdisciplinary communities. These changes in authority helped facilitate communication and promote ii knowledge production during this complex time. Taxonomists without the traditionally recognized expertise in logic chose to read logic on the fly, and likewise philosophers and other biologists without established training in taxonomy could enter the debate in significant and productive ways.

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Acknowledgments

I would like to thank my supervisor Prof Mary P. (Polly) Winsor. There are many things I can say about Polly as a supervisor, from her unflinching editorial eye to her inspirational work in history of biology, but it was her ceaseless love, encouragement, and generosity that carried me through this project. She pushed me beyond what I thought I was capable of intellectually and creatively, and I am a better historian, philosopher, and writer because of her. Polly didn’t just instill in me a love and passion for history of biology—the practitioners, the organisms, the institutions, the issues—she gave me an intellectual family, and was the perfect matriarch. Like a family, we her students laughed together, cried together, worked together, taught together, published together, travelled together, read each other’s dissertations and articles, and (in some cases) went to each other’s foreign convocations. Keynyn Brysse, Conor Burns, Jamie Elwick, Gillian Gass, Gordon McOuat, and especially Sara Scharf (my dear partner in crime), thank you so much for being my family. Polly, thank you for always being “our mum.” I hope I did you proud.

Prof. Paul Thompson, the second member of my supervisory committee, was my rock. His unwavering support and patience with me especially during the most chaotic times of his semesters were rivaled only by his uncanny ability to provide perfectly-timed, exacting, constructive questions that always seem to cut to the heart of the problem. Paul was the perfect balance of administrative magic and philosophical wonder.

I am grateful to Prof. Gordon McOuat, the third member of my supervisory committee, for several lively and provoking conversations and exchanges. His work in nineteenth-century biology influenced parts of this project, and as always, I benefited from his feedback and advice.

I would like to thank Profs Craig Fraser and Denis Walsh, who served on my oral examination committee, for their insightful questions, and their thoughtful contributions to a stimulating conversation during the oral defense, as well as to my external examiner, Prof. Richard Richards, whose invaluable comments and suggestions have been helpful to this project and will be to future work stemming from this project.

The time I spent at the University of Toronto has been rewarding, challenging, and fulfilling. I have benefited from the direction and guidance of an extraordinary supervisory iv

committee on this project, and learned from an astonishing group of scholars at the Institute for the History and Philosophy of Science and Technology. I conducted much of my research using the University of Toronto’s phenomenal library system, in particular the Fisher Rare Books Library, and I want to thank the many librarians and archivists, Richard Landon in particular, who aided my research. I also want to thank the University of Toronto, the IHPST in particular, for the generous funding and scholarships I have received, specifically the travel grant that allowed me to conduct research in London, England on late nineteenth and early twentieth- century logic, and the internship with Cambridge University to work on the Darwin Correspondence Project. I would also like to thank both the IHPST and the Philosophy Department for providing me with many valuable teaching opportunities (both as a teaching assistant and instructor), especially those that dovetail this project. It has been a true pleasure and honour to teach these students. It was because of their faith in me that I was awarded a University Teaching Award for Excellence in Teaching. My time in Toronto was all the more fun because of my fantastic friends, professors, and administrators: Teri Gee, David Gugel, Gavin Hammel, Martha Harris, Angela Heffernan, Drew Hicks, Sarah Hundleby, Lindsay Irvin, Jennifer Keelan, Jessica Lovett, Darcy Otto, Muna Salloum, Jennifer Smolenaars, Colin Stewart, Jonathan Turner, Jai Virdi, Shana Worthen, Prof. Jim Brown, Prof. Bert Hall, Prof. Margaret Hundleby, and Prof. Pauline Mazumdar, you kept me happy and sane. Special thanks are owed to my dear friend Kelli Carr, who kept my head and home in perfect order while I lived in Toronto. That poor girl knows more about nineteenth-century bee taxonomy than any normal person should. She is a saint, and heaven knows she suffered like one with me as her roommate, especially during the ugly Linnaeus years.

The final stage of my writing was completed in Windsor, Ontario. Dr. John Strang kept me on track, which was no small feat. For more weeks than I can count, we were inseparable— John in his office and me in the autism testing room. Thank you, John, for the talks, the laughs, the advice, and our Friday afternoons. My life in Windsor was richer because of my people, so thank you Victoria Cross, Jodi House, Stephen Pender, Bob Pinto, Christine Purcell, Jeff Noonan, Cory Saunders, Josie Watson, and especially my boys Len Wallace and the mighty Tory James. My greatest debt is to my best friend, Catherine Hundleby. Catherine’s friendship and strength sustained me through degrees, moves, heartbreaks, life, and deaths. She is incredible. It is no surprise that I lived under her roof during the final stages of this project.

Finally, I would like to thank my family. I want to thank Bob and Lynn Ross, and David and Kathy Ross not just for their unconditional love and support, but for their tireless efforts to keep us all together as one huge family. You have all done brilliantly. I would not have made it through this without you. I would also like to thank Alakh and Colleen Varma, and Achla and Bageshwari Sinha for their love and support with all my decisions and ambitions, and for holding my hand every time I needed it. Thanks to my cousins Jonathan, Allison and her husband Matt, Heather and her husband Cormac, Andrew, Anvita and Anup for being what I needed when I needed it, which was often just hilarious. Seriously, you people are hilarious. Last, but certainly not least, many thanks to my siblings Kara and her husband Rich, and Adam for their patience, understanding and love for they had the enormously difficult task of putting up with me on this long journey. My sweet, baby India, your smile lights up my day like nothing else. My darling, darling Isaac, your beautiful face always reminds me there is joy in my life.

And monster trucks.

To my mother,

Annette Margaret Styles (1946-2010)

Not a word of this could have been written without you.

Not a day goes by that I don’t miss you with all my heart.

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Table of Contents

Acknowledgments ...... iv

Table of Contents ...... viii

List of Figures ...... xii

Chapter 1 Introduction ...... 1

1.1 Research question ...... 1

1.2 Reasons for needed work ...... 5

1.3 Scope and goals ...... 17

Chapter 2 Taxonomy’s fall from grace ...... 25

2.1 Introduction ...... 25

2.2 1900-1910 ...... 28

2.2.1 Call for reform: E. B. Wilson ...... 28

2.2.2 The role of evolution: Charles Bessey ...... 29

2.2.3 New species definitions: Bailey, Davenport, Hallier, Church, Frisch, Worsdell, and a change in criteria ...... 31

2.2.4 Change in Methodology: Coulter, Oliver, Clements, and Dobzhansky ...... 34

2.2.5 Quagmire ...... 47

Chapter 3 Gilmour ...... 48

3.1 Introduction ...... 48

3.1.1 Gilmour’s plan ...... 50

3.1.2 Botanical debates ...... 52

3.2 Gilmour’s two early papers ...... 57

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3.2.1 Whately’s logical reform ...... 61

3.2.2 Mill’s logic ...... 65

3.2.3 Influence of Mill’s logic on taxonomy ...... 69

3.2.4 Ontological status of classification systems ...... 70

3.2.5 History of classification systems retold ...... 72

3.2.6 The new natural and artificial systems ...... 74

3.2.7 Problems with evolutionary taxonomy ...... 81

3.3 Gilmour’s chapter in The new systematics ...... 84

3.4 Conclusion ...... 96

Chapter 4 Simpson ...... 99

4.1 Introduction ...... 99

4.2 First stage—Types: 1920s-mid 1930s ...... 103

4.2.1 Mentors, evolution, and philosophy ...... 105

4.2.2 “A Mesozoic Mammal Skull from Mongolia” (1924) ...... 108

4.2.3 “Mesozoic Mammalia” (1925-1926) ...... 109

4.3 Second Stage—Statistics: Mid 1930s to 1937 ...... 124

4.3.1 Early thoughts on methodological reform ...... 128

4.3.2 “Data on the relationships of local and continental mammalian land faunas” (1936) ...... 130

4.3.3 “Notes on the Clark Fork, Upper Paleocene, Fauna” (1937) and “Patterns of Phyletic Evolution” (1937) ...... 132

4.3.4 First job: museum and field work, scholar and popular science writing ...... 136

4.3.5 “Patterns of Phyletic Evolution” (1937) ...... 139

4.3.6 “Notes on the Clark Fork” (1937) ...... 140

4.3.7 The Fort Union of the Crazy Mountain Field, Montana, and Its Mammalian Faunas (1937) ...... 141

4.3.8 Quantitative Zoology (1939) ...... 144

4.4 Conclusion ...... 154

Chapter 5 Hennig 1947-1950 ...... 157

5.1 Introduction ...... 157

5.2 Hennig’s early years ...... 159

5.3 “Probleme der biologischen Systematik” (1947) ...... 164

5.3.1 Division hierarchies ...... 167

5.4 “Zur Klarung einiger Begriffe der phylogenetischen Systematik” (1949) ...... 171

5.4.1 Space and multidimensions ...... 172

5.4.2 Enkaptic systems ...... 174

5.5 Grundzüge einer Theorie der Phylogenetischen Systematik (1950) ...... 179

5.5.1 Logic and methodology in Grundzüge ...... 179

5.5.2 Semaphoront and hierarchies ...... 187

5.5.3 Multidimensional multiplicity and Rudolf Carnap ...... 190

5.5.4 Torrey ...... 199

5.5.5 Mereology ...... 205

5.5.6 Axiomatic Method (1937) ...... 210

5.6 Conclusion ...... 212

Chapter 6 Beckner ...... 217

6.1 Introduction ...... 217

6.2 Beckner, Gregg, and the reality of species ...... 224

6.3 Burma, Mayr, and the 1949 Evolution debate ...... 227

6.4 Simpson, species, populations, and logic ...... 234

6.5 Gregg and logic ...... 243

6.6 Gregg’s paradox ...... 248

6.7 Beckner and polytypic species ...... 252

6.8 Conclusion ...... 261 x

Chapter 7 Conclusion ...... 263

Postscript Hennig’s Phylogenetic Systematics (1961/66) ...... 271

7.1 Introduction ...... 271

7.2 Gregg and Woodger ...... 277

7.3 Hennig on hierarchies 1961/66: ...... 281

7.3.1 Part I ...... 281

7.3.2 Part II ...... 284

7.4 Conclusion ...... 292

Bibliography ...... 294

8 Appendix 1 ...... 309

8.1 Woodger’s notion of Parthood ...... 309

8.2 Time ...... 310

8.3 Organized entities ...... 311

8.4 Beginners and enders ...... 312

8.5 Biological relations—division and fusion ...... 312

8.6 Hierarchies ...... 315 1

List of Figures

Hennig Figure 1...... 175

Hennig Figure 2 ...... 175

Hennig Figure 3 ...... 176

Zimmerman Figure 1 ...... 177

Hennig Figure 4...... 283

Woodger Figure 1...... 313

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Chapter 1 Introduction 1.1 Research question

The usual story of the relationship between logic and taxonomy goes something like this.

There was a methodological stasis in taxonomy from Aristotle to Darwin. The stasis was rooted in logical assumption about essences, where taxonomic groups were defined by a set of necessary and jointly sufficient conditions, and these groups structured the taxonomic hierarchy.

In recent years, historians and sociologists of science have challenged the usual story, and in the wake of this controversy, a major historical question remained: what is the relationship between logic and taxonomy?1 The immediate answer begins by exploring taxonomy’s methodological reform from the 1930s through to 1960, specifically how logic found its way into taxonomic methodology. These answers, I argue, led to a new question, namely, how logic was used within interdisciplinary communities during taxonomy’s methodological reform. The answers to this question, I suggest, begin a new story.

This story is not a Shakespearean drama of cause and effect. I want to replace the usual story with a new one. In the usual story, the drama begins with the rising action of centuries of

1What I call the usual story is commonly called the “essentialism story” in the literature. For a succinct discussion of the history of the essentialism story, see Mary P. Winsor “Linnaeus’s Biology Was Not Essentialist,” Annals of the Missouri Botanical Garden 93 (2006): 2-7. For criticisms of this story see: Mary P. Winsor “Non-essentialist Methods in pre-Darwinian Taxonomy,” Biology and Philosophy 18 (2003): 387-400; Gordon McOuat, “Species, rules and meaning: The politics of language and the ends of definitions in nineteenth-century Natural History” Studies in History and Philosophy of Science 27, (1996): 473–519; Gordon McOuat “Cataloguing power: Delineating ‘Competent Naturalists’ and the meaning of species in the British Museum” The British Journal for the History of Science, Vol. 34, No. 1 (Mar., 2001a): 1-28; Staffan Müller-Wille “Gardens of paradise.” Endeavour 25 (. 2001):49–54; Ron Amundson “Typology reconsidered: Two doctrines on the history of evolutionary biology,” Biology and Philosophy 13(1998): 153-77; Sara T. Scharf Identification keys and the natural method: the development of text-based data management tools in botany in the long 18th century, (Toronto: unpublished Phd Thesis, 2007); Charissa S. Varma “Threads that Guide or Ties that Bind: William Kirby and the Essentialism Story” Journal of the History of Biology, Volume 42, issue 1 (February 2009): 119-149; Richards Richard The Species Problem: A Philosophical Analysis. (Cambridge: Cambridge University Press, 2010); and Scott Atran Cognitive foundations of natural history: towards an anthropology of science. (Cambridge: Cambridge University Press, 1996).

2 methodological stasis. The climactic plot twist occurred when naturalists were pulled from this stasis by Darwin and his theory of evolution by natural selection, followed by the falling action of taxonomy’s toppling from grace. In this story’s dénouement, we find the modern synthesis. I do not deny cause and effect in the new story’s narrative. What I deny is that cause and effect worked in that particular way. The new story is different, more complicated, with more factors.

Where the usual story had the plot twist occurring when naturalists were pulled from this stasis by Darwin and his theory of evolution by natural selection, the new story has different branches of logic successfully playing roles in taxonomy’s methodological reform, rather than just set- theory playing the dominant and ultimately failing role as the old paradigm. Different branches of logic, such as induction, mereology, questions of inference, etc., were able to play successful roles in taxonomic methodological reform in part because of changes in the standards of authority within interdisciplinary communities. These changes were a necessary part of how this particular story unfolded, for they helped facilitate communication, ensure new concepts held up under scrutiny, and encourage knowledge production. Taxonomists without the traditionally recognized expertise in logic galloped through sophisticated logic texts. In some cases, they conversed with, and sometimes published with, logicians. This was all part of an effort to build up a background that would enable them to effectively work the relevant logic in their reform agenda. This new environment encouraged partnerships with philosophers who used biology in a similar fashion. In this context, the application of logic to taxonomy can now be seen not as a failure in isolation, as it has been portrayed in the literature, but as a success within an interdisciplinary enterprise.

This dissertation is not an exercise in social history. To flesh out this new story, this dissertation examines the history, logic, and philosophical details of four cases: English botanist

John Scott Lennox Gilmour (1906-1986), American paleontologist George Gaylord Simpson

(1902-1984), German entomologist Willi Hennig (1913-1976), and American philosopher

Morton Beckner (1928-2001). All three biologists were involved in taxonomy’s methodological reform at some point between 1930 and 1960, and discussed some aspect of logic during their early work in the methodological reform. The biologists I examine belonged to transitory interdisciplinary committees (or in Hennig’s case, some of the key people he cited, such as J. H.

Woodger (1894-1981) belonged to one such group). Within these committees biologists were granted authority in disciplines (branches of logic specifically) that they wouldn’t normally be granted. Sociologists and historians of science, such as Joe Cain, Pnina G. Abir-Am, and V.

Betty Smocovitis, have argued that the reason the conditions for granting authority were relaxed in transitory interdisciplinary groups of this period was to help facilitate communication, ensure new concepts held up under scrutiny, and encourage knowledge production. The combination of this approach to interdisciplinary work in an environment promoting quantitative methodologies meant that these biologists were able to use different branches of logic effectively in their reform work. By taking as my starting point the writing of these biologists from the perspective of their interdisciplinary work, rather than their “pillar publications,” I am able to group biologists together that have important differences in reputation (e.g. Gilmour versus Simpson and

Hennig), but still have meaningful contributions on this issue. From this perspective, not only do they have significant things to say, it can be said on reasonably equal footing.

One might say that when it comes to the relationship between logic and taxonomy during the methodological reform, the situation might simply be a matter of “normal scientists” turning to other tools—logic or philosophy being such a tool—as weapons in the struggle in times of dispute. I don’t believe the story to be quite so simple in this instance. These cases will show how different branches of logic figured into explicitly interdisciplinary efforts to work out a way to move taxonomy’s methodology onto a more quantitative path, or in Gilmour’s case, explain

4 the ontological and epistemological landscape. Moreover, during the early years of the reform logic (or any quantitative tool) would not have been weapon of choice for many taxonomists. In the beginning of the twentieth century, the battle between the old and new biologies appeared to be a struggle between two conflicting methodological styles, one largely qualitative and the other largely quantitative. Even when a more quantitative methodology was adapted, describing the situation as “normal scientists” turning to other tools as weapons in the struggle in times of dispute remains awkward. Philosopher David Hull (1935-2010) summed it up well in 1970 when he reflected:

When Huxley called for “more measurement” in the New Systematics, he did not have in mind the processes by which taxonomists judge affinity. It is easy to sympathize with both sides, with the biologists who were less than elated over the prospect of learning all the new, high-powered notations and techniques that were beginning to flood the literature and with the pheneticists whose work was rejected on occasion, not because the particular mathematical techniques suggested were inadequate, but because they were mathematical. Happily, this aspect of the conflict has largely abated, although pockets of resistance still remain. The question is no longer whether or not to quantify but which are the best methods for quantifying.2

It is true that by the late 1950s and 1960s, the relationship between logic and taxonomy was robust enough—there was enough dialogue in the literature to demonstrate a relationship—but as seen from the types of objections launched at the pheneticists, characterizing the situation as

“turning to other tools as weapons in the struggle in times of dispute” would be misleading.

By the 1950s biologists were not the only ones who benefited from fluidity in disciplinary boundaries and relaxed standards of authority. For example, in addition to these biologists, I also look at philosopher Morton Beckner who weighed in on the debates in taxonomic methodology, specifically on the relationship between logic and taxonomy. Beckner’s treatment of taxonomy in The biological way of thought (1959), which fell between Hennig’s

2David L. Hull, “Contemporary Systematic Philosophies” Annual Review of Ecology and Systematics, Vol. 1. (1970): 20.

5 first and second edition of Phylogenetic systematics, signaled the start of philosophers entering the reform dialogue in robust way. Beckner’s book was his PhD dissertation in philosophy, but he also held a degree in zoology from the University of California, Santa Barbara, and began medical school at NYU before pursuing a PhD in philosophy. This training allowed him to communicate more effectively across disciplinary borders. By the late 1960s a new generation of interdisciplinary literature had emerged, beginning with scholars like philosopher Hull and zoologist Michael Ghiselin (1939- ) and their pioneering and widely influential work on biological individuality. Like Beckner, Hull also had a degree in zoology, as well as philosophy, and worked with zoologists, putting him in a similar position. Ghiselin enthusiastically devoured philosophical and logical work in an effort to do his part.

1.2 Reasons for needed work

The history of taxonomy has been understood as part of a larger history, the history of the

“modern” or “evolutionary synthesis.” Julian Huxley’s term “the modern synthesis,” claimed historian Joe Cain, has proven to be a very useful rhetorical tool for biologists, and later historians, in the standard literature. Cain argued it has been deployed in everything from attacks against the director of Soviet biology under Stalin, Trofim Lysenko (1898-1976) during the

3 1940s to battles in funding agencies and within institutions during the 1950s and 1960s. But defining the modern synthesis was not easy. The history of the modern synthesis was complex, as was the history of taxonomy contained within.

Cain claimed that there was much more to evolutionary studies in the 1920s and 1930s than suggested in the usual “commonplace narratives of this object in history.” It is these commonplace narratives that have shaped the familiar account in the literature on the

3Joe Cain “Rethinking the Synthesis Period in Evolutionary Studies” Journal of the History of Biology 42 (2009): 622.

6 relationship between logic and taxonomy during taxonomy’s methodological reform. Most of the literature on the relationship between logic and taxonomy during taxonomy’s methodological reform focused on the relationship between some version of traditional set theory and taxonomy, and the literature tended to emphasize certain players and their account of the relationship between logic and taxonomy as they understood it in the modern synthesis.

In the late 1950s, zoologists Ernst Mayr (1904-2005) and Arthur J. Cain (1921-1999) each wrote about taxonomy’s explosive relationship with logic—past and present.4 Their characterization of the relationship between logic and taxonomy was limited to taxonomy and a type of logic of classes, such as set theory or Aristotelian logic, and logic’s role had been seen by many as serving political ends. Mayr and A. J. Cain claimed that naturalists from Aristotle to

Darwin shared a set of logical and ontological assumptions, and this set of shared assumptions led to a common methodological practice, namely an a priori character weighting system that joined taxonomically relevant characters to the “essence” of the group. The characters essentiales were assumed to form the taxonomic definitions found in their natural history books.

The history of taxonomy Mayr and A. J. Cain presented had Aristotelian (or more accurately

Scholastic) logic playing a significant role in the pre-Darwinian concept of taxonomic groups and methodology. Although not Aristotle’s language, Mayr and A. J. Cain emphasized that pre-

Darwinian naturalists understood taxonomic groups as “sets” or “classes” of organisms, where

4See A. J. Cain, “Genus in Evolutionary Taxonomy” Systematic Zoology 5 (1956): 97-109; A. J. Cain, “Logic and Memory in Linnaeus System of Taxonomy” Proceedings of the Linnean Society of London 169 (1958):144-63; A. J. Cain, “Deductive and Inductive Methods in Post-Linnaean Taxonomy” Proceedings of the Linnean Society of London 170 (1959a):185-217; A. J. Cain, “The Post- Linnaean Development of Taxonomy” Proceedings of the Linnean Society of London 170 (1959):234-44.; Ernst Mayr “Difficulties and Importance of the Biological Species Concept.” (1957) in The Species Problem, edited by Ernst Mayr (Washington, D.C.: American Association for the Advancement of Science) 371-388.; Ernst Mayr “Darwin and the Evolutionary Theory in Biology” (1959a ) reprinted in Evolution and the Diversity of Life: Selected Essays, edited by Ernst Mayr (Cambridge Mass: Harvard University Press, 1976); Ernst Mayr “The Emergence of Evolutionary Novelties” (1959b ) revised and reprinted in Evolution and the Diversity of Life: Selected Essays, edited by Ernst Mayr (Cambridge Mass: Harvard University Press, 1976); Ernst Mayr “Agassiz, Darwin, and Evolution.” Harvard Library Bulletin 13 (1959c.): 165-194.

7 the essential characters formed taxonomic definitions and maintained these definitions had the logical form of Aristotelian definitions, that is, properties of organisms formed a set of necessary and jointly sufficient conditions that defined the taxonomic group. Mayr and A. J. Cain also maintained that classification systems were underwritten by a logical system that included a kind of Aristotelian division principle. For example, A. J. Cain claimed that pre-Darwinian naturalists’ methodology involved a principle, or fundamentum divisionis, that captured the

“essence” of the group, and proceeded at every stage and so far as possible. A. J. Cain argued that Linnaeus employed such fundamentum divisionis in his sexual system of plants. Mayr developed A. J. Cain’s position, and argued that naturalists adopting this kind of Aristotelian division principle proceeded in an analytic “top-down” methodological approach—where groups were arranged by breaking down larger groups into smaller groups. Later in his career, A. J. Cain modified his account of the history of taxonomy, but not before the political ball began to roll.5

What is often forgotten is that although Mayr and A. J. Cain promoted a similar history of taxonomy and one that would be used for largely political ends, they belonged to different camps in taxonomy’s civil war. Mayr belonged to “evolutionary” camp, and Cain to the “phenetic” camp. Hull pointed out in 1970, when he summarized some of the issues in the debates among taxonomists, the main fight was between the pheneticists, such as Arthur J. Cain, Robert Sokal, and Peter Sneath, who maintained that organisms should be classified according to overall similarity without any a priori weighting, and the “evolutionary taxonomists” such as Mayr,

George G. Simpson and Theodosius Dobzhansky, and the “phylogenetic taxonomists” such as

5See Arthur Cain “The Methodus of Linnaeus.” Archives of Natural History 19(1992): 231-250; “Linnaeus’s Ordines naturals.” Archives of Natural History 20(1993): 405-415; “Numerus, figura, proportio, situs: Linnaeus’s definitory attributes.” Archives of Natural History 21(1994): 17-36.; and “Linnaeus’s natural and artificial arrangements of plants.” Botanical Journal of the Linnean Society 117 (1995): 73-133. For more on this story, see Mary P. Winsor “Cain on Linnaeus: the scientist-historian as unanalysed entity” Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences 32 (2001): 239–254.

Willi Hennig, Lars Brundin, and Sergius Kiriakoff, who together insisted not only must evolutionary theory played a central role in taxonomy, but biological classification must have a systematic relation to phylogeny. According to Hull, the latter group was divided with respect to the nature of the relation between classification and phylogeny. However, as Hull aptly observed, taxonomists agreed “essentialism” was a dirty word, and all of them wasted no time applying it freely and widely:

In taxonomy, the essentialist position is known as typology, a word with decidedly bad connotations. In the recent literature, every school of taxonomy has been called typological at one time or another. The phylogeneticists term the evolutionists typologists because they let degree of divergence take precedence over recency of common ancestry in their classifications . . . The pheneticists call both evolutionists and phylogeneticists typologists because they claim to use criteria which are rarely tested and may not actually obtain . . . The pheneticists in turn are called typologists because their classifications are intended to reflect overall similarity . . . The pheneticists reply that they are typologists but without types and of a statistical variety . . . Their opponents reply that this is not typology but nominalism . . . ! To put a nice edge on the dispute, some taxonomists openly claim the honor of being called typologists. “Now the great object of classification everywhere is the same. It is to group the objects of study in accordance with their essential natures.”

As Hull’s summary suggests, it was a history of taxonomy used as a means to a political end, and is still appealed to in some circles. Winsor noted this story lived in biology textbooks, and she cited Douglas J. Futuyma’s textbook Evolutionary Biology (1998). For a while, it structured philosophical debates on the species concept and the units of selection debate, in addition to providing the rhetorical ammunition in debates between rival taxonomic camps.6 But, from the

6 See for example: R. N. Boyd “Homeostasis, species, and higher taxa.” in Species: New Interdisciplinary Essays, edited by Robert A. Wilson (Cambridge: MIT Press, 1999) 141-185; Marc Ereshefsky “The evolution of the Linnean hierarchy.” Biology and Philosophy 12 (1997): 493-519; Marc Ereshefsky “Species and the Linnaean hierarchy.” in Species: New Interdisciplinary Essays edited by Robert A. Wilson, (Cambridge: MIT Press,1999) 285-306; Marc Ereshefsky The poverty of the Linnaean hierarchy: A philosophical study of biological taxonomy. (Cambridge: Cambridge University Press 2001); Marc Ereshefsky “Linnaean Ranks: Vestiges of a Bygone Era.” Philosophy of Science 69(2002): S305-S315; Elliot Sober “Evolution, Population Thinking, and Essentialism” Philosophy of Science 47(1980): 350-383; Elliot Sober “Sets, Species, And Evolution: Comments on Philip Kitcher’s ‘Species’” Philosophy of Science 51(1984): 334-341; David N. Stamos “Pre-Darwinian Taxonomy and Essentialism—A Reply to Mary Winsor” Biology and Philosophy 20( 2005):79–96; David L Hull. “Are Species Really Individuals?” Systematic Zoology, 25 (1976): 174-191; David L. Hull “A Matter of Individuality” Philosophy of Science, 45(1978): 335-360; David L. Hull “Individuality and selection.” Annual Review of Ecology and

9 perspective of this project, it presents the relationship between taxonomy and logic at best through a dirty glass, and at worst a myopic lens. While the usual story certainly presents one aspect of the relationship between logic and taxonomy, it is not the only aspect, or the defining feature of the relationship.

According to Joe Cain, most of the early historical literature on evolutionary studies, and this included the emergence of the modern synthesis, focused on the changes in theory, and their explorations focused on “pillar publications.”7 Included in the “pillar publications” was the usual story. The next wave of historical literature, of which Joe Cain saw his own work as a part, focused instead on organizational and institutional issues, and how research communities emerged and operated in broader scientific contexts. 8 It is within this wave of literature I want to locate my point of departure, specifically the body of work that looks at the writing produced as a result of the transient interdisciplinary groups that emerged beginning in the late 1930s, such as

Association for the Study of Systematics in Relation to General Biology, The Society for the

Study of Speciation, Committee on Common Problems in Genetics, Paleontology, and

Systematics, and Biotheoretical Gathering. Although historians and sociologists of science focused on different issues, this wave of historical and sociological literature roughly mapped out the same set of significant events. What is important about their roadmap is not simply the enthusiasm for interdisciplinary groups and the obstacles involved in making such groups work,

Systematics 11(1980): 311-32; Philip Kitcher “Species.” Philosophy of Science 51(1984): 308-333; Michael Ruse “Definitions of species in biology” British Journal for the Philosophy of Science 20(1969): 97-119. Michael Ruse “Biological species: Natural kinds, individuals or what?” British Journal for the Philosophy of Science 38(1987): 225-42. 7Pnina G. Abir-Am made a similar argument earlier about problems with the historical literature focusing on internalist/externalist dichotomy in “The Biotheoretical gathering, trans-disciplinary authority and the incipient legitimation of molecular biology in the 1930s: New perspective on the historical sociology of science” Hist. Sci., xxv (1987) 1-70. 8Joe Cain cites Mark Adams, William Provine, and Betty Smocovitis as examples of those writing in this historical direction. See Joseph Allen Cain “Common Problems and Cooperative Solutions: Organizational Activity in Evolutionary Studies, 1936-1947” Isis, 84 (1993) 1-25. Also on this topic see Pnina G. Abir-Am “The Biotheoretical gathering, trans-disciplinary authority and the incipient legitimation of molecular biology in the 1930s: New perspective on the historical sociology of science” Hist. Sci., xxv (1987) 1-70.

10 but how certain key players assumed expertise and authority within the confines of these groups, and that they used this authority, for my purposes specifically, to write on logic and taxonomy.

Again, these events are significant because they bind the three biologists I use, and as I mentioned earlier, given the nature of interdisciplinary writing, put them on a more level playing field. Gilmour and Simpson participated in some of these interdisciplinary committees. Although

Hennig did not participate in these committees because of where he was during that time in history, the some of the people he cited, such as J. H. Woodger, did. Woodger famously wrote on the relationship between biology and logic, and Hennig used his mereological ideas in his own taxonomic work. These committees set out a new approach to interdisciplinary work and authority, and for the purposes of this project, helped show that different branches of logic played successful roles in taxonomic methodological reform.

In 1936, Julian Huxley met with prominent researchers at key British botanical and zoological institutions. He compelled them to explore the relationship between evolution and taxonomy, forming the Association for the Study of Systematics in Relation to General Biology

(under the auspices of the Linnean Society of London), with John S. L. Gilmour as secretary.9

Later, in 1939, there were two historic meetings.

The first meeting was in Edinburgh where Huxley and botanist William B. Turrill (1890-

1961) attended the Seventh International Genetics Congress. There they chaired what was, according to Cain, one of the major sections of the program, “Genetics in Relation to Evolution and Systematics” with ten sessions devoted to speciation and taxonomy and forty-six papers on the general topic presented. Huxley delivered the keynote address that covered “evolutionary

9See Cain “Common Problems” 4 and Mary P. Winsor “The English debate on taxonomy and phylogeny, 1937– 1940.” History and Philosophy of the Life Sciences, 17 (1995): 227–252.

11 genetics” and its position in what he saw as the cooperative study of species formation. The historical significance of this meeting was the associated 1940 volume edited by Huxley, The

New Systematics. The aim of Huxley’s “new” systematics was to integrate the various studies of divergence and isolation and relate them to taxonomic groups and evolutionary mechanisms. By calling this project “new,” Huxley sought to highlight both the emphasis on experimental approaches and the effort’s cross-disciplinary confederation.”10 Huxley was not simply calling for a taxonomic reform. He was announcing the direction for the reform. Yes, there was an emphasis on experimental, quantitative methods, but wanted it to be was to be a cooperative enterprise with the new generation of biologists. This “cross-disciplinary confederation” would require a lot of work on everyone’s part. As the volume showed, if a unified vision was the goal, there was much work ahead on that front.

The second meeting took place in America. Julian Huxley convened with Dobzhansky,

Mayr, and botanist Carl Epling (1894-1968) in Columbus, Ohio at the American Association for the Advancement of Science meetings and urged the formation of an official group that would forge some interdisciplinary coordination and cooperation with geneticists, paleontologists, and taxonomists on the study of speciation. The Society for the Study of Speciation was officially founded in the United States in 1940 with entomologist Alfred. E. Emerson (1896-1976) as secretary.11 In addition to these two groups was the West Coast “Biosystematists.” This group was an informal cooperative organization with a diverse background in all branches of taxonomy that also investigated evolutionary studies. According to Smocovitis, the people exerting the most pressure to institutionalize evolutionary studies were those associated with the short-lived

Society for the Study of Speciation. She claimed things really began to take shape in 1943 when

10Cain “Common Problems” 5. 11For more see Joe Cain “Towards a ‘greater degree of integration’: The Society for the Study of Speciation 1939- 1941” British Journal for the History of Science 33(2000): 85-108.

12 those associated with the SSS formed the “Committee on Common Problems of Genetics,

Paleontology, and Systematics” established under the auspices of the National Research Council under the initiative of geologist Walter Bucher (1888-1965).12

This group began as an exchange between paleontologists and geneticists, but under

Mayr’s leadership, it grew into much more. During the war, this group of evolutionists maintained communication through a series of mimeographed bulletins edited by Mayr in which

“common problems” were discussed. Smocovitis argued that it was through these bulletins that a consensus emerged showing that there was in fact a common ground and a common field that should be recognized.13 She drew attention to the fact that Simpson noted the emergence of this common field in the final mimeographed bulletin of 1944.14 This was no small feat, finding common ground among geneticists, paleontologists, and later taxonomists. Where to go from there was the next big problem.

In 1946, the Society for the Study of Speciation was recreated as the “Committee on

Common Problems in Genetics, Paleontology, and Systematics” at a conference in St. Louis,

Missouri, fifty-eight attendees under the initiative of Mayr. Smocovitis noted “that the “founding fathers” of this new Committee signed a document, and entered an alliance under the title “the

Society for the Study of Evolution.”15 Within the year, the first annual meeting was held in

Boston. To facilitate this resurgence, Mayr and Simpson proposed their new journal Evolution with Mayr as editor.16 Mayr and Simpson both believed that the most effective support for

12For more on this see Smocovitis “Unifying biology”, Smocovitis “Organizing evolution”, Cain “Common problems”, Cain “Mayr”, Cain “Integration.” 13Smocovitis “Unifying biology” 45. 14Smocovitis “Unifying biology” 45. 15Smocovitis “Unifying biology” 46. For more on this Society, see Smocovitis “Organizing evolution.” 16On the history of this journal, see Cain “Common problems”, Cain “Ernst Mayr as Community Architect: Launching the Society for the Study of Evolution and the Journal Evolution” Biology and Philosophy 9 (1994): 387-

13 evolutionary research would come from the establishment of a journal, namely because the existing journals seemed to targeted “highly specialized” and “narrow” audiences.17 This new journal, they argued, “will enable [researchers] to avoid the restrictions of overspecialization and it will reach a broad interdisciplinary audience that is not reached by any existing journal.”18

Looking at the history of taxonomy from this perspective, the actions undertaken by interdisciplinary transitory groups, the call for unity, coordination, and cooperation came at a price. As Historian Pnina G. Abir-Am has repeated emphasized to be successful in this era of synthesis, biologists had to be about to communicate and operate across disciplines, and this was no small feat.19 In “The Biotheoretical Gathering, trans-disciplinary authority and the incipient legitimation of molecular biology in the 1930s: New perspective on the historical sociology of science,” she argued that a biologist’s perceived authority over a given subject was a complex

20 issue during this time. Abir-Am provided the following example using the biologists in another relevant transitory group during this period, the Biotheoretical Gathering:

However, in the Gathering former disciplinary marginality emerged as both the norm and as an asset. Thus, Woodger transformed his former marginality within both philosophy and biology into leadership. In the group’s context he was best suited, by virtue of his successive experiences as both scientist and formalist philosopher, to mediate between the scientists (Needham, Bernal, Waddington, Whyte, Wiesner and Moyle Needham), and the philosophers/mathematicians (Wrinch, Black, Barnard, Popper and Floyd). Formerly characterized as a ‘deficient bilingual’ having full ‘linguistic’ competence in neither philosophy nor biology, in a context where all others were even less competent in two ‘languages’, Woodger emerged as a skilled ‘translator’. Furthermore, he acquired

427; Vassiliki Betty Smocovitis “Organizing Evolution: Founding the Society for the Study of Evolution (1939- 1950)” Journal of the History of Biology, 27 (1994): 241-309, and Smocovitis “Unifying biology” 17Cain “Mayr” 410. 18Cain “Mayr” 410. 19See Pnina G. Abir-Am “Biotheoretical gathering.” 20The members of this gathering were (labels loosely applied) biologist/philosopher Joseph Henry Woodger (1894- 1981), biologist Joseph N. T. M. Needham (1900-1995), biologist/paleontologist Conrad Hal Waddington (1905- 75), crystallographer John Desmond Bernal (1901-1971), mathematician/philosopher of science Dorothy Maud Wrinch (1894-1976), biochemist Dorothy Moyle Needham (1896- 1987), physicist L. L. Whyte (1896-1972), philosopher Max Black (1909-1988), philosopher Karl Popper (1902-1994), mathematician George Alfred Barnard (1915-2002 ), logician W. F. Floyd (1910-?).

direct access to experimental frontiers, a crucial asset for a theoretician. Woodger capitalized on his position as ‘translator’ to consolidate his leadership of a group which 21 required continuous mediation between empirical and philosophical goals.

She went on to explain how this was also the case for the other members of the group.

Wrinch’s abilities in applied mathematics and mathematical physics which had been considered weak among ‘pure’ mathematicians, in the group, became the key to their account of theoretical, and later molecular, biology. Like Woodger, Wrinch’s ability to communicate with several

Cambridge scientists in the group enabled her to access the experimental frontier.22 Waddington, although not a certified zoologist, became the group’s expert on embryological data because of his research in experimental morphology. He also gained access to the frontier in the physico- chemical sciences as a result of his ability to communicate with Bernal and Needham and in philosophy of science and mathematics, because of his ability to communicate with Woodger and Wrinch. As a result, he emerged as the “most biological” member. Needham was labeled the group’s expert in both biochemistry and embryology. Abir-Am claimed that although the group considered his actual experience in bridging these disciplines beneficial, Oxbridge considered it controversial.23 Finally, Abir-Am claimed Bernal gained approval for his “multi-disciplinary venture at the triple borderline of physics, chemistry and biology (X-ray crystallography of biological compounds) only within the group but not in Oxbridge at large.24 The transformation of a marginal status served an important function, according to Abir-Am. She claimed that there were also forces of stabilization which resulted from various bi- and tri-lateral alliances. She claimed that “a multiplicity of such alliances would prevent the disintegration of the core-

21Abir-Am “Biotheoretical gathering” 38-9. 22Abir-Am “Biotheoretical gathering” 39. 23Abir-Am “Biotheoretical gathering” 39. 24Abir-Am “Biotheoretical gathering” 39-40.

15 structure into petty alliances by preventing any alliance and/or member from becoming too

25 prominent.”

Cain supports a similar position as Abir-Am with at least one key member of the modern synthesis participating in transitory groups. In “Epistemic and community transition in American evolutionary studies: the ‘Committee on Common Problems of Genetics, Paleontology, and

Systematics’ (1942–1949),” Cain noted that both Simpson and Dobzhansky labeled Mayr a

“geneticist” in the early 1940s, before the Committee on Common Problems of Genetics,

Paleontology, and Systematics had been formally established. In the October 1943 report of

Committee on Common Problems of Genetics and Paleontology, Mayr was listed as a geneticist in the Eastern group.26 Perhaps more significantly, when Dobzhansky decided to leave New

York in 1943 for Brazil, he asked Mayr to chair the genetics section of the Eastern group’s summer 1943 meeting. This was an important request, given taxonomy’s reputation in the biological arena, and Mayr felt for the first time he had a real opportunity to effect change. Cain writes: “Importantly, this new opportunity gave Mayr an insider’s legitimacy [my italics] he had not enjoyed previously.”27 Undoubtedly, this was a strange request. Mayr was not a geneticist.

Cain writes “Mayr recognized this awkwardness from the start. ‘Not being a geneticist myself’, he wrote to members of the Eastern group while constructing the program, ‘I consider myself merely an administrator’. Such self-effacing politeness hides an important point. Mayr was a deliberate choice. Dobzhansky expected him to be neither passive nor simply a caretaker.”28 Cain believes Dobzhansky felt had little to worry about when it came to his decision. Cain describes Mayr as “an experienced, aggressive architect of research and

25Abir-Am “Biotheoretical gathering” 40. 26Cain “Epistemic transition” 292. 27Cain “Epistemic transition”295. 28Cain “Epistemic transition”293.

16 community infrastructure who did not hesitate to seek infrastructural change when he thought it necessary to implement reform.”29 This was because Dobzhansky knew he had an ally in Mayr.

Cain claimed that Mayr introduced himself to Dobzhansky in late 1935 in a letter. After reading

Dobzhansky’s summary on geographic variation in lady-beetles, Cain claimed Mayr believed he too had found an ally—“here is finally a geneticist who talks [my italics] like a naturalist” and wrote to him.30 To cement his position in the group, Mayr seemed committed to talking like geneticists. Mayr did not have direct research experience with genetics, but by early 1943 he did what was necessary to talk the talk and be accepted by the geneticists in the New York area.

Cain summarizes Mayr’s activities at this time emphasizing these ideas. Mayr read

Dobzansky’s Genetics and the origin of species (1937), collected reprints, and attempted to follow the basic literature. Through Dobzhansky’s 1936 Columbia lectures, he had met geneticist

Leslie Dunn (at Columbia University) and geneticist Milislav Demerec (at Carnegie Institution of Washington at Cold Spring Harbor), as well as others geneticists in this large, interacting group, and did not hesitate to engage with them. For example, Cain notes Mayr told Dunn in

November 1937 “I have devoted a whole Sunday to study[ing] your papers carefully and as I may add, I benefited a great deal.”31 Mayr became a frequent visitor to Dunn’s department and his Genetics Seminar. Cain also notes around this time Mayr began to include genetics-related issues in his publications. For example, Cain discusses Mayr sharing a manuscript on sex ratios in wild birds that he hoped would contribute to several types of genetics studies with Dunn, who described it as “extremely interesting and provocative.”32 Cain also notes that reactions by geneticists to his 1942 book, Systematics and the origin of species were also generally positive.

29Cain “Epistemic transition” 295. 30Cain “Epistemic transition”293. 31Cain “Epistemic transition”295. 32Cain “Epistemic transition”296.

The people I selected worked within a similar type of setting or appealed to people who worked in such a setting. Within this type of setting, it is easier to recognize and appreciate not only the different types of relationships between logic and taxonomy during this reform period, but the sometimes strange and unconventional ways in which they emerged and why certain ones held some appeal to particular groups at particular times and places.

1.3 Scope and goals

Taxonomy underwent a tumultuous methodological reform during the twentieth century.

It began with the rise of new disciplines, such as genetics and ecology. Biology assumed a new agenda, and like it or not, taxonomists found themselves compelled to explore a difficult interdisciplinary landscape. These new disciplines had effectively relegated “natural history”

(and associated taxonomy) to the “pre-science” category. By the late 1930s and 1940s, many taxonomists forged fruitful relationships with practitioners of the disciplines that characterized the “new biology,” and in doing many found themselves examining the relationship between logic and taxonomy. Although the methodological reform saw no geographical boundaries, how the relationship between logic and taxonomy figured in the reform differed geographically.

Formal logic played a particularly controversial role. In many of the early reform movements in America and Britain, formal logic did not initially figure into the solution.

Taxonomists, more concerned with epistemic questions, turned to logic on issues of induction and argumentation. Only later, when more ontological questions about species and types filtered into a series of debates on the nature of species and the process of speciation—a series of debates that began in the early 1940s that served to unify not just subjects but biologists—did many taxonomists begin to consider formal logic in their investigations. In most of the familiar taxonomic literature, this became clear especially right around the time when a group of

18 taxonomists called “numerical taxonomists” began to mobilize. In contrast, for many German taxonomists, questions concerning methodological reform centered on issues that Hull referred to as “taxonomic schemata,” and as such philosophy and formal logic were seen as an asset in devising a solution.33 To complicate matters further, taxonomists of all stripes were up against a very serious image problem. At first, it was name-calling in the journals, but by the 1930s, a rift had developed between the two places of knowledge production in biology—the laboratory and the museum. In 1942 the ambitious ornithologist Mayr reiterated Caltech’s rising star

Dobzhansky’s cutting 1937 observation that “[t]here was a tendency among laboratory workers to think rather contemptuously of the museum man, who spent his time counting hairs or drawing bristles, and whose final aim seemed to be merely the correct naming of his specimens.”34

Methodologically speaking, the differences between biology’s new disciplines and taxonomy could not be more striking. These new disciplines tended to embrace techniques and practices, such as measurements and models, indicative of a quantitative methodological approach. These methods stood in contrast to those of traditional taxonomy, which historically moved along descriptive and typically non-numerical qualitative lines. Especially in American and British taxonomic circles, it became clear that if a fruitful interdisciplinary agenda were to proceed, a methodological change along quantitative lines was required. Taking this quantitative turn inspired many taxonomists to re-examine their relationships with non-biological disciplines, such as logic, in order strike a balance between conflicting approaches. With an interest in quantitative approaches came an interest in theory. In Germany, and in pockets of England, groups of biologists tried to put biology on firmer ground by establishing a formal language for

33David L. Hull “Consistency and Monophyly” Systematic Zoology, 13(1964): 1-11. 34Mayr Systematics 3.

19 biology, complete with rules, axioms, and other formal machinery. The strongest voice in this theoretical movement came out of cytology and developmental biology in a movement called

“organicism,” which brought together biologists, philosophers, and mathematicians in important, but transitory groups, such as “the Biotheoretical Gathering”—‘scientific Bloomsbury’ composed of about a dozen men and women.35 For many, establishing a formal language for biology translated to traditional set theory, and attempts were made to do exactly that. Again, by the mid-1960s, these attempts were heavily criticized in biological and philosophical circles.

However, other attempts at establishing a formal language for taxonomy were made, including mereological treatments, which hitherto have been overlooked.

This dissertation takes a fresh look at biologists and philosophers who examined the relationship between logic and taxonomy from within an interdisciplinary context during the early 1930s to 1960 as part of their attempts to incite viable methodological change. I chose three biologists—a botanist, paleontologist, entomologist—and one philosopher. Each of examined the relationship between logic and taxonomy, but assumed a definition of logic that included more than simply traditional set theory or a calculus of classes. They appealed a broader definition of logic: inductive reasoning, or a wider notion of classes, or mereology.

35In England, see Joseph H. Woodger, Biological Principles (London: K. Paul, Trench, Trubner, 1929); Joseph H. Woodger “The ‘Concept of Organism’ and the Relation between Embryology and Genetics”, Quarterly Review of Biology 5, (1931)1–22, 438–463; Joseph H. Woodger “The ‘Concept of Organism’ and the Relation between Embryology and Genetics,” Quarterly Review of Biology 6, (1932) 178–207.; Joseph H. Woodger The Axiomatic Method in Biology (Cambridge: Cambridge University Press, 1937); Theodore W. Torrey, “Organisms in Time” The Quarterly Review of Biology, 14 (1939): 275-288. Morton Beckner provided a summary of these ideas in Morton Beckner, The biological way of thought. (New York: Columbia University Press, 1959). For discussions regarding the history of these people see: Pnina Abir-Am, “The Bio-Theoretical Gathering, Transdisciplinary Authority and the Incipient Legitimation of Molecular Biology in the 1930s: New Perspectives on the Historical Sociology of Science,” History of Science 25, (1987) 1–70. “Synergy or Clash: Disciplinary and Marital Strategies in the Career of Mathematical Biologist Dorothy Wrinch,” in P. Abir-Am and D. Outram (eds), Uneasy Careers and Intimate Lives: Woman and Science, 1789–1979, (New Brunswick: Rutgers University Press, 1987) 239–280, 342–354.; V. Betty Smocovitis, “Unifying Biology: The Evolutionary Synthesis and Evolutionary Biology,” Journal of the History of Biology 25 (1992) 1–65; Unifying Biology: The Evolutionary Synthesis and Evolutionary Biology, (Princeton: Princeton University Press, 1996). In Germany, see Ludwig v. Bertalanffy, Kritische Theorie der Formbildung, Abhandlungen zur theoretischen.

I use induction in at least two significant ways project. For both Simpson and Gilmour, induction is contrasted with deduction, but where the concept differs is its application. For

Simpson, like Fisher, it is a mathematical concept. Simpson’s methodology, as sketched out in

“Notes on the Clark Fork”, and “Fort Union of the Crazy Mountain Field”, then presented fully in Quantitative Zoology, was designed to enable all taxonomists to make evolutionary claims of the sort he made in his paleontological work, specifically ones related to phylogeny. For

Simpson, to make an evolutionary claim, for example about phylogeny, the evidence for such a claim could not be obtained directly, it would involve abstractions and would have to be inferred inductively from morphological, paleontological, genetic evidence. This also involves thinking not about individuals, but about groups, and the properties of the individuals that form the group are statistically analyzed. Not only did Simpson believe his statistical methods would allow taxonomists to better infer from samples to populations, but move on to refute more other kinds of evolutionary claims for example Granger’s claim that there were three distinct species of archaic ungulate, as well as support his own claim for a “single species, variable in all horizons but slowly increasing in size with the passage of time.”36. As seen in his later writing, specifically in his response to Gregg’s system, he was not opposed to sets or to the applications of logic, but to Gregg’s particular approach, which was the traditional deductive, essentialist, set- theoretic approach. Why is this significant? This is another example of a methodological approach that resisted traditional set-theoretic deductive picture.

Gilmour, in contrast, resurrected Mill’s account of induction, and provided a thorough- going pluralism. For Gilmour, induction was used in Mill’s sense of the term, and was used to group organisms and allowed for a different type of inductive logic that accorded with Mill’s type of nominalism. According to Gilmour, Mill’s notion of induction was central to the

36Simpson “Notes on the Clark Fork” 20-21.

21 traditional botanists’ methodology, and this remained, according to Gilmour definition, the most

“natural” system, at the moment. However, like Simpson he was concerned with how taxonomists arrived at evolutionary claims. Where Simpson applied his methodological approach, which included induction, to solve the problem with how to arrive at defensible evolutionary claims, Gilmour critiqued “evolutionary approaches” to classification, by exposing fallacious reasoning.

Set theory, although powerful and useful, has a place in the history of taxonomy, but it should not be understood as the beginning and end of logic’s role in taxonomy’s methods when discussing the relationship between logic and taxonomy in taxonomy’s methodological reform.

As is the case in many disciplines, set theory was brought into taxonomic discussion as the language use to axiomatize the hierarchy and laws found in biology, perhaps seen most vividly in

Gregg’s attempt to axiomatize the Linnaean hierarchy. Set theory is an indispensable feature of logical positivism, and it most certainly would have been part of the philosophical training of the philosophers taking part in these methodological debates. However, there is more to logic than set theory. In addition, one can adopt aspects of set theory without having to buying into logical positivism. This leads to an important distinction: is there some fundamental philosophical distinction in logic to be drawn between set theoretic thinking (the as seen in the traditional history of taxonomy) and mereological thinking?

In logic, set theory deals with lists and elements, whereas mereology with parts and wholes. The more telling feature, however, is that a mereological calculus tends to imply a more fully fledged ontology, because fusions and overlaps become new entities, which is not the case for sets. This idea of new entities was of course important to a cell biologist like Woodger, which was why he designed a mereological calculus to cope with the problems he was facing in

22 cytology. It also appealed to other cell biologists, such as Bertalanffy and Torrey, who were grappling with common problems. When Hennig decided to fashion a new ontology to underwrite his new methodology, this new hierarchy, a part/whole hierarchy that can create new entities was no doubt attractive.

These specific logical topics persisted into the decades that followed. When David Hull first began to write about the problem of biological individuality in the 1970s, he too talked of sets, classes, and individuals, drawing from the Ghiselin, Gregg, Woodger, Mayr, Simpson, and

Beckner’s writing in the late 1950s and 1960s. Hull spoke of individuals as localized in space and time, organisms individuated spatiotemporally and made up of spatiotemporally organized parts. Just like Hennig (as will be seen) noted that parts need not be and frequently were not similar to each other. Hull pushed the issue further, like Ghiselin, making it an issue also in the philosophy of language, arguing that the names of individuals are proper names lacing meaning

(intensional meaning) that can be secured by a definition.37 Hull wrote:

An individual can be described, but its name cannot be defined. For example, “Gargantua” is the name of an individual organism. As a proper name it denotes this individual uniquely and rigidly in the absence of any knowledge save that necessary to identify it as an individual. The name “Gargantua” denotes a particular organism throughout its existence and not some feature or features of that organism. At a particular time, Gargantua was named “Gargantua,” and that is that.38

Hull contrasted individuals with classes, noting that classes have members not parts.

Membership, said Hull, is determined by similarity to each other in one or more respects, and defined intensionally. Classes have the members which they do in virtue of their definitions.

According to the traditional notion of definition class terms are defined by sets of traits which are severally necessary and jointly sufficient for membership in the class. He gave the example of

37 See Ghiselin’s excellent article Michael T. Ghiselin “An Application of the Theory of Definitions to Systematic Principles” Systematic Zoology 15(1966): 127-30. 38 David L.Hull. “Are Species Really Individuals?” Systematic Zoology, 25 (1976): 177.

23 gold, claiming, all atoms with an atomic number 79 and all samples made up predominantly of such atoms count as gold, and vice versa.

With this logic, Hull returned to what is now regarded as a familiar argument in the philosophy of biology. Hull begins with the claim that evolution is a selection process, and selection processes require continuity. He goes on to say that events operating in evolution occur at a variety of levels, and as it turns out these levels are integrated by the part-whole relation.

Nothing is more obvious about the living world than the existence of intermeshed levels of organization from macromolecules, organelles, and cells to organs, organisms, and kinship groups. Each of these levels is related to the one above it by the part/whole relation, not class- membership. Species too, must be individuals. Here Hull makes a claim that species and other taxa belong to the same ontological category as organisms, insofar as he requires consistency in the treatment of biological entities across levels of the biological hierarchy. As far as a mereological claim, Hull only goes as far as saying biological individuals are concrete

(spatiotemporally located) objects, constituted by parts (as opposed to members). The nature of the part/whole relation is left open.

Using this broader definition of logic, a clearer, more detailed picture of the early years of the taxonomic reform emerges. This perspective also provides a deeper, more comprehensive background for understanding how these issues emerged before the complications brought on by numerical taxonomy, how certain logical issues would come together in the 1970s to form the seminal philosophical questions in biology for the next few decades, and why biologists were taking philosophers seriously on these issues. Seeing how different branches of logic functioned successfully within taxonomic methodology during this reform period fills a gap for at least two bodies of literature. In the historical literature, in the history of natural history, it fills part of the

24 hole left by the usual story. In the philosophy of biology literature, it provides a robust historical and logical background for the concept of species, types, and hierarchies in the early twentieth century.

Before looking at the details of the work of these three taxonomists and one philosopher,

I begin this dissertation with brief overview of early twentieth-century taxonomy. What was the taxonomic landscape like in the decades before these three taxonomists began writing in the

1930s? What were the debates? What was at stake? I will begin with a quick background of some of the issues surfacing in the taxonomic literature that prompted Gilmour, Simpson,

Beckner, and Hennig into action.

Chapter 2 Taxonomy’s fall from grace 2.1 Introduction

During the first half of the twentieth century, taxonomists found themselves in a position they had not been in for a long time, deeply worried about the state and future of their discipline.

For centuries, taxonomy, or Natural History, was the jewel in biology’s crown. Amateurs and professionals alike worked enthusiastically to discover the order of nature. In her glory days, taxonomy was a vibrant discipline, taking her disciples on adventurous voyages, constructing vast, magnificent gardens, and amassing spectacular collections. But the twilight of the nineteenth century saw the birth of a new age of biology, an age of test tubes and technology, of experimental science and laboratories. Traditional taxonomy, with her ties to museums and gardens, and her books brimming with detailed descriptions, was fixed under the microscope.

What this new generation of evolutionarily-minded biologists claimed they saw when they gazed down the lens were quiet museum men busily peddling “class hierarchies,” nested sets of taxonomic groups based on essential morphological characteristics that appeared to defined groups in terms of a set of necessary and jointly sufficient conditions.

Unfortunately for taxonomists, not only was this more of a caricature than an accurate characterization, this type of hierarchical, rank-based classifications of organisms had become unfashionable, especially in England and America. Descriptive methodological approaches, such as grouping organisms into class hierarchies based on observed morphological characters seemed archaic when compared to the now more scientifically acceptable, causal methodological approaches, such as grouping organisms according to the factors that caused groups. New disciplines, such as genetics and ecology, not only demanded that full-scale changes be made to

26 biology’s theoretical structure in the light of evolution, but demanded massive methodological changes be made along those lines. This pressure was especially present in British and American circles.

In their reform writing, this new generation of biologists targeted qualitative approaches specifically as being behind the times. After the first few decades of the twentieth century, rumours floated around the biological community that taxonomy was failing to keep pace with the new changes and advances being made. To a growing number of biologists, taxonomic work appeared tedious and trivial, and at least for some biologists, irrelevant.39 Taxonomists soon

39Such comments are not hard to find in the literature, for example, W. T. Calman wrote: The selection of a systematic zoologist for the honor of addressing you from this chair implies a belief that systematic zoology may have something to say that will not be without interest to those whose studies lie in other fields. I am not sure how far this belief is generally shared. . . The systematist is generally supposed to be a narrow specialist, concerned with the trivial and superficial distinctions between the members of some narrow group of organisms which he studies in the spirit of a stamp collector; happy when he can describe a new species, triumphant if he can find an excuse for giving a fresh name to an old one. W. T. Calman “The Taxonomic Outlook in Zoology.” Science, New Series, 72 (1930): 279-284. Later Ernst Mayr wrote: The rise of genetics during the first thirty years of this century had a rather unfortunate effect on the prestige of systematics. The spectacular success of experimental work in unravelling the principles of inheritance and the obvious applicability of these results in explaining evolution have tended to push systematics into the background. There was a tendency among laboratory workers to think rather contemptuously of the museum man, who spent his time counting hairs or drawing bristles, and whose final aim seemed to be merely the correct naming of his specimens. Ernst Mayr Systematics and the origin of species, from the viewpoint of a zoologist (Cambridge: Harvard University Press, 1942): 3. Karl Schmidt wrote: Some ten or fifteen years ago a remarkable change of heart took place among some of the leaders of university biology, and specifically of genetics, from which field had come the classic remark that museum zoologists were in the postage stamp stage. The unthinkable took place, and on the hills of California geneticists were to be seen pursuing their prey, bug net in hand, in nature. There is now a considerable crop of books expressing the trend to restore systematic studies to respectability. I will remind you only of Huxley’s “The New Systematics,” Dobzhansky’s “Genetics and the Origin of Species,” George Gaylord Simpson’s “Tempo and Mode in Evolution,” and Mayr’s “Systematics and the Origin of Species.” What of the old systematics? Was there indeed reason for a “New Systematics”? Let us search some of our own shortcomings. Karl P. Schmidt “The New Systematics, the New Anatomy, and the New Natural History” Copeia, 1946 (1946): 58. E. O. Wilson wrote: “The molecularists were confident that the future belonged to them. If evolutionary biology was to survive at all, they thought…they or their students would do it, working upward from the molecule through the cell to the organism. The message was clear: Let the stamp collectors return to their museums.” E. O. Wilson Naturalist (Washington DC: Island Press, 1994): 227.

27 became known as the “stamp collectors” in the rhetoric of the new biology. Before long, taxonomy started to have difficulty securing interest and new students.40

It was a time of worry, but it was also a time of self-reflection for taxonomists. Initially, taxonomists were not inclined to give up a methodology that grouped organisms into what was characterized formally as “class hierarchies.” For most taxonomists, resistance to methodological change was not indicative of an anti-evolutionary position. In fact, for the taxonomists I consider, along with many other taxonomists, evolution was not the problem. At least part of the problem involved constructing a quantitative approach that would be applicable to the many different branches of tree of life—botany, zoology and paleontology—a quantitative methodology that could identify and organize organisms, as well as successfully generate valid evolutionary claims. This, however, was no easy task.

40This was a common idea. For example, A. S. Hitchcock noted in 1916 that: During the nineteenth century other branches of botanical science asserted themselves and began to compete with taxonomy for supremacy. Toward the end of the century taxonomy not only lost its dominance, but in this country at least was relegated to an inferior place. At present the pendulum indicating the trend of botanical thought has swung far away from the position occupied during the days of Linneus, Hooker, Torrey and Gray. Taxonomic botany in the conventional sense is almost taboo. There is a feeling abroad among botanists that systematic botany is old-fashioned and that to be a taxonomist is to be behind the times. At most of our institutions of learning taxonomic botany as such is not taught at all or is relegated to a minor position. At the meetings of our botanical societies the percentage of papers dealing with taxonomy is disproportionately low. In a recent number of the Plant World it was stated that out of the 45 doctorates in botany conferred by American universities in 1915, two were taxonomic. The same disproportion prevails in most of our journals and periodicals devoted to the whole field of botanical science. It is difficult also to obtain properly trained young men for positions in taxonomic botany. A. S. Hitchcock, “The Scope and Relations of Taxonomic Botany.” Science, New Series, 43 (1916): 332. Raymond Pearl commented on this issue in 1922: From its once dominant position taxonomy has apparently fallen to-day, one must reluctantly confess, into rather lower repute in the mind of the general biological public. Neither our professors nor our students of biology appear, with a few brilliant exceptions, to be interested in it. One forms the impression that perhaps four fifths of the Ph.D.’s turned out in zoology at (the present time not only never have, but probably never will, for themselves, identify an animal strange to them, and as for deciding whether the unknown creature has been previously described, or placing it in proper taxonomic relation to its nearest relatives, such a problem would be as far beyond their powers as it is beyond their desires. Raymond Pearl “Trends of Modern Biology” Science, New Series, 56 (1922): 583.

2.2 1900-1910

2.2.1 Call for reform: E. B. Wilson

In his presidential address delivered at the annual dinner of the American Society of

Naturalists, December 28, 1900, American geneticist E. B. Wilson (1856-1939) addressed three factors he felt motivated the new biology, two of which became a common refrain in the decades to follow: the birth of cell theory and the inclusion of experimental methods. He recounted how

Darwin’s theory of evolution by natural selection raised new questions about inheritance and variation, and he recounted how cell theory was largely responsible for the change in focus to the lowest levels of organisation, such as cells, for answers to such questions in biology.41

According to Wilson, central to developing the new biology was a switch from discovering what organisms do (that is, providing descriptive answers characteristic of museum and field work) to how organisms do what they do (that is, providing causal answers that demanded controlled study conditions found in the laboratory). To a certain extent, this difference was reflected in the new biology’s methodology. Those who discovered what organisms do tended to adopt mainly qualitative approaches, whereas those who discovered how organisms do what they do tended to quantitative approaches.42

Although Wilson exercised cautious optimism regarding taxonomy’s ability to take the necessary steps to become part of evolutionary biology, many other biologists did not share his feelings. As it turned out, some biologists felt taxonomy was at a disadvantage when compared to new evolutionary disciplines like genetics, cytology, and ecology. During the first few decades of the twentieth century, disciplines such as genetics and cytology could (and did) join forces.

41Edmund B. Wilson “Aims and Methods of Study in Natural History” Science, New Series, 13 (1901): 17-18. 42Wilson “Aims and Methods,” 17-18.

One reason why they could do this successfully was because they focused on a similar level of biological organization to solve evolutionary puzzles, namely the level of the cell.43 As history showed, for example, cytological studies of the germ nucleus could be (and were) linked to breeding experiments and this resulted in a materialistically based theory of inheritance. In the first few decades of the twentieth century, many biologists believed ecology would also be a difficult fit with taxonomy. At the time, taxonomy focused on morphological affinities when talking about the interrelations of organisms and organismal groups, and this focus seemed to place taxonomy at odds with ecology, for ecology, among other things, considered other types of relationships besides morphology.

2.2.2 The role of evolution: Charles Bessey

In the first few decades of the twentieth century, these new disciplines had a lot to say about taxonomy’s future in the new biology, but within taxonomic circles, the jury remained out on the question of how to build evolutionary ideas into taxonomic methodology. Again, for many taxonomists, the problem was not with evolution, or even evolution by natural selection per se.

Botanist Charles Edwin Bessey (1845-1915), for example, announced in 1908 that:

43There were a few biologists that believed that cytology, for example, could forge a relationship with taxonomy: It seems at first sight as though the intimate way in which the structure of the living cell is bound up with the physiological functions it has to perform would prevent cytology throwing much light on classification. The cell may be compared to a busy modern town, with an energetic and progressive municipality, bent on having thoroughly up-to-date sanitation, water-supply, locomotion, etc., and consequently making a clean sweep of any antiquated or obstructive buildings. The inevitable result of this is of course the removal of many historic land-marks. But just as in the most modernised town the antiquary generally manages to find some corner which the besom of reform has failed to reach, so the morphologist may hope for some clues to the pedigrees of the plants with which he is concerned from a consideration of the less obvious points in their cytology. In the lower comparatively unspecialised plant types, in which the whole body is made up of similar cells, (e.g. certain Algae), almost the only place in which we can look for characters of taxonomic value is in the structure of the cells themselves. If we compare the cells of two such plants living under the same conditions, it seems safe to assume that the characters in which they differ are phyletic, for such differences cannot be accounted for as a modern response to external conditions, (compare for instance Spirogyra with its spiral, and Zygnema with its stellate chromatophores). The importance of cytological features in classification holds good throughout the Algae. The unicellular genus Chlamydomonas contains nearly thirty species, discriminated by their remarkably constant cytological characters !” Agnes Robertson “Cytology and Classification. A Lecture” New Phytologist, 4 (1905): 134.

TO-DAY every botanist is an evolutionist . . . It may be asserted without fear of contradiction that all scientific botanists hold that the vegetable kingdom as we know it to-day is the result of a series of evolutions from lower to higher types of plants, and that every higher plant owes its present structure to the favorable modification of ancestral lower plant. To-day when we study the particular structure of any plant we consider it to be the result of the modifications that have taken place in its phylogenetic history. No botanist now considers a species to be a separate or special creation, but rather a more or less distinguishable variation from some other form.44

Believing evolution to be the case was one thing. Changing your methodology in response to that belief, was quite another.

Bessey discussed this problem in the “Address for the American Association for the

Advancement of Science.” He acknowledged a lack of agreement regarding how modifications discussed by biologists with an evolutionary bent could be effected. Bessey claimed, for example, that botanists had not reached a consensus on “whether [modification] were by slow and almost imperceptible deviations from the parental type, or those more marked variations that we are in the habit to-day of calling ‘mutants.’”45 He also noted a lack of consensus on the role of some significant evolutionary concepts, such as the “survival of the fittest” versus “survival of the unlike,” or if the “struggle for existence” accounts for the diversity of plant forms or rather

“adaptation,” or if the “inherent tendency” in plants to vary is a potent factor or if all variation is a result of “environment.”46

While there might be consensus on the truth of evolution, as Bessey claimed, there was another position rapidly gaining popularity outside taxonomic circles, the idea that taxonomic terms must be redefined in terms of evolution. Bessey claimed that “a natural classification must be an expression of a theory of evolution,” and consequently taxonomic terms such as “higher,”

44Charles E. Bessey “The Phyletic Idea in Taxonomy” Science, New Series, 29 (1909): 91-92. 45Bessey “The Phyletic Idea,” 91. 46Charles E. Bessey “Address of the vice-president and chairman of Section G-Botany-of the American Association for the Advancement of Science, Baltimore, 1908.” 92 Science N. S. Vol. XXIX. No. 733.

“lower,” “primitive,” “derived,” “relationship,” “affinity,” etc., must acquire their significance by “the doctrine of evolution.”47 Bessey deemed any system that failed to do this was arbitrary and artificial. To make this point clear, Bessey compared the traditional taxonomist to a rancher, and the practice of grouping and naming based on morphological characters to branding domesticated animals. He wrote:

In the common systematic characters as drawn up by many botanists in the recent past there has been something of the old time notion that we are dealing with fixed groups whose limits are indicated to us by certain rather definite structural characters which nature has accommodatingly attached to all plants in these groups. The thought seems to have been that plants are “tagged” or “branded” with the peculiar marks of the group, these marks having otherwise no particular significance. One is reminded of the similar use which stockmen on the plains make of arbitrary names, monograms or hieroglyphics for indicating what animals belong to this or that particular ranch.48

Notice the association of branding with claims of grouping as artificial and arbitrary. The traditional methods of taxonomy were starting to be seen as artificial and arbitrary, as not capturing real groups in nature. Bessey was not the only one to make this claim. Many biologists began to think that real species—species in nature—must be defined in evolutionary terms.

Bessey, like many others, believed that taxonomy’s survival depended on taxonomists’ willingness to start making changes along evolutionary lines. Unfortunately, defining species along evolutionary lines was not nearly as straightforward as this new generation of biologists imagined. Moreover, it seemed everyone had an idea about what constituted a real species.

2.2.3 New species definitions: Bailey, Davenport, Hallier, Church, Frisch, Worsdell, and a change in criteria

When it came to redefining species, everyone had ideas. For some, the problem lay not with morphology, but on what you were focusing within morphology. For example, in early twentieth-century botanical circles A. H. Church (1865-1937) claimed that botanists should be

47Bessey “The Phyletic Idea” 92. 48Bessey “The Phyletic Idea” 92.

32 focusing on the “growing body” rather than the “adult body” when it came to achieving the phylogenetic perspective.49 For F. E. Fritsch (1879-1954), seedlings should be the focus, from a phylogenetic point of view.50 For I. W. C. Worsdell, the study of plant organs was necessary for a phylogenetic account.51 For others, morphology lay at the heart of the problem. For example, botanists L. H. Bailey (1858-1854) believed species should be defined on more physiological grounds, rather than morphological traits.52 Others, such as zoologist Charles Davenport (1866-

1944), argued for the inclusion of functions:

The structural descriptions of the systematist give us a no more adequate idea of the characteristics of species than does the sight of this exposition on a Sunday when all wheels are stopped and only the form, beautiful and grand as it is, remains give us an adequate idea of it. And so in the study of species we can not [sic] understand the form characteristics without considering also the function characteristics.53

Then there were those, such as botanist Hans Hallier (1868-1932), who argued for the inclusion of many different factors, rather than focusing on just morphological attributes, if capturing the

“true” shape of nature was the goal. Hallier maintained:

49A. H. Church “Descriptive Morphology.-Phyllotaxis” New Phytologist, 1 (1902): 52-3. 50F. E. Fritsch “ ‘From the phylogenetic point of view the structure of the seedlings is most important, as has been sufficiently shown by Miss Sargant’s recent work on the Monocotyledons.’ The Use of Anatomical Characters for Systematic Purposes” New Phytologist, 2 (1903): 184. 51I. W. C. Worsdell “The Principles of Morphology.” New Phytologist, 4 (1905): 124. 52Bailey wrote: These varying grades of species and varieties are the results of processes of evolution, and some, if not all, of these processes are still in operation. Therefore, the new definitions of species-concepts must rest on physiological or functional grounds, not merely on morphological and anatomical grounds. Many of us feel that the present methods of nomenclature and description will be outgrown, for these methods are made for the herbarium and the museum, rather than for the field. It is a most suggestive commentary that the botanist may know the ‘species’ when it is glued on an herbarium sheet, but may not know it when growing. The nurseryman or gardener may know it when growing, but not when it is in a herbarium. This is not merely because the botanist is unfamiliar with the field, or the gardener unfamiliar with the herbarium; these men have different fundamental conceptions of what a species is; they use different ‘marks,’ one morphological, the other largely physiological. I believe that the gardener is nearer the truth. I recall a characteristic remark made by my master, Sereno Watson, when, in the confidence of youth, I asked whether a certain binomial would be accepted a hundred years from now. He shrugged his shoulders and said quietly, ‘I don’t know; they may call plants by numbers then.’ L. H. Bailey “Systematic Work and Evolution” Science, New Series 21, (1905): 532-535. 53Charles. B. Davenport “Animal Morphology in Its Relation to Other Sciences” Science, New Series, 20 (1904): 702.

As a result of these various influences I reached the conviction that there can exist only one really natural system, namely that which is identical with the tree of descent; to reconstruct this, systematic botany should be founded on a much broader and more universal base than at present, comprehending not only the morphology of the reproductive organs, but also all the other branches of botany, such as comparative morphology of the vegetative organs; comparative anatomy, ontogeny and embryology; phytochemistry, physiology and ecology; structure of pollen and seed coat; relations to climate, seasons and to the surrounding organic world; plant geography; palaeo- phytology, etc.54

The above is just a small sample of species definitions from a few figures at the beginning of the twentieth century. To complicate the picture further, new ways to define species were emerging at the end of the nineteenth century that carried tremendous influence. For example, Winsor discussed some late nineteenth-century heavy-hitters in botany, such as Hugo de Vries (1848-

1935) and Johannes Paulus Lotsy (1867-1931), who also attempted to re-define species. Both de

Vries and Lotsy re-defined species along breeding lines, and the resulting species definitions were named according to the botanist with whom they were associated:

Hugo de Vries, whose theory of mutation attracted much attention between 1901 and 1920s, declared that the species of taxonomists were a fiction, that the only real, objective entities in nature were his “elementary species” of identical forms that bred true. Likewise J. P. Lotsy in 1916 declared traditional concepts arbitrary and meaningless. “He who ventures to write on the origin of species, ought to define what a species is”, he mocked. Lotsy dubbed the Linnaean species the “Linneon”, and honored one of the pioneers of plant transplant experiments, Alexis Jordan, by calling sections of the Linnaean species “Jordanons”. Lotsy reserved the word “species” for his own true- breeding unit.55

And with ecology and genetics came even more new species terms. By the late 1930s, new species terms such as “linneons,” “jordanons,” were joined by “biotypes,” “ecotypes,”

“coenospecies,” and myriad of other species terms rooted in non-traditional methodological practices abounded.

54Hans Hallier “Provisional Scheme of the Natural (Phylogenetic) System of Flowering Plants” New Phytologist. 4, (1905):152. 55Mary P. Winsor “Species, Demes, and the Omega Taxonomy: Gilmour and the New Systematics” Biology and Philosophy 15. (2000): 356. For more on this, see McOuat, Gordon R. Species, Names and Things, from Darwin to the Experimentalists. Unpublished dissertation (1992).

2.2.4 Change in Methodology: Coulter, Oliver, Clements, and Dobzhansky

Perhaps against this churning sea of species concepts and taxonomy’s woefully qualitative methodology, one should not be surprised that many biologists lacked confidence in taxonomy’s preparedness to answer the pressing biological questions of the day. Even American biologist Raymond Pearl’s (1879-1940) relatively generous remarks (for the time) regarding taxonomy status and role were tempered by his willingness to place strict limits on taxonomy’s usefulness:

The labors of the taxonomists have alone given us such picture as we have of the interrelationships, unity in diversity, and diversity in unity, of animate nature as a whole. It is the systematist who has furnished the bricks with which the whole structure of biological knowledge has been reared. Without his labors the fact of organic evolution could scarcely have been perceived, and it is he who to-day really sets the basic problems for the geneticist and the student of experimental evolution. His facts are the raw material from which the laws of organic evolution, in the sense that we speak of physical laws, must be worked out.56

For Pearl, taxonomy only set “the basic problems for the geneticist and the student of experimental evolution,” she did not actually help with the solution. Taxonomy furnished the bricks, but she did not seem do any of the building.

More critical remarks, such as the ones levelled by botanist John M. Coulter (1851-1928) at the beginning of the twentieth century, continued to ring familiar in the literature in the decades to follow:

It seems clear to one who was originally trained in taxonomy, and who has passed through all the phases of morphology described above, that the conception of species has become so radically changed that a reconstructed taxonomy is inevitable. When the doctrine of types disappeared, and when experimental morphology showed the immense possibilities of fluctuation in taxonomic characters, the taxonomy of the past was swept from its moorings. Taxonomy must continue its work as a cataloguer of material, but to catalogue rigid concepts, is very different from cataloguing fluctuating variations. The attempt to do the latter on the old basis is being attempted in certain quarters, but it soon passes the limit of usefulness and sets strongly towards the record of individuals. Some

56Raymond Pearl “Trends of Modern Biology” Science, New Series, 56 (1922): 583.

new basis must be devised, and it must be a natural and useful expression of the relationships of forms as suggested by experimental morphology.57

Coulter, like many others, took aim at taxonomy’s methodology. Considering how common this kind of criticism was in the literature, it gives one pause to wonder: had Coulter hit the nail on the head? Did the doctrine of types condemn the traditional taxonomist to a life of cataloguing rigid concepts and recording individuals? Did the doctrine of types assume species were a determined by a set of necessary and jointly sufficient conditions? Was the doctrine of types at the heart of the methodological problem?58

2.2.4.1 Types

Consider briefly the role of types of taxonomy methodology in order to answer these questions. Stepping back at least as far as the early nineteenth century, taxonomists employed a methodology that relied on “type concepts,” and made use of a number of different type concepts available to them. How early nineteenth-century taxonomists weaved these different type concepts in their methodology was no mean feat. For example, in “The Type Concept in Zoology in the First Half of the Nineteenth Century,” historian Peter Farber described the complex way taxonomists incorporated various type concepts in their work59:

Discussing the interpretations that were given to the type-concept during the first half of the nineteenth century is in some ways similar to describing the rules of a three- dimensional board game. . . [T]here were at least three different uses [my italics] of the term “type”: a taxonomic model, a name-carrying specimen, and a morphological plan. In

57John M. Coulter “Development of morphological conceptions” Science, New Series, 20 (1904): 623. 58Others made similar claims, regarding the role of types. For example, Charles Davenport wrote: “The search for homologies has led to the idealization of the “type,” and this more than anything else has blinded morphologists to the facts of variation and evolution.” In Charles B. Davenport “Animal Morphology in its relation to other sciences.” Science, New Series, 20, (1904): 700. 59 I use Farber’s short seminal account of types in the nineteenth century here, but there are other accounts in the historical literature that support a position similar to his, in so far as it assumes that there were various type concepts at play in the nineteenth century and earlier, and they were not essentialist. For example, in botany see David Kohn, Gina Murrell, John Parker and Mark Whitehorn. “What Henslow taught Darwin.” Nature : 436.7051 (2005): 643; and Peter F. Stevens The Development of Biological Classification: Antoine-Laurent de Jussieu, Nature, and the Natural System,(Columbia University Press: New York, 1994); in zoology see Lynn Nyhart Biology Takes Form: Animal Morphology and the German Universities, 1800-1900 (Chicago: The University of Chicago Press,1995).

addition, there were a number of interpretations [my italics] of what a type is: an ideal form, a stable physiological configuration, a convenient category, and so on. Zoologists concerned about the ontological status of the type-concept further complicated the issue by debating its temporal dimension: Were types static or developmental?60

In his analysis of type concepts used in zoology in the nineteenth century, Farber outlined three kinds of type concepts, each of which admitted a number of interpretations: the classification type concept, the collection type concept and the morphological type concept. Farber admitted his list was by no means exhaustive, but his exploration of type concepts in zoology provided a glimpse of the various ways in which taxonomists could (and did) use type concepts in their methodological approach.

Farber’s classification type concept can be summed up as a name and a description of one taxonomic group used either as a model or as a name-carrier for the taxonomic group above it on the hierarchy. In other words, a particular species can act as the classification type for a genus, a genus for a family, and so on.61 In telling the history of this type concept, Farber acknowledged its implicit use before the nineteenth century, citing Buffon’s use of “flycatchers” as an example, and explained its explicit use afterwards as a result of an enormous increase in zoology’s empirical base during the first half of the nineteenth century. 62 Farber claimed this type concept’s virtue lay not only in its ability to aid in “rationally organizing nature,” but in its use as

“a fundamental device for simplifying descriptive monographs as well as arranging collections and writing catalogues of those collections.”63

Farber’s collection type concept, in contrast, was not a description, but an actual specimen (and in some cases a set of specimens), used by taxonomists to establish a new species.

60Farber “Type Concept in Zoology” 105. 61Farber “Type Concept in Zoology” 113. 62Farber “Type Concept in Zoology” 94. 63Farber “Type Concept in Zoology” 95.

Farber noted that some of the first instances of collection type concepts in zoology referred to a single specimen on which the descriptions of a new species were based. However, with the growth of collections, Farber discovered that nineteenth-century zoologists often used the word

“type” for each of several specimens grouped to illustrate, for example, a range of variation.64

Many of the criticisms of “type concepts” coming out of the twentieth century were ignorant of this fact, assuming that type concepts always and only referred to a single specimen.

Like the classification type concept, the collection type concept also served as a model and/or a name carrier, but differed from the former in a least one obvious way: collection type concepts referred to a particular specimen in a known collection, whereas classification type concepts referred to a general group.65 Of course, this was not the only way in which these two type concepts differed. Farber noted differences in how these type concepts were used. He wrote:

The type-specimen was used for comparison, whereas the classification type served as a model of comparison and contrast. On the species level, for example, a type species [my italics] embodied its essential genus characteristics, but it also carried its own important distinctive specific characteristics. Species of the same genus could be identified as such if they had the same generic characters and in addition could be described by how they differed from the model species. The type-specimen [my italics], in contrast, was not only restricted to the species level, but also could be used only to determine the characters of the original specimen used by an author in establishing a new species [my italics]. Unlike the classification type-concept the collection type-concept was narrowly defined and did not admit of a wide range of interpretation.66

64Farber “Type Concept in Zoology” 100. Kohn et al found this practice of a set of specimens as a collection type in botany as well. They claim that one distinctive feature of John Stevens Henslow’s herbarium was his practice of comparing specimens called ‘collation.’ The aim of collation was “to analyse the limits of variation within ‘created’ species” and often reflect variations such as: height, leaf shape, branching pattern, and flower colour. A collated Henslow sheet contained several plants of a single species from one or more locations, each numbered, with a label indicating location, date of collection and collector’s name. Kohn noted that “collated sheets that show height variation have several distinctive display patterns, such as bell curves and ascending/ descending series. They can depict continuous variation within a single population, or may include plants from across Britain.” David Kohn, Gina Murrell, John Parker and Mark Whitehorn. “What Henslow taught Darwin.” Nature : 436 (2005): 643. 65Farber “Type Concept in Zoology” 97. 66Farber “Type Concept in Zoology” 97.

In other words, each type concept played a different and important role in taxonomic analysis, and it was common for taxonomists to use many type concepts simultaneously in their work. For some aspects of taxonomic work, a variation of a collection-type concept did the best job, and for others, a variation of the classification-type concept did the best job.

Lastly, Farber’s morphological type concept referred to a morphological plan on one taxonomic level, several such levels, or all of levels. Like the other two type concepts, the morphological type concept allowed for a wide range of interpretation. Like the classification type concept, Farber found instances of it used implicitly before the nineteenth century, but noted a much more explicit use afterwards. Unlike the collection or classification type concept, the morphological type concept tended to be riddled by theoretical disagreement during the first half of the nineteenth century. According to Farber, two main interpretations dominated the morphological writing of the nineteenth century.

Zoologists Georges Cuvier (1769-1832) and Louis Agassiz (1807-1873) were two examples Farber provided of the first kind of morphologist involved in the debate, the functional morphologist. According to Farber, functional morphologists: “. . . contended that morphological types are fixed patterns of organization, on several taxonomic levels, that are the consequence of the general animal economy.”67 In other words, form was understood in terms of function, and so a better understanding of morphological types would be gained by a better understanding of functions. From an evolutionary perspective, there were reasons to be wary of functional morphologists. For a functional morphologist, forms resulted from physiological necessities, and as a result did not undergo transformations. To think of one form changing into another, or to think along evolutionary lines, was difficult to entertain from this perspective.

67Farber “Type Concept in Zoology” 116.

Farber introduced the morphological ideas of Etienne Geoffroy Saint-Hilaire (1772-1844) and Carl Gustav Carus (1789-1869) to illustrate the opposing position. On this account: “. . .

[f]unction is secondary to form and that morphological types are ideal plans in nature, often times thought of as variations on a single plan, or archetype. These ideal plans were interpreted by some as regularities that could be discovered in nature by abstraction. For others they were presented as deductions from a priori principles.”68 On this position (and it admitted of numerous variations), form was prior to function, and form was treated as a manifestation of an ideal plan. In contrast to functional morphology, this position appeared more compatible with evolution, because “if all animals share a unity of type, individuals differ from one another by various degrees of development and modification of analogous (in Geoffroy Saint-Hilaire’s sense of the word) parts.”69

The message Farber left was that the taxonomists’ type concept was not a simple concept.

It was complex in both theory and practice. This complexity might have been obvious to pre-

Darwinian taxonomists, but was much less so to contemporary eyes, as Winsor explained in

“Non-essentialist methods in pre-Darwinian taxonomy.” When studying past taxonomists,

Winsor reminded us to treat “as an empirical question” what various taxonomists claimed ontologically (that is, what they claimed in their world view), and ask “as a separate question, requiring separate evidence,” what they held epistemologically (that is, what they claimed to know and could use methodologically).70 She wrote:

[a]lthough we may think that people’s beliefs about the nature of reality should [my italics] be tightly correlated with their research procedure, we ought not to prejudge the connection. If we assume, for example, that a person who believed in the existence of essences must have used the essentialist method, we run the risk of distorting the past

68Farber “Type Concept in Zoology” 116. 69Farber “Type Concept in Zoology” 109. 70Mary P. Winsor “Non-essentialist methods in pre-Darwinian taxonomy” Biology and Philosophy 18 (2003): 389.

through the lens of our expectation, thereby missing the opportunity to learn anything from history.71

In other words, what a nineteenth-century taxonomist may believe in theory could have been

(and often was) quite different from what he did in practice. As a rule, then, when embarking on historical investigations, one should keep ontological and epistemological questions separate.

She provided examples from the eighteenth- and nineteenth-century natural history, as well as citing examples from Farber’s work on the use of the type concept to illustrate her point.

Returning to the original cluster of questions regarding types and methodology, were types, as construed by Collier and others, a methodological problem? Absolutely. Even nineteenth-century taxonomists knew that. Historian Gordon McOuat’s work on the species debate in nineteenth-century Britain not only is an excellent illustration of Winsor’s historiographical lesson, but is a clear example that a prominent group of nineteenth-century taxonomists knew how damaging type concepts could be in taxonomic methodology, if one did not maintain an ontological/epistemic divide.

According to McOuat, the ontological/epistemic divide played a pivotal role in nineteenth-century British natural history. McOuat reported that nineteenth-century taxonomists learned by experience that ontological battles over definitions resulted in instability, especially when it came to questions regarding the fundamental units of life. If natural history was to form an indisputable ground for all of the life sciences, this kind of instability would never do. As a result, claimed McOuat, taxonomists took action in the form of The Rules of Zoological

Nomenclature.

71Winsor “Non-essentialist methods” 389.

McOuat discussed in detail the history of The Rules of Zoological Nomenclature, a piece of work that legislated species demarcation not just nationally, but internationally.72 The Rules of

Zoological Nomenclature began as a set of rules presented to the British Association for the

Advancement of Science in 1842 by a committee of leading and established naturalists, with

Hugh E. Strickland (1811-1853) at the helm.73 At the start, the Rules sought to calm the growing radical reform on traditional meanings and boundaries of species. According to McOuat, British taxonomist thought the problem with classification systems was they were “were sloppy, asymmetrical things made from comparing empirically observed characters. They are liable to change as new information comes in.”74 If stability was the goal, not much headway would be gained by starting with classification systems in a constant state of change. Moreover, debate bubbled and boiled on the question of what the right sort of system was. Stability was important, and taxonomists knew it. As McOuat reported, from where Strickland stood, stability rested in species names.

According to McOuat, Strickland’s brilliant, yet controversial move was to claim that names were not definitions, thereby removing the ontological baggage from names. In fact,

Strickland emphatically declared that names “may have no meaning or etymology at all, and still accurately indicate its object.”75 With Strickland’s declaration, McOuat concluded that “. . . naturalists reached a compromise. Simply, ‘species are what natural historians say they are’.”76

72Gordon McOuat “Species, rules and meaning: The politics of language and the ends of definitions in nineteenth- century Natural History” Studies in History and Philosophy of Science 27, (1996) 473–519; “From cutting Nature at its joints to measuring it: new kinds and new kinds of people in biology” Studies in History and Philosophy of Science, 32 (2001) 613–645.; “Cataloguing power: Delineating ‘Competent Naturalists’ and the meaning of species in the British Museum” The British Journal for the History of Science, 34 (2001): 1-28. 73McOuat noted that the committee included Richard Owen, John Henslow, Leonard Jenyns, John Richardson, William Shuckard, John Phillips, William Ogilby, J. O. Westwood, William Broderip, William Yarrell, George Waterhouse, and Charles Darwin. 74McOuat “Cataloguing power” 27. 75McOuat “Cataloguing power” 27. 76McOuat “From cutting Nature at its joints” 617.

The philosophical beauty of this solution, as McOuat pointed out, was that now the nineteenth- century “realists” about species could peacefully coexist with the staunch “nominalists,”

“creationists” with “transmutationists.”77 This was also why, McOuat claimed:

. . . so very few raised any alarm when Darwin laid out species in the Origin in what seems like a starkly conventionalist (and seemingly most anti-realist) manner . . . Darwin wasn’t saying anything remarkably new there. By the middle of the century, this ‘conventionalism’ with respect to the species category was well established. Darwin had helped establish it long before he published the Origin.78

In other words, ontological battles could continue to rage, but there would be a pragmatic peace resulting from the stability of names. Names, declared McOuat, were the currency of nineteenth- century natural history. McOuat also argued the Rules helped maintain a gap between theory and practice because ontological disputes over definitions would open up dialogue with radicals and such dialogue could jeopardize stability.

According to McOuat, the Rules did a little more than just set out precise guidelines for species-naming, the Rules granted authority. Naming a species was not simply a matter of following a strict set of naming rules, nor was it enough to simply be a taxonomist. To name a species, you had to be the right sort of taxonomist. You had to be published within certain

“accepted” journals, and you had to be a member of a select group. “Real” species were demarcated by a select group. In other words, species were what elite naturalists said they were, and nothing more.79

77McOuat “From cutting Nature at its joints” 617. 78McOuat “From cutting Nature at its joints” 617. 79In the museum, McOuat discussed John Edward Gray’s agreement with Strickland that the names and their species had to remain stable while all else changed. However, Gray disagreed with Strickland over the locale of stabilizing authority, the locale of competency. Where Strickland located stabilizing authority and competency with “competent naturalists,” Gray located institutionally—the Museum, its catalogues, and its network of naturalists.

2.2.4.2 Post types

Perhaps it is suspect to jump from the Strickland code story of the 1840s across sixty years with assumption that the acceptance of the code implies an acceptance of the philosophy.

However, it is important to remember what the Strickland code was. The Strickland code was the explicit statement of what naturalists were doing and why they had to do it, this came to light in response to a particular political situation between the British and the French. As it turns out, what is happening sixty years later is the need for an explicit statement of what taxonomists are doing. Taxonomists weren’t doing anything wrong, but the methodological and political arena was changing and the lessons from sixty years ago suddenly seemed relevant again.

So, it seems that established taxonomists had learned their lesson about types, in which case one is left wondering why Coulter and others are raising such a fuss about types. Were taxonomists misunderstood? Or perhaps there is no longer an interest in keeping ontological issues separate. Even if taxonomists were misunderstood or if ontological issues should not be set aside, this new generation of biologists continued to weigh in on taxonomic questions during the first half of the twentieth century, and the ways in which ecologists and geneticists devised new methods for determining species differed radically from traditional taxonomists’ methods.

New studies into the material basis of heredity coming out of genetics and cytology at the turn of the century, coupled with new studies on the role of variation in a theory of evolution by natural selection coming out of population genetics aggressively challenged the way taxonomists had established the boundaries of taxonomic groups, as well as how these groups could be used to tell an evolutionary account of life. The combination of cell theory and Darwin’s evolutionary theory in the early twentieth century resulted in investigations into the causal mechanisms for evolutionary change that focused on the lowest levels of biological organisation—cells, and later genes. Taxonomists, as a rule, dealt in organisms, in individuals. Many of these pioneering

44 investigations had a methodological perspective in common: a quantitative, statistical, and sometimes experimental approach that focused on populations. This stood in contrast to the qualitative approach that focused on the organism and the individual, found in traditional taxonomic methods that dealt in types. Consider two typical methodological proposals.

2.2.4.3 Ecology

Botanists pursuing an ecological agenda in the 1920s and 30s launched a direct attack on what they characterized as “traditional taxonomy,” namely morphological taxonomy. Four such promoters of experimental taxonomy from 1915 to 1930 include: American ecologist Frederic

Clements (1874-1945), American botanist H. M. Hall, American botanist E. B. Babcock (1877-

1954), and Swedish botanist Göte Turesson (1892-1970). Clements, for example had a problem with the traditional taxonomic approach precisely because it focused on single organisms. He claimed that an approach that took single organisms as its basic unit was not taking the necessary evolutionary turn. In contrast, his experimental approach did begin with populations. Clements wrote the following, with regard to the problems of traditional taxonomic methods:

It is evident that the method of morphological differences greatly facilitates the provisional cataloguing of a flora, but it suffers from a universal and serious fault. This is the use of a few herbarium specimens in lieu of a large number of field individuals. Practically every collector selects a few individuals that appear typical, while for the purpose of scientific species-making he should collect as complete a series as possible of divergent individuals. Even if this were done, the ecologist must continue to regard the method as a mere preliminary, which serves to arrange the material and hence to facilitate the real study of species.80

From a collections perspective, the distinction Clement wanted to draw was between a collection based on types that showcased a typical individual versus a collection based on a series that showcased as many as possible divergent individuals. More importantly, Clements’s new

80Frederic E. Clements, “An ecologic view of the species conception. I. Past and present practise in species-Making” The American Naturalist, 42 (1908) 257.

45 experimental method involved more than just a change in collecting. For Clements, “the questions of what a species is, what are species and what are not, and of the origin of species and of forms must then be decided by experiment.”81

In a nutshell, Clements’s methodology consisted of two processes: (1) field observations throughout the habitat of the species concerned and (2) experiment. The second process consisted of three steps: (1) the exact measurement by instruments of the original habitat and the new one, (2) the experiment itself and (3) the measurement of results, i.e., the determination of the degree of morphologic and histologic difference.82

Against a background of experimental laboratory science packed with quantitative analyses and causal explanations, it came as no surprise that the detailed descriptions crafted by taxonomists were seen as relics. Against such a background, it also came as no surprise that taxonomists were characterized as feather-counting museum men whose work was unworthy of scientific attention. But ecologists were not the only ones taking issue with taxonomists and inciting methodological reforms. Geneticists were chomping at the methodological reform bit.

2.2.4.4 Genetics

Geneticist Theodosius Dobzhansky was another fine example of an attempt to revise the species concept along evolutionary lines. Central to his attempt was the use of genetic, geographical, and reproductive, rather than purely morphological, attributes. In a short summary piece for the journal Philosophy of Science in 1935, Dobzhansky outlined the biological and

81Clements “An ecologic view” 258. 82Clements “An ecologic view” 258.

46 causal relationships on which he felt taxonomists should base their species concept.83

Dobzhansky wrote:

The role of the sexual method of reproduction as an obstacle in the way of the formation of discontinuous groups of individuals has been clearly recognised for a long time. Darwin devoted no little attention to this point, and all the more recent evolutionists were fully aware of it. The development of genetics brought a clarification of the understanding of the mechanisms involved.84

Identifying causes was not enough for Dobzhansky. Biologists needed to discover and describe the mechanisms for evolutionary change. To help elucidate his position, Dobzhansky described his causal picture of the mechanism of species change in the following way:

Every discrete group of individuals represents a definite constellation of genes. If the different groups interbreed freely with each other, a new equilibrium is established in which the different genic constellations become fused into a single one. It necessarily follows that no discontinuous variation can exist in a perfectly panmictic population. Mutatis Mutandis, the existence of two or more discrete groups of individuals is proof that free interbreeding between them is prevented by some factor or factors.85

This passage contained the two main ingredients of Dobzhansky’s new definition of species.

First, he placed an emphasis on causal, instead of morphological, relationships. Second, he gave a nod to genetics and lower levels of biological organisation as the level of organization at which fundamental biological questions were directed and answered. Passages like this made it easy to see what direction geneticists were urging taxonomists take. Geneticists, before and after

Dobzhansky, targeted and attacked traditional taxonomy’s methodological practices that based grouping on similarity relations, until they got a response from taxonomists.

83These same ideas were given a more detail treatment in Theodosius Dobzhansky, Genetics and the Origin of Species. (New York: Columbia University Press, 1937). 84Theodosius. Dobzhansky, “A critique of the species concept in biology” Philosophy of Science, 2 (1935) 348. 85Dobzhansky “A critique of the species concept” 348.

2.2.5 Quagmire

The first thirty years of the twentieth-century was a whirl wind of species concepts and methodological proposals, but no real synthesis. Bateson summed it up nicely when he said:

I had expected that genetics would provide at once common ground for the systematist and the laboratory worker. This hope has been disappointed. Each still keeps apart. Systematic literature grows precisely as if the genetical discoveries had never been made and the geneticists more and more withdrawn each into his special “claim”—a most lamentable result. Both are to blame. If we can not [sic] persuade the systematists to come to us, at least we can go to them. They too have built up a vast edifice of knowledge which they are willing to share with us, and which we greatly need. They too have never lost that longing for the truth about evolution which to men of my date is the salt of biology, and the impulse which made us biologists. It is from them that the raw materials for our researches are to be drawn, which alone can give catholicity and breadth to our studies. We and the systematists have to devise a common language.86

So, where did this leave taxonomy? By the late 1930s, taxonomists were stuck in a philosophical quagmire, a methodological mess of theoretical terms: types, species, and populations. In

England and America, movements towards a synthesis of disciplines and a quantitative biology had taxonomists such as Gilmour and Simpson rethinking taxonomy’s relationship with logic initially along more inductive lines, in an attempt to work out an epistemological framework for their methodological reform. In Germany, work in theoretical biology had taxonomists like

Hennig rethinking taxonomy’s relationship with formal logic, in an attempt to provide a new language for biology in an effort to put taxonomy on firmer ground.

86William Bateson, “Evolutionary faith and modern doubts.” Science 55 (1922): 60.

Chapter 3 Gilmour 3.1 Introduction

In the early twentieth century, taxonomists could not avoid the possibility of a methodological reform. A critique of their discipline by the new generation of evolutionarily- minded biologists began with rumbles about the inability to infer evolutionary claims from qualitative methodologies, this continued with complaints about taking individuals as the basic units of evolution, and it ended with questions about what types of factors should be used to determine taxonomic groups. By the late 1950s, this concern sharpened into an accusation that hierarchical classification systems found in practice presupposed a branch of formal logic—set theory—that was at ontological odds with Darwinian thinking. Botanist John S. L. Gilmour was a curious character in this drama, with many eager to cast him in a curiously anti-evolutionary role.

When considering the relationship between logic and taxonomy, many philosophers and biologists have interpreted Gilmour’s work in the late 1930s and early 1940s as promoting logical positivism or logical empiricism. For example, anthropologist Scott Atran spoke of

“Gilmour’s avowed adherence to logical empiricism” in his book Cognitive foundations of natural history: towards an anthropology of science.87 David Hull made a similar claim in

Science as a Process:

Gilmour began his contribution to Huxley’s volume by noting that a new research program termed “logical positivism” had recently arisen among physicists, philosophers, and mathematicians. In agreement with the new program, Gilmour argued that the fundamental principles of classification cannot be formulated in isolation from an

87Scott Atran, Cognitive foundations of natural history: towards an anthropology of science (Cambridge: Cambridge University Press, 1996): 36.

adequate epistemological theory of how scientists obtain knowledge of what is commonly termed “the external world.”88

In Metaphysics and the origin of species, Michael Ghiselin argued that Gilmour was promoting a

“phemomenalistic approach” popular with logical positivists, such as Rudolf Carnap, although he noted that Gilmour did not cite Carnap, but a considerably more obscure paper by H.

Dingle.89 More recently, biologist Olivier Rieppel characterized Gilmour’s work as positivist:

Gilmour (1940), commenting on the ‘New Systematics’ from a positivist point of view, lamented the fact that Woodger was largely ignored by contemporary biologists (see also Hull, 1969; Cain, 2000), and called attention to the fact that individuals (i.e. particulars), such as you, me, tables and chairs, are ‘concepts, a rational construction from sense-data’ (Gilmour, 1940).90

Even Cambridge botanist S. M. Walters commented on logical positivism and Gilmour in

Gilmour’s obituary:

Gilmour’s other contribution to botanical science is in a more controversial area where relatively few botanists (or horticulturists) operate. Ideas on the philosophy of classification which, at least in botanical circles, are increasingly called “Gilmourian” were set out in papers some 50 years ago, when he was in his late twenties. They are characterized by a severely pragmatic attitude to all human classificatory activities, and are presented against a philosophical background which is that of “logical positivism”.91

Agreeing with this assessment of Gilmour is tempting, especially if Gilmour’s chapter in

Huxley’s The new systematics is read in isolation. However, there are reasons to resist this interpretation of Gilmour’s work. When Gilmour’s three early works on the philosophy of

88David L. Hull, Science as a Process: An Evolutionary Account of the Social and Conceptual Development of Science (Chicago: University of Chicago Press, 1988), 104. 89See Ghiselin’s discussion on page 170 of Michael T. Ghiselin, Metaphysics and the Origin of Species. (Albany: State University of New York Press, 1997). Ghiselin does agree that Gilmour’s concept of “natural,” which I will discuss later, was just like John S. Mill’s, except that Ghiselin believed that Gilmour’s had a “phenomenalistic” ring to it. Ghiselin also saw Gilmour’s paper as positivist in Michael Ghiselin, The triumph of the Darwinian method (1969). 90Olivier Rieppel “Semaphoronts, cladograms and the roots of total evidence” Biological Journal of the Linnean Society, 80(2003):176-77. 91S. M. Walters “Obituary of John Scott Lennox Gilmour” Plant Systematics & Evolution 167 (1989): 94-95.

50 classification are viewed as a whole, it becomes clear that he does not fit the bill, when it comes to logical positivism.

Once Gilmour’s philosophical approach is detached from logical positivism, at least two historically significant insights appear. First, Gilmour’s work on classification is a nice illustration of how the relationship between logic and taxonomy during the twentieth century was not restricted to deductive logic. Specifically, Gilmour’s work on the philosophy of classification is an excellent example of a taxonomist relying on inductive logic not only to organize nature, but to diffuse debates, to illustrate fallacious reasoning, and to encourage progress in this period of reform. Second, Gilmour’s 1940 paper is a nice example of an attempt to provide a logical and epistemological critique of how inferences are made in an evolutionary taxonomy.

One important feature of Gilmour’s critique was its emphasis on what could be accomplished in practice, when discussing the limits of an evolutionary taxonomy. Gilmour’s emphasis on practicality was often overlooked in the literature in favour of the later ontological debates that took place in the methodological reform, and acknowledging this oversight serves as a gentle reminder that during this time there was a very real divide between what taxonomists maintained ontologically and what they could actually do in practice. Gilmour’s belief in this divide was consistent with the sort of thing that many other taxonomists, such as Simpson, also maintained during this period.

3.1.1 Gilmour’s plan

Gilmour was not a professional philosopher. He was a professional botanist and an avid bibliophile who spent the majority of his career at the helm of the Cambridge Botanic Garden.

What he did do was read philosophy and logic, and then applied it to the methodological problems facing taxonomy. Gilmour’s “energy, ability, enthusiasm, and charm” was well-known

51 in taxonomic circles, and he was remembered by his community as an administrator whose

“unfailingly good manners” were often called upon during frustrating meetings.92 Some went as far as characterizing him as often erring of the side of investing time and energy in problem- solving over research.93 During the 1930s, Gilmour believed that if he could convince this generation of feuding botanists to adopt his philosophy of classification, he would accomplish two things: he could help diffuse the methodological debates plaguing botany, and he could put himself in a strong position to encourage botanists to take a hard logical and epistemological look at how they constructed and used their classification systems.

Although Gilmour accepted the theory of evolution, at this time he believed evolutionary classification systems demanded serious examination and revision. Looking at the fresh crop of evolutionary classification systems available, Gilmour explained how the inferences that justified the evolutionary claims made were the result of circular reasoning. Gilmour was not alone in raising concerns about the problem of inference in evolutionary taxonomy. The topic of inferences would become an unavoidable issue for those like Simpson who wanted to provide a viable evolutionary classification.

92S. M. Walters “Obituary of John Scott Lennox Gilmour.” Plant Systematics and Evolution 167(1989): 93-95. 93Winsor noted this: . . . everyone personally acquainted with Gilmour testify to his kindhearted nature, we may assume that he felt real distress to see his colleagues so at odds. Congruent with temperament was his deeply held moral sense. Soon after moving to Kew he had experienced a personal epiphany that left him convinced that an atheistic humanism that replaced religion with rationality could improve the wellbeing of mankind (Gilmour, personal communication; Walters 1987 and personal communication). Yet Gilmour, unlike Gregor, was not generating new botanical data. His administrative duties at Kew were occupying his full attention, and his plans to do experimental botany faded away, nor would he ever manage to become a productive researcher (Stearn 1989). Yet he continued to care about the issues, and he found other ways to contribute to the debate. Mary P. Winsor “Species, Demes, and the Omega Taxonomy: Gilmour and the New Systematics” Biology and Philosophy 15(2000): 358.

3.1.2 Botanical debates

Early in his career, Gilmour was in a good position to take on this sort of project. In fact, he believed he was in a better position than most. In discussing the tensions in botany during this period, Winsor noted:

. . . [m]ost taxonomists only knew about genetics, ecology, and cytology from their reading, if the jargon of these new disciplines did not bar outsiders entirely. For their part, the devotees of these intense new specialties consulted taxonomists or their literature when they needed a name for the plants they were manipulating, sometimes coming away with a low opinion of old-style botany.94

Gilmour, Winsor reflected, was different. Gilmour stepped into the reform movements in ecology and genetics while studying botany in Clare College, Cambridge, from 1925 to 1930.95

She also noted that in the spring of 1930, Gilmour began a correspondence with experimental botanist Göte Turesson, and was good friends with another experimental botanist J. W. Gregor.96

When Gilmour was hired at Kew, he became a colleague of another experimental botanist,

William Bertram Turrill, “who had also been inspired by Turesson’s experiments.”97 Gilmour did more than just read about experimental botany and befriend experimental botanists.

According to Winsor, in 1930 Gilmour decided to try his hand at it, and obtained a plot of garden to undertake his own experimental work.98 All told, Gilmour felt he could move comfortably between taxonomy and ecology.

Gilmour’s survey of the botanical debates and botany’s history in the three works I examine was brief, mainly because he did not intend the papers to be history papers. If history were his intention, it would have made more sense, for example, for Gilmour to elaborate on

94Winsor “Species, Demes”, 354. 95Winsor “Species, Demes”, 354. 96Winsor “Species, Demes”, 354. 97Winsor “Species, Demes”, 356. 98Winsor “Species, Demes”, 355.

Hugo deVries’s defense of an experimental Darwinian approach to botany, rather than provide sound bites from one of deVries more recent followers. As a key critic of traditional taxonomy, and a vocal spokesman for closing the gap and a believer that real groups were natural groups, deVries played a major part in shaping the intellectual landscape in which experimental botanists

Gilmour cited had lived.99

One of the more enthusiastic de Vriesians Gilmour included in his survey was botanist

Leonard Cockayne (1855-1934). Cockayne’s assessment of traditional taxonomy followed deVries insofar as it exemplified the type of objections raised by those who set their sights on garden methodology as the source of the problem. Like de Vries, Cockayne recognized that taxonomic groups were named and organized in the garden by methods that were developed and dependent on the garden. He believed that standard methods of comparison relied on type specimens that focused on the individual rather than the population, and treated variation as background noise. As a result, Cockayne was quick to accuse traditional methodological practices of being anti-Darwinian for not adopting a population approach, and for not seeing the role of variation as important. In other words, it was a methodology that obstructed scientific progress. In contrast, Cockayne endorsed a methodology grounded in an experimental science, rather than descriptive science, and he played off a normative interpretation of the natural/artificial dichotomy.

In his more polemical writing, Cockayne often restated de Vries’s attack on traditional taxonomy in terms of natural and artificial groups. For example, Cockayne’s lively critique of the species concept began with a philosophical assessment of what he called “the Linnaean account of species,” to which he compared “the Jordonian account of species” that de Vries

99Winsor “Species, Demes,” 354-55.

54 endorsed. Like de Vries, Cockayne maintained that the “Linnean” species were not real—they were a naturalist’s creation not a natural creation. He claimed Linnean species were subjective, arbitrary groupings, and used de Vries to drive this point home:

. . . an elementary species, as De Vries has termed it—and such must receive a name ; such elementary species are realities, whereas collective Linnean species are merely ideas. The final court of appeal as to “specific value” is no longer the herbarium or study of the systematist, but the seed-bed of the experimental garden.100

The “elementary” species, in contrast, were real.

Cockayne believed he had good reason for his claim that the Jordonian species concept better captured real groups. By grounding the species concept in an experimental practice that boasted of repeatability, Cockayne believed that “elementary species” concept better reflected real boundaries:

Moreover, a change of the highest moment is the substitution of elementary species as the raw material for the evolutionary process, rather than the Linnean species, which, as shown below, are frequently ideas merely and not living entities.101

For de Vries and his followers, the only way to determine accurately taxonomic groups was with cultivation-breeding experiments.

Cockayne’s support of the experimental approach was evident in other passages as well:

Few will deny, whatever be their opinions as to its truth, that the most awakening contribution of late years to the evolution question has been the mutation theory of De Vries. Leaving out of consideration for the present the value of the theory as a means of evolution, the introduction of careful experimental methods—i.e., a return to Darwin’s own procedure—rather than mere argument in favour of this or that dogma has given new life to the study of evolution. Moreover, a change of the highest moment is the substitution of elementary species as the raw material for the evolutionary process, rather

100L. Cockayne “On the Supposed Mount Bonpland Habitat of Celmisia lindsayi, Hook. f.” Transactions of the New Zealand Institute (1911): 350. 101L. Cockayne “Observations concerning evolution, derived from ecological studies in New Zealand” Transactions of the New Zealand Institute (1911): 3.

than the Linnean species, which, as shown below, are frequently ideas merely and not living entities.102

The significance of this passage is Cockayne’s emphasis on experimental methods, rather than connections to evolutionary theory. This distancing from Darwin was, perhaps, not surprising since the “Jordon species” was developed by Alexis Jordon before Darwin published the Origin.

Cockayne’s rejection of the reality of the Linnean species led to a spirited discussion of the polemical terms “artificial” and “natural” systems. Part of Cockayne’s strategy to adopt a more de Vriesians methodology involved convincing his readers that traditional taxonomic groups were always artificial, that they were subjective groupings serving mainly diagnosis purposes. In a pointed passage, Cockayne claimed:

Without going into further details, it is evident that the species of New Zealand taxonomists are rather the creation of man than of Nature. In saying this I am not hypercritical. The main object of a flora is to enable a plant to be readily identified, and this, from, the very nature of the case, demands a more or less artificial classification. Where such precise and copious information as to variation is given as in Cheeseman’s most careful and exact work there need be no mistake, and the worker in the field knows exactly what he may expect.103

He went on to explain what he believed caused the confusion regarding the species concept—the failure to recognize that different species concepts were in play:

But, as a rule, writers on evolution have quite neglected to distinguish between taxonomic and physiological species, which latter alone are their concern. Although breeding- experiments can alone decide as to fixity of form, ecology should tell something. If a certain set of individuals remain unchanged over wide areas, so far as their specific marks, go; an under varying conditions, it may be assumed with tolerable confidence that they reproduce their like, and are therefore species, elementary or Linnean, the case may be.104

Cockayne’s aim was to help his reader appreciate this de Vriesian concern.

102L. Cockayne “Observations,” 3. 103Cockayne “Observations,” 5. 104Cockayne “Observations,” 5.

According to Cockayne and others like him, Linnaeus’s species, as well as the “Linnaean species,” were made in the herbarium, and as long as that species concept remained glued to herbaria sheets, it was useful only to taxonomy practiced in the garden. The new generation of botanists, of which Cockayne saw himself a part, believed that species should be made in the field, followed by reassurances from the lab or vice versa. What these botanists proposed was a new methodological approach to ground a new species concept.

One controversial corollary of de Vries’s species concept was the claim that experimental evidence was both necessary and sufficient to determine a species. In other words, all botanists needed to do to determine the existence of a new species was to ascertain whether new characters indicative of that species bred true. By taking this parsimonious position, not only did the de

Vriesians imply that other kinds of information, such as biogeographical information, was irrelevant to taxonomy, but because information such as biogeographical information was not gained experimentally, such information was a subjective form of evidence, like comparative morphology.

It was important to note that Cockayne was not quite the thorough-going de Vriesian as he might appear from these quotes. Cockayne abandoned a strictly de Vriesian position when he was willing to consider other kinds of evidence, in addition to breeding experiments, to support a species concept that would best capture real groups. Cockayne worried that without some supplementary evidence, species picked out under the “elemental” or “jordonian” species or “de

Vriesian” concept could be mere varieties. Cockayne didn’t require taxonomists to use as many kinds of evidence as possible, rather, he used other kinds of information, such as biogeographical information, as a checks and measures system. Cockayne’s early insight into de Vries’s

57 parsimonious stance and his proposal to include a number of different kinds of factors in his species concept was indicative of an epistemic rift developing between botanists.

If Cockayne’s natural/artificial polemic was truly a good example of the rhetoric used by this new generation of botanists, then it begins to become clear why Gilmour thought redefining the term “natural” as it was used in concepts such as “natural” and “artificial systems” was an important step in diffusing the debates in botanical classification. What set Gilmour’s redefinition apart from the others was his attempt to define classification systems epistemically, rather than ontologically. By doing this, Gilmour could argue that the differences between rival systems were a difference in degree rather than in kind. Once free of ontological baggage,

Gilmour would be able to arrange his botanists (and later his biologists) along a continuum that reflected the generality of their resulting systems: at one end were the more specialized artificial systems that allowed fewer inductions, and at the other end were the more general natural systems from which more inductions could be made.

If botanists accepted Gilmour’s philosophy and excised the ontological baggage from the term “natural”, Gilmour believed they could focus on the real question, a more philosophical question about the use of evidence and inference in taxonomic systems. To this end, Gilmour pressed biologists to examine whether their classification systems really served their intended purpose. Did the evidence gathered license the claims made? According to Gilmour, in the case of the evolutionary classification systems, the answer was no. Gilmour developed his critique in three works written between 1936 and 1940.

3.2 Gilmour’s two early papers

In 1936, Gilmour was slotted to give a paper at the meeting of the British Association in

Blackpool. Gilmour’s talk “Whither taxonomy” was a survey of the state of botany as he saw

58 it—a fractious debate among taxonomists, ecologists, and geneticists. Gilmour suggested a way to resolve the conflicts between rival methodological practices, and raised concerns regarding attempts to synthesize or reduce classification systems. In chronicling this period in Gilmour’s life, Walters noted that Gilmour was approached after his talk by the editor of Nature, who suggested he publish an article for Nature based on his talk. And Gilmour did. It appeared under a different title “A taxonomic problem” in Nature for 19 June 1937.105

As Gilmour’s ideas on this topic developed, the scope of his work grew. In his talk

Gilmour investigated his idea of natural and artificial systems within a set of problems faced by botanists in the late 1930s, and pitched this idea to an audience of largely botanists. In his Nature paper, Gilmour revamped his idea for a more diverse audience, as well as offering some new insights. In between these papers, Gilmour served as secretary for an interdisciplinary committee called the “Taxonomic Principles Committee out of the newly-founded Association for the Study of Systematics in Relation to General Biology” between 1937 and 1940.106 One of their goals was to define the relationship between evolution and taxonomy.107 Julian Huxley (1887-1975) headed the committee. Gilmour’s thoughts on methodological reform were shaped partly by a series of philosophical questions he circulated to the committee members in order to gage their

105S. M. Walters “Appendix 2 Two early papers on classification by J. S. L. Gilmour, Foreword by S. M. Walters” Plant Systematics and Evolution 167 (1989): 97. 106In addition to Gilmour and Huxley, the other biologists included: W. T. Caleman, C. R. P. Diver, W. D. Lang, J. R. Norman, R. Melville, O. W. Richards, M. A. Smith, T. A. Sprague, H. Hamshaw Thomas, W. B. Turrill, B. P. Uvarov, A. F. Watkins, E. I. White, and A. J. Wilmott. 107A similar phenomenon was occurring in America around the same time. Within the American Association for the Advancement of Science, groups of biologists were starting to pool together to work out a synthesis. Mayr described the three groups that formed the synthesis as the population geneticists who dealt exclusively with genetic variation in a population and completely neglected all problems of diversity, including macroevolution, the paleontologists who dealt with macroevolution, with fossil histories, and the causes of evolutionary changes, almost unanimously rejected natural selection and were regrettably unaware of the advances that had been made by geneticists, and the taxonomists who inhabited an uncomfortable middle ground. See Ernst Mayr “Forward” vii-viii, from Joe Cain (ed). 2004. “Exploring the Borderlands: Documents of the Committee on Common Problems of Genetics, Paleontology, and Systematics”, 1943-1944. (Philadelphia: American Philosophical Society) http://www.aps-pub.com/ See also Joe Cain, “Common Problems and Cooperative Solutions: Organizational Activities in Evolutionary Studies, 1937– 1946,” Isis 84(1993) 1–25; “Ernst Mayr as Community Architect: Launching the Society for the Study of Evolution and the Journal Evolution” Biology and Philosophy 9 (1994) 387–427.

59 position on the relationship between evolution and taxonomy: What are the nature, purpose, and principles of classification in general? What is the meaning of “natural classification” and its relationship to phylogeny? What does it mean to say that something is “phylogenetic natural”

(according to ancestry) versus “logically natural” (according to the maximum number of characters in common)?108

In her careful study of this committee’s work, Historian Mary P. Winsor compiled compelling evidence for the claim that most of the botanists believed taxonomy was a “practical matter,” one that should be kept distinct from “phylogenetic speculation,” whereas the zoologists insisted that for taxonomy to remain viable, taxonomists must ground their classification systems in evolutionary theory. Resisting such a move, claimed the zoologists, would lead their discipline’s demise. Winsor noted that with no compromise forthcoming, taxonomy appeared

“poised to play several roles in the coming synthesis.”109 Gilmour approached this topic again, but more broadly, in his contribution to Huxley’s landmark book The new systematics (1940).

There are many differences between Gilmour’s talk and his Nature paper, not the least of which was the tone and scope. Compare his opening remarks in his talk with those in his Nature paper. He opened his talk with: “My purpose to-day is to attempt to show that some of the present confusion in biological taxonomy is due to a failure to apply certain of the general principles of classification to the world of living things”—a focused beginning for a talk aimed at botanists.110 He opened his Nature paper with a more general claim that applied to more than just botany, and appealed to a more diverse audience:

108Mary P. Winsor “The English debate on taxonomy and phylogeny, 1937–1940.” History and Philosophy of the Life Sciences, 17 (1995): 227–252. 109Winsor “The English debate.” 227. 110Gilmour “Whither taxonomy,” 98.

Among present-day biologists there is widespread interest in, and considerable disagreement on, the proper relationship between taxonomy and other branches of their science, especially genetics, cytology and ecology. Should the data provided by these branches be incorporated into the existing taxonomic categories, or should new categories be created to meet their needs?111

Gilmour structured his talk around a philosophy of classification he believed would help resolve the problems botanists faced, whereas he structured his Nature paper around the question of a synthesis of disciplines and the role of taxonomy would play in biology generally. Nevertheless,

Gilmour believed all of these questions could be answered by the framework he was about to present.

Common to both the talk and paper was Gilmour’s logical and epistemological account of classification. Generally speaking, said Gilmour, classification involved grouping individual objects in a way that enabled taxonomists to infer something about a particular object by virtue of it belonging to a particular group defined by a certain collection of attributes. In his talk he said:

For example, when we say that a certain man is a mathematician, a certain plant is a perennial, or a certain rock is granite, we mean that the man, the plant or the rock in question possesses certain attributes which we have agreed to indicate by the terms mathematician, perennial or granite. In other words, in order to make general statements about particular objects, we need to first classify them into groups, which makes classification ‘a process necessary to all rational thought’.112

He made similar statements in his Nature paper, but included the following footnote:

A full discussion of these principles may be found in the standard works on logic and scientific method [See especially: “Logic” by J. S. Mill (1843); “Logic” by A. Bain (1878); “The principles of science”, by W. S. Jevons (1883); “Logic”, by Carveth Read (1898); “The English utilitarians”, by L. Stephen, Vol. 3 (1900, esp. pp. 124- 131); “The use of words in reasoning”, by A. Sidgewick (1901); “Inductive logic”, by T. Fowler(1904); “Formal logic”, by F. C. S. Schiller (1912); “A new logic”, by C. Mercier (1912); “The philosophy of biology”, by J. Johnstone (1914); “Scientific method”, by A.

111Gilmour “A taxonomic problem,” 103. 112Gilmour “Whither taxonomy,” 98.

D. Ritchie (1923); “Biological principles”, by J. H. Woodger (1929); “Modern introduction to logic”, by L.S. Stebbing (1930).] , and only those points most relevant to the present problem will be dealt with here.113

Although Gilmour cited logicians in the Nature paper, it might be tempting to regard this footnote as a quick afterthought; perhaps designed to impress his readers with the breadth of his knowledge, or perhaps the obsessive act of a self-identifying bibliophile. Whether the list was a deliberate selection or an unreflective list of logic texts popular in Cambridge at the time

Gilmour wrote the paper, from the perspective of the history of logic, the inclusion of Mill and

Jevons in a discussion of the philosophy of classification by a taxonomist is significant. Both

Jevons and Mill were significant figures in logic’s reform during the nineteenth century. One of their triumphs involved putting induction back on respectable ground. But that was not all that

Gilmour would have found attractive about Mill’s philosophy.

3.2.1 Whately’s logical reform

To understand how Mill would come into the hands of naturalists, it would help to understand a bit about the place of Mill’s logic in the history of logic. Mill’s seminal logic book was published during Britain’s logical reform period, a reform which began on a political note with Richard Whately’s resurrection of Scholastic logic in Britain’s education reform.

It is worth noting that Whately identified himself primarily as a theologian and philosopher. He resisted identifying himself as a logician because at the time no one in Britain devoted himself to logic, hence no one self-identified as a logician. Van Evra noted that C. S.

Peirce claimed that he was the first person since the Middle Ages to completely devote his life to logic.114

113Gilmour “A taxonomic problem,” 103. 114Cf. Fisch, 1985, xviii.

From 1400-1900,not only was logic almost exclusively found in compendiums, but only two books graced the schoolboy shelves of Oxford and Cambridge: Robert Sanderson’s 1615 text and Henry Aldrich’s 1691 fifty page compendium.115 Precious little of what filled the pages of these texts looked like what current students would recognize as logic, the vast majority being devoted to topics no longer found in contemporary logic textbooks, such as discussions of speech or the mind. Historian of logic James Van Evra noted that the account of the figures and rules of the syllogism in Sanderson’s text occupied only three of the three hundred and fifty pages. To contemporary eyes, even the account of syllogisms looks rather strange. Van Evra wrote that

“[the syllogism] is interpreted, following Aristotle, as a kind of discourse, but not one based on a distinct conception of logical form (there is, for instance, no formal representation of the syllogism in the text).”116As a logic text, Aldrich’s compendium was not much better. It contained the bare bones of an Aristotelian logic text: a classification of terms and propositions, an account of syllogistic structure, method, and an appendix on fallacies. This would have been the logic with which early naturalists would have been familiar, and this was the logic Rev.

Richard Whately (1787-1863) famously challenged.

Whately was recognized by his peers as clarifying logic’s boundaries, and he saw this as necessary task. By better defining logic’s scope and limits, he could respond to the centuries of attack that played on misconceptions of logic’s nature and purpose. Whately held two initial assumptions that set his view of logic apart from those of his predecessors. His first assumption was that logic was a science on par with other prominent sciences such as chemistry, physics or algebra, which also lay dormant for long periods before receiving the theoretical support needed

115James Van Evra “The Development of Logic as Reflected in the Fate of the Syllogism 1600-1900” History and Philosophy of Logic 21 (2000): 118-20. 116Van Evra “The Development of Logic,” 119.

63 for scientific progress.117 In doing so, he transformed the long-standing definition of logic; that is, deciding whether logic was an art or a science. 118 Whately judged logic to be primarily a science, and an art only derivatively and in application.119 As a science, logic rose to the status of a discipline based on clear theoretical principles with intrinsic worth. No longer was logic simply a tool employed by other disciplines.120 By doing this Whately felt he could distance his account from what he believed to be misguided claims about logic, such as: logic was used to investigate nature (speaking to Bacon and Locke), logic was the instrument of truth (the

Scholastic version), and logic was the art of rightly employing the rational faculties. The redefinition of logic as a science had the favourable consequence of encouraging more people to do more work in “pure logic.” Although Whately was not the first to claim logic as science, his was the first influential British logic textbook to defend this claim explicitly.121

The first step in fashioning logic into a science involved working out logic’s theory because, as Whately said, no science progressed unless it was founded on such principles.122

Whately tried to provide a generalised and abstract representation of all demonstration, and he tested his approach on the syllogism. Whereas the Scholastics understood the syllogism as kind of argument, Whately argued that the syllogism was a purely formal device. Once axiomatized,

Whately believed that syllogisms would serve as a canonical test of the validity of actual

117Richard Whately Elements of Logic (London:1826) 11. 118See James Van Evra, “Richard Whately and the rise of Modern Logic”, History and Philosophy of Logic 5, (1984), 1-18; and C. Jongsma, Richard Whately and the Revival of Syllogistic Logic in Great Britain in the early Nineteenth Century (unpublished dissertation, Toronto 1982). 119See Whately Elements 1, 127–28. 120James Van Evra “Richard Whately and Logical Theory” in Handbook of the History of Logic British Logic in the Nineteenth Century Edited by Dov M. Gabbay and John Woods Volume 4, (2008) 83. 121Blakey notes that Kirwan, in his 1807 “Logic” volume 1 page 1 made this same claim, see R. Blakey, Historical Sketch of Logic: From the Earliest Times to the Present Day (Baillière, 1851), 449. Also see Van Evra, “Rise of Modern Logic” 9. 122Whately Elements 2.

64 arguments, placing the syllogism the theoretical core of the science of logic.123 This move has led historians of logic to credited Whately’s re-evaluation of the role of the syllogism as inspiring the direction of the pioneers of algebraic logic.124

Whately’s Elements prompted two very different lines of criticisms. The first criticism launched by Mill’s cousin, botanist George Bentham (1800-1884), but made famous by William

Hamilton (1805-1865) and Augustus De Morgan (1806-1871), involved an attack on Whately’s formalization of the syllogism.125 Bentham’s contribution to the debate was his attempt to quantify of the Scholastic predicate term, and histories of logic remember the quantification of the predicate term as an important part of the familiar history of logic that explained the transition from traditional syllogistic logic to algebraic logic to the formal logic recognizable today.

William Whewell (1794-1866) and Mill famously launched the second criticism that targeted Whately’s account of induction. Whewell’s objection was not usually included in the standard histories of logic that move from George Bentham to George Boole (1815-1864) to

Bertrand Russell (1872-1970), and this historiographical bias in favour of mathematical logic was in place when Gilmour was writing his paper. If the historiographical end point was mathematical logic, Whewell’s work on induction would not be seen as relevant. Only recently have historians and philosophers of logic, notably philosopher Volker Peckhaus, called for the

123See Van Evra, “Rise of Modern Logic.” 124See Van Evra, “Rise of Modern Logic.” 125For an account of Bentham’s role in this see: See T. S. Baynes, “Mr. Herbert on Sir Wm. Hamilton and the quantification of the predicate” Contemporary Review 21 (1873): 796-798.; W. S. Jevons, “Who discovered the quantification of the predicate?” Contemporary Review 21 (1873): 821-824.; H. Spencer, “The study of sociology IX - the bias of patriotism” Contemporary Review 21 (1873): 475-502; G. McOuat “The Logical Systematist: George Bentham and His Outline of a New System of Logic.” Archives of Natural History 30 (2003): 206, M. Filipiuk, ed. George Bentham, Autobiography 1830-1834. (Toronto: University of Toronto Press, 1997), 484-485; Charissa S. Varma and Gordon McOuat “Bentham’s logic” in Handbook of the History of Logic British Logic in the Nineteenth Century Edited by Dov M. Gabbay and John Woods Volume 4, (2008).

65 inclusion of work often deemed “too philosophical” to be a relevant part of the history of logic of this period, in order to get a more complete picture of the history of logic.126

Removing this bias would fracture nineteenth-century logic into different streams—one leading to the formal logic made famous by Russell and Whitehead, another leading to a severing of the relationship between reason and mind (with psychology leaving logic), and the last leading to issues of reason and method in science. If this bias were removed, the definition of logic during the nineteenth century would be seen as much wider than it is now, and one could have followed the last stream which would arrive at Whewell’s work on induction. But the historiographical bias was in place when Gilmour was writing, so it is not surprising that

Whewell would not show up on a list of logicians. Mill, however, is a different story.

3.2.2 Mill’s logic

Mill’s logic text System of logic (1843), which contained his version of nominalism and his critique of Whately’s notion of induction, stood on the schoolboy shelves soon after publication. Used by students and cited by logicians, Mill’s System of logic proved influential.

However, what makes Mill relevant to this discussion is that Mill’s Logic contained ideas about classification that would appeal and appease naturalists.

When Gilmour’s work is read against Mill’s Logic, one is left with the impression that

Gilmour borrowed at least three ideas from Mill’s book, which Gilmour referred to as “Logic” in his footnote: his nominalist notion of classes and kinds, his approach to classification systems, and his empiricism. Whether or not Gilmour used Mill’s Logic as his logic text book when he was a student, it was clear from his footnote that he wanted to direct his reader’s attention to this

126See Volker Peckhaus “19th Century Logic between Philosophy and Mathematics” The Bulletin of Symbolic Logic, 5 (1999) 433-450.

66 particular aspect of Mill’s Logic, as he referred his readers to Stephen’s commentary on Mill in

The English utilitarians and that commentary dealt with this particular section of Mill’s logic.

Stepping back in time one finds, perhaps not surprisingly, that what Mill proposed for his notion of “classes” in 1843 in Logic was remarkably similar to the philosophical position on species found in The Rules of Zoological Nomenclature presented to the British Association for the Advancement of Science in 1842. In Logic, Mill argued against essences. Mill argued that names bind a group. What was shared was not an essence, Aristotelian, Platonic or otherwise, but common attributes. To make this point, Mill used taxonomy as an example:

A naturalist, for purposes connected with his particular science, sees reason to distribute the animal or vegetable creation into certain groups rather than into any others, and he requires a name to bind, as it were, each of his groups together. It must not however be supposed that such names, when introduced, differ in any respect, as to their mode of signification, from other connotative names. The classes which they denote are, as much as any other classes, constituted by certain common attributes, and their names are significant of those attributes, and of nothing else. The names of Cuvier’s classes and orders, Plantigrades, Digitigrades, &c., are as much the expression of attributes as if those names had preceded, instead of grown out of, his Classification of Animals. The only peculiarity of the case is, that the convenience of classification was here the primary motive for introducing the names; while in other cases the name is introduced as a means of predication, and the formation of a class denoted by it is only an indirect consequence.127

For Mill, names did not connote groups bound by essences; classes were bound by common attributes.

Just as naturalists like Strickland had discovered, Mill found answering ontological questions difficult and ontological debates acrimonious. And Mill was not a stranger to natural history. When Mill tackled the ontological status of classification systems and groups, he again discussed taxonomy. On the question of classification systems, Mill was willing to grant two types of classification systems, one made by nature and the other made by us. In practice,

127John Stuart Mill System of Logic Ratiocinative and Inductive Being a Connected View of the Principles of Evidence and The Methods of Scientific Investigation (London: Longmans, Green, Reader, And Dyer 1843).160-1.

67 however, he argued, this distinction made little difference because the one made by nature remained a social construct. He was able to make this claim because he promoted a fairly radical form of empiricism to underpin his notion of “real kinds.”

For Mill, a “real kind,” or a species, had an indeterminate number of properties that were not derivable from each other. This stood in contrast to a “logician’s kind” which was finite and could be derivable from each other. Consider Mill’s example using Newton:

Isaac Newton would be said to be of the species man. There are indeed numerous subclasses included in the class man, to which Newton also belongs; for example, Christian, and Englishman, and Mathematician. But these, though distinct classes, are not, in our sense of the term, distinct Kinds of men. A Christian, for example, differs from other human beings; but he differs only in the attribute which the word expresses, namely, belief in Christianity, and whatever else that implies, either as involved in the fact itself, or connected with it through some law of cause and effect.128

In other words, by claiming Newton was a man, Mill was attributing to Newton a multitude of properties connoted by the term “a man.” In contrast, by claiming Newton was a Christian, Mill only attributed to him a particular belief and whatever consequences that followed from holding that belief.

Mill believed objects were held together in coherent and many-propertied clusters. Mill’s empiricism assumed not only that our knowledge of properties must rest upon direct observation, but that there was absolutely no connection or “cause” to be known. One consequence of this position is found in Mill’s discussion of classification systems. Mill wrote:

There is no impropriety in saying that, of these two classifications, the one answers to a much more radical distinction in the things themselves, than the other does. And if any one even chooses to say that the one classification is made by nature, the other by us for our convenience, he will be right ; provided he means no more than this,—that where a certain apparent difference between things (though perhaps in itself of little moment)

128John Stuart Mill System of Logic Ratiocinative and Inductive Being a Connected View of the Principles of Evidence and The Methods of Scientific Investigation (London: Longmans, Green, Reader, And Dyer 1843).

answers to we know not what number of other differences, pervading not only their known properties, but properties yet undiscovered, it is not optional but imperative to recognise this difference as the foundation of a specific distinction ; while, on the contrary, differences that are merely finite and determinate, like those designated by the words white, black, or red, may be disregarded if the purpose for which the classification is made does not require attention to those particular properties. The differences, however, are made by nature, in both cases; while the recognition of those differences as grounds of classification and of naming, is, equally in both cases, the act of man: only in the one case, the ends of language and of classification would be subverted if no notice were taken of the difference, while in the other case, the necessity of taking notice of it depends on the importance or unimportance of the particular qualities in which the difference happens to consist.129

So, nature may have determined a natural or “real” order to things, but all classification efforts, even those designed to reflect that natural order, were human constructs.

Lastly, Mill believed classification systems served particular purposes. Again, Mill used taxonomy as an example of a classification that might appear to be ordered by nature, but it too had been deliberately constructed with a purpose in mind. He wrote:

And here, to prevent the notion of differentia from being restricted within too narrow limits, it is necessary to remark, that a species, even as referred to the same genus, will not always have the same differentia, but a different one, according to the principle and purpose which preside over the particular classification. For example, a naturalist surveys the various kinds of animals, and looks out for the classification of them most in accordance with the order in which, for zoological purposes, it is desirable that his ideas should arrange themselves. With this view he finds it advisable that one of his fundamental divisions should be into warm-blooded and cold-blooded animals; or into animals which breathe with lungs and those which breathe with gills; or into carnivorous, and frugivorous or graminivorous; or into those which walk on the flat part and those which walk on the extremity of the foot, a distinction on which two of Cuvier’s families are founded. In doing this, the naturalist creates as many new classes , which are by no means those to which the individual animal is familiarly and spontaneously referred ; nor should we ever think of assigning to them so prominent a position in our arrangement of the animal kingdom, unless for a preconcerted purpose of scientific convenience. And to the liberty of doing this there is no limit.130

Mill went on to discuss how real kinds were ordered in a classification:

129Mill Logic 167. 130Mill Logic 175.

In the examples we have given, the new classes are real Kinds, since each of the peculiarities is an index to a multitude of properties belonging to the class which it characterizes: but even if the case were otherwise—if the other properties of those classes could all be derived, by any process known to us, from the one peculiarity on which the class is founded—even then, if these derivative properties were of primary importance for the purposes of the naturalist, he would be warranted in founding his primary divisions on them.131

According to Mill, even if taxonomists were grouping real kinds, they were constructing classification systems with a purpose in mind.

3.2.3 Influence of Mill’s logic on taxonomy

Comparing the differences between Gilmour’s talk and the Nature paper, as well as comparing the Nature paper with the Huxley chapter, seems to suggest Gilmour was doing more than simply referencing logic books for the sake of ego or obsession. Echoes of Mill reverberate in Gilmour’s work. For example, when the definition of classification and the role of classification in general thinking as presented in Gilmour’s talk are compared with the definition of classification and the role of classification in general thinking as presented in the Nature paper, a change in vocabulary appears. Gilmour used logical terms such as “inductive process” to make his point in the Nature paper. Compare the passage in the talk where he said: “In essence, classification may be said to consist of grouping individual objects in such a way that a statement that a particular object belongs to a particular group indicates that the object possesses certain attributes” with the passage in the paper, where he wrote: 132

In its simplest terms, classification consists in grouping individual objects (and, ultimately, sense data, expressed as qualities and relations) into classes, so that all the individuals in one class have certain attributes in common. . .Viewed thus, classification is seen to be a necessary stage in the inductive process by which the human mind obtains an ordered knowledge of the universe. Ritchie (1923: 79) has expressed this concept of classification as follows: “ . . . our general knowledge of the external world as expressed

131Mill Logic 175. 132Gilmour “Whither taxonomy?” 98.

by laws of nature is a product of the interaction of two processes, selection from and classification of what is experienced and the discovery of laws relating to the classes.”133

In both cases there was a Millian undertone, with respect to the role of attributes, but a stronger role for logic emerged in the taxonomic discussion with the introduction of role of induction.

3.2.4 Ontological status of classification systems

Gilmour shared Mill’s understanding of classifications systems, especially when it came to the ontological status of classification systems. Like Mill, Gilmour promoted nominalism, both for the system and for groups. Mill entertained the possibility of two types of classification systems, one made by nature and the other made by us, but he said in practice, this distinction was inconsequential because even the one made by nature was a social construct when all was said and done. Nature may have determined a natural order to things, but all classification efforts, even those designed to reflect that natural order, were human constructs designed with a purpose in mind. He arrived at this conclusion because of the radical form of empiricism he used to defend his notion of “real kinds” or species which spoke to the ontological status of groups.

Again, for Mill, a real kind had an indeterminate number of properties not derivable from each other, versus a “logician’s kind” which was finite and could be derivable from each other. For

Mill, names did not connote groups bound by essences; classes were bound by common attributes. As can be seen from the following papers, ontologically, Gilmour followed suit.

What remained constant from the talk to the paper was a consequence of Gilmour’s philosophy of classification, namely that all classification systems served a particular purpose, an idea found in Mill. According to Gilmour, classification systems did not reflect a true order of nature or something inherent in the universe, but instead were “conceptual orders” people imposed on their experience in ways that suited their purposes. Although the classification

133Gilmour “A taxonomic problem,” 104.

71 systems were not real, the objects classified were real, according to Gilmour. The classification systems taxonomists constructed were no different from any other kind of classification system.

Again, this was reminiscent of Mill. Classification systems were simply tools “by the aid of which the human mind can deal effectively with the almost infinite variety of the universe.”134

Here, however, things start to get tricky.

In the talk, Gilmour cited instances suggestive of this kind of thinking in some botanical authors:

This point has been well expressed in the biological sphere by Cockayne and Allan as follows: “As soon as we pass from the ‘individual’ to the ‘species’ we have passed from the region of fact to that of interpretation. In a recent paper Stoyanoff emphasizes the same point of view. This conception of classification as a human product is fundamental to the consideration of any more specialized aspects of taxonomy.135

To claim that Cockayne and Allen are pushing for this kind of nominalist approach is a bit of a stretch. In the paper where this quote was taken, Cockayne and Allen provided a critical summary of the species concepts in play. The concept that took the hardest hit is the Linnean species, mainly because of its ties to the herbarium. Their statement that when taxonomists passed from the individual to the species they moved from fact to interpretation was part of

Cockayne and Allen’s plea to get taxonomists out of the herbaria and into the field, to include the ecological information in order to capture real species. It was not likely an endorsement of the kind of nominalism Gilmour was proposing. Nevertheless, Cockayne and Allen were clear that each new species concept mirrored the standpoint of its author, and would likely agree with

Gilmour’s claim that “We can sum up these preliminary remarks on the nature of classification

134Gilmour “Whither taxonomy?” 98. 135Gilmour “Whither taxonomy?” 98.

72 as follows: all classifications are devised from a particular standpoint, and the attributes used as a basis for any particular classification depend on the nature of that standpoint.”136

Where Cockayne and Allen, and many of Gilmour’s botanists would disagree with

Gilmour was on Gilmour’s assessment of the consequences this Mill/Strickland position, with its nominalist undertones, would have on botanical classification. Gilmour expressed his position as follows:

. . . there cannot be one ideal and perfect classification of living things. Biological classifications, in common with other types, must vary according to the standpoint from which they are devised. Though this fact has been pointed out more or less clearly by several writers notably Hayata and Turrill, many biologists nevertheless assume that one all-embracing system is possible, and, indeed, that to construct such a system should be the aim of all taxonomists. As we have seen, this aim, from the very nature of classification, is unattainable.137

On his penultimate point, Gilmour was absolutely right. Cockayne was a clear example of a botanist who believed there was a real order of nature out there, and that taxonomists aimed to capture it in their classification systems. This is a realist position, as opposed to the nominalist position Gilmour was endorsing. This was one reason why they employed the terms “natural” and “artificial” systems in a normative way, describing natural systems as better than artificial systems because they reflected the true order of nature. Gilmour appreciated this understanding of natural and artificial systems, and his appreciation of exactly this point structured the brief history of taxonomy he provided.

3.2.5 History of classification systems retold

When Gilmour turned his attention to the traditional classification systems in his talk— the methodological practices and species concepts that have come under attack for the past thirty

136Gilmour “Whither taxonomy?” 99. 137Gilmour “Whither taxonomy?” 99.

73 years—he drew attention to two features: how taxonomists grouped organisms (these classification systems were based on morphological characters), and the ontological status of the taxonomic groups themselves (real taxonomic groups were family, genus, species, variety, etc., rather than groups based on medicinal or economic uses). Gilmour could not escape the fact that many of the taxonomists in the eighteenth and nineteenth century believed that they were providing systems that reflected God’s plan, but he reminded his audience that in spite of taxonomists’ intentions, many eighteenth- and nineteenth-century classification systems really did no such thing, and taxonomists knew that.

Gilmour believed that the reason why many current taxonomists seem to equate the ontological position these past taxonomists held with the classification systems they produced was in part due to the incredible popularity of the Linnaean system. So dominant was the

Linnaean system, that current taxonomists often forgot that there were other kinds of systems in play. Gilmour expressed the above sentiment in the following: “Indeed, so universal is its use that it has come to be considered the classification par excellence, and the fact that it is only one of many others is often forgotten.”138 Gilmour then pointed out what many historians who had studied Linnaeus had also pointed out, that there were pragmatic and cultural factors that contributed more to the dominance of the Linnaean hierarchy than any ontological claim about its ability to reflect reality. Gilmour provided three pragmatic reasons for the Linnaean hierarchy’s “universality”: “Firstly, the morphological characters of living things are of great importance to man for a variety of purposes; secondly, they are easy to observe, and, thirdly, they are often the best single index of other attributes.”139

138Gilmour “Whither taxonomy?” 99. 139Gilmour “Whither taxonomy?” 99.

By playing off the implicit common belief regarding the ontological status of the

Linnaean system, Gilmour wanted his audience to appreciate how this belief contributed to the taxonomist’s need to evaluate the merits of a classification system based on the system’s ontological status, rather than evaluate it by more pragmatic criteria. By asking taxonomists to distance themselves from these ontological debates, Gilmour believed that they would be able to recognize and appreciate the value of the many different systems available. Gilmour linked this idea to his philosophy of classification in the following passage:

But for many specialized purposes classifications based on other attributes have been devised. As examples we can quote the early classifications based on medicinal and economic properties; the life-form classification of Raunkiaer, based mainly on the method of overwintering; H. C. Watson’s classification into rupestrals, viaticals, etc., based on habitat; the geneticists’ classification into homozygous and heterozygous; the cytologists’ into diploid, triploid, tetraploid, etc.; the physiological classification of bacteria and fungi, and many others.140

All classification systems served a purpose, and some purposes were more specialized than others.

3.2.6 The new natural and artificial systems

When comparing different types of classification systems in order to redefine natural and artificial systems, Gilmour adopted a stance reminiscent of Mill and Jevons. Gilmour claimed that, of all the classification systems presently available, the morphological classifications were the most natural. If his audience considered the definition of “natural” and “artificial” systems used in botany prior to Gilmour, this seemed puzzling. And Gilmour agreed. It is puzzling because of the urge to include an ontological assumption that linked “natural” to “real.” That was why, Gilmour went on to explain, taxonomists should excise the ontological assumptions built into these terms. In the current debate, as Gilmour saw it, the term “natural” was mainly tossed

140Gilmour “Whither taxonomy?” 99.

75 around by those who believed evolutionary relationships were real, thus natural. Gilmour gently reminded his audience that those eighteenth- and early nineteenth-century naturalists who strove for the one, ideal, all-embracing classification system also believed that their system would be based on “natural relationships.” Since evolution by natural selection with genetics was a twentieth-century innovation, it was clear that “natural” had not always involved genetics or evolutionary considerations. And the normative spin on the terms “natural” and “artificial” was not a twentieth-century innovation.

To help his audience see how ontological considerations were built into this distinction,

Gilmour compared Jussieu’s system of plant classification (identified in the eighteenth century as a “natural system”) and Linnaeus’s sexual system of plants, which Linnaeus himself had no problem calling “artificial.” The difference Gilmour saw between the two systems was not a difference in the kind of evidence used, since both used morphological criteria as a basis of classification. The first obvious difference was in the number of characters built into the divisions. Linnaeus based his main class and order divisions on a single character, while Jussieu based his divisions on more characters. What was significant about the difference between

Jussieu’s natural system and Linnaeus’s artificial system was not this prima facie observation about numbers of attributes employed to make taxonomic division. Instead, claimed Gilmour, by using one attribute, Linnaeus provided a limited expression of those attributes he would use to generate a picture of morphological resemblance that would ground the grouping, whereas

Jussieu developed a fuller expression of these attributes which he would use to generate a more general picture of morphological resemblance that would ground his groupings. Gilmour believed these naturalists knew this, and consequently they understood the terms “natural” and

“artificial” as purely relative terms.

Somewhere along the way, biologists lost sight of this. Gilmour further believed that if biologists understood that the reason for preferring natural system over artificial ones was not because they better mapped onto reality, but because by taking into account a greater range of characters to express those attributes, then taxonomists would be able to produce more efficient instruments for the purpose they intended to serve.

In the paper, as in his talk, Gilmour attempted to explain why morphological systems held such a prominent position in taxonomy. In the paper, Gilmour adopted a slightly different strategy. He began by saying that if taxonomists looked at methods of reproduction and the work done on the inheritance of parental characteristics, and if this work showed that these factors had an influence on the attributes of plants and animals found in morphological classifications, then such taxonomists would be in a position to claim to have a classification system that was more

“natural” (in Gilmour’s sense) than any others. Gilmour observed that organisms belonging to the same species in a “morphological classification may very often belong to the same group in one of these classifications based on other criteria” and this observation led him to the conclusion that because morphological resemblance was often a good index of similarity in other properties, morphological classification systems were more natural than some of the other systems.141 Gilmour claimed that traditional taxonomy held a privileged position it did because it managed to construct a morphological classification system that was based on inherited attributes.

In his Nature paper Gilmour constructed a second argument for his new definition of natural and artificial classification systems. Rather than simply appealing to a similar argument made by dead botanists from a bygone era, Gilmour resurrected nineteenth-century logicians

141Gilmour “Whither taxonomy?” 99.

77 who he believed made a similar argument. Gilmour wrote: “The term “natural classification” is a general one, the significance of which is not confined to the grouping of living things. It is usually stated in logic that a system of classification is the more natural the more propositions there are that can be made regarding its constituent classes.”142 Again, this change in vocabulary from the talk to the paper was evident in his next stage of his second argument for his new definition of natural and artificial classification systems:

Thus a natural classification is one founded on attributes which have a number of other attributes correlated with them, while in an artificial classification such correlation is reduced to a minimum. From the point of view of function, a natural classification can be used for a great variety of purposes, while an artificial one serves only the limited purpose for which it was constructed.143

In other words, if there was one factor that influenced a particular collection of objects more than any other, then a classification based on attributes that are connected with that factor will be more natural than any other.

To drive this point home he borrowed an example from Jevons that went something like this. Imagine you were confronted with a group of people. You can divide this group into smaller groups in many ways, for example you can group people according to nationality or by the first letter of their last name. Gilmour believed that his readers would find the first grouping more natural than the second because more propositions can be made about an Englishman than can be made about people with surnames beginning with “E.” In order to drive home his point of about the relative nature of natural and artificial groupings, he asked his to imagine that a dictator arrived and proclaimed that all those with a last name beginning with the letter “E” will be executed. Now, claimed Gilmour, the formerly very artificial grouping suddenly seems more natural. Gilmour explained that this was because the attributes used to define that group was

142Gilmour “A taxonomic problem.”104. 143Gilmour “A taxonomic problem.” 104.

78 suddenly connected to a factor, namely the execution of people with the last name beginning with “E,” that was relevant to the set of people in question. Gilmour concluded from this that the more attributes connected with a factor that has an important influence on the objects being classified, the more natural the classification becomes. Following Jevons further, Gilmour went on to say that if we compare the two groupings (groupings by nationality and grouping by first letter of last name) “even in so artificial a class as those whose names begin with E, there will probably be an abnormally high proportion of Welshmen owing to the presence of a large number of Evanses.”144 All told, the results of comparing the difference in Gilmour’s approach to the definition of natural and artificial systems in these papers, specifically the change in vocabulary, was suggestive not only of the idea that the logicians he mentioned in the footnote were not a whimsical addition, but that a brief foray into logic could help clear up some confusions in taxonomy.

In contrast to his talk, in the paper Gilmour made a point of defining natural systems by a more direct appeal to logic. For Gilmour, if taxonomists want to discover laws that relate particular attributes of organisms, they need to organize those attributes into “distinct classifications of greater or less complexity,” making classification “a stage in inductive investigation.”145 With this in mind, it comes as no surprise that he would then define a natural classification as: “first and foremost, as that arrangement of living things which enables the greatest number of inductive statements to be made regarding its constituent groups, and which is therefore the most generally useful classification for the investigation of living things.”146

144Gilmour “A taxonomic problem.”105. 145Gilmour “A taxonomic problem.” 106. 146Gilmour “A taxonomic problem.” 106.

The last difference between the talk and paper lies in the ending. Both the talk and the paper conclude with a critique of the current state of taxonomy, based on the framework Gilmour constructed, but the critiques differ in tone and scope. Before he concluded his talk, Gilmour provided the following summary of his position: “No comprehensive system for all purposes being possible, biological classifications must vary according to the standpoint from which they are made, and, further, in order to be efficient for their purpose they must be constructed on as natural a basis as possible.”147 He also tried to explain why things came to a head in botany during the first few decades of the twentieth century.

Gilmour noted that Darwin’s theory of evolution by natural selection did not inspire any significant methodological reform in the first few decades after its publication. Gilmour believed that the winds of change only began to be felt when “genetics, cytology and ecology undertook promising investigations into the mechanisms of evolution.”148 These investigations allowed this new generation of biologists to ask questions typically left to traditional taxonomy, such as what were the limits of taxonomic groups, such as species? When these biologists entered taxonomy’s intellectual domain, taxonomists were forced to either devise new terms to “express the concepts of this evolutionary taxonomy—for example, jordanons, linneons, clone, pure line, biotype, ecotype, ecad, and a host of others” or to redefine their existing terms. 149 Traditional taxonomists not only had to face the evolutionary biologist’s claim that evolutionarily-minded taxonomy would be the most natural, but the idea that there exists a criterion of degree of phylogenetic relationship, apart from degree of similarity of attributes, which would capture

“real” groups.

147Gilmour “A taxonomic problem.” 100. 148Gilmour “A taxonomic problem.” 100. 149Gilmour “A taxonomic problem.” 101.

Gilmour believed that traditional taxonomy could avoid being bullied by the new kids on the block if only they would insist on everyone severing the ontological ties between classification systems and the “real” order of nature. If successful, Gilmour could provide them with the perfect solution, one that would preserve both kinds of classification, avoid trying to reduce one to the other, or declaring one system obsolete. Gilmour’s solution began with the claim that every classification has been constructed from “a particular standpoint, and that the attributes on which it is based depend on the nature of that standpoint.”150 Evolutionary biologists, then, would be forced to define the standpoint of their new evolutionarily-minded taxonomy in order to determine how it differed from the older morphological taxonomy.

A curious thing happens if the problem is approached in this way. If the standpoint of the older morphological taxonomy is defined as “the study of the morphological diversity of living things” and the standpoint of evolutionary taxonomy is defined as “the investigation of how this diversity came about,” then the difference between the standpoints suggests that morphological taxonomy is static and evolutionary taxonomy is dynamic. In other words, morphological taxonomy becomes a study of results and evolutionary taxonomy becomes a study of processes.

If that was the case, said Gilmour, then taxonomists have good reason for keeping the resulting classifications distinct, as they serve such different purposes.

Gilmour provided the following analogy to help his audience appreciate the differences in kinds of standpoints and how that would result in a claim to keep them distinct:

Let us suppose that we wish to study the human bodies on the earth from the point of view of whether they are alive or dead. We should classify them quite simply into two groups: living bodies and corpses [similar to the morphological approach]. If, on the other hand, we wished to discover how the living bodies became dead, we should have to

150Gilmour “A taxonomic problem.” 101.

adopt quite a different classification, using such terms as murder, accident, disease, suicide, old age, etc. [similar to the evolutionary standpoint]151

In other words, there was no need to alter or toss out morphological terms like family, genus and species, etc., taxonomists just needed to recognize their applicability was limited by their original purpose. Gilmour cited botanist George Harrison Shull on the continued use of this kind of system: “[morphological classification systems] continue to represent the relatively crude, relatively superficial triangulation of the entire field of biology’, and, as such, will remain an indispensable branch of biological work. In other words, any attempt to redefine the morphological concepts in evolutionary parlance would be self-defeating.”152

3.2.7 Problems with evolutionary taxonomy

Gilmour ended his talk on a somewhat aggressive note, with a critique of the state of evolutionary taxonomy. He claimed that when arguing for the naturalness of evolutionary classifications, some taxonomists began with the claim that evolutionary taxonomy is concerned with the degree of relationship. However, Gilmour suggested earlier that what evolutionary taxonomists were actually concerned with were the methods of evolution. But why shouldn’t evolutionary taxonomists be concerned with the degree of relationship? What sparked Gilmour’s scepticism?

Gilmour justified his suspicion of the idea that “the expression ‘degree of relationship’ can be validly applied in connexion with the process of evolution”153 in his talk by claiming that phrase “degree of relationship” in biology had suffered the same fate that Gilmour thought

Singer believed the term “inheritance” in biology had. Singer claimed that because the term

“inheritance” was derived from the concept of legal inheritance in human affairs, and many of

151Gilmour “A taxonomic problem.” 101. 152Gilmour “A taxonomic problem.” 102. 153Gilmour “A taxonomic problem.” 101.

82 the legal associations of the word have been carried over to biology, the result was that biologists were now in a position where its “biological” meaning is obscured. The same vein, argued

Gilmour, the term “relationship” had been commonly applied to the products of the sexual reproductions of human individuals, which gave the term “quite a definite meaning.”

For example, claimed Gilmour, “relationship” qua genealogical relationships allowed people to make sense of claims such as: two brothers are more nearly related than two cousins.

However, this kind of claim can be made, said Gilmour, only because “the degree of relationship depended on the repetition of a uniform process, namely mating and birth.”154 Sadly, this was not the case when it came to evolution. In reflecting on the state of evolutionary biology,

Gilmour claimed that biologists are now learning that evolution is not a uniform process, but “an immensely complicated tangle of many different processes.”155 Gilmour provided the following example to help illustrate his point:

. . . take the case of a population of plants spreading in a certain direction. At one point part of the population may become isolated by a natural barrier and may develop into a distinct morphological type with a different genotypic constitution, while at another point altered conditions may induce a doubling of the chromosomes resulting in a second distinct morphological type. One cannot, I think, say that these derivative populations are equally related to the original population, nor that one is more nearly related to it than the other. They have certainly both been derived from the original population, but by quite different methods, and one cannot, I think, speak of degree of relationship in connexion with the process.156

This example helped illustrate that adopting an evolutionary perspective made it difficult to talk of plants being more nearly or more distantly related to each other on the assumed understanding of the term “relationship.”

154Gilmour “A taxonomic problem.” 101. 155Gilmour “A taxonomic problem.” 102. 156Gilmour “A taxonomic problem.” 102.

In light of this problem, concluded Gilmour, the course of evolution cannot be illustrated as a diagrammatic phylogenetic tree, as was the case for human and animal pedigrees.

Diagrammatic trees, according to Gilmour, would need to be replaced by a diagram that resembles a “network with meshes of different sizes and cords of different thicknesses.”157 Only a cursory glance at Lam’s paper on trees, mentioned Gilmour, would reveal how difficult this task was.158

In his Nature paper, as was the case of his talk, Gilmour raised concerns about the claim that evolutionary taxonomy was a natural system and traditional taxonomy was not, and natural systems differed fundamentally from artificial ones. Like his talk, his Nature paper targeted the notion of a phylogenetic relationship in evolutionary taxonomy as the problem. However, in his

Nature paper he presented two different concerns with phylogenetic relationships. He illustrated his first concern using the brother/cousin example he presented in his talk.

To justify the claim that two brothers were more nearly related than two cousins, the degree of remoteness of a common ancestor would need to be determined, and that would require access to the genealogy of every individual in any group under consideration. While this was at least sometimes possible in cases of humans and some domesticated animals and plants, was clearly not possible in most other cases. In the absence of the complete genealogical record of all the individuals in a group, Gilmour entertained the second concern, the possibility of accepting that “the degree of similarity of attributes as an invariable indication of degree of relationship.”159 Although morphological similarity was often indicative of such a relationship, it was not an invariable indication. He concluded that since neither option would work,

157Gilmour “A taxonomic problem.” 102. 158See H. J. Lam, “Phylogenetic Symbols, Past And Present (Being an Apology for Genealogical Trees)” Acta Biotheoretica, 2(1936): 153-194. 159Gilmour “A taxonomic problem.” 106.

84 taxonomists needed to give up on the idea that evolutionary taxonomy, at least for now, was a natural system that differed fundamentally from artificial ones.

3.3 Gilmour’s chapter in The new systematics

In many respects, Gilmour’s chapter in Huxley’s The new systematics was simply a restatement of the ideas he developed in his talk and in his Nature paper. However, this chapter had some important differences. Of the three works by Gilmour, this one doubtless reached the most people. Huxley’s The new systematics was remembered as one of the landmark publications in taxonomy’s methodological reform debates.

This piece also earned Gilmour the reputation of promoting logical positivism. It was true that Gilmour’s chapter in Huxley’s The new systematics contained a brief discussion of logical positivism, his summary of Herbert Dingle’s philosophical ideas in particular seemed to smack of positivism. Early in this piece, Gilmour claimed that recently scientific epistemology captured the attention of philosophers, especially a group of philosophers he referred to as “logical positivists” and proceeded to list names of people and periodicals where one could find the latest work.160 Perhaps it was not surprising that Gilmour mentioned logical positivism, given that the

International Congresses for the Unity of Science was held at Cambridge in 1938. Gilmour summarized the unity of science movement as seeking to “elaborate a common basis for the logical, empirical, and pragmatic aspects of scientific activity” and noted that “this movement for the unity of science” was project run almost entirely by philosophers, physicists, and mathematicians.161 The notable exception, claimed Gilmour, was a biologist named Joseph H.

160Periodicals such as The Philosophy of Science, Erkenntnis, and Analysis, included a critical summary of current views was published by Benjamin (1937), new International Encyclopaedia of Unified Science, part of volume i. also appeared (Neurath, O., 1938). 161John Gilmour “Taxonomy and Philosophy” in Julian Huxley The new systematics (Oxford: Clarendon Press, 1940): 462.

Woodger, and Gilmour drew attention to Woodger’s The axiomatic method in biology (1937) in which methods of logical analysis were applied to biological data.162 Gilmour stated that he saw a need for a “closer co-operation between philosophers and biologists in this very important task, and the present chapter is a preliminary and tentative attempt to bring the two viewpoints nearer together in the field of taxonomy.”163

On closer examination, this summary of positivism and Dingle’s work was the only allusion to logical positivism found in Gilmour’s work at this time, and at best it is only a hint of positivism. Gilmour was happy to concede that taxonomic knowledge came from valid inferences, but nowhere in this piece, or in the others discussed, did he promote a deductive scheme indicative of logical positivism. Nowhere in this or the early works discussed was

Gilmour found maintaining that evolutionary claims were justified formally, that is, derived according to logical rules, stated axioms, and premises. Gilmour did not claim that taxonomic statements obtained synthetically were “cognitively meaningful” if and only if they were empirically testable (i.e., verified or falsified) as many positivists maintained. Instead, he promoted an inductive approach more like that found in Mill and Jevons. Gilmour also did not support the reduction of taxonomy to any other science. Gilmour did not even reduce one classification system to another. Instead, he presented a view of the many classification systems available as lying along a continuum. Gilmour claimed that classification systems should be evaluated in terms of the degree to which they realized their intended purpose and other purposes. In Gilmour’s terms, system A is deemed more natural than system B, if A could realize its own and more purposes than B. Gilmour’s seemingly Carnapian assumption plucked from

Dingle’s paper that amounted to denying the brain any cognitive a priorisms can be better tied to

162Gilmour “Taxonomy and Philosophy” 463. 163Gilmour “Taxonomy and Philosophy” 463.

86 the methodological history of taxonomy that included Mill’s philosophy and the nominalism popular in the nineteenth century, than to Carnap’s positivist philosophy.

On first glance, it looked as though Gilmour decided to present an epistemological theory based on sense-data theories consistent with the recent logical positivists he cited. However, on closer inspection, it becomes clear that the epistemological argument Gilmour presented really was just the same one he presented before with some new (albeit awkwardly used or perhaps misused) philosophical vocabulary: classification systems are tied to a purpose:

Any given series of data can, of course, be clipped together in a number of different ways, depending on the purpose of the classifier, i.e. depending on which particular data he is interested in at the moment. Thus the range of data grouped under the class ‘man’ can be subdivided into nations, into professions, into age-groups, and so on. The important point to emphasize is that the construction of these classes is an activity of reason, and hence, provided they are based on experienced data, such classes can be manipulated at will to serve the purpose of the classifier.164

Gilmour’s empiricism was not new. Recall in the footnote in his Nature paper he cited Mill, a strong promoter of empiricism, and he drew attention to a specific set of pages in Stephen’s The

English utilitarians that explained Mill’s empiricism:

Thus Mill pushes his empiricism to assuming not only that our knowledge of properties must rest upon direct observation, but that there is absolutely no connection or ‘cause’ to be known. The ‘kind’ after all, which was meant to be an essential bond, turns out to be itself a purely arbitrary collection of attributes, and we have to ask whether it does not lose all the significance which he attached to it. The ‘collocation’ means that the attributes simply lie side by side, and yet are always conjoined. The tie which combines them is undiscoverable, and therefore for us non-existent. It is, as he rightly insists, important that our classification should correspond to natural kinds. ‘Kinds’ he says are classes ‘between which there is an impassable barrier’; the logical class is arbitrary, but the real class is an essential fact.”165

164Gilmour “Taxonomy and Philosophy” 465. 165Leslie Stephen, The English Utilitarians In Three Volumes, Vol. III; (London: Duckworth And Co. Henrietta Street, Covent Garden, 1900), 130.

Here Stephen summarized Mill’s ideas on “Kinds” and his empiricism, showing just how extreme Mill was willing to go, with respect to his empiricism. When set against the arguments of Gilmour’s talk and his Nature paper, Gilmour’s quotes from Dingle read less like a push for logical positivism and more like support for an earlier Mill-style claim that classifications were human constructs that served particular purposes, support for his argument for the role of inductive reasoning in taxonomy.

Given the context, perhaps this kind of philosophical confusion should be expected.

Gilmour was not a trained philosopher, but he attempted to learn enough quickly to help facilitate communication to serve a particular purpose, and was granted the authority within his community to provide this kind of philosophical analysis in an effort to mediate debates during taxonomy’s methodological reform. Missteps are bound to occur in such instances. However, it is important to be clear on where the confusion lies. Gilmour cited someone who identified with positivism, but Gilmour badly explained positivism in this case. Gilmour’s explanation of Mill, however, was just fine. Again, given the relationship between Mill and the history of taxonomy, coupled with Gilmour’s background, it is not surprising that Mill would be a comfortable philosophical and logical fit for someone like Gilmour. Logical positivism, in contrast, would not.

There were other differences between this piece and the early work discussed, in addition to the brief, somewhat confusing, foray into logical positivism. In this piece, Gilmour consciously situated his ideas in a broader biological arena—his ideas were not limited to botany anymore. This was clear by Gilmour’s opening remarks that taxonomists, not simply botanists, were concerned that their discipline was at a standstill.

To solve this problem, Gilmour raised a series of questions he believed taxonomists needed to address in order for taxonomy to progress. His four questions concerned taxonomic theory. Not surprisingly, the first question concerned the species concept: how should taxonomists come to a consensus about the definition of a species (or any taxonomic category) with so many definitions currently available? The second question was equally unsurprising in light of Gilmour’s work, and this related question regarding taxonomists’ perception of species had a philosophical ring: were species subjective or objective groups? Gilmour’s third question generated significant controversy: what was the significance of a natural classification and what was its relationship to phylogeny? Gilmour reminded his readers that he has addressed this question in his earlier paper, and noted Dutch botanist Herman J. Lam (1892-1977) had also taken up this question in his excellent paper on the history of taxonomic trees, as did geneticist

Dobzhansky in his powerful endorsement of phylogenetic thinking.166 Gilmour also remarked that this question was “exhaustively debated by the Taxonomic Principles Committee of the

Association for the Study of Systematics in relation to General Biology, and a certain amount of agreement had been reached.”167 In his reflections on this committee’s work, Gilmour highlighted the fact that biologists were divided on this question, and that this division fell along disciplinary lines.

Gilmour recalled that the zoologists agreed that a “natural classification” was one based on the phylogeny of the groups concerned. He cited Dendy as providing a concise statement of the zoologists’ position: “. . . if only our knowledge of classification and phylogeny were so

[complete]; we should then doubtless see at once that the taxonomic tree and the phylogenetic tree are, after all, one and the same thing, for we should arrange all organisms strictly in

166Gilmour “Taxonomy and Philosophy” 461. 167Gilmour “Taxonomy and Philosophy” 461. For a summary of the work done by this committee, see Winsor “The English debate.”

89 accordance with the course of their evolution.”168 Gilmour remembered the botanists as being more skeptical. At the root of their skepticism lay the claim that “a ‘logical’ classification (based on correlation or coherence of characters) is always and necessarily a phylogenetic one.”169 They did not think enough data was available to reconstruct phylogeny for all or even most organisms, and raised the case of flowering plants as one such organism lacking the relevant data. Lastly, they cast a skeptical eye on the term “phylogenetic relationship” claiming that on this point, things were not yet fully understood.

Gilmour’s fourth question, which he felt was related to the third question, was whether there was a final, ideal classification “towards which taxonomists are consciously or unconsciously striving.”170 Again, Gilmour’s observations from the committee led him to conclude that the division fell along disciplinary lines. The zoologists believed in one true classification system, reflected by the reconstruction of a phylogenetic tree. The skeptical botanists questioned whether such a thing was even attainable. Gilmour believed his last question was related to the first question, a question concerning what to do with the new kinds of data coming out of cytological, genetic, and ecological investigations.171 Should we modify our exiting taxonomic categories to accommodate this data, or should we create new categories specific to this new data?

As was the case in his work previously mentioned, Gilmour claimed that in addition to being rational and empirical, the activity of classification was pragmatic; it served a particular purpose defined by the classifier. As was the case with his work previously mentioned, Gilmour claimed that the more natural the system, the more inductive generalizations can be made, and it

168Gilmour “Taxonomy and Philosophy” 461. 169Gilmour “Taxonomy and Philosophy” 461. 170Gilmour “Taxonomy and Philosophy” 462. 171Gilmour “Taxonomy and Philosophy” 462.

90 was these inductive generalizations that comprised useful knowledge. He provided an example of grouping humans to make his point about induction: “[the classifier] constructs occupational and nationality classes among mankind, and by comparing the resulting groups he can make generalizations e.g. that at the present time there is a greater proportion of clergymen in England than in the U.S.S.R. These generalizations are then used as guides to human action.”172 Unlike the case in his previously mentioned work, Gilmour structured his discussion of natural and artificial systems around two common interpretations of natural and artificial systems.

First, claimed Gilmour, there were some taxonomists who made the following associations: natural systems were phylogenetic, making them real, and artificial systems were morphological, making them arbitrary and subjective. Gilmour claimed that biologists who made claims about the “biological reality” of their systems understood “biological reality” to mean such groups were defined by attributes that indicated that the group had reached “subspecific or specific differentiation, namely a distinct geographical distribution and a certain degree of sexual isolation.”173 What was significant about these attributes was their role in evolutionary processes. This connection to evolutionary theory of gave the group a “distinct biological character.” Gilmour called this “distinct biological character” “biological objectivity.” 174 The problem, as Gilmour saw it, was that these biologists falsely equated “biological objectivity” with what Gilmour called “metaphysical objectivity” or what we normally think of as “reality.”

Gilmour objected to this equivocation because it implied the difference between natural and artificial systems was a difference in kind rather than a difference in degree. By doing this, they were obscuring “the basic difference in number of correlated attributes.”175 This was

172Gilmour “Taxonomy and Philosophy” 465. 173Gilmour “Taxonomy and Philosophy” 467. 174Gilmour “Taxonomy and Philosophy” 467. 175Gilmour “Taxonomy and Philosophy” 467.

91 problematic, as Gilmour noted in his earlier papers. The virtue of a system with as many correlated attributes as possible, as Gilmour had emphasized in earlier papers, was that the more correlated attributes the taxonomist had, the more inductions she can make, thus the more natural the system. Drawing from the epistemological discussion earlier in his chapter, Gilmour added the further claim that: “[f]rom the philosophical point of view a natural group is, of course, no more real than an artificial one; both are concepts based on experienced data.”176

Second, claimed Gilmour, there were some taxonomists who believed the difference between natural and artificial groups boiled down to numbers. On this account, natural groups classed together organisms with more attributes in common than artificial groups, again, a

Millian insight. Gilmour modified this definition to help his readers appreciate the significance of having more attributes. As in his previous mentioned work, he claimed that:

. . . [a] natural group, being based on a large number of attributes, can be used for a wider range of inductive generalizations than can an artificial group, which is useful only in the particular sphere for which it was created. Thus many generalizations can be made regarding a natural family of plants. (e.g. with reference to distribution, chemical properties, wood structure, &c.), whereas regarding an artificial group very few of such generalizations are possible.177

At this point in the chapter, Gilmour believed that he had provided his reader with enough information to answer the question at the beginning of the paper regarding the definition a species and other taxonomic groups.

This brought Gilmour to a claim about hierarchies. If “natural” and “artificial” were defined in the way Gilmour suggested, then the difference between ranks of the Linnaean hierarchy could be understood as a difference in the degree of resemblance between the organisms comprising them. For example, organisms in a species resemble each other more

176Gilmour “Taxonomy and Philosophy” 467. 177Gilmour “Taxonomy and Philosophy” 466-7.

92 closely than organisms in a genus. The taxonomic ranks, on Gilmour’s account, can be defined in terms of degree of resemblance. Gilmour noted that his solution may have solved one problem, but it raised an even more difficult one. Can taxonomists come to any general agreement on these various degrees of resemblance?

Gilmour believed that if we could define accurately a unit character, then we could use the number as “a basis for the definition of degree of resemblance and difference.”178

Unfortunately, the concept of a unit character at this time was just as vague and problematic as the species concept, and so Gilmour was doubtful that taxonomists could ever come up with a precise definition of taxonomic categories based on resemblance. In light of the problem of defining resemblance, Gilmour provided what he deemed to be the only plausible definition of species: “. . . a group of individuals which, in the sum total of their attributes, resemble each other to a degree usually accepted as specific, the exact degree being ultimately determined by the more or less arbitrary judgment of taxonomists.”179 This species definition should ring familiar. In many respects it resembled the nineteenth-century definition—a species is what a competent taxonomist says it is—but it did have a new spin. There was an emphasis on resemblance and degree.

Gilmour ended his chapter in Huxley’s book on the same note as his previous papers, addressing the generally accepted claim that biological classification had been regarded as having some phylogenetic significance. Gilmour admitted that not even the most ardent phylogenetic taxonomist would claim that correlation of attributes was identical to phylogenetic relationship. What phylogenetically-minded taxonomists usually endorsed was some version of the more generally accepted claim that the correlation of attributes was merely indicative

178Gilmour “Taxonomy and Philosophy” 468. 179Gilmour “Taxonomy and Philosophy” 469.

93 phylogenetic relationships. The implication of this latter claim was that phylogenetic relationships must be based on some criterion other than correlation of attributes. When Gilmour examined how the term “phylogenetic relationship” was actually used in practice, he identified two different criteria.

First, there was the “phylogenetic taxonomist.” Gilmour described this kind of taxonomists as someone who, when working with living groups, usually expressed his phylogenetic judgments in the following way: “a group A is monophyletic if the groups composing it have originated from a single group’ (i.e. presumably a group of equivalent rank to

A, or lower rank), or two groups are more closely related phylogenetically than two others if the former possess a more recent group ancestor than the latter.”180 Gilmour called this concept of phylogeny the “group concept.” On the phylogenetic taxonomist’s account, because the phylogenetic relationship between groups was analogous to the genealogical relationship existing between individuals, phylogenetic tree construction was analogous to genealogical tree construction.

These taxonomists differed from the second kind of taxonomist Gilmour identified—the paleobiologist. According to Gilmour the paleobiologist worked with fossil material, rather than organisms, which recorded the actual evolutionary histories, allowing the paleobotanist to be concerned with actual genealogical relationships between the individuals. Consequently, the paleobiologist expressed her phylogenetic judgments in terms of lineages. On this account, the

“true affinity” that existed between members of the same lineage was not a result of a correlation of attributes, but evidence of an actual genealogical relationship of the organisms composing the groups. So, which of the two taxonomists provided a better criterion?

180Gilmour “Taxonomy and Philosophy” 469.

Problems with the group concept were not new. Gilmour cited Bather’s 1927 address as identifying one of the biggest problems with the “group concept” approach, namely that the group concept approach involved petitio principii or circular reasoning.181 Bather provided the case of justifying an evolutionary classification of the genus Balanocrinus as evidence of this kind of fallacy in taxonomy. This genus, Bather claimed, was derived by a number of different lineages from the genus Isocrinus. On the group concept approach, if Isocrinus is a single genus,

Balanocrinus was monophyletic because it was derived from a single group of equivalent rank.

But, if the various species of Isocrinus that formed the starting points of the lineages were raised to generic rank, then Balanocrinus would become polyphyletic, having been derived from a number of different groups of equivalent rank. Which view was taken depended on a taxonomic judgment, a judgment that Bather and Gilmour claim boiled down to an assessment of the correlation of attributes. In other words, phylogenetic relationships were defined in terms of a correlation of parts.

The lineage concept did not suffer the same fate as the group concept. Because the lineage concept rested on the genealogy of organisms, making its criterion independent of taxonomic judgment, it avoided the petitio principii. Gilmour’s familiar brothers and cousins example helped make this clear. On the “lineage concept” account, the relationship between two cousins remained the same whatever their attributes may be. However, the lineage concept approach was not without serious problems, one of which Gilmour raised in his talk.

The problem started when biologists moved from the assumption that the phylogenetic relationship was analogous to the genealogical relationship, to the claim that phylogenetic tree construction was analogous to genealogical tree construction. According to Gilmour, in order to

181 Francis Arthur Bather “Biological Classification, Past and Future: An Address to the Geological Society of London at Its Anniversary Meeting on the Eighteenth of February 1927” Geological Society of London (1927): 63.

95 measure the degree of relatedness, you need to have a repeating uniform process. This was had in the case of genealogical relationships, namely the processes of mating and birth. Because these processes were uniform and repeating, taxonomists were able to construct genealogical trees that allowed them to determine the degree of relatedness between three or more individuals by measuring the degree of remoteness of a common ancestor. The cousins and brothers example was a case in point. As Gilmour mentioned before, the problem with evolution was that it did not have repeating uniform processes that applied to all the organisms in question, making it difficult to measure relatedness by measuring the degree of remoteness of a common ancestor, thus making difficult to construct a simple two dimensional phylogenetic tree. In his talk, Gilmour cited geographical barriers and altered conditions as evolutionary processes that could prompt speciation, and expanded on this list in his Huxley paper by discussing polyphyly and convergence as further complications. So, the repeating, uniform processes that defined the relationship that taxonomists took as holding between individuals in a genealogical tree were not analogous to the many possible processes that could hold between groups within an evolutionary framework. In other words, it was virtually impossible to make a diagram that reflected the true evolutionary situation.

What evolutionary taxonomists had, as Lam’s paper (which Gilmour cited in the Huxley chapter, as well as in his earlier works) beautifully showed, were many different kinds of diagrams that represent each author’s particular standpoint. Gilmour was careful to remind his readers that the consequences of his objection to the lineage concept approach did not render such approaches useless. Quite the contrary. They were useful insofar as they provided information based on the perspective of the taxonomist. What this did mean, however, was that the morphologist’s classification remained more natural than many of these evolutionary classifications.

3.4 Conclusion

Over the course of three works, Gilmour developed an account of natural and artificial systems that he fixed not only to the histories of botany and taxonomy, but also to inductive logic. Reflecting on taxonomic works printed during the first few decades after the publication of the Origin, Gilmour repeated Bather’s observation: “The acceptance of the doctrine of evolution in the middle of last century at first had very little effect on biological taxonomy. The only notable change was that morphological resemblance, which formed the basis of the “natural” systems then in use, came to be regarded as evidence of actual phylogenetic relationship rather than as the result of the plan of a Creator.”182 Shortly after the publication of the Origin,

“natural” was still defined in a more nominal, pragmatic way. However, as the theory of evolution by natural selection took root in the quantitative minds and agendas of biologists, a new generation of biologists was looking for a classification system that reflected their realist, ontological position.

Gilmour believed that experimental biology’s increased popularity incited a shift in what biologists thought the purpose and design of classification systems should be, and Gilmour identified this shift in thinking as a source of many of the problems in botany. This shift in thinking had to do with the idea of “natural” as “real”—”natural” classification systems were those that reflected the way things really were, and in that sense, they had to be evolutionary.

And he also noted that this was a relatively recent shift.

I argued that during the late 1930s, Gilmour explained how competing methodological practices in botany led to philosophical questions about what is the “best” classification system.

182John S. L. Gilmour “Whither taxonomy? Text of a paper given by J. S. L. Gilmour to Section K (Botany) of the British Association for the Advancement of Science at its meeting in Blackpool, 1936.” In “Appendix 2 Two early papers on classification by J. S. L. Gilmour, Foreword by S. M. Walters” Plant Systematics and Evolution 167 (1989): 100.

He believed that these philosophical questions opened the door to a rigorous discussion and redefinition of the concept “natural” as it occurred in discussions of natural and artificial systems. On the question of whether a gap should exist between what taxonomists believed regarding the shape of nature and how they constructed their classification systems, Gilmour’s response was not to bridge the gap, but to explain why the gap was necessary. On the question of species concepts, he drew from logic and philosophy to extend the nominalism prevalent in the nineteenth century with species naming to the debate involving species concepts in which he was embroiled. He also proposed a pluralist account of classification systems, explaining that classification systems were human constructs lying along a continuum. Rather than measuring a classification system’s virtue against an ontological yardstick, Gilmour recommended that a classification system’s virtue be judged on its ability to serve its intended purpose, and its ability to serve other purposes as well. Gilmour’s philosophy of classification was reminiscent of nineteenth-century philosopher John S. Mill’s work on inductive logic, which called for a renewed tolerance for the acceptance of many different kinds of classification systems. I argued that these are central themes in the work from Gilmour I have selected from this period, not the aspects of logical positivism, which others have tried to maintain.

While Gilmour did not reject the idea of an “evolutionary taxonomy,” he did object to the recent attempts to construct an evolutionary taxonomy because he believed they were examples of poor arguments. In the case of phylogenetic classification systems, he argued that the reasoning involved when constructing this type of system was circular, casting a skeptical light on any and all inferences drawn from it. Gilmour felt there was ample room for improvement on this front.

What is significant here is Gilmour’s strategy. Gilmour was not a trained logician or philosopher, but a self-proclaimed bibliophile. Perhaps in a different time and place, Gilmour’s philosophical and logical background might have been a hindrance, but in this period of interdisciplinary work, expectations were relaxed in an effort to encourage communication. As seen from McOuat’s work on late nineteenth-century natural British natural history, Gilmour did read the relevant philosophy and logic that not only explained the taxonomy of the past, but allowed him to fashion a potentially helpful philosophical position for taxonomy’s methodological reform. Sokal and Sneath appealed to his philosophical position when they outlined their numerical taxonomy. Even Simpson was willing to concede to some of Gilmour’s philosophical position in Principles of animal taxonomy (1961).183 Gilmour was able to effectively translate the philosophical and logical position held by the traditional taxonomists that were coming under attack, and explain how their position was being misunderstood.

183George Gaylord Simpson, Principles of animal taxonomy 25-28.

Chapter 4 Simpson 4.1 Introduction

Like Gilmour, during the 1930s, American paleontologist George Gaylord Simpson believed that some of the methodological problems taxonomists faced were not rooted in ontology, but logic and flawed arguments. That is to say, Simpson did not think taxonomists held misguided ontological claims, but their arguments did suffer from serious logical and epistemological problems. Over the course of a long and tremendously influential career,

Simpson helped develop solutions to those problems. Both Gilmour and Simpson recognized that there was a gap between how taxonomists viewed nature and what they could realistically build into their methodology. Like Gilmour, Simpson was concerned with the types of arguments presented in evolutionary classifications. However, Simpson presented a very different kind of solution. But there was more to Simpson’s reform agenda.

Around the time Gilmour presented a new philosophy of classification that he hoped would defuse the raucous methodological debate in botany, Simpson fashioned a new methodology, one that took the usual taxonomic evidence collected, and pumped it through a new statistical machine that should enable taxonomists to make better inferences that would help answer evolutionary questions. Simpson’s methodological approach had extensive impact. From a paleontological perspective, the flaws in traditional taxonomic methods were exposed early in

Simpson’s career when he tried to use traditional taxonomic methods to make inferences to support evolutionary claims. As a paleontologist, Simpson faced different challenges than his zoological and botanical counterparts, but like them, he found traditional methods would not permit the inferences necessary to make justifiable evolutionary claims. Part of his response to

100 this problem involved proposing a quantitative, statistical methodological approach. Although it focused on morphological attributes, it took populations, rather than individuals, as the basic methodological units. In this sense, he called his approach an “evolutionary approach.” His notion of a population was informed by a new branch of statistics tailored to biological work. By focusing on populations, this approach, argued Simpson, not only better captured Darwinian intuitions, but avoided the fallacious reasoning common to earlier, traditional evolutionary approaches. One of the logical features of his statistical method about which he was pleased was its inductive approach, moving from particulars to generals.

Simpson too attempted to bridge what seemed to be an impossible gap between the quantitative methodological sciences and the qualitative methodological sciences by successfully communicating a new kind of mathematics and logic to taxonomists. As Simpson became more involved in interdisciplinary endeavors, his work on the relationship between logic and taxonomy necessarily took a more explicit turn. Like it or not, as someone who assumed a central role in these interdisciplinary groups, he was asked to weigh in on questions coming out of debates in journals like Evolution and later Systematic zoology. When researching the methods for Quantitative Zoology, Simpson read the relevant literature on statistics, including R. A.

Fisher’s Statistical Methods for Research Workers. He incorporated the mathematics into his own work before embarking on Quantitative Zoology. Quantitative Zoology was an interdisciplinary work, co-authored with his wife Anne Roe, a psychologist. Roe had been using these mathematical techniques in her own research for years.

As historian Joel Hagen showed in “The Statistical Frame of Mind in Systematic Biology from Quantitative Zoology to Biometry,” even their revised second edition was an interdisciplinary work, as Simpson and Roe brought Richard Lewontin on as a junior author,

101 whose specialization was Drosophila population genetics. Quantitative Zoology remained a work with a taxonomic bias. Hagen wrote that even though Lewontin was responsible for all the revisions, Simpson still held the reins. Simpson believed it was prudent to exercise caution when navigating interdisciplinary waters. For example, Lewontin pushed to include some examples from his own research and Simpson refused stating: “The reason is that drosophilists are almost always comparatively sophisticated in statistics, that other zoologists know this, and that it frightens (or even annoys) them to run across a treatment of Drosophila as an example for them to follow.”184 Hagen also claimed that Simpson and Lewontin also disagreed on the reception of statistics in different biological disciplines, and Simpson believed this difference needed to be reflected in the book: “Simpson claimed that the success of the revised edition of recognizing the statistical naiveté of systematists who were ‘quite literally terrified’ by standard statistics textbooks. Experimentalists, he believed, would not be interested in the type of elementary presentation that had made the original Quantitative Zoology appealing to many systematists.

Simpson’s general viewpoint, which was not shared by Lewontin, largely prevailed as is clearly evident in the opening sentence of the Preface of the revised edition: “Zoology, for our purposes, is a systematic branch of biology, distinct from the primarily experimental branches.”185

This chapter looks at Simpson’s early work on the relationship between logic and taxonomy, before he participated in the debates on species and sets. Laporte discussed the evolution of Simpson’s thought in stages, with no clear lines of demarcation: types, statistics, and ecology.186 The first step in the evolution of Simpson’s solution to the methodological

184Joel Hagen “The Statistical Frame of Mind in Systematic Biology from Quantitative Zoology to Biometry” Journal of the History of Biology 36(2003): 364. 185Hagen “Statistical frame” 364. 186See Léo F. Laporte. George Gaylord Simpson : paleontologist and evolutionist. (New York: Columbia University Press, 2000) as well as in “Simpson on Species” Journal of the History of Biology, Vol. 27, No. 1 (Spring, 1994), pp. 141-159. My discussion will depart from Laporte’s in a number of ways, specifically in my focus on the relationship between logic and taxonomy.

102 problem took root in the mid-1920s, during the first stage in the evolution of Simpson’s thought.

During this stage, Simpson shared many of Gilmour’s concerns when it came to the relationship between logic and taxonomy, specifically concerns about inference and argument. Simpson began raising questions concerning evidence gathering and argument presentation, specifically his attempt to challenge the kinds of arguments found in evolutionary debates. Simpson was skeptical of arguments that relied on a priori claims, as well as metaphysical speculation. Also, because he was operating within a qualitative methodology of types, he raised a critical eye and tentatively laid the groundwork for a more quantitative approach, with his inclusion of more measurements, charts, and descriptive statistics.

The second step of the evolution of Simpson’s solution to the methodological problem began in the mid-1930s, during the second stage in the evolution of Simpson’s thought. During this step, Simpson focused on a new type of statistics, a new concept of populations and a new interest in inferences. During this step, Simpson took a more interdisciplinary approach. Simpson developed a new quantitative methodology that relied on statistics pioneered by biologist R. A.

Fisher (1890-1962) in Statistical methods for research workers (1925). Simpson read Fisher and other mathematical and statistical work. He also worked with his wife, psychologist Ann Roe.

Simpson believed this new methodology that relied on a new kind of statistics was better suited for an evolutionary taxonomy not only because it focused on populations and not individuals, but because it helped make better inferences from particulars to generals. The quantitative shift drew attention to the relationship between logic and taxonomy, broadening the scope to include issues in logic, but not deductive logic or set theory. Questions about individuals and populations in this new taxonomic methodology led Simpson to more philosophical questions about the logical composition of groups, as well as the ontological status of taxonomic groups. The quantitative

103 shift also invited old methodological concerns that came with interdisciplinary endeavors, including questions concerning the confidence one should place on formal tools in taxonomy.

4.2 First stage—Types: 1920s-mid 1930s

Before Simpson and Gilmour were writing in the 1930s, it seemed everyone had an idea what constituted a species. It also seemed that everyone had an opinion how taxonomy should be done. The popular opinion was that that species should be redefined along evolutionary lines, and, as discussed earlier, this demanded a methodological reform. Many of the methodological suggestions from the new disciplines had a quantitative spin that firmly fixed species definitions in the lab or the field, not in the museum or the garden. The kind of methodological suggestions leveled at taxonomists from genetics and ecology were difficult for many botanists and zoologists to put into practice, but they proved even more difficult, and in many cases impossible, for palaeontologists.

Simpson began his career as a Mesozoic mammalogist. Like most paleontologists, he often worked with only bits and pieces of specimens. Fractured jaws, broken teeth, crushed skulls, and worn limb bones lined the paleontologist’s shelves. As a Mesozoic mammalogist,

Simpson dealt primarily in teeth. When compared to neozoologists and botanists, the collections with which Simpson worked were small, and his organisms were extinct. In the absence of large numbers of organisms with which to set up an experimental garden or laboratory, many of the new species concepts proved inapplicable in a paleontological setting. Methodologically speaking, not only did paleontologists continue to use an approach that relied on types, they also did not seem to enter into the methodological debates. Their absence in these debates, sadly, often earned them an unfortunate reputation in the biological community.

104

In his reflections on the role of paleontology in the first half of the twentieth century,

Ernst Mayr described the paleontologists of the 1920s as “regrettably unaware” of recent advances in biology: “[N]o other group of evolutionists was as divided as the paleontologists.

Almost unanimously they rejected natural selection, and as a group, they were regrettably unaware of the advances that had been made by geneticists.”187 Writing on the history of paleontology, geologist Léo F. Laporte supported Mayr’s assessment of these paleontologists as having a reputation of being isolated from the progress and debate in the new biology as a result of their methodological choices during this period:

Paleontology at the beginning of the twentieth century in the United States was something of an orphan within the biological sciences. Because of its emphasis on the older tradition of comparative morphology and the use of fossils by geologists in determining relative ages of rocks, paleontology had neither a home in the new institutional centres established for biology, nor was it considered a formal discipline within biology. Worse yet, it did not demonstrate “much likelihood of becoming a foundation for serious programs of research in biology.”188

“Bones in stone” claimed Laporte “were a world apart from fruit flies in bottles.”189 It is true that disciplines, such as genetics, were seen as piloting the new research programme in biology, but how accurate were these assessments of paleontologists?

Simpson’s early and later paleontological writing revealed his mentors adhering to the methodological tradition of types, but it also revealed explicit attempts to build evolutionary ideas into paleontological research. Like Gilmour, Simpson was found casting skeptical glances at the reasoning and argumentation employed in evolutionary discussions. Unlike Gilmour, he was more optimistic regarding an evolutionary taxonomy. Methodologically speaking, Simpson was certain there was a better way to proceed, but he proceeded slowly and with caution.

187Mayr “Forward” 7. 188Léo F. Laporte. George Gaylord Simpson : paleontologist and evolutionist. (New York: Columbia University Press, 2000) 17. 189Laporte George Gaylord Simpson 18.

105

4.2.1 Mentors, evolution, and philosophy

Many believed bones in stone were worlds apart from fruit flies in bottles, but Simpson maintained evolution was never far from many paleontologists’ minds in the 1920s. Contrary to

Mayr’s assessment of paleontologists’ beliefs during the 1920s, Simpson cited his graduate advisor paleontologist Richard Swann Lull (1867-1957) as one who believed in the reality and importance of natural selection.190 Simpson characterized Lull as one of a growing number of cutting-edge paleontologists who built evolutionary theory into their work. Simpson, reflecting on his own education, claimed that:

Lull was considered a great authority on evolutionary theory—and he was, in the sense of being well informed on the ideas, old and new, in this field. He never had an original idea of his own about theories of evolution, but just expounded everyone’s views as if all were equal. That was very useful to me only in telling me what the established alternatives were and what to read.191

Simpson completed his PhD at Yale, under the supervision of Lull. When he arrived, he discovered the Mesozoic mammal collection in the basement of the Peabody Museum and campaigned to work on the collection for his doctoral work. Initially he was rejected, so he worked on impressing Lull for a second chance at the collection.192 At the end of his first year of graduate work, Simpson applied and obtained a position as a field assistant to William Diller

Matthew (1871-1930), who was collecting Tertiary mammals in Texas and New Mexico.193

Matthew was chairman of the department of paleontology at the American Museum of Natural

History and one of the leading paleomammalogists. Matthew, it turned out, would be Simpson’s ticket to the Peabody basement.

190George Gaylord Simpson Tempo and mode in evolution. (New York Columbia University Press 1944) xv-xvi 191Simpson Tempo and mode 20. 192For a comprehensive biography, see Laporte George Gaylord Simpson. 193Léo F. Laporte. “Rock stars: George Gaylord Simpson (1902-1984)” GSA Today (September 2004), 16.

106

In spite initial misgivings and clumsiness, Laporte noted that by summer’s end, Simpson had made a favourable impression on Matthew. Lull was impressed by Simpson’s discoveries and work, and Simpson was given the green light to study the Mesozoic mammals in the basement of the Peabody.194 Simpson’s work with Matthew on this trip not only secured him the

Mesozoic mammals in the Peabody collection; it also provided an opportunity to publish papers that year on Mesozoic mammals, notably the series of papers Mesozoic mammalia: American

Triconodonts. These papers helped establish Simpson’s scholarly reputation and served as the basis of his doctoral work.195

Lull was not the only evolutionary thinker in Simpson’s intellectual upbringing. Simpson recalled Henry Fairfield Osborn (1857-1935) as another paleontologist who actively pursued an evolutionary agenda. Simpson credited Osborn as encouraging him to consider the theoretical and philosophical aspects of evolutionary theory when Simpson joined the American Museum of

Natural History staff in the late 1920s. Simpson was, of course, keenly aware of Osborn’s failed attempts at a kind of early evolutionary synthesis.196

Simpson described Osborn’s theoretical work in evolution as testimony to what appeared to be, at the time, a virtually unbridgeable divide. On one side were the “realist paleontologists,” who Simpson believed lacked Osborn’s knowledge of biological philosophy and failed to understand (or perhaps did not trust) his idealist tendencies. On the other, claimed Simpson, were the early geneticists who believed that evolutionary investigations began and ended with experimental biology, and dismissed paleontology as a purely descriptive science that had “no

194Laporte “Rock stars” 17. 195 While the best known pieces of Simpson’s work during this period centred on Mesozoic mammal research, Simpson’s work wasn’t simply restricted to mammals. For example, in 1926, he reinterpreted the anapsid fish, “Lasanius,” from the Silurian Dowtownian of Scotland, arguing that previous reconstructions mistakenly inverted the fish. See “New construction of Lasanius.” Geological Society of America Bulletin 37(1926): 397-402. 196Simpson Tempo and mode xv-xvi.

107 further fundamental contribution to make.”197 Nevertheless, Simpson described Osborn as a tireless, public champion of his cause. Simpson recalled, for example, Osborn making no secret of the fact that he was always on the hunt for a bright, young radical thinker. Simpson recalled that in his address at the opening of a new building for the Peabody Museum at Yale University in December 1925, Osborn declared: “Perhaps within the very walls of the Peabody Museum, where adaptation is set forth so transparently by the master hand of Lull, some young Aristotle or

Darwin may find his inspiration to grasp the problem of the origin of species which has baffled man for two thousand five hundred and eight-five years.”198 Although Simpson never fancied himself the next Darwin (or Aristotle for that matter), when he took up his position at the

American Museum of Natural History, he approached his concerns and doubts on paleontological matters not unlike Darwin—quietly harboring any controversial revolutionary theoretical ideas, while patiently collecting evidence and establishing himself professionally.

Simpson confessed in his early years he was “inclined toward Neo-Darwinism to the extent of considering natural selection as the principal but not necessarily the only non-random or directive element in evolution.”199 He also confessed it was not out of a lack of interest in such issues that he was quiet: “I was intensely interested in evolutionary theory, but for about my first ten years I did not think I knew enough to judge extant theories well or perhaps even to add something to them.”200

This was not a self-deprecating remark. It characterized well how Simpson approached his work during the predissertation and postdoctoral writing period. A quick survey of his career during the 1920s and early 1930s had Simpson in his graduate work, his post-doctoral work, and

197“Henry Fairfield Osborn.” Dictionary of American Biography. (New York: Charles Scribner’s Sons, 1944). Gale Biography in Context. 198Simpson Tempo and mode xv. 199Simpson Tempo and mode xvii. 200Simpson Tempo and mode xvii.

108 during the first years of his job at the American Museum of Natural History touring all the usual places where Mesozoic mammals could be found. During these years, he did everything one would expect from a brilliant, blossoming young paleontologist. He dug for specimens, took careful measurements, compared specimens to type specimens, and wrote up his results in much the same way other paleontologists presented their results. The bulk of Simpson’s work was in alpha taxonomy and he soldiered on in the traditional way, working within the confines of a traditional qualitative orientation towards field work and collection, and within the methodological boundaries set by his mentors Lull, Matthew, and later Osborn. Simpson’s work, like much of the paleontological work during this period, appeared largely unfettered by grand controversial philosophical and logical ideas about classification and method. When the opportunity presented itself, Simpson wrote with enthusiasm not only in the history of his discipline, but in the history of the problems on which he was working. Simpson inherited not only the traditional tools of his trade from his teachers, but a rich history of his discipline. During the first decade of his career, when he challenged his predecessors, he did so on their terms, using their tools.

4.2.2 “A Mesozoic Mammal Skull from Mongolia” (1924)

Before examining the series of papers Mesozoic mammalia: American Triconodonts, consider a publication from 1924 as an example of Simpson at his most traditional, methodologically speaking. In the “A Mesozoic mammal skull from Mongolia” Simpson expressed his gratitude to Osborn and Matthew for the “extraordinary opportunity” to name and describe this Mesozoic mammal. Simpson remarked that the specimen was found in the

Djadochta formation at Shabarakh Usu in Mongolia was only the second Mesozoic mammalian skull found at the time, and had attached lower jaw. This specimen, continued Simpson,

109 belonged to the order Multituberculata (an order Simpson would later publish on extensively), and he named the new genus and species Djadochtatherium matthewi. From a methodological standpoint, some noteworthy features of this paper included: very few numbers and measurements, comparatively many photos and illustrations, and descriptive vocabulary and comparisons to existing type specimens. On the whole, this paper adopted exactly what one would expect from a traditional qualitative approach. This paper also made little or no evolutionary claims, it stuck mainly to pure alpha taxonomic investigations.

4.2.3 “Mesozoic Mammalia” (1925-1926)

Simpson employed the same method of types in the series of papers he published on four orders of Mesozoic mammals: Triconodonta, Pantotheria (a now abandoned order), a new order he called “Symmetrodonta,” and Multituberculata This series of papers not only better illustrated the type methodology Simpson used early in his career, but gave a clearer window into the kind of inferences made by paleontologists to determine taxonomic groups. This series of papers displayed how Simpson cautiously weighed in on evolutionary debates, for example when proposing the new order “Symmetrodonta,” and also his concerns about the kind of inferences made by paleontologists when drawing evolutionary conclusions.

Simpson began the first paper in this series with a bit of history. According to Simpson, paleontologist Othniel Charles Marsh (1831-1899) set out for Wyoming to hunt for dinosaurs, but instead unearthed remarkable upper Jurassic mammalian fauna. Marsh described these in a series of publications.201 The collection was divided between the National Museum and Yale.

Many of the types were prepared for the National Museum’s collection, but in the basement of the Peabody Museum at Yale was a small but impressive collection of primitive mammals

201Marsh 1878, 1879.A, 1879.B, 1879.C, 1880. 1881 and 1887.

110 encased in Mesozoic aged rocks waiting to be processed. The Peabody collection, still mostly inaccessible to the greater paleontological community, would form Simpson’s doctoral dissertation.202

In many respects, the Peabody Collection was a perfect group for a talented young paleontologist to cut his taxonomic teeth. There were types waiting to be prepared and illustrated, and now technology existed to re-describe type specimens not available at the time collection was established. Simpson opened this series of papers with remarks to that effect:

Furthermore a reconnaissance of both the Yale and National Museum collections, which include all of Marsh’s types, reveals the fact that many types were never figured, some were insufficiently prepared for study, and a great deal of material in the Yale collection had never been so exposed from the matrix as to be available for comparison and description. The National Museum collection had been very thoroughly and skillfully prepared by Mr. Gidley, but no systematic description of the new material has been published. In view of these facts it is hoped that the careful redescription of Marsh’s types, after thorough preparation and with the use of better optical aids than were available at the time of original description, as well as the publication of the very considerable amount of new material in the collections may help to clarify our knowledge of the tiny creatures whose remains “still retain some of the ambiguous meaning which was signalized in the name Amphitherium” and to add to the “few positive facts which they have yielded [and which] when viewed against the general background of paleontological knowledge, appear as important landmarks in mammalian history.”203

Unlike the 1924 paper, this series of papers involved more than merely naming, there was an evolutionary component. The series consisted of four papers. The first three looked at

Triconodonta, Pantotheria, and Symmetrodonta, while the last examined the Multituberculata.

The first two papers were detailed taxonomic descriptions, the first examining lower jaws, and the second examining the upper jaws. The third paper was a more general discussion of

Triconodonta, Pantotheria, and Symmetrodonta with broader evolutionary conclusions. The fourth paper was a bit curious. Laporte claimed the fourth paper differed from Simpson’s other

202Laporte “Rock stars” 16. 203George G. Simpson, “Mesozoic mammalia I. American triconodonts.” American Journal of Science, 210 (1925):147-8.

111 predissertation and postdoctoral writing because it was one of only two predissertation articles on Mesozoic mammals in which Simpson explicitly considered “fossils as once-living.”204

Rather than a pure taxonomic investigation, this paper examined the history of a debate, whether the multituberculates were herbivores or omnivores. Laporte remarked that Simpson referred to this article as “a study in paleobiology, an attempt to consider a very ancient and long extinct group of animals not as bits of broken bone but as flesh and blood living beings.” 205More importantly, this paper was an early example of Simpson’s critique of reasoning in paleontology.

Simpson saw this series of papers as a basis for an “an extended treatment of the broader taxonomic relationships” of these early mammals for our knowledge of phylogeny and morphology, as well as “their place in nature and how they filled it.”206

4.2.3.1 “Mesozoic Mammalia I”

This series painted a clear picture of the kind of methodology Simpson and other paleontologists used—the methodology Simpson would soon reform. Similar to the “A Mesozoic

Mammal Skull from Mongolia,” Simpson used type concepts and comparisons, illustrating the qualitative nature of the descriptions he provided. In this series, he provided more detail with respect to type concepts. For example, in the first paper, Simpson provided a comprehensive description of the type specimens he used in his taxonomic analysis. Note the qualitative vocabulary in the following example—lots of descriptive words and comparatively few measurements:

The triconodont lower premolar consists essentially of a single high compressed trenchant cone. This is supported by two stout, slightly divergent fangs. The proportions vary considerably. It may be low and long antero-posteriorly, or high and piercing. The anterior edge is sharp, simple, distinctly convex as seen from the side. The posterior is

204Laporte Simpson 21. 205Laporte Simpson 21. 206Simpson “Mesozoic Mammalia I,”148.

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less convex or straight. On the posterior slope and generally about half way up it, is borne a small accessory cusp. There are usually small, sharp, anterior and posterior cingulum cusps, hut they may be reduced or lacking. There is no external cingulum, and this surface is convex in all directions, slightly swollen around the base and contracting a little on passing into the roots.207

After the descriptions of the type specimen, Simpson described and compared the type specimens to the specimens in the Peabody Collection. Consider the following three examples that illustrate how Simpson arrived at his taxonomic conclusions. In the first two comparisons,

Simpson was confident that the specimen in the collection was the same as the type, and the last one Simpson was undecided:

Cat. No. 10345 Y. P. M.

This may be referred to this species with some confidence. It adds to the type [my italics] assurance of the possession of four premolars and a knowledge of the crown of P 4 which is a typical triconodont premolar with a small cingulum cusp anteriorly, and a tiny cingulum shelf posteriorly. The main cusp is high and trenchant. There are two small mental foramina beneath PI and P 2 respectively.208

Cat. No. 13636 Y. P. M.

This specimen is a trifle smaller than the type [my italics]. but has the same characters and proportions. The canine is large and directed well forward. There is no appreciable diastema. The symphysis is much as in Priacodon (see below), and at a distinct angle to the lower border, as was anticipated.209

Triconodon spp. indet.

Cat. No. 13632 Y. P. M.

In external view this jaw checks exactly with the type [my italics] of T. bisulcus. The anterior angle of the masseteric fossa is Similar in position and depth. The parts of the teeth preserved are the same in size and shape. Internally the teeth again are quite similar to those of T. bisulcus save that on 11;) the cingulum instead of sinking a little on the midcone rises a little, and is also a little less sharp. The faint rounded ridge anterior to the dental foramen is apparently lacking. The most remarkable feature, however, is that the internal groove is not on the lingual surface of the mandible but is apparently represented by a double shallow groove on the inner half of the lower border. It will be remembered that the lower groove of the type of T.

207Simpson “Mesozoic Mammalia I.” 149. 208Simpson “Mesozoic Mammalia I.”158. 209Simpson “Mesozoic Mammalia I.” 158.

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bisulcus is very low. A shift of less than a millimeter would bring it into the position of the groove on this specimen. This probably represents a new species closely allied to bisulcus but the material is insufficient for its definition.210

In some cases, Simpson was able to identify a specimen with confidence, and in other case he found he did not have enough evidence to make a definitive case. Methodologically speaking,

Simpson was toeing the party line.

4.2.3.2 “Mesozoic Mammalia II”

The second paper had a bit more of a quantitative ring than the first, as Simpson included charts with measurements on pages 336, 337, 351, and 352, but Simpson soldiered on, working well within the tradition of the type concepts. In the second paper, Simpson marched into the debate concerning the number of genera of “true triconodonts.” True triconodonts were identified by having three cusps arranged in a straight fore-and-aft line.211 Based on the Purbeck specimens, Owen claimed there were two genera: the triconodon and the triacanthodon.212

Marsh claimed there were three: triconodon, the triacanthodon, and the priacodon213. Osborn objected to Marsh’s claim, and supported Owen’s original two genera. Simpson provided evidence for Marsh’s claim, as well as evidence for his own claim for the existence of two more genera: phascolodon and aploconodon. A few features of Simpson’s argument stand out.

Simpson provided his evidence primarily in the form of charts that compared taxonomically relevant dental characters.214 Although still part of a qualitative tradition, his leaning towards a more quantitative approach was evidenced in this series. He wrote in the fourth installment of the series: “In the face of these several different opinions, all vehemently supported by very careful

210Simpson “Mesozoic Mammalia I.” 158. 211George G. Simpson, “Mesozoic mammalia II. American triconodonts.” American Journal of Science 210 (1925): 354. 212Simpson “Mesozoic Mammalia II.” 354. 213Simpson “Mesozoic Mammalia II.” 354. 214Simpson “Mesozoic Mammalia II.” 355, 356.

114 arguments, it is necessary to discard a priori theories and to consider the observable facts objectively and, when possible, quantitatively.”215 Simpson’s further line of objection to

Osborn’s arguments involved questioning Osborn’s evidence. He drew attention to the difficulties presented by the English specimens on which Osborn based his objections. He claimed that a reanalysis of those specimens would be required if Marsh’s claim were to be overturned.216

4.2.3.3 “Mesozoic Mammalia III”

When Simpson took stock of his specimens, he discovered that not all of them fit comfortably into the existing orders Triconodonta and Pantotheria, so he proposed a new order,

Symmetrodonta. This paper affords a taste of the sort of typical quantitative analysis found in an overall qualitative approach. This kind of quantitative approach Simpson would soon find lacking. Simpson came to his conclusion by tabulating eighteen key characters of the three orders, and weighed these characters with respect to their value in indicating affinities. Here we get a sense of what kind of argument he presented for his evolutionary conclusions.

Simpson claimed that all three groups had characters 1-8, 12, and 14 in common. He went on to make the following evolutionary conclusion “in so far as they indicate affinities at all, they merely indicate that these groups were derived from ancestors with broadly similar potentialities and that they have evolved in the same general (i.e. mammalian) direction. They do not indicate that these Mesozoic forms constitute a natural unit.”217So, what characters would link the group?

215George G. Simpson, “Mesozoic mammalia IV. American triconodonts.” American Journal of Science 210 (1926): 232. 216Simpson “Mesozoic Mammalia II.” 356. 217George G. Simpson, “Mesozoic mammalia III. American triconodonts.” American Journal of Science 210 (1925): 562.

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According to Simpson, the first three characters constitute the minimum definition of the

Class Mammalia.218 He went on to say that characters 4,219 6,220 7,221 8,222 and 12,223 were commonly found in primitive mammals. He claimed that these characters were probably all inherited from the reptilian ancestry, so probably not indicative of close affinities.224 Of the characters that might link the three groups as a unit, Simpson considered 5225 and 14.226

However, he claimed that both features, although eliminated before the incoming of the

“primitive” mammals of the Tertiary, were probably primitive and inherited from the general ancestral stock.

Of the characters that divided the forms into different groups, Simpson drew attention to

9, 10, 11, 15-18. Simpson cautioned his readers with putting too much emphasis on 9, because he claimed that although the differences were constant and tended to separate the Triconodonta from the other two groups, they were simple and slight. Characters 10 and 11, Simpson noted, were valuable from a phyletic point of view as they involved “fairly complex morphological differences of long standing, with intimate relationships to the musculature and general structure.”227

Character 15 was a bit tricky for Simpson, for resemblances resulting in homoplasy and convergence could not be eliminated. While the evidence indicated a sharp separation of the

218The first three characters are: mandible a single bone, with direct squamosal articulation; dental series differentiated into incisors, canines, premolars and molars; and all post-canine teeth, and sometimes also the canine, are bifanged, respectively. 219Moderately slender, long, evenly curved horizontal ramus. 220Size always small. 221Rami united by cartilage at symphysis, latter long and at a slight or no angle to the lower border. 222Broad recurved coronoid. 223Incisors mostly styliform, spaced, in a longitudinal series. 224Simpson “Mesozoic mammalia IV. ” 562. 225Internal groove on mandible. 226Molars plus premolars 7-9. 227Simpson “Mesozoic mammalia III.” 562.

116 pantotherians, Simpson believed that “the resemblances between the premolars of the symmetrodonts and the Stonesfield triconodonts were not deep lying,”228 and Simpson believed they could be explained by the fact that these two groups shared common food habits rather than a blood relationship. Simpson wrote: “In triconodonts and symmetrodonts the premolars cut, in pantotherians they grasp, but all are simple and none have progressed far from the reptilian stage.”229 Characters 16-18 concerned molars. Simpson noted that taxonomic distinctions in these mammals were most often and easily seen in the lower molars, and “the classification of the Mesozoic forms still rest largely on these.”230 Simpson carefully grouped these characters and ranked them in a particular way so that he could make his argument for a new Order.

Now consider the arguments Simpson presented against the idea that these groups shared a common mammalian ancestor:

Most recent writers agree that all the evidence, paleontological, morphological, and embryological, points to the origin of cusps about where they are found, migration or rotation playing no part, or at best a very slight one, in the formation of the molar pattern. If this be true, and the writer is convinced that it is, then any common ancestor of the triconodonts and of the symmetrodonts must have been in an essentially one cusped stage, i. e. before either group existed as such. Even at such a remote stage it is, for mechanical reasons, quite improbable that the two groups had a common ancestry. The ancestors of the triconodonts had flattened, laterally compressed cutting molars, the tendency of which was simply to shear past each other in occlusion. The ancestors of the symmetrodonts, on the other hand, had more or less rounded or somewhat triangular piercing teeth the tendency of which was to fit wedge-like into the interspaces of the occluding teeth. Starting with this different heritage, the symmetrodonts turned their molars to much the same use as did the triconodonts, that is, the cutting of food (flesh), and hence many superficial resemblances between the two groups have arisen.231

228Simpson, “Mesozoic mammalia III” 565. 229Simpson, “Mesozoic mammalia III” 565. 230Simpson, “Mesozoic mammalia III” 565. 231Simpson, “Mesozoic mammalia III” 566-7.

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In other words, based on the dental evidence it was quite improbable that the symmetrodonts and triconodonts shared a common ancestor. If the symmetrodonts and triconodonts did share a common ancestor, based on the dental evidence, it would have been very long ago.

Simpson went on to say that it was:

. . . “more probable that Spalacotherium is related to the Trituberculata [Pantotheria] in spite of the difference in the angle,” then it must be that the relationship is very remote, harking back, indeed, to a period when the tooth consisted of but a single cusp and the secondary cusps were just arising. It is quite possible that at some such state as this the two groups did have a common ancestry, an ancestry which emphasized the wedge relationship of upper and lower molars rather than the shear relationship developed in the triconodonts. But it is certain that if we had this common ancestor before us we should not call it a pantotherian mammal. We might, indeed, call it a reptile.232

Simpson concluded that the tricondont, symmetrodont, and pantotherian groups were entirely separate, and that their ancestry had been separate for so long that it was not possible to think of any one of the three as derived from one of the other two. It is, however, possible that the symmetrodonts and pantotherians had a very remote, probably premammalian, common origin.233 As such, Spalacotherium, Tinodon, and Amphidon could not be thought of as belonging either to the Order Triconodonta or the Order Pantotheria. Instead, a new Order,

Symmetrodonta, was considered appropriate.234

4.2.3.4 “Mesozoic mammalia IV”

The last paper in the series departed significantly in style from the first three. In this paper, Simpson used the history of debates to explore and critique methods and arguments.

Although Simpson did not present a new methodology in this paper, he provided reasons for change, and suggestions for a new direction. Relatively speaking, claimed Simpson, the

232Simpson, “Mesozoic mammalia III” 568. 233Simpson, “Mesozoic mammalia III” 569. 234Simpson, “Mesozoic mammalia III” 569.

118 multituberculates were a dominant group that lived a very long time, and captured morphological interest in paleontology circles because of their evolutionary isolation. Despite their longevity and dominance, the multituberculates appeared to “have little direct bearing on the phylogeny of

Tertiary and recent mammals.”235 With so little phylogenetic impact, one might wonder why

Simpson would revisit a debate on eating habits of this particular group. The answer was simple and pragmatic. Simpson was anxious to test current methodology: “Within the limits of the now available material, it offers an almost unparalleled occasion for the testing and application of the recently developed methods of reconstituting the anatomy, movements, and adaptations of an extinct group of animals.”236

Simpson’s main concern, when he evaluated the history of this debate and looked at the evidence currently available, was to avoid a priori theories and, wherever possible, take a more quantitative path. As mentioned earlier, Simpson wrote:

In the face of these several different opinions, all vehemently supported by very careful arguments, it is necessary to discard a priori theories and to consider the observable facts objectively and, when possible, quantitatively . . . It is from the characters of the skull and teeth that the food habits must be inferred. The following facts have a bearing on this problem in the group here being considered (multituberculates with trenchant premolars).237

It is important to be clear what Simpson meant when he used the term “a priori” in this context, especially since he used this term before. When Simpson used this term, often he simply meant

“ahead of time,” something like “before empirical evidence was in hand.” This can be seen in various instances when he used the term: “The generic affinities of the northern glyptodonts also present a difficult problem. On the basis not only of a priori probability but also of the positive

235George Gaylord Simpson, Herbert Oliver Elftman “Hind limb musculature and habits of a Paleocene multituberculate.” American Museum Novitates 333 (1928): 1. 236Simpson and Elftman “Hind limb musculature” 1. 237Simpson, “Mesozoic mammalia IV” 232.

119 knowledge so far gained, it seems very unlikely that any of the known remains really belong to

Glyptodon, unless that genus be improperly used for all later glyptodonts with a rosette-like plate pattern.”238 or: “They [the didelphids] may then have disappeared, but their mere absence in the collections means nothing, and it is much more probable, a priori, that they remained in North

America continuously to-the present time, although unquestionably with fluctuations of northern limit as the climate varied.”239 or in 1936: “Another striking fact, although one that might be assumed a priori, is that the larger fauna gives a better basis for inference as regards the smaller than does the smaller for the larger.”240 In each instance, Simpson used the term in a way consistent with the idea of “ahead of time.” This interpretation of “a priori” fit the analysis of the debate Simpson provided in the paper, as well as his use of the term in other papers. Simpson expanded his concern to include metaphysical speculation that this can be found in a paper in which he tracked a debate about early uintathere molars, “A new Paleocene uintathere and molar evolution in the Amblypoda” (1929).

In “A new Paleocene uintathere and molar evolution in the Amblypoda” (1929), Simpson described how, in 1898, Osborn presented the families pantolambdidae, coryphodontidae, and uintatheriida, as successive families forming a structurally ancestral series based on the analysis of their teeth. Osborn determined that the premolars of cat-like pantolambda and hippo-like coryphodon were similar, in light of their homologous parts. The rhino-like uintatherium different premolars led Osborn to conclude that it arose from the complete suppression of the internal heel. As a result, Osborn claimed the uintatherium had a very different history from the pantolambda and coryphodon.

238George G. Simpson, “Pleistocene Mammalian Fauna of the Seminole Field, Pinellas County, Florida.” Bulletin American Museum of Natural History VIII. (1929): 583. 239George G. Simpson “American Eocene Didelphids” American Museum Novitates (1928): 2. 240George G. Simpson “Data on the Relationships of Local and Continental Mammalian Faunas” Journal of Paleontology 10 (1936): 413.

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Twenty-five years later, Wood challenged Osborn’s conclusions about these families, claiming that the coryphodon and uintatherium upper molar patterns were not formed by homologous elements. That same year, Simpson noted that Matthew confirmed Wood’s theory, albeit with a few modifications. From Matthew’s investigations of the specimens from the Clark

Fork formation, and in consideration of the above theories, Simpson proposed that:

The coryphodonts, uintatheres, and perissodactyls seem to me to afford a striking example of the view that when different phyla acquire similar habiti some time [sic] after their separation from a common ancestry, there is no inherent tendency for these modifications to arise in the same way in the independent lines. The homologous parts are those alone which were already present in the common ancestry in ungulate upper molars generally, only the three primary cusps and possibly the conules. There may be a tendency (to call it inherent would involve a personal definition of the word) to form lophs, for instance, but there appears to be no fixed tendency for these to form in the same way or from the same parts in independent groups, except when these phyla had identical or closely similar molars at or after the inception of lophiodonty. Animals which fulfil this last condition are usually closely related, and an apparent inherent tendency to form lophs in the same way in related phyla is consequently often seen, but I conceive the conditioning factor to be not the metaphysical one of germinal predestination but the physical one of mechanical resemblance.241

What is evident from this passage was Simpson’s concern that Osborn relied on a metaphysical claim about germinal predestination to explain convergent similarity in his evolutionary story, a claim for which Osborn had no empirical evidence. Unlike Osborn, Simpson was not prepared to believe that if different phyla acquired similar ways of life in the period after their break from a common ancestor, then there was a necessary condition stating that such later modifications would arise in the same way in independent lines.

For Simpson, Osborn’s “metaphysical” account of germinal predestination to explain convergent similarity was an example of the kind of speculation a taxonomist should not tolerate, even if it was done in the name of evolutionary theory. In his entry on Osborn in the American

241George G. Simpson “A New Paleocene Uintathere and molar evolution in the Amblypoda” American Museum Novitates Number 307 (1929): 7-8.

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Dictionary of Biography Simpson spoke of Osborn’s heart belonging to philosophy more than biology, describing Osborn as “a philosopher who reluctantly disciplined himself to the drudgery of basing his philosophy on factual data.” As tempting as might be, Simpson maintained that one should not adopt unjustified philosophical assumptions when interpreting biological facts. It seemed that Osborn found it hard to resist the temptation in this case. The paleontologists

Simpson discussed in his 1926 paper may not have relied on a metaphysical claim, but Simpson was concerned that their inferences were not based on proper evidence and methods.

Simpson noted that the multituberculates discussed in “Mesozoic Mammalia. IV. The multituberculates as living animals” were characterized by their “trenchant lower premolars,” and this characteristic taken alone led to conflicting conclusions regarding eating habits.

Simpson began his examination of the debate in 1857 with Falconer’s work on the genus

Plagiaulax. Falconer claimed that Plagiaulax was either herbivorous or frugivorous. Falconer based this conclusion on trenchant lower premolars, and by comparing teeth and jaw specimens with those from the recent genus Hypsiprymnus (the Australian kangaroo rat) that were also herbivorous. Falconer noted the similarities, as well as a lack of evidence of characteristics indicative of carnivorous or insectivorous behaviours.

In contrast, Owen wrote in 1860 and 1871, that the Plagiaulax was a predaceous carnivore that preyed on the contemporary insectivores and lizards.242 The argument to counter

Owen’s came in 1909 from Gidley. Gidley described a complete skull and jaws of Ptilodus, which targeted Owen’s claims about grinding. Gidley observed that there was a grinding area, and it occupied nearly three quarters of the contact surface between upper and lower teeth. He also noted that “the crowns were low, but broad and massive, and well supplied with short stout

242Simpson “Mesozoic mammalia IV” 229.

122 tubercles. Such a set up was inadequate for the job of masticating meat, but well suited for grinding hard substances.”243 Gidley also noticed that when the lower jaw was aligned, many of the incisor and condyle characters Owen discussed in terms of carnivores disappeared. The condyle, when properly aligned, was above the molar level, and the grooves of the premolars were vertical. Gidley concluded that Ptilodus and Plagialllax were:

. . . frugivorous, since the incisors were well fitted for picking small fruits or berries, while the large cutting blades of the lower premolars were admirably adapted to cutting and slicing the rinds of tough-skinned berries, or to chopping up fleshy fruits held against the blunt-pointed premolars of the upper jaw. For masticating the seeds of such small fruits and berries the multitubercular molars were amply sufficient.244

Simpson continued by noting that in 1910, Broom challenged Gidley’s conclusions and backed

Owen’s original claim of carnivore, based on the following evidence:

1. The temporal fossae were large and could accommodate powerful temporal muscles.

2. The grinding surface was only of limited extent.

3. There was a perfected cutting mechanism.

4. The pointed incisors, their mode of implantation and of passing between the upper incisors also support this view.

On this account, one couldn’t rule out the possibility of an insectivore. However, one could probably rule out an herbivore and a frugivore, the latter based on inferences regarding limb- length. The Ptilodus seemed to be a ground-hopping animal and unable to climb trees, which it would need to do to be a successful frugivore. Also, Broom claimed that fruits and berries are only ripe at one or two seasons of the year, so successful frugivores must be able to fly, like bats and birds.245

243Simpson “Mesozoic mammalia IV” 231. 244Simpson “Mesozoic mammalia IV” 231. 245Simpson “Mesozoic mammalia IV” 231.

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Broom also deemed the powerful incisors and large cutting teeth found in Pteropus an unnecessary feature of a frugivore. Lastly, Broom claimed that the Plagiaulax lived in the

Jurassic period, and when Broom published his work, evidence of fruits and berries, did not occur before the Cretaceous.

Broom’s argument was one with which Simpson took issue. Gidley stated that “the relatively large proportions of the pelvis and hind limbs strongly suggest that Ptilodus was saltatorial in habits.”246 Broom used this as an argument against arboreal life, and hence against their being frugivorous. Simpson claimed the latter did not necessarily follow, especially if the term “frugivorous” was extended to include eating of the more resistant fruits, berries, and nuts paleontologists now knew existed during the Jurassic period, but Simpson did think it was interesting to consider the habitual means of locomotion as far as these may be inferred from the

“scanty material.”

In response to the limb-bone argument, Simpson took measurements of the limb bones of small and medium-sized mammals, chiefly rodents, insectivores and marsupials, aiming to derive a quantitative criterion of the mode of locomotion from a comparison of humerus and femur lengths. The results showed the following three things: that the ratio between these two figures was a very good indication of whether an animal is bipedal or quadrupedal, a more uncertain indication as to whether they run or hop (move limbs alternately 01” together), and no indication at all of a terrestrial or arboreal habitat. On page 248, selected series of typical ratios illustrated this fact.

In general the higher the ratio, the more rapid the locomotion, and the more frequently the animal hopped rather than ran, but this rule was not universal for many bipedal animals, even

246Simpson “Mesozoic mammalia IV” 247.

124 those which ran with alternating strides. According to Simpson, above about 1.30 the animals were generally swift moving and often hopped. Above about 1.50 they were generally bipedal.

Ptilodus has a ratio of 1.33, and Simpson concluded that it was probably a swiftly moving and agile quadruped, and that there was nothing in the known proportions of the limbs which indicated in any certain way of either a terrestrial or an arboreal habitat.247

This series of papers showed Simpson as working within a traditional methodological framework. However, within this framework Simpson began to challenge the aspects of the traditional qualitative approach: challenging the inferences made (especially when he worried about a priori arguments), the evidence collected (when he thought the evidence could not support the claim), and a push for a more quantitative approach (his charts and his presentation of material). In spite of his push for a more quantitative approach, Simpson exercised caution with respect to the limits of such an approach. Even as early as the late 1920s, Simpson had his eye always on the practical, and would not sacrifice biological fact for elegant tools or theory.

This idea shaped the relationship between logic and taxonomy in the next stage of this work.

4.3 Second Stage—Statistics: Mid 1930s to 1937

Simpson’s writing in the mid-1930s showed a more significant change in methodology, specifically a move away from the exclusively “means and range” mathematics found in his work on Mesozoic mammals, and a move toward more sophisticated statistics (e.g., the t-test for determining the probability that two samples were from the same statistical population). Simpson believed this change in methodology, the change to small sample statistics, reflected a change from thinking of species as types to species as populations, and was the mark of an evolutionary taxonomy. Small sample statistics enabled Simpson to view a small number of specimens as

247Simpson “Mesozoic mammalia IV” 247.

125 small samples from which the larger biological population might be inferred. So, rather than using a method of strict comparison of individual specimens found in type methodology (be it quantitative or qualitative), he began using simple statistical analysis in his taxonomic methodology to infer the characters of the biological population from which his specimens were drawn in order to support his species determinations. Found in his writing during the late 1930s and early 1940s was the cautious implementation of the population as against the typological concept of species.

Simpson picked up a statistical programme from R. A. Fisher that was begun by biometrician Karl Pearson (1857-1936). Fisher departed from Pearson on a number of mathematical and ideological points, but both believed in the value of statistical reasoning for social and scientific problems.248 This addition to taxonomy’s methodological toolbox amounted to a change in the taxonomy’s relationship with logic. In his discussion of statistics, Fisher wrote:

I welcomed also the invitation, personally, as affording an opportunity of putting forward the opinion to which I find myself more and more strongly drawn, that the essential effect of the general body of researches in mathematical statistics during the last fifteen years is fundamentally a reconstruction of logical rather than mathematical ideas, although the solution of mathematical problems has contributed essentially to this reconstruction. I have called my paper “The Logic of Inductive Inference.” It might just as well have been called “On making sense of figures.” For everyone who docs habitually attempt the difficult task of making sense of figures is, in fact, essaying a logical process of the kind we call inductive, in that he is attempting to draw inferences from the particular to the general; or, as we more usually say in statistics, from the sample to the population.249

Simpson, as we will see, made similar remarks.

248Theodore Porter discussed this in detail in “The culture of quantification and the history of Public Reason” Journal of the History of Economic Thought 26 (2004): 165-177, and Trust in Numbers. Fisher discussed this in Statistical methods for research workers (1925). 249 Ronald A. Fisher “The Logic of Inductive Inference.” Journal of the Royal Statistical Society, 98 (1935): 39.

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When Simpson proposed a quantitative methodology for zoology grounded in statistics, he knew one of the biggest obstacles he faced was striking a balance between statistics and biology in the eyes of zoologists. Statistics enjoyed the perk of being recognized as “objective,” whereas zoological taxonomy suffered from a reputation of being “subjective.”250 While zoologists would be happy with reaping the benefits of having an objective tool in their methodological tool box, they were deeply concerned that when conflicts arose between statistical tools and biological fact, zoologists would err on the side of privileging their statistical tools. Math and logic, per se were not the problem. Dogmatically adhering to a mathematical or logical system when it conflicted with evolutionary biology, was the problem. Simpson knew he had to proceed with caution, and his work during this period reflected his cautious advance.

Biases aside, according to Simpson, the first real practical problem with applying Fisher’s statistical thinking to taxonomy was the math. The math was hard and complicated. To make matters worse, Fisher’s presentation in Statistical Methods for Research Workers (1925) did not help.251 Because the math was so difficult to follow, it was unlikely that taxonomists would put

250Simpson brought up this distinction between objective and subjective in Quantitative Zoology as part of an argument to include statistics as a tool in a quantitative methodology. For more on this distinction in the quantitative turn, see: Peter Galison and Lorraine Daston, Objectivity (Boston: Zone Books, 2007); Lorraine Daston, “Objectivity and the Escape from Perspective,” Social Studies of Science 22 (1992): 597-618; Theodore M. Porter, “Objectivity and Authority: How French Engineers Reduced Public Utility to Numbers,” Poetics Today 12 (1991): 245-65; Theodore M. Porter, “Quantification and the Accounting Ideal in Science” Social Studies of Science 22 (1992): 633-651. 251In an unsigned review in Nature we find: Mr. Fisher’s book is written for a more advanced type of reader, and it has much to commend it. It treats of the interesting and important subject of small samples in statistical work; it has originality; its author is full of ideas; and its appearance is all that can be desired. But unfortunately the book suffers from an introductory chapter which seems unnecessarily hard to follow, and from the difficulty of the subject, which has, we fear often prevented Mr. Fisher from writing down to his reader. The book is intended for biological research workers, and it is apparently assumed that they already know sufficient of the theory to accept, without proof, the methods given, or that they will adopt these methods on Mr. Fisher’s authority. A statistical “research worker” may be willing to dispense with rigid mathematical proofs when it can be seen from several arithmetical examples that a method carries its own justification, but in the present work the absence of proof goes rather far, and we fear that readers with little knowledge of the most recent statistical work will find the book as a whole difficult to follow, while those unfamiliar with the terms used in biological research work will have trouble with some of the examples. Nature 116 (1925): 815.

127 it into practice. Simpson worried that even those taxonomists with considerable mathematical training would find Fisher’s work unreasonably difficult. Incidentally, Laporte claimed that

Simpson was among the few biologists not deterred by Fisher’s presentation, and in fact enjoyed reading Fisher’s theoretical papers. Simpson credited these papers with helping inspire him to consider applying statistics to his taxonomic research in the1930s. Laporte documented that

Simpson’s interest in statistics accompanied his shift from typological to population thinking about species, and he provided evidence of Simpson during the 1930s moving from characterizing variation and delimiting groups by using mathematics such as determining the mean to characterizing variation and delimiting groups using t-tests, a statistical method developed during the first decade of the twentieth century to determine the probability that two

Or by “student” in the Eugenics Review: Chapter I is not easy to follow for those unfamiliar with the “jargon” of the science and such readers are advised to skip freely after Section 2, but to return and read it carefully after they have become accustomed to the use and implications of the various terms employed. This advice, however, does not apply to Example 1 which is difficult alike to those unfamiliar either with mathematics or with the higher genetics, for it may be neglected by both classes since it does not illustrate any of the methods exhibited in the later chapters of the book. Eugenics Review 18 (1926): 148-150. Or by Leon Isserlis: The book will undoubtedly prove of great value to research workers whose statistical series necessarily consist of small samples, but will prove a hard nut to crack for biologists who attempt to use it as a first introduction to statistical method. (1926) Review of Statistical Methods for Research Workers (R. A. Fisher), Journal of the Royal Statistical Society, 89, 145-146. Or an anonymous reviewer in British Medical Journal Mr. Fisher has designed his book for readers without special mathematical training, and is conscious that the inclusion of a good deal of matter which is “advanced,” and has, indeed, not been published before, needs some explanation. If he feared that he was likely to fall between two stools—to produce a book neither full enough to satisfy those interested in statistical algebra nor sufficiently simple to please those who dislike algebra—we think that Mr. Fisher’s fears are justified by the result. The laboratory worker will, as we have said, find the book useful when dealing with small samples, but will not find in it a sufficiently simple and comprehensive account of the general principles of statistical methodology. The illustrations are sometimes—for example, that dealt with on pages 94 et seq. [IV. §22]—only illuminating to students with special knowledge of modern genetics. The trained statistician interested in Mr. Fisher’s researches will miss a detailed justification of his conclusions, and may resent the somewhat arrogant way in which the law is laid down upon points respecting which there is difference of opinion among persons possibly as well informed as Mr. Fisher. A conspicuous example of this latter failing is the reference to Professor Karl Pearson on page 17 [I. §4]. Even if the statement that Professor Pearson’s treatment of a fundamental problem contained a “serious error” had not been disputable, and therefore improper in a work addressed to elementary students, it would have reminded anyone of Macaulay’s remark on a similar situations—”just so we have heard a baby, mounted on the shoulders of its father, cry out, “how much taller I am than Papa!” Anon. “Review of Statistical Methods for Research Workers (R. A. Fisher)”, British Medical Journal, 1(1926): 578-9.

128 samples were drawn from the same population.252 In this section, the relationship between logic and taxonomy is examined during this shift in Simpson’s thinking, specifically the role of inference, the role of induction, and his early ideas on notion of a population.

Although Simpson acknowledged that many taxonomists might find the repetitive calculations involved in statistical tests tedious, tedious work could not be counted as a serious objection. However, many taxonomists were rightly suspicious of applying statistical methods developed to analyze experimental data, believing that such methods were inherently inappropriate for the investigating the evolutionary phenomena of interest to taxonomists. Later, when taxonomists discovered that perhaps these methods were not inappropriate, they feared methodological reduction.

4.3.1 Early thoughts on methodological reform

Simpson’s second wife, Anne Roe (1904-1991), played a pivotal role in pointing him in the direction for his methodological reform. Her own research in psychology involved studies using small-sample statistics, and her knowledge of small-sample statistics became her ammunition in some of her more “critical” exchanges with Simpson:

We engaged in many sometimes critical discussions. He maintained that psychology [was] not a science, while I countered that paleontologists who dealt with samples of varying sizes, usually very small, should do more with their data statistically than just note means and ranges. Ultimately we wrote a text on statistics applicable to biological data, Quantitative zoology. This was really the first attempt to apply statistical methods to field material, living or fossil, that was comprehensible to someone not mathematically trained.253

252See Léo F. Laporte. George Gaylord Simpson : paleontologist and evolutionist. (New York: Columbia University Press, 2000) 253Laporte as quoted in “Simpson on Species” 146.

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Simpson took a long hard look at how taxonomists used the available evidence to group organisms and make evolutionary claims, and asked whether a more sophisticated quantitative approach might replace the speculative approaches common to evolutionary claims.

For guidance on applying small sample statistics to zoology, Simpson immersed himself in studies of the application of small sample statistics in biology, specifically noted population geneticist R. A. Fisher’s work. A notoriously difficult read for the beginner, Fisher’s Statistical methods for research workers (1925) aimed to guide the reader through the mathematics of small sample statistics and explain how to apply it to biological research.254 In the mid to late 1930s, using the logic of inductive inference was a pretty radical move no matter what circle you were in. Fisher himself noted that even in mathematical and logical circles, it was a bold move:

Such inferences we recognize to be uncertain inferences, but it does not follow from this that they are not mathematically rigorous inferences. In the theory of probability we are habituated to statements which may be entirely rigorous, involving the concept of probability, which, if translated into verifiable observations, have the character of uncertain statements. They are rigorous because they contain within themselves an adequate specification of the nature and extent of the uncertainty involved. This distinction between uncertainty and lack of rigour, which should be familiar to all students of the theory of probability, seems not to be widely understood by those mathematicians who have been trained, as most mathematicians arc, almost exclusively in the technique of deductive reasoning; indeed, it would not be surprising or exceptional to find mathematicians of this class ready to deny at first sight that rigorous inferences from the particular to the general were even possible. That they are, in fact, possible is, I suppose, recognized by all who are familiar with the modern work. It will be sufficient here to note that the denial implies, qualitatively, that the process of learning by observation, or experiment, must always lack real cogency.255

It was still the heyday of logical positivism, so deductive inference was what mathematicians and logicians favoured. Fisher was proposing a new spin on inductive inference, and a role for it in the sciences. Simpson was going to show just how useful it would be in taxonomy.

254Simpson wrote in Quantitative Zoology “Although it is intended as an introduction, experience has suggested that it is almost completely incomprehensible to anyone not already well grounded in statistics.” (400) 255R. A. Fisher “The logic of inductive inference” Journal of the Royal Statistical Society, 98(1935): 39-40.

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4.3.2 “Data on the relationships of local and continental mammalian land faunas” (1936)

One of the first publications suggestive of Simpson’s concern with the philosophical problem of inference, and one of the first places he provided a tentative proposal for a new quantitative way to solve it, was “Data on the relationships of local and continental mammalian land faunas” (1936). According to Simpson, paleontologists often found themselves in a situation where they needed to infer a whole continent’s worth of fauna from fossils found at only one or a few places. Simpson, of course, did not exempt himself from making such inferences, and gave what he took to be the usual account of the Eocene land fauna of North America as an example of exactly this type of sketchy inference move. However, in this paper, he did think there might be a better way to approach this problem.

What was known about Eocene land fauna of North America, claimed Simpson, had been inferred almost exclusively from specimens taken from a “few basins scattered through the

Rocky Mountain area.”256 The knowledge of pre-Pliocene mammals at the time was inferred from relatively limited and marginal areas of Patagonia, making it another example of the prevalence of this kind of inference move in paleontology. “It is obvious” claimed Simpson “that such data cannot give a complete picture of the fauna of a whole landmass.”257 This problem raised two questions for Simpson: How can we make sense of these relationships? How do we give some concrete basis for their evaluation? Simpson’s answer to these questions was ingenious. He designed a novel way to test this type of inference by comparing two well-known groups of animals: the recent mammalian faunas of Florida and of New Mexico. He claimed:

“The primary object of the comparison is to see what could safely be inferred of the fauna of the

256George G. Simpson “Data on the relationships of local and continental mammalian land faunas.” Journal of Paleontology 10 (1936): 410. 257Simpson “Mammalian land faunas” 410.

131 other if the mammalian fauna of only one of these two states were known. Hence some judgment is possible as to the limits of safe inference regarding the regional fauna in cases of fossil faunas known only from one part of a large landmass.”258

Simpson gathered sizeable data on the orders, families, genera and species for both groups, and in this paper he plotted them on a graph. The graph demonstrated that the number of orders was almost the same, the number of families was pretty close, but the number of genera and species were divergent. His comparison of the recent mammalian faunas of Florida and of New

Mexico yielded the following conclusions:

1. “If we knew all the mammals of one state, we could infer almost exactly how many orders occur in the other, and fairly well how many families, but might be badly mistaken regarding the lesser units.” 2. “More important than the number of units is their character. Somewhat contrary to expectations, the example suggests that in similar cases and within certain broad limits, the character of the fauna of one region can be inferred from that of the other.” 3. “The larger fauna gives a better basis for inference as regards the smaller than does the smaller for the larger. New Mexico, with its highly varied fauna, gives a reasonably accurate picture of the mammalian life of at least the central part of North America. If we knew its fauna and not that of Florida, we would nevertheless be familiar with all the orders, almost all the families, and two-thirds of the genera that do occur in Florida.” 4. “Applied to paleontological data, the accuracy of such inferences depends on numerous factors which can be approximately evaluated, although any close approach to statistical accuracy would necessitate the accumulation and interpretation of many more data than have yet been studied, and would even then be an extremely complex and difficult problem. There is, however, no reason to believe it insoluble.” 5. Therefore, concluded Simpson, it seems probable not only that a large and varied Tertiary fauna could be inferred as representative, but also “give an excellent representation of the mammalian orders present on the whole continent, a good idea of the families, and will probably even include most of the genera”, even if it is from a single and fairly local geological formation.259

Simpson then applied this reasoning to the mammals of the Bridger fauna, presenting the following argument:

258Simpson “Mammalian land faunas” 411. 259Simpson “Mammalian land faunas” 412.

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1. The Bridger fauna probably ranged over an area comparable to that of Florida.

2. The position of their area was very central on the Eocene continent.

3. The local environments represented are clearly numerous.

4. Knowledge of the fauna is fairly complete.

5. Therefore, this fauna probably represents well the middle Eocene life of all of North America.260

So, from a paleontological perspective, the claim Simpson promoted in “Data on the relationships of local and continental mammalian land faunas”—that given the evidence analyzed, the Bridger formation mammals were representative for North America during middle

Eocene—was the highlight of the article. However, from the perspective of methodological reform, the innovative feature was Simpson’s interest in the problem of inference, in this case, inferences with respect to relationships of local and continental mammals. But this was just the beginning.

4.3.3 “Notes on the Clark Fork, Upper Paleocene, Fauna” (1937) and “Patterns of Phyletic Evolution” (1937)

The year after “Data on the relationships of local and continental mammalian land faunas” found Simpson doubting the traditional qualitative taxonomic method in print, extending his concerns about inference moves with respect to relationships of local and continental mammals to inference moves from specimens to taxonomic groups. When he expanded the scope of the inference problem, he introduced a few more philosophical problems, which he explored in “Notes on the Clark Fork, Upper Paleocene, Fauna” (1937) and in “Patterns of Phyletic

Evolution” (1937).

260Simpson “Mammalian land faunas” 414.

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Philosophically speaking, Simpson’s new methodological approach was radical, and he knew it. Unlike the no-nonsense “Data on the relationships of local and continental mammalian land faunas,” Simpson began “Notes on the Clark Fork” and “Patterns of Phyletic Evolution” with a small philosophical digression, permitting himself a few words to justify his departure from traditional methodology. In both “Notes on the Clark Fork” and “Patterns of Phyletic

Evolution,” he took the radical step of reversing the traditional methodological assumption that groups are secondary and the individuals are the primary units. He believed this reversal necessary for all Darwinians.

Building an evolutionary account of variation into taxonomic method and taxonomic reasoning was a serious problem for taxonomists. In both papers, Simpson aimed to distance himself from a methodology that exclusively compared individual specimens to known type specimens and recorded the mean of the morphological characters, because by this point,

Simpson was beginning to think that comparison approaches failed to capture the concept of variation in Darwinian evolution by natural selection. Instead, Simpson urged taxonomists to think of species as “populations” in a rather different way.

According to Simpson, species understood as “populations” rather than “types” entailed the following two claims. First, the single “typical” specimen that literally and figuratively embodied the relevant diagnostic characters museum taxonomists used to characterize a species needed to be replaced by a set of specimens that represented the full range of variation in a species. Second, taxonomists needed new statistical techniques for summarizing, analyzing, and reporting the data (for example, statistical tools such as the t-test) that would determine the probability that two samples were from the same statistical population (as was the case in the

“Data on the relationships of local and continental mammalian land faunas” paper). The familiar

134 mathematical tools common in tradition methodology, such as recording the means of a given anatomical character, just were not cutting it anymore. The new statistical tools he proposed taxonomists use would enable taxonomists to infer the characteristics of the biological population from which their specimens were collected, and use them as evidence for species determinations (as was demonstrated in “Notes on the Clark Fork” and “Patterns of Phyletic

Evolution”).

To better understand the logical undertones of the new statistical tool Simpson proposed, consider Fisher’s explanation of statistics and logic:

The statistical examination of a body of data is thus logically similar to the general alternation of inductive and deductive methods throughout the sciences. A hypothesis is conceived and defined with necessary exactitude; its consequences are deduced by a deductive argument; these consequences are compared with the available observations; if these are completely in accord with the deductions, the hypothesis may stand at any rate until fresh observations are available.261

As seen in the passage above, Fisher began by discussing the role of both induction and deduction in traditional statistics, emphasizing the role of deduction. As Fisher continued, he highlighted deduction in the theory of probability, the problems of distribution, Bernoulli’s distribution, Laplace’s normal distribution, and Poisson’s series:

The deduction of inferences respecting samples, from assumptions respecting the populations from which they are drawn, shows us the position in Statistics of the Theory of Probability. For a given population we may calculate the probability with which any given sample will occur, and if we can solve the purely mathematical problem presented, we can calculate the probability of occurrence of any given statistic calculated from such a sample. The Problems of Distribution may in fact be regarded as applications and extensions of the theory of probability. Three of the distributions with which we shall be concerned, Bernoulli’s binomial distribution, Laplace’s normal distribution, and Poisson’s series, were developed by writers on probability. For many years, extending over a century and a half, attempts were made to extend the domain of the idea of

261Fisher Statistical Methods 10.

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probability to the deduction of inferences respecting populations from assumptions (or observations) respecting samples.262

Fisher then turned his discussion to an objection or limitation to this approach to inferences, and proposed a new approach, the concept of “likelihood”:

Such inferences are usually distinguished under the heading of Inverse Probability, and have at times gained wide acceptance. This is not the place to enter into the subtleties of a prolonged controversy; it will be sufficient in this general outline of the scope of Statistical Science to express my personal conviction, which I have sustained elsewhere, that the theory of inverse probability is founded upon an error, and must be wholly rejected. Inferences respecting populations, from which known samples have been drawn, cannot be expressed in terms of probability, except in the trivial case when the population is itself a sample of a super-population the specification of which is known with accuracy. This is not to say that we cannot draw, from knowledge of a sample, inferences respecting the population from which the sample was drawn, but that the mathematical concept of probability is inadequate to express our mental confidence or diffidence in making such inferences, and that the mathematical quantity which appears to be appropriate for measuring our order of preference among different possible populations does not in fact obey the laws of probability. To distinguish it from probability, I have used the term “Likelihood” to designate this quantity; since both the words “likelihood” and “probability” are loosely used in common speech to cover both kinds of relationship.263

What made Fisher’s concept of “likelihood” significant, from a logical perspective, was it involved induction rather than deduction. Fisher discussed this in “The logic of inductive inference”:264

262Fisher Statistical Methods 10-11. 263Fisher Statistical Methods 11-12. 264Fisher reiterated the claims in Statistical Methods in “The logic of inductive inference”: The inferences of the classical theory of probability are all deductive in character. They are statements about the behaviour of individuals, or samples, or sequences of samples, drawn from populations which are fully known. Even when the theory attempted inferences respecting populations, as in the theory of inverse probability, its method of doing so was to introduce an assumption, or postulate, concerning the population of populations from which the unknown population was supposed to have been drawn at random; and so to bring the problem within the domain of the theory of probability, by making it a deduction from the general to the particular. The fact that the concept of probability is adequate for the specification of the nature and extent of uncertainty in these deductive arguments is no guarantee of its adequacy for reasoning of a genuinely inductive kind. If it appears in inductive reasoning, as it has appeared in some cases, we shall welcome it as a familiar friend. More generally, however, a mathematical quantity of a different kind, which I have termed mathematical likelihood, appears to take its place as a measure of rational belief when we are reasoning from the sample to the population.(40)

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The best use I can make of the short time at my disposal is to show how it is that a consideration of the problem of estimation, without postulating any special significance for the likelihood function, and of course without introducing any such postulate as that needed for inverse probability, does really demonstrate the adequacy of the concept of likelihood for inductive reasoning, in the particular logical situation for which it has been introduced.265

So, Fisher’s new statistical tool had a subtly different logical approach than others. Simpson was certain that regardless of the merits of this new methodology, some practical issues needed to be addressed before such a methodology could be put into place.

One of Simpson’s goals in “Notes on the Clark Fork” and “Patterns of Phyletic

Evolution” was to test his new quantitative methodology for determining species in cases where the evidence permitted this type of analysis. Not only were discussions with Roe and reading of

Fisher central to Simpson’s statistical turn, his collecting efforts at the American Museum of

Natural History changed the fossil collections he used as evidence in important ways. For the first time, Simpson had a collection that, for many species, had enough specimens for each presumed species that he could perform a simple bivariate statistical analysis.266

4.3.4 First job: museum and field work, scholar and popular science writing

In a sense, Simpson was partly responsible for having such a collection. When Simpson returned to America in the fall of 1927 to take up a position with the American Museum of

Natural History, it was a move that proved fruitful not simply in terms of his work in alpha taxonomy, but in terms of the growth of the American Museum of Natural History collections. In addition to housing one of the finest collection of Mesozoic and early Cenozoic mammals, the

American Museum of Natural History supported a series of collecting expeditions, most notably expeditions to Patagonia in 1930-31 and 1933-34 led by Simpson to study Eocene mammals.

265Fisher “Inductive Inference” 41. 266Laporte “Species” 146.

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Simpson was able to convince one of the Museum’s patrons, Mr. H. S. Scarritt of New York, to fund the expedition—no easy task given the Depression. Patagonia was high on Simpson’s list of places to collect. Because South America was an island continent during the Eocene period, places such as Patagonia promised to be a treasure trove for an evolutionarily-minded paleomammalist, because it was rumoured to yield unusual and important fauna.

Simpson described the purpose of the expeditions as “to collect and to study early

Tertiary fossil mammals, especially those of South America”267 and publically announced that his expedition was important for two reasons. The first reason was to bolster the museum’s collection. This kind of exploration in South America had not been undertaken by the American

Museum of Natural History, so the first aim of the Scarritt Expeditions was to fill this gap in the exhibition and study series. Such a collection would “cast needed light on the most neglected part of the world problem of early mammalian evolutionist.”268 The second reason had to do with securing the American Museum of Natural History museum’s fossil mammal collection’s place on the intellectual map. Simpson noted that this kind of exploration had been “vigorously pursued in many parts of the world”269 by excellent paleontologists, many of whom Simpson had worked, and the American Museum of Natural History should not be left out.270

Simpson’s two Patagonian expeditions “traveled over 12,000 miles in the field and made a reconnaissance, from the view-point of its special aims, of an area of over 30,000 square miles.”271 His team engaged in geological and taxonomic studies at twenty-five separate

267George Gaylord Simpson “The Scarritt Expeditions of the American Museum of Natural History, 1930-34” Science, New Series 80 (1934) 207. 268George G. Simpson “The Scarritt Expeditions” 207. 269George G. Simpson “The Scarritt Expeditions” 207. 270These palaeontologists included: Wortman, Granger, Matthew, and Andrews. 271George G. Simpson “The Scarritt Expeditions” 207.

138 localities. 272 New discoveries abounded, from the stratigraphic results he believed would

“considerably alter the present conception of the Cretaceous-Tertiary transition in South

America”273 to the amazing Scarritt Collection of fossil vertebrates.

Mammals, of course, were top on Simpson’s collection list, but he also collected specimens from: “. . . all the known pre-Patagonian (i.e., Paleocene through Oligocene) mammal-bearing formations, including the oldest, the Rio Chico Formation, first recognized and defined by us, as, well as the Casamayor, Musters, Deseado and Colhue-Huapi, from which, respectively, came the Notostylus, Astraponotus, Pyrotherium and Colpodon faunas of

Ameghino.”274 Not only were a number of new forms were discovered, but many relatively complete mammal specimens were also discovered whose previous identification was based on bits and pieces of jaws and teeth. In addition to collecting and writing about mammals, Simpson also collected and wrote on “hitherto neglected or undiscovered groups”275 of fish, frogs, birds, crocodiles, turtles and snakes fossils; to provide “a remarkably complete picture of the early

Tertiary life of the region.”276

Simpson’s collecting efforts and advances in alpha taxonomy resulting from the Scarritt

Expeditions took two forms. The popular science publication Attending marvels: A Patagonian journal was a successful travel narrative that chronicled Simpson’s fieldwork in South America from 1930-1931. 277 This publication not only caught the public eye with a front-page spread in the New York Times Sunday Book Review, but the public ear when Simpson hit the radio waves

272Simpson claimed that fifty-four detailed geologic sections were measured, and many others sketched or estimated. 273George G. Simpson “The Scarritt Expeditions” 207. 274George G. Simpson “The Scarritt Expeditions” 208. 275George G. Simpson “The Scarritt Expeditions” 208. 276George G. Simpson “The Scarritt Expeditions” 208. 277George G. Simpson Attending marvels: A Patagonian journal. (Macmillan, New York and London, 1934).

139 with an interview in New York City. The expedition also produced series of scholarly articles, including thirty-five articles in the American Museum Novitates ranging from 1932-1985.

4.3.5 “Patterns of Phyletic Evolution” (1937)

In “Patterns of Phyletic Evolution” Simpson raised the question: what is a species? He challenged the claim held by most paleontologists that a fifteen percent difference in any linear dimension justified recognition of a different species. He challenged this on practical grounds.

Regardless of what paleontologists were taught, claimed Simpson, every paleontologist who grappled with variation in their alpha taxonomic work knew on the one hand that “there is hardly any geographic race, let alone any species, in which some variants are not more than 15 percent larger in some dimensions than are others” and on the other hand “a difference in the average dimensions of two groups of individuals may be a perfectly valid and highly significant specific character, even though the difference is less than 15 percent.”278 If this was the definition of a species, according to the old way of thinking, the old way of thinking was not working.

In an effort to persuade paleontologists to rethink their methodological rules, Simpson suggested imagining a case where a fossil was increasing in size through a vertical sequence of rock strata. Simpson claimed that there were three different ways to interpret this case: first, the data could represent the case where a smaller species declined while another species increased; second, the data could represent the case where the character of one species was increasing over time; or third, the data could represent the case where one larger species gradually diverged from the smaller ancestral species.279 Which interpretation should we choose? Simpson used his new statistical analysis (which provided the frequency distributions of the character under

278George G. Simpson “Patterns of Phyletic Evolution” Geological Society of America Bulletin, 48 (1937) 307. 279Simpson “Patterns of Phyletic Evolution”

140 investigation from the different successive horizons) to demonstrate how this new methodology could help the taxonomist choose the correct interpretation.

4.3.6 “Notes on the Clark Fork” (1937)

“Notes on the Clark Fork” found Simpson playing tentatively with this new statistical tool in his new methodology. Unlike “Patterns of Phyletic Evolution” where Simpson invited his readers to participate in a thought experiment, in “Notes on the Clark Fork” Simpson used actual data to test his new methodological approach. In “Notes on the Clark Fork,” Simpson believed that his new quantitative approach had the advantage of placing paleontology “on a more exact, more objective and less intuitive basis,” a claim he would later expand and defend in

Quantitative zoology. 280 Although Simpson was not alone in characterizing the traditional and usual methodological approach as subjective (one only has to recall the botanical debates that had ensnared Gilmour), at least some of his reasons for this characterization were tied to his concern regarding the worrisomely simple quantitative approaches implicit in traditional methodology, namely that taxonomic comparisons were made by comparing individual specimens and calculating means. So often was this done in taxonomy, worried Simpson, that even when groups of specimens were available and were compared, the comparison was of the several individuals of the group to the type specimen, and not of the group itself as a unit.281

This led Simpson to apply a Fisher’s statistical analysis of the group in an effort to distinguish real group differences from individual variation. In an effort to ease paleontologists into taking this particular statistical turn, Simpson reported in a footnote:

The constants and methods here employed are in wide use in other fields, although few paleontologists have hitherto used them. All are given in the following manual: Fisher, R.

280George G. Simpson “Notes on the Clark Fork, Upper Paleocene’ Fauna.” American Museum of Natural History Novitates, 954 (1937) 2. 281Simpson “Notes on the Clark Fork” 2.

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A., 1925, “Statistical methods for research workers.” Biological Monographs and Manuals, V. They are also explained and their peculiar adaptability to paleontological work discussed in a paper on the use of numerical data soon to go to press.282

One way “Notes on the Clark Fork” differed from Simpson’s earlier alpha taxonomy papers was that “Notes on the Clark Fork” applied both the qualitative descriptive analysis found in traditional methodology, and the new statistical approach he was developing for paleontologists.283 Using Fisher’s statistics, Simpson was hoping to provide a better way to infer from a sample to a population. This combination of techniques was evident in this paper, where

Simpson wove traditional taxonomic illustrations associated with the traditional qualitative analysis with new kinds of tables and calculations associated with his new statistical approach.284

Using his new methodology, Simpson was able to refute Granger’s claim that there were three distinct species of archaic ungulate, as well as support his own claim for a “single species, variable in all horizons but slowly increasing in size with the passage of time.”285

4.3.7 The Fort Union of the Crazy Mountain Field, Montana, and Its Mammalian Faunas (1937)

Simpson’s explicit demonstration of this new statistical approach (before Quantitative zoology) arrived later that year in his impressive monograph The Fort Union of the Crazy

Mountain Field, Montana, and Its Mammalian Faunas.286 “Notes on the Clark Fork” and

“Patterns of Phyletic Evolution” introduced the philosophical problem of inference when applied to determining species, but in this work on early Cenozoic mammals, Simpson explicitly

282Simpson “Notes on the Clark Fork” 2. 283Laporte noted that: “During the 1930s he [Simpson] moved from characterizing variation using simple descriptive statistics to using t-tests, a statistical method developed during the first decade of the twentieth century by W. S. Gossett to determine the probability that two samples were drawn from the same population.”[2003, 357] 284See pages 9-10 in “Notes on the Clark Fork” for an example of this mixed analysis for the new species Esthonyx grangeri. 285Simpson “Notes on the Clark Fork” 20-21. 286George G. Simpson The Fort Union of the Crazy Mountain Field, Montana, and Its Mammalian Faunas (United States National Museum, Bulletin 169, 1937) 1-287.

142 introduced the statistical techniques he employed to discriminate between fossil species. He introduced the idea of including statistics in his analysis by talking about the difficulties with coming up with an objective criterion for “due allowance” when it came to variation/nonvariable characters on the question of species:

Matthew, in the paper cited above, and most other writers on the question of species making in paleontology have insisted on making due allowance for variation, or using for taxonomy only nonvariable characters, but they have adduced no real, objective criterion as to what “due allowance” should be, and they sometimes seem to overlook the fact that there is no such thing as a truly and completely “nonvariable” character. Not merely as mechanical, mathematical procedures but as a general system of logic and a grouping method useful both explicitly and as an implicit background for dealing with both numerical characters and attributes, the methods of statistics provide the desired means of measuring variation accurately and the necessary criterion as to whether this variation is or is not of the sort normal within a species. These tests and this logical background have been the basis for taxonomy in this study. If the specimens pertaining to one genus could not indubitably be separated into different groups, the conclusion has been that the fundamental hypothesis of one species to each genus was correct. If they necessarily had to be separated into different groups, and these groups could not be interpreted as based on nontaxonomic differences (such as age or sex), then and only then has the hypothesis been discarded.287

Simpson proposed statistics, specifically the kind outlined by Fisher, as a solution to the problem. Statistics, believed Simpson, could provide the “provide the desired means of measuring variation accurately and the necessary criterion as to whether this variation is or is not of the sort normal within a species.”

Simpson began the method’s section in a curious way, but a way that underscored the importance he put on statistics in taxonomy’s methodological reform. Even though one of the sets of organisms Simpson examined returned no useful result, he still felt compelled to demonstrate what he believed to be a useful techniques used to make sense of this difficult data set:

287Simpson The Fort Union 65.

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The identification of this large multituberculate collection and its classification in genera and species have been peculiarly difficult, and the work was accomplished, as far as it was possible at all, only after prolonged and tedious analysis. Much of it led to no useful result and so is wholly omitted here. An outline of the useful methods employed will, however, be given, because they are similar to those used throughout this work and are in some parts unfamiliar to many paleontologists.288

Following a brief illustration of the statistical tools he employed, Simpson credited his quantitative analysis with enabling him better deal with the variation he observed, thus better enabling him to draw his species determinations:

These statistical data, furthermore, when considered from a taxonomic biological viewpoint, suggested the degree of variation to be expected in species of this family and also gave a criterion for judging the greater or less usefulness of certain characters for taxonomic distinction. Thus, in turn, a check was possible on the groups too small for the useful calculation of these derived data. . . After full consideration of all these primary and secondary data, it was clear that of the eight groups finally achieved and checked each represents a variable morphological unit, that the variation in each is not greater than commonly occurs in natural species, but that no two can be combined without producing a unit statistically heterogeneous and morphologically much more variable than a species. The biological conclusion is thus that eight species are present.289

Over the course of this work, Simpson called attention to instances where his new methodological approach provided better results than the traditional approach. For example:

Most paleontologists would think it wholly unjustified, for instance, to place a lower premolar measuring 7.0 mm in length in the same species with one measuring 9.1. But the coefficient of variation of the whole group to which these belong is only 5.3, and that is small, rather than large, for a linear dimension of teeth of a single mammalian species, so that there is no reason to believe that the graphs have permitted confusion of two species. These statistical data, furthermore, when considered from a taxonomic biological viewpoint, suggested the degree of variation to be expected in species of this family and also gave a criterion for judging the greater or less usefulness of certain characters for taxonomic distinction. Thus, in turn, a check was possible on the groups too small for the useful calculation of these derived data. 290

And

288Simpson The Fort Union 73. 289Simpson The Fort Union 76. 290Simpson The Fort Union 75-76.

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How misleading the best judgment may be when not aided by statistical treatment is shown by the fact that although Gidley clearly relied on size of P4 chiefly for specific separation (as shown by the nature of his groupings and also by his unpublished specific names, all of which denote size), he placed the small sinclairi specimens in one species but divided the large montanus into three species, although the variability of the former is nearly twice that of the latter. The misleading factor is that the absolute difference in the extremes is less for the small than for the large species. Although this is the striking character to the eye, it is not the essential factor either from a statistical or from a biological point of view.291

Common to all of the preliminary tests of his new methodology was an emphasis on the data, and only a brief discussion of the details of the methodology. This was a wise strategy.

Given the general feeling regarding formal tools, such as mathematics and logic, in zoology, Simpson felt it was better to quietly and modestly employ a new quantitative method in his research and demonstrate its great results than to outline in tedious detail a new methodology and insist loudly that others use it. This strategy also underscored the idea that new advances in taxonomy were forged through a balance between theory and practice. Simpson did not promote a new methodology that he was not confident could be put into practice and generate better results than its predecessor.

4.3.8 Quantitative Zoology (1939)

Simpson’s ideas on methodological reform found its clearest statement after these papers, in the textbook Quantitative Zoology: Numerical concepts and methods in the study of recent and fossil animals (1939), which he co-authored with Roe. Simpson and Roe began this textbook by acknowledging the difficulties faced when proposing a mathematically infused zoological methodology in what appeared to be a climate hostile to formal tools.292 But there was hope. At first glance, the marriage between statisticians and evolutionarily-minded zoologists seemed

291Simpson The Fort Union 78 footnote. 292For more on the role of statistics, as well as Simpson and Roe’s strategies in convincing their audience in Quantitative Zoology see Joel Hagen “The Statistical Frame of Mind in Systematic Biology from Quantitative Zoology to Biometry” Journal of the History of Biology 36 (2003) 353–384.

145 perfect, especially considering both dealt in “populations.” Simpson had been building an account of populations in his work previous to this monograph, and the notion of populations was found in statistics. On closer inspection, however, there was a significant gap between each practitioners’ concept of populations. Simpson and Roe acknowledged this difference in their opening statement, one designed to summarize the position zoologists took with respect to the difference between mathematical and biological viewpoints: “The exclusion of zoology from the roster of the exact sciences has usually been a subject of self-congratulation for zoologists and of reproach for their more mathematically inclined associates.”293According to Simpson and Roe, some zoologists congratulated themselves for what they took to be a sensible rejection of an irrelevant new tool.

However, the first serious problem with adopting a statistical approach was a practical problem. Simpson and Roe lamented this fact at the onset:

If zoology and paleontology have lagged behind most other sciences in their numerical methods, a major reason has been the extreme difficulty of learning the methods that are known in other fields and of adapting them to this one. In order to obtain the mathematical and statistical information pertinent to his own problems, the zoologist has had to wade through great masses of difficult material, most of it not directly useful to him and none of it specifically arranged for his purposes. This was the experience of the senior author of the present text some ten years ago when he set out to work toward a conscious, rational numerical methodology the absence of which was increasingly apparent to him in his own work and in that of almost all his colleagues. In order to accomplish anything in this line without abandoning his regular work, it was necessary to seek the aid and collaboration of someone who, without being a professional mathematician, was thoroughly familiar with the desirable mathematical and statistical concepts and was accustom to using them in practical research in some life science. The junior author of this volume possessed these qualifications, and for several years she has devoted much of her time to the joint research in methodology of which this book is one result.294

293George G. Simpson and Anne Roe Quantitative Zoology: Numerical concepts and methods in the study of recent and fossil animals (McGraw-Hill, New York and London, 1939) 1. 294Simpson and Roe Quantitative Zoology viii.

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Zoologists did not have the training or the textbooks available to help them learn this type of methodology. As Simpson said, the mathematics was there, but not in a form that was easily accessible to the working zoologist. However, even when the math was packaged up with a bow,

Simpson and Roe knew significant problems lay ahead.

One of the first real bones of contention, as even Fisher noted in the introduction to

Statistical Methods, was that much of formal statistical theory assumed populations to be idealized and infinite, and these idealized, infinite populations comprised the statistician’s

“ultimate reality.”295 The zoologist, in contrast, worked with natural populations, populations that were not infinitely large. In fact, often times the populations were relatively small, making the tools of formal statistics, by the admission of most traditional statisticians, irrelevant to zoological work. Simpson and Roe observed that “a homogenous sample of 30 specimens is a rarity in palaeontology, and a large part of zoology is also based on smaller samples than this.”296 It was no wonder that the paleontologist would fail to be impressed with this particular formal tool. Simpson and Roe addressed the conflict between the formal statistical and biological conception of populations, and how it affected the application of statistical tools in Chapter XI on small samples and single specimens. They wrote:

Measures and procedures that are only approximations or that are slightly inconsistent as estimates of population characteristics are sufficiently reliable and accurate in dealing with large samples, but some of them become unreliable when the samples are small. Many statisticians therefore do not use such methods on small sample, and some go so far as to say that it is impossible to obtain any useful information about a population from a small sample.297

The fact that zoologists could not use statistical tools did not seem to bother this generation of zoologists at all, since from their perspective, an infinite population was a “useless

295Simpson and Roe Quantitative Zoology 129. 296Simpson and Roe Quantitative Zoology 203. 297Simpson and Roe Quantitative Zoology 203.

147 abstraction.”298 Simpson and Roe made this clear when they considered the case where the tails of the normal curve approached the x-axis asymptotically. From a mathematical perspective, this kind of description was fine, but from the perspective of the zoologist, it was “utter nonsense.”

Why? Because, if the zoologist had a case where animal size were distributed normally, it meant that she had collected impossible specimens— “a mouse with ears a mile long or a snake long enough to girdle the earth at the equator.”299 Statisticians and zoologists, according to Simpson and Roe, had very different and seemingly irreconcilable perspectives.

Simpson and Roe cited this acknowledged irrelevance from statisticians and zoologists as possibly responsible for closing conversation between them. Skeptical zoologists believed that traditional statistical theory’s use of abstract ideas licensed them to ignore some potentially useful statistical techniques that could be applied to small samples. Likewise, many statisticians felt justified in turning a blind eye to the types of problems faced by taxonomists; in part because they employed small samples that were not useful from their perspective. In an effort to restore lines of communication, Simpson and Roe drew attention to problems with this line of objection, namely that it “stultifies their [zoologists’] whole work.”300 They argued that if zoologists used small samples, and they agreed that small samples are useless in the estimation of population characters, then:

. . . the sciences of zoology and palaeontology would become practically futile. . . [s]uch a conclusion really means that it is impossible from a usual zoological sample to learn anything useful about a population; and if this be true, zoologists are not studying nature, species, or general principles but are only amassing meaningless and incoherent observations.301

298Simpson and Roe Quantitative Zoology 132. 299Simpson and Roe Quantitative Zoology 130. 300Simpson and Roe Quantitative Zoology 203. 301Simpson and Roe Quantitative Zoology 203.

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To remedy this situation, Simpson and Rose introduced a new generation of statisticians: “. . . statisticians more conversant with the problems of small samples and zoologists more rational and realistic in their attitude towards their own problems have shown beyond question that small samples and even single observations do, or can, give useful information about populations.”302

These statisticians demonstrated that many of the procedures that were valid for large samples were also valid for small samples, and Simpson and Roe used these findings to urge zoologists to

“take the best available and to do as much with this as possible, not to adopt the attitude that anything less than perfection is hopelessly bad.”303 Simpson and Roe were eventually successful, but initially their success was recognized only in more experimental disciplines, such as genetics and ecology, that happened to be friendlier to quantitative techniques.

The application of statistical analysis to zoology involved forging a relationship between experimental and non-experimental methods to determine some common ground between biological and mathematical points of view, and in doing so, Simpson and Roe needed to discuss roles of objectivity and subjectivity in a collaborative approach. Why was there so much hesitation in forging a relationship between zoology and statistics? One reason was that Simpson and Roe were not simply proposing the addition of statistical tools into zoology’s toolbox; they were creating a new methodology that might potentially privilege mathematics over biology.

In spite of their promotion of a biologically relevant statistical approach, Simpson and

Roe knew that a situation could arise in which the formal methods of statistics conflicted with the more intuitive methods of taxonomy, and the zoologist would have to choose between mathematics and biology. Simpson and Roe’s concern underscored not only the inconsistency

302Simpson and Roe Quantitative Zoology 203. 303Simpson and Roe Quantitative Zoology 204.

149 between the viewpoints, but the normative difference between the statistical and biological viewpoints.

Simpson and Roe discussed the current perception of statistics, namely, that scientists tended to characterize the statistical viewpoint as formal and objective, in contrast to the biological viewpoint, which was characterized as intuitive and subjective. As historian Joel

Hagen pointed out, according to statisticians working at this time, when faced with such a conflict, taxonomists tended to choose “bad math” and “good biology,” and statisticians argued that this was a poor choice, since classification and phylogenetic reconstruction had a reputation of resting on subjective, intuitive judgments rather than objective reasoning.304 Simpson and Roe claimed that taxonomists had a long history of not being bothered by this kind of objection, because they saw their discipline as being both an “art” and a “science.” However, in this period of experimental science, and objectivity defined by measurement and mathematics, taxonomists were worried that the next generation of zoologists would be tempted to choose “good math” and

“bad biology.” To a certain extent Simpson and Roe were sympathetic to this concern. The sin that Simpson and Roe hoped to avoid (and that some taxonomists would later accuse Hennig of committing) was that the zoologist, in an effort to be “objective,” would privilege formal tools over biological fact. Simpson and Roe reassured their zoological readers that although they were proposing a quantitative methodology, they were not endorsing a position that privileged statistics over biology. They wrote:

The zoologist is not, and surely should not be, interested in reducing his observations or theories to a purely numerical basis simply because he likes numbers. His interest is not at all in formulas or digits, but in animals. He is concerned with the anatomy, behavior,

304Hagen “Statistical Frame” 358. According to McOuat, the terms “objective” and “intuitive” were not contraries, until the first few decades of the twentieth century. When the biologists worked on intuitions (or multiple experiences) they considered themselves objective, and the statisticians were entirely subjective. See McOuat “Kinds of people.”

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and relationships of these animals; and he quite properly refuses to fit his studies into any a priori framework, such as that of formal mathematics or statistics.305

Simpson and Roe reassured their audience that zoologists need not pay a high price for this quantitative method—biology remained in the foreground.

One of their goals was to make clear the role of statistics in zoology, such that zoologists would not be replaced by mathematicians or computers. If successful, they believed they could help zoologists move away from characterizing variation using simple descriptive numerical approaches (i.e., recording the means of a given anatomical character) to more sophisticated tools. The lesser evil, maintained Simpson and Roe, involved not walking along mathematical paths with blinders on, but continue along a loudly empiricist zoological trails armed with some formal tools.306

Simpson and Roe began their quest to convert zoologists to a quantitative approach by reminding zoologists that they have been employing mathematical concepts for a long time. In their first chapter, Simpson and Roe wrote:

When a zoologist sets out to describe or discuss any animals, he almost inevitably finds that he is using some numbers. Usually, measurements of the dimensions of individual animals are given; the proportions of the different parts of the animal are considered; different animals are compared as to size and proportions; abundance or scarcity of a species may be mentioned; the number of teeth, scales, fin rays vertebrates and the like are recorded; and in many other ways essentially numerical facts and deductions enter into the work.307

They also provided examples of zoological statements that did not seem numerical, but actually were numerical:

305Simpson and Roe Quantitative Zoology pp. vii–viii. 306Claims such as this can be found in Simpson and Roe Quantitative Zoology 205, 130, and 358. 307Simpson and Roe Quantitative Zoology 1.

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Commonly these observations are given by actual numbers; but not infrequently they may be expressed in words and without the use of figures. When it is said that one species is larger than another, that a given animal is abundant in a certain area, or that a mammal lacks canine teeth, for instance, this is only a verbal expression of a numerical idea. If such an observation can be reduced to concrete figures, the expression will usually be made more accurate and more succinct.308

By reminding zoologists that they do use numbers regularly, Simpson and Roe shifted the problem away from claims that zoologists feared including numbers, to the claim that zoologists lacked the tools to handle numerical data effectively. To drive this last point home, Simpson and

Roe wrote: “Zoological literature is replete with long tables of measurements that prove nothing and the publication of which was unnecessary, expensive, and really a discourtesy to other students.”309 By including statistical methods into zoological methodology, Simpson and Roe aimed to “provide definite tests as to whether the measurements really are significant, facilitating the selection of essential and rejection of the non-essential data; and they also assist in reducing raw data to the most compact and useful form.”310 Simpson and Roe stressed this point because of how they saw this kind of numerical approach figuring into a more general picture of science.

According to Simpson and Roe “[t]he logical transition from the particular to the general is the most difficult part of research, and it is the point where the student is most likely to go astray.”311 As seen from Simpson’s earlier work, he discussed inductive inferences, moving from a small sample to a whole population or from individuals to species, and he identified this kind of inference as a difficult problem. Even for Simpson, a scientist coming from a descriptive tradition, science was not simply a collection of uninterpreted facts or observations. Simpson and

Roe maintained that: “[o]bservation, in itself, is not science and has no value except as a basis for interpretation and some degree of generalization . . . Undue preoccupation with what is

308Simpson and Roe Quantitative Zoology 1. 309Simpson and Roe Quantitative Zoology 18. 310Simpson and Roe Quantitative Zoology 18. 311Simpson and Roe Quantitative Zoology 96.

152 actually observed and failure to relate it to broader issues and conclusions are a constant danger of the method.”312 At least this much they believe zoologists would find unproblematic.

Simpson and Roe suspected that the zoologist’s concern with their new methodology would begin with their claim that “[z]oology is, or should be, a study of populations.”313

Although Simpson would later tie this claim to Darwin, at this stage the impetus to make such a claim came out of his concerns about inference in zoology. Taxonomists could not avoid the serious ramifications that a focus on populations would have on their methodology. Simpson had worried for a while that taxonomists appealed to a single “type” specimen in the collection when characterizing a species. If species were understood as populations, museums and herbarium collections would need to change from collections of individual type specimens to sets that reflected adequately the full range of variation in a species. But this was not the only problem.

Taken literally, the claim that zoology should be the study of populations raised additional practical problems for the zoologist: a whole population cannot be brought into the laboratory or examined in the field. So, in addition to a change in collections, a change in collecting was required. Specifically, taxonomists needed an approach that would enable them to collect samples randomly, a new method for organizing and interpreting the data, as well as licensing valid inference moves from particular instances to a general case, which could be brought into the lab or examined in the field. The method Simpson and Roe suggested was the method of samples.314 By applying sampling methods, claimed Simpson and Roe, “populations” could be taken literally (as applying to a natural group of animals) and figuratively (as applying

312“Any particular set of observations usually has little or no interest unless it reveals characteristics of a broader scope and wider application than those actually observed. Even observations that are truly unique, such as those of abnormalities not repeated, have no value unless they cast light on more normal and widespread processes like heredity and embryology.” 313Simpson and Roe Quantitative Zoology 166. 314Simpson and Roe Quantitative Zoology 166.

153 to all existing phenomena of which few are observed). Introducing the sampling method, however, was not without its problems.

If zoologists wanted to infer the properties of a whole population from a given sample,

Simpson and Roe claimed that the first step involved reducing the original observations to more compact form that enabled them to be tabulated in the form of a frequency distribution. From this frequency distribution, general conclusions could be confidently drawn.315 Simpson and

Roe’s defined “frequency” as “the number of observations that fall into any one defined category”316 and “frequency distribution” as “a list of those categories with the frequency of each.”317 The problem with sampling, however, was that values calculated from sample were not accurate measures applicable to the whole population. Simpson and Roe acknowledged the mathematical impossibility of a sample to have the same mean, standard deviation, coefficient of variation, or other parameters, as the population to which it belonged, because all these values depended on each individual observation in the sample, and these individual observations were selected by chance from the population.318 In spite of this fact, Simpson and Roe maintained that there were better and worse methods for moving from particulars to general.

One way to ensure more accurate inferences from particulars to generals, Simpson and

Roe claimed, would be to begin with a sufficiently large random sample. That way its distribution would approximate that of the population, and the calculated parameters that were accurate for the sample would be “more or less good approximations of those of the population.”319 Although Quantitative Zoology provided a quantitative analysis for zoology

315Simpson and Roe Quantitative Zoology 34. 316Simpson and Roe Quantitative Zoology 34. 317Simpson and Roe Quantitative Zoology 34. 318Simpson and Roe Quantitative Zoology 149. 319Simpson and Roe Quantitative Zoology 149.

154 more generally, in the 1940s Simpson elaborated on the relevance of this methodology to taxonomy more specifically.

4.4 Conclusion

Quantitative Zoology was remembered as one of taxonomy’s most influential books of the twentieth century, but it took time for Quantitative Zoology to achieve this status. Hagen claimed that the publisher, McGraw-Hill discontinued the book in 1947, due to poor sales.320 In the eight years between editions, Hagen described a change in the biological landscape. The rise in status of population genetics had included more mathematical training for a new generation of biologists. In addition to this change in training, Simpson was involved in societies with the express goal to encourage an interdisciplinary approach for evolutionary studies. During the

1940s and 1950s, Simpson was involved activities such as: Committee on Common Problems of

Genetics, Paleontology, and Systematics, the creation of the journal Evolution, and the Society for the Study of Evolution. In taxonomic circles, methodological reform was certainly underway, and given the number of interdisciplinary groups and publications appearing, the direction of that reform was taking shape along quantitative lines. Such changes in the intellectual terrain prompted McGraw-Hill to approach Simpson with an offer for to issue a revised edition, which he rebuffed.321 Instead, he and Roe approached a young Drosophila geneticist named Richard

Lewontin to help write their revised edition for Harcourt Brace.

In the second edition of Quantitative Zoology, Simpson, Roe, and Richard Lewontin reflected on how far zoology had come, methodologically speaking, in a few decades. They noted zoologists lacked of quantitative training when Simpson and Roe’s book was first launched, and this lacuna prompted them to publish the book in 1939:

320Hagen “Statistical Frame” 363. 321 Hagen “Statistical frame” 363.

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The use of quantitative methods in zoology has changed considerably since the first edition of this book was written (mostly in 1937) and published (1939). Then the application of any but extremely elementary numerical techniques was quite unusual in this field. Students were almost never given explicit training in handling quantitative data. Practicing zoologists were not only, as a rule, profoundly ignorant of the principles of statistics but also, in many cases, outspokenly antagonistic to any statistical approach to their problems. It was that situation and our dissatisfaction with it that led the original authors to write this book.322

Simpson, Roe, and Lewontin also credited part of the change in attitude towards quantitative approaches to Huxley’s book, The New Systematics, which they believed helped taxonomists prepare for methodological change:

A change was then in the air, especially as regards systematics which among all the ramifications of zoology necessarily remained its basic discipline. The practice of systematics was still usually typological in 1939, but a change to population systematics was incipient. The New Systematics, which as much as any one work both signalized and stimulated the change, appeared in 1940, the year after Quantitative Zoology. The satisfactory treatment of populations absolutely requires the application of statistical concepts and the use of some, even if only the simplest, statistical methods.323

Species as populations solved some methodological problems, but in doing so raised some complicated logical and ontological problems that Simpson would face in the 1940s. Although

Lewontin was responsible for the bulk of the important changes to Quantitative Zoology, Hagen noted Simpson vetoed many of Lewontin’s suggestions. Simpson had affected a lot of change, he still moved with caution.

The statistical position he maintained in his work, coupled with the interdisciplinary work he was involved in from the 1940s onwards, led to Simpson weighing in on issues in taxonomy that touched on formal logic, specifically set-theory. His background in statistics put him in a position to effectively debate with numerical taxonomists about the mathematics underpinning

322George G. Simpson, Anne Roe, and Richard C. Lewontin, Quantitative Zoology: Numerical concepts and methods in the study of recent and fossil animals (Dover Publications, Inc., New York, 2003) 1960 iv-v. 323Simpson, et al Quantitative Zoology 2003 v.

156 their programme.324 In Principles of animal taxonomy (1961), he commented on Woodger’s The axiomatic method in biology (1937), Biological principles (1948), Biology and language (1952),

Gregg’s The language of taxonomy (1954), Beckner’s The biological way of thought (1959), and dedicated a section to set-theory and taxonomy, where he presented the objections but didn’t claim that applications of logic to taxonomy as a rule is doomed to fail.325 In fact, he presented a list of set-theoretical symbols and encouraged others to take up the challenge. Evidently, the young philosopher David Hull accepted in “Consistency and Monophyly,” as did mathematician and philosopher of science Nicholas Jardine in “The Application of Simpson’s Criterion of

Consistency to Phenetic Classifications.”326 In the growing interdisciplinary world, they were not alone taking up Simpson’s challenge.

324Nicholas Jardine wrote a number of articles on this topic at the time. For example, see Nicholas Jardine and R. Sibson “Quantitative Attributes in Taxonomic Descriptions” Taxon, 19 (1970) 862-870; Nicholas Jardine “A Logical Basis for Biological Classification” Systematic Zoology, 18 (1969) 37-52; Nicholas Jardine “The Application of Simpson's Criterion of Consistency to Phenetic Classifications” Systematic Zoology, 20 (1971) 70- 72. For a broader view see Joel Hagen “The Statistical Frame of Mind in Systematic Biology from Quantitative Zoology to Biometry” Journal of the History of Biology 36(2003): 353–384. 325Simpson Principles 25-28 326David L. Hull “Consistency and Monophyly” Systematic Zoology, 13 (1964)1-11.; Jardine “ Simpson's Criterion” 70-72

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Chapter 5 Hennig 1947-1950

5.1 Introduction

Taxonomy’s need for methodological reform transcended geographical boundaries.

However, the approach to this reform was different in Germany than in Britain and America.

Specifically, on the relationship between formal logic and taxonomy, as well as philosophy and taxonomy, there seemed to be more explicit discussion in Germany. For example, although later accused of promoting logical positivism, Gilmour’s work involved no set theory and the references made to formal logic were brief. Instead, his work reflected a relationship between logic and taxonomy that emphasized how taxonomists had used inductive logic not only to organize nature, but to resolve debates, to illustrate fallacious reasoning, and to encourage progress in this period of reform. Rather than focus on the compositionality of species, Gilmour focused on taxonomic inferences, providing a logical and epistemological critique of how inferences were made in an evolutionary taxonomy.

Likewise, on the relationship between logic and taxonomy, the target of Simpson’s investigations began with taxonomic inference before turning to questions of taxonomic schemata, like the compositionality of species. Simpson’s work relied on a new kind of statistics that focused on populations not individuals, and his quantitative shift drew attention to the relationship between logic and taxonomy, specifically a methodology that targeted inductive inference. Simpson’s methodology was designed to make better inferences from particulars to generals. Only later did questions about individuals and populations in this new taxonomic methodology lead Simpson to more philosophical questions about the logical composition of groups, as well as the ontological status of taxonomic groups. In general, questions regarding

158 formal logic and taxonomic methodology, specifically set-theory, really did not become a popular topic of debate in British and American taxonomic circles until the 1950s. In contrast, when Hennig tackled taxonomy’s methodological problems, he peppered his text liberally with philosophy and logic, in particular formal logic. One of his primary issues was with taxonomic schemata.

Hennig believed the structure that best represented the complex taxonomic relations was hierarchical. Not only did he believe that structure was hierarchical, but he took the radical position that when discussing the structure of taxonomic groups, the relevant structure was a mereological “division hierarchy,” not a traditional set-theoretic hierarchy. He had at least two reasons for holding this position. His reasons were controversial, and many prominent taxonomists argued unsupportable, but he presented his ideas as early as 1947 and maintained his position consistently through both editions of the Grundzüge einer Theorie der Phylogenetischen

Systematik (1950), as well as Phylogenetic systematics (1966). First, Hennig assigned ontological status not just to species, but to higher taxonomic categories. He believed that species and higher taxonomic groups were real, and because division hierarchies were mereological, resulting in individuals, not sets or classes, it is not surprising Hennig would find this formal account appealing. Hennig was clear about this ontological feature when he discussed division hierarchies. When it came to individuals, Hennig was not caught up with logical puzzles such as the Ship of Theseus style puzzles that focus on the persistence of identity over time. Hennig was not searching for essences, and he knew individuals were not simply bound by skin or bark.

Drawing from a motley collection of philosophers and biologists, including: Theodor Ziehen,

Rudolf Carnap, Walter Zimmerman, Nicolai Hartmann, Joseph H. Woodger, Theodore Torrey, and Ludwig von Bertalanffy, Hennig would argue that individuals were segments of the temporal stream of successive breeding populations that had a beginning and end in time. Second, Hennig

159 believed that phylogenetic relationships occurred through time. Division hierarchies had a notion of time built in, whereas traditional set-theoretic accounts were atemporal.

Hennig began sketching out his account of hierarchies in a short paper in 1947 when he introduced the term “Teilungshierarchie” or division hierarchy—a logical term coined by cell biologist Joseph Woodger. Hennig’s account of hierarchies has been a source of debate in the literature, from the role played by Rudolf Carnap’s logic in Hennig’s work and later to role of

John Gregg and Woodger’s logic in his account of hierarchies in Phylogenetic systematics

(1966). In this chapter, I will expose and then resolve some of the misconceptions surrounding

Hennig on the topic of formal logic and its relationship to taxonomy, specifically with respect to

Carnap and Woodger, as it played out in his account of hierarchies and as it developed in his writing from 1947-1950.

5.2 Hennig’s early years

Words flowed from Hennig’s pen. It seemed they always did. Unlike Simpson, who moved cautiously on radical ideas as a young man, Hennig virtually exploded with ideas and enthusiasm, throwing caution to the wind. Hennig wrote an essay at eighteen titled “First essay. 4

May 1931. The position of systematics in zoology.” showing:

. . . his enthusiasm for systematics in terms of phylogeny, his almost impatient need to emphasize its general importance, -to fight against improper superficiality, to give reasons for various misinterpretations, etc.; and it also expresses his views that relationships and systematics are identical (“...clarification of relationships and thus systematic affinity...”).327 Where his high school essay bore the sheer exuberance and passion of youth, his first published paper demonstrated his exuberance and passion balanced by the skill and talent of a promising

327Translation of “Schlee, D. 1978. In Memoriam Willi Hennig 1913-1976 Eine biographische Skizze. Entomologica Germanica 4:377-391” Also see Rudolf Meier “Role of dipterology in phylogenetic systematics: The insight of Willi Hennig” pg 46 in The evolutionary biology of flies By David K. Yeates, Brian M. Wiegmann.

160 alpha taxonomist. Most of Hennig’s taxonomic work was on flies, but his first paper in 1932 at nineteen with W. Heise was on the snake genus Dendrophis. 328 On Hennig’s early work in alpha taxonomy, Hennig’s biographer Michael Schmitt noted that:

Willi Hennig pounced avidly on these challenges, and the papers produced demonstrate that he succeeded surprisingly well for his age, and these papers on reptiles are still useful up today [sic]. Here, Willi Hennig learned to cope with nomenclatorial problems, with taxonomic descriptions, and with zoogeographic data. The revision of the genus Draco, 67 pages long, is an example of careful observing and measuring and show that Willi Hennig mastered quite a lot of statistics (in later papers, he rarely returned to statistical analyses).329 Even as a student, Hennig’s alpha taxonomic work walked hand-in-hand with his more revolutionary ideas. Henning scoured the literature for inspiration. Schmitt wrote:

However, here lay the beginnings of the first major contributions Willi Hennig made to systematics: to define “relationship” in a strictly genealogic way, i.e. distinguishing relationship from similarity. However, he did not invent this distinction, but rather took it from the writings of Adolf Naef, especially from his papers published in 1917 and 1919.330 Naef’s work was just one of many that helped steer Hennig towards the radical ideas that would make up the Grundzüge einer Theorie der Phylogenetischen Systematik (1950).

Hennig entered the University of Leipzig in 1932 and completed his thesis by 1936.331

Even as a student, Hennig plowed through his days with an enviable work ethic. While at

Leipzig, Hennig published eight papers, mainly on Diptera, bringing his publications total to approximately five hundred pages including his thesis.332 After graduation, Hennig studied briefly at the State Museum of Zoology in Dresden, before joining the German Entomological

328A second paper was published in 1935. 329Michael Schmitt “Willi Hennig and the Rise of Cladistics” Proceedings from the 18th International Congress of Zoology. (2003): 371. See also Schmitt “Willi Hennig” 318. 330Schmitt ‘Rise of cladistics” 371. 331Schlee “In Memoriam Willi Hennig” 4, Schmitt “Willi Hennig” 319-320; Schmitt ‘Rise of cladistics” 371. 332Schlee “In Memoriam Willi Hennig” 4.

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Institute of the Kaiser-Wilhelm-Gesellschaft.333 By 1939 Hennig’s list of his publications exploded, bringing his page total to over a thousand.334 Most of Hennig’s papers focused on

Diptera taxonomy, but he had his thumbs in many pots: other insects, reptiles, and broader issues in classification.

Schmitt noted that Hennig’s broke with methodological tradition in 1936 when he did more than note that using similarity to classify larvae and adults of the same taxa often resulted in different classifications, even though they shared the same phylogenetic history.335 Schmitt claimed that it was becoming increasingly clear to Hennig that similarity was not a reliable choice for estimating evolutionary relationships, and Hennig used this insight to challenge the generally accepted view that overall similarity can be used to construct phylogenetic trees.336

Defining “relationship” genealogically and distinguishing relationship from similarity was a crucial first step in Hennig’s phylogenetic agenda. In fact, perhaps the most basic principle of

Hennig’s phylogenetic systematics was the idea that similarity was not synonymous with “blood relationships” and he discussed this at length in the Grundzüge.

By 1936, Hennig had started to examine the relationship between geographic distribution and systematic classification of some dipteran families with respect to the problem of classifying taxa of higher order. In “Beziehungen zwischen geographischer Verbreitung und systematischer

Gliederung bei einigen Dipterenfamilien: ein Beitrag zum Problem der Gliederung

333Schlee “In Memoriam Willi Hennig” 4. 334Schlee “In Memoriam Willi Hennig” 4. 335Willi Hennig “Beziehungen zwischen geographischer Verbreitung und systematischer Gliederung bei einigen Dipterenfamilien: ein Beitrag zum Problem der Gliederung systematischer Kategorien höherer Ordnung.” Zoologischer Anzeiger, 116(1936): 161–175, and “Ein Beitrag zum Problem der “Beziehungen zwishen Larven-und Imaginalsystematik.” Arbeiten Morph. Taxon. Entomol. (Berlin) 10(1943):138-145. For more, see Schmitt “Willi Hennig, the cautious revolutioniser” Palaeodiversity 3( 2010). 336Hennig “Beziehungen zwischen geographischer Verbreitung und systematischer Gliederung bei einigen Dipterenfamilien: ein Beitrag zum Problem der Gliederung systematischer Kategorien höherer Ordnung.” 1936, “Ein Beitrag zum Problem der “Beziehungen zwishen Larven-und Imaginalsystematik.” 1943.

162 systematischer Kategorien höherer Ordnung.” (1936), Schmitt noted Hennig’s two significant insights. First, that Hennig distinguished between primitive characters as “independently retained inheritance from the ancestor of all tylids” and the “progressive characters shared by Tylinae and

Neriinae,” the latter of which suggested closer phylogenetic relationships of the two subfamilies mentioned. Second, Hennig stated explicitly “that a systematic classification must be done according to phylogenetic relationship rather than to morphological differentiation.”337

In 1938, Hennig’s research was interrupted by the shortened basic military training he received for the infantry. In the spring of 1939 he was conscripted. According to Schlee:

The terror of war continued to have a lasting effect on him even in his later years. He himself, seriously wounded, was one of five survivors of an entire company and one of his brothers did not return from Stalingrad. Even much later, particularly during the time of the annual siren testing, he used to remark how intensely his war experiences had made him aware of the limitations imposed on his creative output and how much he felt obliged to use the available time to the utmost.338

Hennig served in the infantry in Poland, France, Denmark, and Russia, before being wounded in

1942, and bounced around several field hospitals. After a six month “working leave” in Berlin, the Medical Academy of the Army in Berlin sent Hennig to work on malaria control in Greece and Northern Italy. There he was captured by the British in 1945 and shortly after being captured, Hennig worked with the British anti-malaria service.339 In keeping with his claim that he felt obliged to use the available time to the utmost, Hennig wrote while a prisoner of war.

According to Schmitt, after Hennig was wounded in 1942, he was appointed a military entomologist in Italy, and his duties included controlling malaria and other

337Schmitt “Rise of cladistics.” 372. 338Schlee “In Memoriam Willi Hennig” 5. 339Schmitt “Rise of cladistics” 371.

163 epidemics. His role as entomologist continued when he was taken prisoner of war in 1945 by the

British, and put into the British anti-malaria service only after a few weeks of captivity.340

Hennig crafted his seminal work, the Grundzüge, in turmoil. Intellectually, it was born in the throes of taxonomy’s methodological reform. Physically, Hennig began writing the manuscript in a 170 page, cardboard-covered Italian notebook while in prison.341 Hennig’s wife,

Irma, played an important role in the Grundzüge’s formation. Her background made her well- suited for her role in gathering crucial literature and necessary research for Hennig, which she managed to get it to him through the army postal service.342 Hennig met his wife in at the

University of Leipzig, where she was also a biology student.343 Her skills also made her valuable resource in other roles, such as proof-reading, which she took on as she raised their children in the harrowing uncertainty of 1940s Germany.344

When Hennig returned to Germany, he was not able to reunite with his family. He was released to West Germany because of concern that he might end up as a Soviet prisoner of war if he return to the East Germany. The rest of his family continued to live in Leipzig.345 In 1945, he became Acting Director of the Zoological Institute at the University of Leipzig, during which time he crossed the East German border to join his family illegally, and he was able to do this because those within the Zoological Institute knew that Hennig never supported any aspect of the

340Schmitt “Rise of cladistics” 372. 341Schlee “In Memoriam Willi Hennig” 5. 342Schmitt noted that from periodically Hennig asked Irma to copy by hand passages from papers he needed. See Schmitt “Willi Hennig and the rise of cladistics” Proc. of 18th Cong. of Zoology 2003 p. 373. 343Schmitt “Willi Hennig” Darwin & Co.: eine Geschichte der Biologie in Portraits hrsg. von Ilse Jahn und Michael Schmitt.- München: Beck 2001. Schlee noted that Irma Hennig had a background in both mathematics and biology and continued her interest and actively supported her husband’s work her entire life. He also noted that she may well have been a guiding influence on the career development in their sons as all three attended university, two studied biology and chemistry, and are engaged in research at the Max Plank Institute, and the third has completed studies as a secondary school teacher of German and history. 344Schlee “In Memoriam Willi Hennig” 5. Hennig met his wife before the war at the University of Leipzig. Irma Wehnert began as a biology student. See Schmitt “Willi Hennig” 320. 345Schlee “In Memoriam Willi Hennig” 6.

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Nazi regime.346 Two years later, Hennig resigned from the University of Leipzig and returned to the German Entomological Institute in Mecklenburg.

5.3 “Probleme der biologischen Systematik” (1947) In 1947, Hennig published “Probleme der biologischen Systematik;” a short theoretical paper discussing the state of taxonomy. In this paper Hennig toyed with more philosophical notions regarding hierarchies and began developing concept of a semaphoront (although he did not use the term in this paper), and issued a promissory note for further discussion on these and other topics in his forthcoming manuscript.347 On the state of taxonomy, Hennig claimed that phylogenetic systematics was not only a descriptive or ideographic science, but nomothetic or law-like science. He argued that the nomothetic and ideographic aspects of taxonomy might be able to be kept apart during one’s training, but they could not be separated from each other in research—an idea he would develop in detail in the Grundzüge.348 Given this understanding of taxonomy, it is not surprising that Hennig would appeal to physics and philosophy (and work in biology that drew from physics and philosophy) in his methodological reform, and include more technical vocabulary found in philosophy and logic in his work. With respect to logic, in this paper he used the technical term “Teilungshierarchie” which translated to “division hierarchy” in

346Schlee “In Memoriam Willi Hennig” 6. 347Hennig wrote: Die wichtigen unmittelbaren Zukunftsaufgaben der Systematik sehe ich im allgemeinen in der weiteren Klärung ihrer eigenen theoretischen Grundlagen und im speziellen in einer Objektivierung ihrer Gruppenkategorien, ohne die an eine exakte Lösung der skizzierten Aufgaben nicht zu denken ist. Wenn es heute nicht möglicht ist, anzugeben, in welcher Hinsicht Gruppen, die in verschiedenen Bezirken des Systems, z.B. bei Pflanzen und in verschidenen Tier”stämmen”, mit derselben Kategorienbezeichnung belegt werden (etwa Familien, Ordnungen usw.), auch wirklich vergleichbare Einheiten sind, so ist dies ein Mangel, der die erfolgreiche Inangriffnahme der geschilderten Aufgaben der phylogenetischen Systematik zur Zeit am stärksten behindert. Für die Beantwortung der Frage, wie dieser Mangel zu beheben ist, muß ich auf meine im Manuskript vorliegende umfassende Darstellung verweisen. [Hennig “Probleme” 279] 348Hennig wrote: Alle diese Überlegungen zeigen zugleich, daß es nicht angeht, die phylogenetische Systematik als idiographische, nur beschreibende Wissenschaft anderen, nomothetischen, auf die Erkenntnis von Naturgesetzen abzielenden Wissenschaften gegenüberzustellen. Nomothetische und idiographische Gesichtspunkte können allenfalls in der Lehre, nicht aber in der Forschung voneinander getrennt werden. [Hennig “Probleme” 277]

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English. Although Hennig provided no bibliography in “Probleme der biologischen Systematik,” he associated “Teilungshierarchie” with biologist Ludwig von Bertalanffy (1901-1972) who borrowed the term from Woodger.

He opened “Probleme der biologischen Systematik” with a concern that many biologists did not view taxonomy as important as other scientific disciplines, and according to Hennig, the blame for taxonomy’s low esteem could be firmly placed on taxonomists not being able to explain taxonomy’s problems and methods.349 So, for Hennig, taxonomists had a great deal of work ahead of them, and their first order of business was to specify their problems and clean up their methods. One place to start was with the notion of relations. In his earlier work, Hennig distinguished between taxonomic relationships and similarity. In this paper, Hennig looked deeply at the idea of relations.

Hennig was concerned with what he called “morphological” or typological” systematics because he believed that such systems arranged organisms according to similarity of form or

“Gestalt.” He noted that after the rise of evolutionary theory, taxonomists began to “reinterpret” morphological similarity genetically. However, he claimed that after a while biologists began to reinterpret systems so much that they were becoming combined systems, and the different organizing principles were becoming more and more detached from each other, so much so that systematics as a discipline seemed to be eliminated.350 Systematics, he thought, needed to be brought back.

349Hennig wrote: Im Bewußtsein vieler Biologen ist die Systematik ein Gebiet dessen Ergebnisse sich an allgemeiner Bedeutung grundsätzlich nicht mit denen anderer Teildisziplinen ihrer Wissenschaft messen können. Die Schuld an dieser geringen Wertschätzung trägt zu einem großen Teile die Systematik selbst, der es bisher nicht gelungen ist, ein umfassendes Lehrgebäude ihrer Probleme und Methoden zu errichten. [Hennig “Probleme” 276] 350Hennig wrote:

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Although he did not use the term “semaphoront” until the Grundzüge, he began to develop the concept in this paper. Hennig began looking at relations, in particular genetic relations and how they were connected to the concept of an individual. These were the ideas that would become central to his concept of an individual. In this paper, he talked about “the carriers” or “die Merkmalsträger” as comprising short periods of an individual’s life, during the course of which they changed so thoroughly in their “physical, psychological and ecological systems,” that they can be seen as “different phases” of the same individual. He argued such an individuality claim could only be made if one could uncover the links connecting the different phases—a genetic link could be made. Hennig went on to discuss metamorphosis of the common flesh fly as an illustration of his point.351 Hennig credited his insights along these lines to Walter

In dieser Frage stehen sich heute namentlich die Vertreter einer genetischen und einer morphologischen Systematik mit voneinander abweichenden Anworten gegenüber. Von vielen wird die Auffassung vertreten daß aus historischen und logischen Gründen dem morphologischen oder typologischen System in dem die Lebewesen nach ihrer Gestalt ähnlichkeit geordnet sind, vor anderen der Vorzug gebühre Aus historischen Gründen, weil die älteren Systeme durch weg nach diesem Prinzip aufgestellt und dann erst, nach dem Aufkommen der Deszendenztheorie, von einer genetischen Systematik genetisch „umgedeutet“ worden sein. Aus logischen Gründen, weil das genetische System wenigstens für die höheren, auf entfernterer genetischer Verwandischaft ihrer Komponenten Beruhenden Kategorien ausschließlich undeine Umdeutung der morphologischen Befunde angewissen sei. Beide Begründungen beruhrn auf irrigen Voraussetzegen Historischen haben auch die ältesten Systeme bereits genetische Kriterien verwertet. Sie waren nicht System der morphologischen Ähnlichkeitsbeziehungen, die später erst genetisch umgedeutet wurden, sondern vielmehr kombiniert Systeme, in denen die verschiedensten Prinzipien, nach dem Organismen geordnet werden können und müssen (e. Obes.) miteinander kombiniert wurden. Hier hat wissenschaftges schichtlich eine „Entwicklung“ im eigentlichen Sinne dieser Wortes stattgefunden, indem die verschiedenen Ordnungsprinzipien immer mehr voneinander gelöst bzw. Teilweise auf des Aufgabengebiet der eigentlichen „Systematik“ ausgeschieden wurden. [Hennig “Probleme” 276] 351 Hennig wrote: In Wirklichkeit sind „die Merkmalsträger“ die wahren Elemente der systematischen Arbeit d. h die Individuen innerhalb kurzer Zeitspannen ihrer Lebens, in Verlaufe deren sie sich selbst und damit ihrer Beziehungen zu anderen nicht verändern. Daß dem wirklich so ist, lehrt die Beobachtung daß viele Individuen sich im vielen Eigenschaften ihrer Gestalt (von ihrer räumlichen Verteilung ganz abgesehen) im Laufe ihres Lebens so gründlich verändern können, daß die verschiedenen Stadien, z.b. in physiologischen, psychologischen, ökologischen System an ganz verschiedenener Stelle erschienen müssen, und del sie als Phasen ein und „desselben“ Individuums nur durch Aufdeckung des zwischen ihnen bestehenden lückenlosen genetischen Zusammenhanges erkannt werden können. Die Richtigkeit der Behauptung, daß die Kategorie „Individuum“ bereits eines Gruppenbildung der genetischen Systematik darstellt, geht weiterhin daraus hervor, daß die verschiedeme Komponenten dieser Kategorie, z. B. Metamorphosestadiea ohne Kenntnis des genetischen Zusammenhanges vielfach in verschiendene höhere Gruppen des Systemes eingeordnet worden sind, obwohl die genetischen Beziehungen dieser Art, sowen soe bekannt waren, in jedem System bisher berücksichstiger worden sind. So hat man die Larven einer unserer häufigster Fleischfliegen am Anfange des vorigen Jahrhunderts in der Gattung Ascaris (Spulwürmer) beschrieben. [Hennig “Probleme” 276]

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Zimmermann, another biologist who believed in cleaning up taxonomic methodology along more formal lines. Zimmerman placed an emphasis on genetic relations, which he called “hologenetic relations.” 352 Hologenetic relations would also get a much more detailed treatment in the

Grundzüge.

5.3.1 Division hierarchies When Hennig used the term “Teilungshierarchie” or “division hierarchies” he used it in a specific context to highlight a specific kind of relation, namely phylogenetic relationships defined with respect to reproductive communities. Before he discussed division hierarchies, he talked about hierarchies in taxonomy more generally. He said that although there were other types of systems available to taxonomists, noting the “periodic system” for butterflies and the network structure of family relations, the most suitable system for representing the phylogenetic system was a hierarchical system.353 Hennig went on to specify the kind of hierarchical system he had in mind when he was sketching out the structure of genetic relationships in reproductive communities when they split in two. Hennig wrote:

352Hennig wrote: Nun sind die leicht feststellbaren Beziehungen zwischen den verschienden Stadien eines der Metamorphose unterworfenen Individuums und die ebenso leicht erkennbaren genetischen Beziehungen zwischen Eltern und ihren oft so stark wenigstens geschlechtsverschiedenen Nachkommen aber nur ein Teil der hologenetischen Beziehungen (Zimmerman). Die alle lebenden und erloschenen „Merkmalsträger” miteinander verbinden.[ Hennig “Probleme” 277] 353Henning made a similar claim in the Grundzüge, but in this paper he wrote: Über der bevorzugten Stellung der Art kategorie darf die Bedeutung der höheren Gruppenkategorien im genetischen System nicht vergessen werden. In ihnen sind die in der heutigen Organismenwelt unterscheidbaren Arten nach Maßgabe ihrer Entstehung durch den Zerfall älterer Stammarten derart zusammengefaßt, daß die jeweils höheren Kategorien mehrere niedere Artengruppen umfassen, von denen angenommen wird, daß sie durch den Zerfall einer Stammart entstanden sind, von der außer ihnen keine anderen lebenden Arten abzuleiten sind. Damit ist aber auch die Frage entscheiden, ob die heute vorherrschend angewandte hierarchische Form des Systems tatsächlich auch diejenige ist, in der die genetischen Verwandtschaftsbeziehungen der Arten am zutreffendsten zum Ausdruck gebracht werden können. Vielfach hat man die Auffassung vertreten, daß andere Systemtypen dafür geeigneter wären, und es sind es sind auch Versuche gemacht worden, solche in die Systematik einzuführen. So ist für die Schmetterlinge ein “periodisches System” entworfen worden. In anderen Fällen ist von der Netzstruktur der Verwandtschaftsbeziehungen gesprochen worden, die auch in einem entsprechend konstruierten Systeme zum Ausdruck gebracht werden müßten. [Hennig “Probleme” 278]

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Alle diese Versuche beruhen auf irrigen Vorstellungen von der Struktur der genetischen Beziehungen. Mit der Erkenntnis, daß die Gesamtheit der Organismen in eine Anzahl von Fortpflanzungsgemeinschaften zerfällt, daß diese Fortpflanzungsgemeinschaften (Arten) durch Spaltung zerfallen und mit der Entscheidung, daß die so entstehenden “phylogenetischen” Beziehungen zwischen den Nachfolgearten als natürliche Fortsetzungen der innerhalb der Arten bestehenden genetischen Beziehungen es sind, die im Phylogenetischen System und damit im allgemeinen Bezugssystem “der Systematik” dargestellt werden sollen, ist auch entschieden, daß in der Systematik nur der hierarchische Systemtypus Verwendung finden kann: Das System bezeichnet eine Teilungshierarchie mit der Art als der sich teilenden Einheit, wie die Hierarchie der Histosysteme im Einzelorganismus auf der Zelle als der sich teilenden Einheit basiert. Für andere, nicht-phylogenetische Systeme, die in der Biologie möglich und mehr oder weniger durchgearbeitet auch notwendig sind (s. oben), können andere Systemformen adäquat sein.354 All these attempts are based on mistaken ideas about the structure of the genetic relationships. Having recognized that all organisms break down into a number of reproductive communities (species) and that these reproductive communities break down through fission, and having determined that the resulting “phylogenetic” relations among the successor species are natural continuations of the existing genetic relations within the species – which continuations should be represented in the phylogenetic system and thus in the universal reference system of “taxonomy” – it is also certain that in taxonomy only the hierarchical system type can be used. The system describes a “division hierarchy” with the species as the dividing unit, much like the hierarchy of the Histosystem in the individual organism is based on the cell as the dividing unit. For other, non-phylogenetic systems, which are possible in biology and even more or less necessary (see above), other system types may be adequate.

Hennig believed he was doing something new. Although taxonomists had used hierarchies in the past, and Hennig argued they should continue to be used, he proposed a different type of hierarchy be used for the phylogenetic system—the division hierarchy.

It was clear Hennig had a technical understanding of “Teilungshierarchie” in mind because he also used the term “Histosysteme” in the same passage. The term “Histosysteme” can be found in Bertalanffy’s Theoretische Biologie (1931, 1942), a work which Hennig cited often in the Grundzüge. “Histosysteme” was a term Bertalanffy borrowed from German anatomist

354Hennig “Probleme” 278.

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Martin Heidenhain (1864–1949).355 According to Bertalanffy, Heidenhain coined the term

“histosystem” to refer to the organic components that comprised the different levels of complexity that made up the fundamental components of biological organization, contributing to the fundamental biological property that characterized all life and propagated through division.

What was significant about Heidenhain for Hennig on this issue was that Heidenhain opposed the prevailing understanding cells at the time, namely understanding the organism as merely an aggregate of cells—seeing the whole as simply the sum of its parts. Heidenhain, in protest, introduced his concept of the “enkaptic structure” of organisms to explain how organic parts came together to form a complex whole, promoting a non-summative approach, and explained how organisms formed through division. Heidenhain discussed what he called an

“enkaptic hierarchy” in cell biology, and according to Bertalanffy, Woodger provided a calculus for such a hierarchy, including the part-whole relation and a notion of division. Heidenhain was not cited by Hennig, but Bertalanffy wrote about Heidenhain in the pages before he wrote about

Woodger and division hierarchies in Theoretische Biologie.356

“Division hierarchy” was a specific type of hierarchy used in mereology. Woodger coined the term in cell biology to explain the organization of cells, where cells were treated as logical individuals that exhibited the part-whole relation, and hierarchies were generated by divisions and were not necessarily summative.357 Although “division hierarchy” was a technical term in logic, Woodger was a biologist. Woodger attended University College, London and worked on vertebrate zoology with J. P. Hill (1873-1954) on problems in avian embryology.

355For more See Rieppel “Hennig’s enkaptic system” Cladistics 25 (2009) 311–317; Hueck, W. “Die Synthesiologie von Martin Heidenhain als Versuch einer allgemeinen“ Theorie der Organisation. Naturwissenschaften 14, (1926):149–158. 356In 1949 and in the Grundzüge (1950), Hennig would use the term “Enkaptic.” 357On way to think of the principle of summativity is to think of the sum of all entities at one level of organization being equal to the sum of all entities at some other level.

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According to historian Marshall Allen, Woodger went to Mesopotamia in the war in 1915 in and worked in the Central laboratory in Amara, gaining experience in protozoology while studying fruit flies as carriers of disease transmitting parasites.358 When Woodger returned to UCL in

1919, he was appointed assistant in zoology and comparative anatomy, and collaborated with J.

Bronte Gatenby (1892-1960) who worked on cell morphology and embryology, golgi bodies and gametogenesis (ideas about cell reproduction, origin and development of germ cells). Working mainly as a technician, he was still able to engage in the lab’s research which was to demonstrate the power of chemical techniques in revealing and identifying intracellular parts, which helps explain his interest in a discussion of cell parts.

To help appreciate where the logic comes in, in 1926, Woodger was given a leave and travelled to Vienna to work with Hans Przibram (1874-1944) to work on transplantation of annelids. Allen noted that because the earth was frozen in early spring, Woodger instead attended interdepartmental workshops on the methodological problems raised by the new experimental science (experimental embryology—Entwicklungsmechanik) that began with Roux (1850-1924) on transplantation and regeneration.359 Allen also noted that during his time in Vienna, Woodger picked up philosophy, and given where he was and who he was with, it would be safe to assume it was philosophy consistent with logical positivism.360 When he returned to England, Woodger started reading some British philosophers, specifically, Russell, Whitehead and Broad, to complement what he had been reading in Vienna.361

358Marshall William Allen. “J. H. Woodger and the Emergence of Supra-Empirical Orders of Discussion in Early Twentieth Century Biology.”( Master of Science, History, Oregon State University, Corvallis, OR, 1975). 359Allen “J. H. Woodger” 57 360Allen “J. H. Woodger” 58 361 John R. Gregg and F.T.C. Harris, edited. Form and Strategy in Science: Studies Dedicated to Joseph Henry Woodger on the Occasion of his Seventieth Birthday (Dordrecht: Holland, D. Reidel Pub. Co. 1964), 4.

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Woodger first introduced the term “division hierarchy” in his three part series “The

‘Concept of Organism’ and the Relation between Embryology and Genetics.” (1931-2), and then developed it in more formal detail in Axiomatic method as part of a mereological calculus—a logic of parts and wholes—to help explain some of the finer points of cytology.362 Although

Woodger did not appear in Hennig’s bibliography in the Grundzüge, his name appeared in the text, and he figured largely in Bertalanffy’s work and was discussed by Torrey, both of whom were cited by Hennig. Hennig used “Teilungshierarchie” in “Probleme der biologischen

Systematik” in a way consistent with Woodger’s use. Hennig explained that he was borrowing the term from cell biology and he too was using it as part of an account of individuality.

5.4 “Zur Klarung einiger Begriffe der phylogenetischen Systematik” (1949) During the ten months of the Berlin blockade in 1948, professionally Hennig set himself the task of organizing the Staatliches Museum fur Naturkunde holdings, privately he returned to the manuscript of the Grundzüge.363 Hennig also wrote another short, philosophical paper, “Zur

Klarung einiger Begriffe der phylogenetischen Systematik” (1949). In this paper, Hennig expanded on the philosophical and theoretical ideas he introduced in “Probleme der biologischen

Systematik” and would expand upon in Grundzüge. Specifically, he explored on the notion of hierarchies, and discussed the philosophical notion of space.

In this paper, Hennig discussed German philosopher Bernard Bavink, psychiatrist and philosopher Theodor Ziehen, and philosopher Rudolf Carnap, which seemed at first glance an odd trio to bring to a conversation about biological hierarchies.

362 For example, see Michael Ruse’s critique of Woodger’s axiomatic programme in “Woodger on genetics a critical evaluation.” Acta Biotheoretica XXIV (1975): 1-13. 363Schlee “In Memoriam Willi Hennig” 6.

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5.4.1 Space and multidimensions Hennig began “Zur Klarung einiger Begriffe der phylogenetischen Systematik” by discussing problems with the morphological system, a topic he discussed in “Probleme der biologischen Systematik” (his footnote 4). Specifically, Hennig claimed that phylogenetic systematics was based on the conviction of the existence of real, natural species, but thwarted by problems with methodology and attempts to determine the structure of phylogenetic relationships. He presented a graphic interpretation, explaining that morphological change can be represented by inserting a temporal dimension and a morphological dimension, but such an account ran into tremendous difficulty.

One problem Hennig encountered when constructing a solid foundation for taxonomy was one of space, time, and measurement, leading Hennig to introduce philosophers who wrote on physics, specifically Bavink, Ziehen, and Carnap. Hennig began with Bavink and referred to

Bavink’s Ergebnisse und Probleme der Naturwissenschaften, a book widely read both in

Germany and internationally.364 According to Hennig, a good morphological system required a measurable foundation. Citing Bavink (Hennig’s footnote 1), Hennig claimed that there was no mathematical basis to determine the exact measurements of similarities and differences in form.

In other words, there was no mathematical basis for the morphological system.365 Hennig

366 repeated this point in both editions of the Grundzüge, and Phylogenetic systematics.

364See Klaus Hentschel, “Bernhard Bavink (1879-1947): Der Weg eines Naturphilosophen vom deutschnationalen Sympathisanten der NS-Bewegung bis zum unbequemen Non-Konformisten,” Sudhoffs Archiv 77 (1993): 1-32.; “Obituary: Prof. B. Bavink (1879-1947)” Nature 161(1948):122. 365Hennig wrote: Für die phylogenetische Systematik [4] ergibt sich aus unserer Gewißheit der realen Existenz dieser natürlichen, “Arten” genannten Organismengruppen hinsichtlich der Methodik und Problematic ihrer Arbeit eine deutliche Zweigliederung ihrer Aufgaben: Es müssen einerseits die existierenden Arten ermittelt, andererseits aber die zwishen diesen Arten bestehenden Phylogenetischen Beziehungen aufgesucht und dargestellt werden. Das allgemeine Strukturschema der zwischen den Arten bestehenden Phylogenetischen Beziehungen ergibt sich aus dem, was wir über die Entstehung neuer Arten in mehrere Tochterarten zerfallen (Abb. 1). Diese Tochterarten pflegen sich von der gemeinsamen Stammart auch in äußerlich erkennbaren morphologischen Eigenschaften zu unterscheiden. Man kann diesen Vorgang der

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In the next paragraph Hennig discussed space, introducing Ziehen (Hennig’s footnote 6) and Carnap (Hennig’s footnote 3). Hennig proposed an account of life as a “multidimensional diversity.” On this account, Hennig claimed organisms differed in many different directions or dimensions, and as such, saw relations interconnecting the multidimensional diversity. He said:

Die Arten unterscheiden sich unter Umständen in vielen Eigenschaften voneinander. Wenn wir die Richtung dieser nicht aufeinander zurückführbaren Verschiedenheiten mit “Dimensionen” gleichsetzen [6], dann können wir anschaulich von einer verschiedenen Lage der Arten im vieldimensionalen “Eigenschaftsraume” sprechen.367 Species may differ in many characteristics from each other. If we equate the direction of these not reducible differences with “dimensions” [6], then we can clearly speak of a different position/location of the species in the multi-dimensional “feature space.” Here Hennig referred to Ziehen’s Erkenntnistheorie (1934, 1939), expanded on this idea in greater detail in the Grundzüge, where he talked about the multidimensional multiplicity, and how this applied to taxonomic methodology.368 After this, Hennig referenced Carnap. Hennig wrote: “ Mit dieser Anwendung des Raumbegriffes befinden wir uns in Übereinstimmung mit einer durchaus einwandfreien, auch sonst gebräuchlichen Übung [3].”369 “With this application of the concept of space, we find ourselves in agreement with a completely proper and otherwise common practice [3].” In the footnote Hennig cited Carnap’s doctoral dissertation Der Raum:

Ein Beitrag zur Wissenschafislehre (1922)—a work that came up with an ingenious solution to a philosophical problem of space.

von morphologischen Veränderungen begleiteten Artspaltung und Entstehung höherer systematischer Kategorien anschaulich darstellen (Abb. 1), indem man in der einen Dimension (t) eines Koordinatensystemes das zeitliches Fortschreiten des Zerfallsprozesses und in einer 2. Dimension (m) die morphologischen Veränderungen ihrer Größe nach zum Ausdruck bringt. Allerdings stößt eine solche Darstellung auf Schwierigkeiten, weil es schwer bsw. Mit den heute bekannten Methoden grundsätzlich sogar unmöglich ist, den Betrag von Gestaltänderungen und Gestaltverschiedenheiten einwandfrei zu messen [1]. Nur bei verhältnismäßig sehr ähnlichen Gestalten ist das mit Näherungsmethoden möglich.[Hennig “Zur Klarung” 136] 366Hennig Phylogenetic systematics 23. 367Hennig “Zur Klarung” 136. 368For more on Ziehen see Rieppel “Cladograms”168-172; “Concepts” 484-6; on Ziehen and Rensch, see Rieppel “Dichotomy” 107 and “Metaphysics” 350-1; 369Hennig “Zur Klarung” 136.

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5.4.2 Enkaptic systems

Hennig did not use the term “Teilungshierarchie” in this paper, but he did mention enkaptic systems twice. Hennig’s first mention of enkaptic systems was in conjunction with diagram 2. Hennig wanted to draw a connection between enkaptic systems and phylogenetic systems. Hennig emphasized that when species were arranged according to their phylogenetic relationships, such an arrangement was equivalent to an enkaptic system, a system where the symbolic boundary lines of the stem species were drawn around their successor species. Hennig wrote:

Im Gegensatz zu den morphologischen (und dasselbe gilt für die ökologischen) sind die phylogenetischen Beziehungen der Arten stets richtig und exakt in einer Dimension (t in Abb. 1) darzustellen, soweit in der Praxis eben nicht die tatsächliche Unvollkommenheit unserer Kenntnisse auch die Darstellung dieser Beziehungen ungenau macht. Den phylogenetischen Beziehungen entspricht in anderer Darstellungsweise der hierarchische oder enkaptische Systemtypus (Abb. 2), in dem die Reihenfolge der einander von innen nach außen folgenden Umgrenzungslinien dem Nacheinander entspricht, in dem sich die umgrenzten Arten von der ihnen und nur ihnen gemeinsamen Stammart getrennt haben.370

In contrast to the morphological (and the same applies to the ecological), the phylogenetic relationships of the species should always be correctly and accurately represented in a dimension (t in Figure 1), so long as in practice the actual incompleteness of our knowledge does not also make the representation of these relationships imprecise. The phylogenetic relationships correspond in a different manner of representation to the hierarchical or enkaptic system type (Fig. 2), in which the sequence of boundary lines following one another from the inside outwards corresponds to the one following, in which the bounded types have separated from the ancestral species common to them and only them.

370Hennig “Zur Klarung” 136.

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Hennig Figure 1.

371

Hennig Figure 2.

Hennig included a similar diagram to his figure 2 in the Grundzüge on page 204, in the second edition of Grundzüge on page 77, and Phylogenetic systematics on page 71.

371Hennig “Zur Klarung” 136.

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Hennig Figure 3.

It is tempting to assume that Hennig was constructing Venn diagrams, and this would be consistent with reading Hennig as providing a set-theoretic treatment of species. Venn diagrams were used to teach traditional set theory by illustrating logical relations that exist between a finite collection of sets, and such relations include: union, intersection, relative and absolute complement, symmetric difference. However, this would be a bad assumption to make.

Donoghue and Kadereit maintained that Hennig reproduced Zimmerman’s figure 172 from “Arbeitsweise der botanischen Phylogenetik und anderer Gruppierungswissenschaften”

(1931) to make his point, arguing that in his revised second edition he credited Zimmerman and

Bigelow for his definition of monophyly.372

372Donoghue and Kadereit “Zimmermann” 79.

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Zimmerman Figure 1.

According to Donoghue and Kadereit, in “Arbeitsweise der botanischen Phylogenetik” when

Zimmermann defined the “phylogenetic relationship” in reference to his Figure 172, he talked about two plants or organs being more closely related to a third, and the common ancestor of those two existing more recently that the ancestor of all three. He claimed the relative age relationship of the ancestors was the only direct measure of phylogenetic relationship.

Zimmerman went on to argue that no other representation was consistent with phylogenetic grouping:

A statement about phylogenetic relationship which cannot be expressed in the basic scheme of Figure 172b does not exist. . . . Whoever believes that he cannot illustrate relationships in this basic scheme . . . does not have a phylogenetic but an “idealistic” or purely systematic “relationship” in mind.373

However, the most important feature of this diagram was how in both Zimmerman and Hennig’s case, it was not a Venn diagram showing represent nested sets. Instead, it showed a relation. For

373Donoghue and Kadereit “Zimmermann” 78.

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Hennig, if there were three things described in a diagram, namely x, y, and z, then the diagram would describe x as more closely related to y than z. This was a relation that could be measured.

This was the type of relation Hennig was looking to illustrate. By abandoning the idea that the figure is a Venn diagram and instead assume the same figure, just rotated and viewed from above, and the author simply drew circles around the objects more closely related, the right interpretation is achieved. Again, this was not an example of nested sets. For Hennig, as for

Zimmerman, Heidenhain or Woodger, this figure was supposed to illustrate a feature of an enkaptic system.

Although Hennig did not provide much in the way of background or detailed explanation for enkaptic systems in “Zur Klarung einiger Begriffe der phylogenetischen Systematik,” he did cite his earlier paper “Probleme der biologischen Systematik,” and in that paper he referenced

Bertalanffy’s work. Recall that in the context of Bertalanffy’s work Hennig mentioned the term

“Histosysteme.” This was a term used by Heidenhain who also discussed enkaptic systems.

Recall also in the context of Bertalanffy’s work, that immediately following Bertalanffy’s summary of Heidenhain was a discussion of Woodger’s division hierarchies, drawing a connection between enkaptic systems and division hierarchies. So, although the stem species’ symbolic boundary lines were drawn around their successor species, that it did not imply a summative property, as was the case with a set-theoretic hierarchy, where a set was defined by its members. Heidenhain argued, in enkaptic systems, the whole was more than the sum of its parts. The next time Hennig mentioned enkaptic systems, he discussed relations, distinguishing between enkaptic system that reflected phylogenetic relations and morphological relations that could be reduced to similarity relations.374

374 Hennig wrote:

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5.5 Grundzüge einer Theorie der Phylogenetischen Systematik (1950)

5.5.1 Logic and methodology in Grundzüge As was the case with almost all the taxonomists embroiled in the taxonomic reform during this time, Hennig raised concerns about taxonomy’s place at the scientific table in the

Grundzüge. In 1947, Hennig discussed the problems with taxonomy, and by 1949 he had begun to explore solutions with space, time, and measurement using the philosophy of physics. When

Hennig tackled these issues at manuscript length, he began each edition with remarks expanding on precisely those ideas:

Diese Überlegungen machen auch deutlich, wie die einander entgegenstehenden Auffassungen verschiedener Systematiker zu werten sind, von denen die einen glauben, daß die “Beziehungen der Arten netzartig zu denken wären und sich im Stammbaumschema oder im hierarchisch-enkaptischen System nur unvollkommen darstellen lassen, während die anderen das Stammbaumschema und hierarchische System für geeignet halten, die Beziehungen der Arten zueinander richtig zum Ausdruck zu bringen. Auch die netzartig verlaufenden Beziehungen werden in diesem Meinungsstreit von den Vertretern der zuerst genannten Auffassung häufig als “phylogenetische: Beziehungen bezeichnet. Es handelt sich dabei aber offensichtlich um die “morphologischen Beziehungen phylogenetisch in bestimmtem Grade miteinander verwandter Arten”, die im Schema der Abb. 1 der Dimension m zugehören und nicht um die phylogenetischen Beziehungen im eigentlichen Sinne, die stets nur in der Dimension t verlaufen. Begünstigt werden diese Unklarheiten durch die unterschiedliche Anwendung des Begriffes der “Verwandtschaft,” der einmal in weitgehender Übereinstimmung mit dem chemischen Affinitätsbegriffe zur Bezeichnung von Gestaltähnlichkeit, Ähnlichkeit auch im chemischen Aufbau des Körpers (“Eiweißverwandtschaft” in der Serumdiagnostik) andererseits aber auch im rein genealogischen Sinne zur Bezeichnung der Abstammungsbeziehungen Verwendung finden. Um alle Mißverständnisse und Unklarheiten zu vermeiden sollte man die Bezeichnung “Verwandtschaft” ausschließlich der genealogischen, in der Dimension t verlaufenden Beziehungen vorbehalten und zur Kennzeichnung der Beziehungen, die sich auf die Dimension m im besprochenen Sinne reduzieren lassen, den Ausdruck “Ähnlichkeit” (Gestaltähnlichkeit, Ähnlichkeit in der Lebensweise) gebrauchen.

These considerations make it clear how the mutually conflicting views of different taxonomists ought to be assessed, among whom some believe that the relations of the species ought to be thought of in a net-like manner and should only be represented in the family tree diagram or hierarchical enkaptic system rudimentarily, while others deem the tree scheme and hierarchical system appropriate for correctly expressing the relationships of the species to one another. In addition, the reticulate relationships are frequently referred to in this controversy by the representatives of the first-mentioned opinion as “phylogenetic” relationships. However, what is actually being referred to here is obviously the “morphological relationships – phylogenetic to a certain degree – of interrelated species,” which belong to Dimension m in the schema of Figure 1, and not the phylogenetic relationships in the strict sense, which only ever operate in the dimension t. These ambiguities are encouraged by the inconsistent application of the concept of “relatedness,” which on the one hand is used in broad agreement with the concept of chemical affinity for the description of shape similarity as well as similarity in the chemical structure of the body (“protein family” in the Serumdiagnostik), and on the other hand is used in the purely genealogical sense to refer to the lineage relationships. To avoid any misunderstanding and confusion the designation “family” should be used exclusively for genealogical relationships operating in dimension t, and the term “similarity” (shape similarity, similarity in the way of life) should be used to identify the relationships that can be reduced to the dimension m in the sense discussed.

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Wohl in keiner anderen Naturwissenschaft sind die Gegensätze und der Konkurrenzkampf zwischen den einzelnen Teilgebieten so stark wie in der Biologie. Das rührt, mindestens zum Teil, daher, daß in keiner anderen Naturwissenschaft die Probleme und damit auch die Methoden so verschiedenartig sind wie eben in der Biologie. Diese Verschiedenartigkeit erfordert eine hohe Konzentration und Spezialisation dessen, der sich mit einem der vielen gegebenen Problemkomplexe beschäftigen will, und führt damit zu einer verhältnismäßig starken Isolierung der einzelnen Teilgebiete. . . Wenn die biologische Systematik in diesem Konkurrenzkampf in neuerer Zeit genüber anderen und, wie man vielfach hören kann, jüngeren oder moderneren Teilgebieten etwas an Boden verloren hat, so liegt das weniger an der geringeren praktischen oder theoretisch- wissenschaftlichen Bedeutung der Systematik als vielmehr daran, daß diese es nicht recht verstanden hat, ihre Bedeutung im Rahmen der biologischen Gesamtwissenschaft in das gebührende Licht zu setzen und ein festgefügtes Lehrgebäude ihrer Probleme, Aufgaben und Methoden zu errichten.375 In no other science are the contrasts and struggle for the survival among subdivisions of the field so strong as in biology. This is at least partly because the problems, and therefore the methods, are more varied in biology than in any other science. This diversity demands intense concentration and specialization by anyone dealing with any of its numerous problems with in turn leads to considerable isolation of its subdivisions. . . If in this struggle for survival biological systematics has recently lost ground to other and, as is often heard, younger and more modern disciplines, this is not so much because of the limited practical or theoretical importance of systematics as because systematists have not correctly understood how to present its importance in the general field of biology, and to establish a unified system of instruction in its problems, task, and methods.376 He also referenced characterizations of taxonomy consistent with those made in the American and British literature, and mentioned such characterizations in all editions. Specifically, Hennig targeted the criticism of taxonomy as a descriptive science whose only use was similar to a “card catalog”:

Es war aber andererseits zweifellos nötig; zunächst etwas ausführlicher darzustellen, welches der eigentliche, ursprüngliche und in vielen Wissenschaften - außer der Biologie - noch durchaus aktuelle gebräuchliche Sinn des Begriffes Systematik ist, denn es gibt in der Biologie auch heute noch Systematiker, die über die Bedeutung der biologischen Systematik nichts besseres zu sagen wissen, als daß die Systematik für die Wissenschaft ebenso notwendig sei wei eine Kartei für die Bücherei (HEINTZ 1939).377 On the other hand, it was unquestionably necessary to present in more detail the essential and original sense of the concept of systematics as it is currently used in many sciences outside biology. In biology even today there are systematists who know nothing better to

375Hennig Grundzüge 1950: 1; Grundzüge 1982:9. 376Hennig Phylogenetic systematics:1. 377Hennig Grundzüge 1950:10; Grundzüge 1982: 15.

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say of biological systematics than that is necessary for science in the same way as a card catalog is for a Library (Heintz 1939)378 Although his concern regarding taxonomy’s place did not wane over time, his presentation of this concern changed subtly between the first and second edition of his book.

Within Hennig’s philosophical programme, logic’s role had more of an explicit presence in the Grundzüge than it did in Phylogenetic systematics. Logic was tied to his ideas about physics and the relationship to the external world, methodology, and helped explain his complex account of hierarchies. Although, in the first chapter of Phylogenetic systematics titled, “The position of systematics among the biological sciences,” Hennig made no reference to the role of logic in methodological reform, in Grundzüge, he discussed logic’s role near the end, as a part of his philosophical programme. Hennig worried about a false dichotomy that governed the scientific arena, with physics connected to the exact and explanatory sciences and biology with the descriptive science. Taxonomy, of all the biological sciences, seemed to most people, to be the most connected to the descriptive sciences. Hennig was keen on ditching this dichotomy.

This was not the only dichotomy he hoped to ditch.

His approach began with philosophy, specifically appealing to Hartmann and Ziehen’s ideas. Hennig aligned taxonomy with ideas such as “nomothetic,” “order,” “rationalization” because, like Hartmann and Ziehen, Hennig believed that there should not be a divide between nomothetic and idiographic approaches to science. He wrote:

Das Aufsuchen von Gestzlichkeiten in den Beziehungen, die zwischen komplexen Naturdingen einer bestimmten Ordnungsstufe bestehen, die Einordnung dieser Gestzlichkeiten in ein weitere Ordnungsstufen umfassendes allgemeineres System von Naturgesetzen einerseits (nomothetische Betrachtungsweise) und der Versuch, den Zustand, in dem sich die Betreffenden individuellen Naturgesetze bedingte Folge eines andersartigen Vorzustandes zu begreifen (idiographische Betrachtungsweise) sind zwei

378Hennig Phylogenetic systematics 7.

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Seiten der wissenschaftlichen Tätigkeit, die in keiner Wissenschaft voneinander zu trennen sind.379 The search for laws that exists in the relations between complex natural things at a certain classification level of order, the ordering of those laws into a more general system of laws that encompasses further classification levels of order (the nomothetic way of seeing), and the attempt to understand the current state of individual natural things as the effect of a preceding state (the ideographic way of seeing) are two sides of scientific research that cannot be separated in any science.380 In this sense, for Hennig, there was much more common ground between biology and physics.

Hennig wrote:

Wenn hier Ordnung und Rationalisierung als Gegensätze gefaßt sind, so widerspricht der übernächste Satz Hartmanns selbst dieser Gegenüberstellung: “Die Physik befaßt sich mit den Vorgängen der Welt und sucht diese Vorgänge in ein System von logischen Gesetzen zu bringen, die gewissermaßen zeitlos unindividuell sind.” Zweifellos bedeutet aber die Aufstellung eines “Systems von logischen Gesetzen” nichts anderes als “Ordnung.” “Ordnung” und “Rationalisierung” der Erscheinungswelt können daher auch nicht als etwas Verschiedenes aufgefaßt werden.381

If this order and rationalization are conceived of as opposites, then even Hartmann’s next sentence contradicts this comparison: “Physics is concerned with the processes of the world and studies these processes in a system to bring logical laws which are in a sense timeless and not individual.” No doubt, but the establishment of a “system of laws of logic” is nothing more than “order.” “Order” and “rationalization” of the phenomenal world cannot therefore be regarded as something different.

As well:

Wir müssen nach alledem feststellen daß “Systematik” Rationalisierung und damit Ordnung der Erscheinungswelt bedeutet: “Systematik hat es immer mit der begrifflichen Ordnung der Erscheinungen zu tun; das ist ihr allgemeinster Sinn” (Naef 1919). Der begriffliche, logische Charakter der Ordnung bezieht sich dabei aber nur auf die formale Struktur. Was in ihr unter Beachtung der Prinzipien der Logik zur Darstellung gebracht wird, sind im übrigen nicht rein formale logische, transzendentale, sondern naturgegebene und in diesem Sinne reale Beziehungen, die zwischen Naturdingen und Vorgängen (wobei diese letztern beiden Begriffe nicht als reine Gegensätze verstanden werden dürfen) unabhängig von der menschlichen Absicht, diese Ordnung zur Darstellung zu bringen, vorhanden sind. “Systematik”--auch in der Biologie--ist in diesem Sinne also Ordnung, Rationalisierung der Erscheinungswelt und damit Inbegriff der nomothetischen naturwissenschaftlichen Tätigkeit überhaupt.382

379Hennig Grundzüge 1950: 3. 380Rieppel translated this passage with hierarchy, but I chose to use classification. 381Hennig Grundzüge 1950: 5. 382Hennig Grundzüge 1950:5.

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We must finally assert that “scheme” means rationalization, and hence order of the phenomenal world: “Taxonomy has always dealt with the conceptual order of phenomena that is its most general sense” (Naef, 1919). However, the conceptual, logical character of the order refers only to the formal structure. Those things in it which are portrayed under the consideration of the principles of logic are in general not purely formal logical, and transcendental, but rather inherent and in this sense real relationships that exist between natural things and processes (these latter two concepts may not be understood as mere opposites) independent of the human endeavor to portray this order. Therefore, “systematics - even in biology – is in this sense order, rationalization of the phenomenal world, and, as a result, the epitome of the nomothetic scientific activity in general. Claims about order, rules, and the laws of logic start to make sense against the cast of characters

Hennig introduced in his philosophy of biology. When Hennig was writing in the 1940s, he pursued aspects of an agenda shared by biologists like Bertalanffy and Woodger, aspects of an agenda shared by those responding to neo-Kantianism and phenomenology, such as Carnap,

Bavink, and Ziehen, and to the philosophical programme of German idealistic morphology exemplified by Troll and criticized by Naef and Zimmermann, the consequences of which informed some of his major insights, not just his position on species as individuals, but his position on developing clear procedures and schemata for taxonomy.

As seen in the two previous passages ending Hennig’s “The position of systematics among the biological sciences,” in an effort to put taxonomy on firmer ground, Hennig attempted to make taxonomy more theoretical, and he finished with the belief that adopting a logical procedure could be seen as streamlining the phenomenal world. Hennig’s words were consonant with methodology and metaphysical claims made by Zimmermann, Naef, Bavink, Hartmann,

Carnap, and Ziehen.

These ideas were also consonant with some ideas in the broader biological literature. For example, Hennig’s approach, with its appeal to a conceptual clean up that would include logic, was not unlike with statements written earlier in the Preface of The axiomatic method of biology, where Woodger maintained:

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In every growing science there is always a comparatively stable, tidy, clear part, and a growing, untidy confused part. I conceive the business of theoretical science to be to extend the realm of the tidy and systematic by the application of the methods of the exact or formal sciences, i.e. pure mathematics and logistic.383 Woodger proposed formal sciences, such as logic, be called upon to clean up the biological sciences. Similar remarks can be found in other philosophical work. For example, consider

Whitehead’s remark in a more metaphysical vein:

Every element of space or of time (as conceived in science) is an abstract entity formed out of this relation of extension (in association at certain stages with the relation of cogredience) by means of a determinate logical procedure (the method of extensive abstraction). The importance of this procedure depends on certain properties of extension which are laws of nature depending on empirical verification. There is, so far as I know, no reason why they should be so, except that they are.384 Whitehead stressed the importance of a logical procedure in science. Whitehead made the general claim, and Woodger’s remarks made a more specific claim for biology regarding not just the importance of a logical procedure, but its role in a conceptual clean-up. Hennig’s claim was more specific still, for his regarded the role of logic in taxonomic methodology in the

Grundzüge.385

Both Woodger and Hennig can be read as taking Whitehead’s suggestion seriously, as both sketched out an abstract entity by means of a formal logical procedure.386 Woodger

383Woodger Axiomatic vii. 384Alfred North Whitehead, An enquiry concerning the principles of natural knowledge. (Cambridge: University Press, 1919) 73. 385Woodger and Whitehead were not the only ones voicing such a concern. Torrey, for example, wrote: With considerable justification biology has been accused of lagging far behind the physical sciences in the formulation of broad principles serving to embrace the theoretical results attained from the detailed investigations of its many branches. It is usually argued in defense, of course, that the ‘science of life’ is not ‘ready’ for such a synthesis, but this defense has always borne the faint aroma of an alibi. So far there seem to have been few biologists who have indicated a very great willingness even to try. Most have persisted instead in grubbing away mole-fashion to build higher and higher the already mountainous mass of unorganized factual data, deriving ruminative pleasure from the size of the heap and having little concern about the truths that may be buried in its bowels. Torrey 275. 386Woodger cited Whitehead in his work, but Hennig did not. Rieppel has tried to work out a direct link between Hennig and Whitehead, and has not met with success (see Rieppel “Semaphoront” 170). However, Hennig was not unaware of Whitehead’s work, as he read authors who did cite authors who read and cited Whitehead profusely, such as Woodger, Bertalanffy, Torrey, Carnap, and others.

185 provided one for cells, and Hennig for species. This appeal to formal logic was a feature that distinguished Hennig’s approach to the methodological reform from those typically found in

America and Britain. Woodger aimed to “provide an exact and perfectly controllable language by means of which biological knowledge may be ordered.”387 For Woodger, this language was logic.388 In a certain sense, this was also the case for Hennig.

Hennig’s interest in making taxonomy a “science” through the application of more formal tools did not appear from nowhere. Taxonomy had a history of ambling along as an apprenticeship, behaving more like an art than a science. Remarks such as “a species is what a competent naturalist says it is” had many virtues, but for Hennig (and others) such remarks often underscored taxonomy as more of an “art” than a science. This concern was now spreading from issues in nomenclature to other areas in taxonomy. A fine illustration of the ways in which

“taxonomy-as-an-art” could be seen as a vice was the emerging debate coming out of evolutionary studies on construction of phylogenetic trees.

When Hennig began to write on taxonomic reform, he faced a dizzying multitude of phylogenetic trees. He was not alone in his frustration with a decided lack of empirical rigor in what amounted to a jumble of attempts at a unified method for reconstructing genealogical relationship among species. That this forest of phylogenetic trees was in reality just a tangled mess private methods was no secret. This was a familiar sentiment found in Naef’s work. Naef lamented:

For decades, phylogenetics lacked a valid methodological basis and developed on the decayed trunk of a withering tradition rooted in the idealistic morphology and the

387Woodger Axiomatic vii. 388Woodger wrote: “I began the study of the Principia Mathematica of Whitehead and Russell, which seemed to provide the necessary framework for a language which would enable us to calculate in biology. I have accordingly made use of that work in the present book in order to construct a biological calculus.” viii

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systematics of pre-Darwinian times. There was talk of systematic ‘tact’ and morphological ‘instinct’, terms which were felt rather than understood and consequently insufficient to form the frame of a science which required sound definitions and clearly formulated principles.389

This idea of “of systematic ‘tact’ and morphological ‘instinct,’ terms which were felt rather than understood” rang through the taxonomic literature. As Lam, another author Hennig cited in the

Grundzüge, pointed out in his comprehensive 1936 summary, each tree represented a biologist’s opinions, based on his experience.390 Lam wrote:

The form chosen and the features included largely depend upon the subject to be represented and upon the personal vision of the author. FRANZ (1931, p. 186) and ZIMMERMANN (1931, p. 1043) express themselves very aptly in saying that genealogical trees are to the phylogenetics what tables, diagrams and curves are to the physiologist, viz. incomplete, but useful and even indispensable auxiliaries to verbal considerations. They can never reflect in a perfectly satisfactory way what they are meant to; they can never contain as many data at the same time as one should like to enter; therefore in many cases several diagrams, schemes, trees, etc. have to be combined in order to result in a satisfactory pictural representation of our ideas.391

Experience and perspective guided tree design, said Lam. Konrad Lorenz, also cited by Hennig, wrote about the “Classifying Instinct,” suggesting that “the ‘classifying instinct’ does all this without the man who possesses it needing to analyse it himself. However, only when the analysis is accomplished does his performance become science.”392 Like Naef, Hennig was keen to transform taxonomy from an art to a science, and he saw part of that change involving the conceptual clean-up of phylogenetics. 393 This would involve, among other things, logic. Hennig

389Naef 1921–23, pp. 6–7, from the English translation, Naef 1972a, p. 12 390 H. J. Lam “Phylogenetic symbols, past and present (Being an Apology for Genealogical Trees)” 1936. 391 Lam “Phylogenetic symbols”178 392K. Lorenz. 1953. “Comparative studies on the behaviour of the Anatinae.” Avicultural Magazine 57, 58, 59: 1-87 [English translation of K. Lorenz, 1941, 57:157-182, 58:1-17, 61-72, 86-93, 172-183. 1951- 1952]. (Lorenz, 1941: 198, 1953: 2). Hennig also cited Lorenz, but this paper is not in the bibliography. 393 Olivier Rieppel “Proper names in twin worlds: Monophyly, paraphyly, and the world around us.”, Diversity & Evolution 5 (2005): 91 and Schmitt “Hennig” 343 for example, applauds the fact that Hennig transformed systematics from ‘‘a skill or an art to a truly scientific method, which justly found its place in hypothetico-deductive science such as the one sketched by Popper.’’

187 felt the same even as he sat down to write the second edition. He began the second titled “Tasks and Methods of Taxonomy with the following:

“Taxonomists are more like artists than like art critics; they practise their trade and don’t discuss it” (Anderson 1952). This remark certainly characterizes the disinclination of many systematists to engage in extensive discussions of the theoretical basis and methods of their science. But systematics is a science and not an art, and in every science there comes a time when significant progress is no longer possible without such discussion.394

5.5.2 Semaphoront and hierarchies

Hennig’s work on semaphoronts and individuality has been covered in the literature but the most comprehensive historical treatment has done by Rieppel.395 Rieppel presented a case for what he called Hennig’s “relationalism” which he adopted from German philosopher Ernst

Cassirer via German psychiatrist Theodor Ziehen.396 He summarized Hennig’s argument that idiographic and nomothetic approaches couldn’t be separated from one another in any science, drawing attention to an important passage:

The search for laws that exists in the relations [Rieppel’s emphasis added] between complex natural things at a certain hierarchical level of order, the ordering of those laws into a more general system of laws that encompasses further hierarchical levels of order (the nomothetic way of seeing), and the attempt to understand the current state of individual natural things as the effect of a preceding state (the idiographic way of seeing) are two sides of scientific research that cannot be separated in any science.397

394Hennig Phylogenetic systematics 28. 395See Hull Science as process; A. Hamilton, Haber, M. “Are clades reproducers?” Biological Theory 1 (2006) 381– 391., M. H. Haber, Hamilton, A. “Coherence, consistency, and cohesion: clade selection” in Okaska and beyond. Phil. Sci. 72 (2005) 1026–1040.; M. H. Haber, Hamilton, A. “Clade selection and levels of lineage: a reply to Rieppel.” Biological Theory 4(2010) 214–218.; Olivier Rieppel “On concept formation in systematics” Cladistics 22 (2006): 474–492; Olivier Rieppel “Hennig’s enkaptic system” Cladistics 25 (2009) 311–317; Olivier Rieppel “Proper names in twin worlds: Monophyly, paraphyly, and the world around us.”, Diversity & Evolution 5 (2005) 89–100., “Semaphoronts, cladograms and the roots of total evidence” Biological Journal of the Linnean Society, 2003, 80, 167–186., Rieppel, Olivier “On concept formation in systematics” Cladistics 22 (2006) 474–492; Olivier Rieppel “Willi Hennig on transformation series” Taxon 55 (2006): 379-80; Olivier Rieppel “Willi Hennig’s dichotomization of nature” Cladistics 27 (2011) 103–112. 396 See E. Cassirer, Substance and Function, and Einstein’s Theory of Relativity (Translated by Swabey, W.C., Swabey, M.C.) (Dover, New York. 1923. [1953]); Th. Ziehen. Erkenntnistheorie. Zweite Auflage. Erster Teil. Allgemeine Grundlegung der Erkennnistheorie. Spezielle Erkenntnistheorie der Empfindungstatsachen einschliesslich Raumtheorie. (Gustav Fischer, Jena. 1934); Th. Ziehen. Erkenntnistheorie. Zweite Auflage. Zweiter Teil. Zeittheorie. Wirklichkeitsproblem. Erkenntnistheorie der Anorganischen Natur (Erkenntnisheoretische Grundlagen der Physik). Kausalita¨ t. (Gustav Fischer, Jena,1939). 397Hennig, 1950: 3; in Olivier Rieppel “Concept formation,” 478.

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From this, continued Rieppel, Hennig claimed that taxonomy, the construction of systems tied together by lawful relations, was by no means restricted to biology, but was “an integral part of all science.”398 He went on to claim that its goal was to “order particular phenomena (and therewith also particular events) into a system of universal relations, and to comprehend the success of such ordering as the essence of scientific explanation.”399 According to Hennig, it was because organisms can be ordered hierarchically that taxonomists can provide reasons for phylogeny and the theory of evolution.400 As will be shown, where Rieppel’s theory goes awry is his connection to Carnap’s logic. Rieppel was right to focus on relations, but instead the focus should be on Hennig’s account of hierarchies and the recognition that his cladograms could not be substituted for Venn diagrams, but illustrations, the sort that harken back to botanist Walter

Zimmermann that dealt with relations amenable to measurement.

A semaphoront, according to Hennig, was an abstract entity, the smallest or ultimate individual to participate in a life process. Hennig constructed organisms by logical reconstruction using semaphoronts, that is, ‘fusing’ temporally successive semaphoronts of an individual life- cycle into a semaphoront complex. Semaphoronts were fused together into groups by genetic relationships he called “ontogenetic relationships.” Likewise, he constructed species by logical reconstruction, that is, by fusion of semaphoront complexes. Semaphoront complexes were fused together into groups by genetic relationships he called “tokogenetic relationships.”401

Ontogenetic relations differ from tokogenetic relations which were the relations that form from bisexual reproduction. Tokogenetic relations form species, and new species arose when there was “a gap in the fabric.”

398Hennig, 1950, p. 4 ; in Rieppel “Concept formation” 478. 399Hennig, 1950, p. 3; in Rieppel “Concept formation” 478 400Hennig1950: 24; in Rieppel “Concept formation” 478 401Hennig, 1950: 19.

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Semaphoronts also bore many kinds of characters such as: morphological, ethological, ecological, physiological and geographical, and this idea was important to Hennig’s philosophical position. It was common knowledge among taxonomists that one could construct a hierarchical system out of any kind of character similarity, but Hennig argued that none of those hierarchies would result in a phylogenetic system. The phylogenetic system, claimed Hennig, was not built on the similarity of semaphoronts, but on the history of species, that is, on their phylogenetic relationships. This system claimed logical primacy amongst all other systems built on some kind of similarity, because all other systems were related to it.402

Hennig’s concept of individuality was tied to his notion of a semaphoront. He built the notion of time into his concept of a semaphoront and used that to explain the categories of the phylogenetic system in terms of individuals with a beginning and ending in time. Individuals, on

Hennig’s account, were segments along a temporal stream of successive breeding populations.

On Hennig’s account, although species were individuals, they were of a strange sort. They were not bound by the conventional skin or a membrane, so in a certain sense they were “scattered” since they were fused by tokogenetic relations. Moreover, clades were individuals made up of appropriately related species. So, to investigate speciation, for Hennig, would be to investigate a relationship between organisms over time, and not the persistence of identity through time. As such, Hennig grouped related species by their beginning and ending points: a clade began when a species branched and ended when there was a further branching in one of the daughter species.403

This was because Hennig wanted to avoid what he understood as the traditional morphological approach, or any approach for that matter that assumed ideal types, because he maintained that

402 Hennig Grundzüge 1950 181 403Haber and Hamilton make similar claims in Haber and Hamilton, 2005; Hamilton and Haber, 2006, Hamilton 2010

190 ideal types have neither individuality nor reality precisely because they are “timeless.” This was a criticism he would raise to Gregg’s position in Phylogenetic systematics.

Why would Hennig introduce such a complicated and strange concept like a semaphoront? Rieppel asked the same question and his response was Hennig wanted to “base the logical primacy of the phylogenetic system on a ‘concise foundation’ of ‘unequivocally defined, central concepts’ and the semaphoront was one of those” and he cited Hennig 1974 reflections.404 On a more practical note, Hennig built the notion of time into his concept of a

“semaphoront” because he believed that phylogenetic relationships were, in theory, perfectly measurable. Because these relationships were measurable, he believed that it would be necessary to slice through the space-time continuum that contains organisms and species.405 Understanding why Hennig would introduce such a concept, however, requires understanding a bit more of his philosophical position.

5.5.3 Multidimensional multiplicity and Rudolf Carnap

Early in the Grundzüge Hennig filled in the metaphysical picture he outlined in his 1947 and 1949 papers. Building on Ziehen’s 1939 ideas on order, Hennig argued that taxonomy was not simply a descriptive science, it was a science that “ordered” nature, it was “law-like” or nomological; it helped explain the world of phenomena. Rieppel identified Hennig’s passage explaining Ziehen’s discussion of “order” as one of Hennig’s more difficult passages. Hennig wrote:

ZIEHEN (1939, II, p. 10) definiert “Ordnung” als “den Inbegriff durch progressiv abgestufte Vizinalähnlichkeiten mehr oder weniger bestimmter Lagerelationen mehr oder

404Rieppel “Semaphoronts” 169. The more familiar translation of Hennig’s paper in Systematic Zoology has the following translation of the passage as: “The logical priority of the phylogenetic system, as a general reference system, arises from its foundation in a biological theory with unambiguously defined central concepts.” [246] Willi Hennig “Cladistic Analysis or Cladistic Classification?: A Reply to Ernst Mayr” Systematic Zoology. 24 (1975) 244-256 405Hennig, 1953: 7

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vieler (selbst unendlich vieler), im Grenzfalle aller Etwasse innerhalb eines endlichen oder unendlichen Ganzen”. Unter “Lage” versteht er dabei (l.c. p. 9) “eine mehr oder weniger bestimmte Relation eines einfachen oder zusammengesetzten Etwas zu anderen demselben einheitlichen Ganzen angehörigen Etwassen mit Bezug auf Qualität oder Intensität oder Lokalität oder Temporalität oder Zahl”.406

Rieppel commented:

One of the sentences that must have been almost unintelligible for most readers of Hennig (1950: 6, 1966: 3f) is the definition of ‘order’ as: ‘the totality of progressively graduated vicinal similarities of more or less determined positional relationships of several or many, even an infinite number, maximally all, “somethings” within a finite or infinite whole’, whereby ‘position’ is meant to be ‘a more or less defined relation of a simple or complex something to other somethings that belong to a unified whole in regard to quality, intensity, locality, temporality, or number’.”407 True, this is a difficult sentence to digest. This sentence began Hennig’s attempt to paint what was later recognized as a controversial metaphysical picture. According to Hennig, we exist in a

“multidimensional multiplicity.” What does that mean, in practical terms, for a taxonomist?

According to Hennig, the world was populated by a vast number of organisms, and these organisms differed in a variety of respects which Hennig referred to as dimensions. Hennig discussed the differences among organisms in the dimensions in terms of three directions: morphological, psychological, and physiological. Hennig further explained that biological disciplines, such as cytology, histology, physiology, etc., investigated the different directions. He went on to say that there were disciplines that investigate relations that held between the multidimensional diversity, or tried to connect different dimensions.

Organisms can be arranged in a number of different systems, and the differences among the systems are determined by the particular relationships of which they are concrete expressions. In theory, all these systems exist together and the relations between them can be the subject of scientific investigation. However, according to Hennig, it is not the task of science to

406Hennig Grundzüge 1950 6, Hennig Grundzüge 1982 11 407Rieppel “Semaphoront” 168.

192 combine several systems because one and the same organism cannot be presented and understood at the same time and in its same position as a member of “different totalities.” In fact, once a standard of measure was picked, that was it. Different systems result from different standards, and the different systems need to be kept apart to avoid category mistakes.408 Hence the catch, different systems cannot be combined in a simple presentation without losing the value each has for itself.409

It is easy to see how things get confusing in the Grundzüge. Not only did Hennig paint the metaphysical picture he had only hitherto sketched in his earlier papers, but now it became a tricky matter as to how certain authors figured into Hennig’s philosophical composition, especially in terms of logic. Rieppel suggested that Hennig considered Carnap “to be of broad relevance to his subject matter, rather than providing support for a specific point being argued” and he presented an argument for applying Carnap’s notion of relations to Hennig’s work. 410

Rieppel’s argument will follow, but he did include a historical claim. Rieppel claimed that

Carnap was influenced by Ziehen.411 He also noted that Ziehen was frequently cited in the

Grundzüge.412 Unfortunately, it does not follow from either of these facts that Carnap was of broad relevance. However, I believe Carnap’s ideas did played a more modest role in the

Grundzüge, and I suggest the departure point for determining Carnap’s relevance be “Zur

Klarung einiger Begriffe der phylogenetischen Systematik” (1949), where Hennig cited Carnap.

408Rieppel discussed this in more detail in Rieppel “Concept formation” 484. 409Hennig Phylogenetic systematics 4; 25-6. 410Rieppel “Semaphoront” 168. 411Rieppel stated: “Ziehen’s philosophy was classified as positivist by Rensch (1968: 146) as is evident in its reductionist nature, and it did have some influence on logical positivism as is reflected by Ziehen’s influence on Carnap’s programme which aimed at the logical reconstruction of the world (Plümacher, 1997; cf. Carnap, 1922: 22).”pg 169 412Rieppel stated “In this context, it is important to note (as will be discussed below) the frequent citations earned by the philosopher Theodor Ziehen in Hennig’s (1950, 1966) books and especially the citation of Carnap (1922) by Hennig (1950): while Hennig (1950) listed Carnap (1922) (who in turn cites Ziehen) in the list of references, he did not quote him in the text.” “Semaphoront” 168.

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Rieppel began his argument with a discussion of what he took to be Carnap’s philosophy of relations, and used the example of Desdemona and Cassio, an example Rieppel borrowed from Bertrand Russell’s Principles of philosophy (1912) in order to do two things: to illustrate the notion of argument structure, and to illustrate the notion of “direction” in judgment.

Borrowing from Russell was entirely appropriate, for Carnap drew on Russell’s work in Der

Raum. Using a Carnapian analysis, said Rieppel, “Desdemona loves Cassio” could be formalized as “A loves B,” where “A” and “B” fill the two argument places, and made a judgment about

Desdemona’s feelings towards Cassio.413 Rieppel went on to say that according to Carnap a sentence with a single empty argument space specified a concept, whereas a sentence with two empty argument spaces (as in the case of Desdemona and Cassio) specified a relation.414

According to Rieppel, the “structure description” was part of Carnap’s “construction theory” which he merely sketched in 1922.

Rieppel went on to explain that a “relation description” was called a “structure description” if the relations that comprised it were not specified, and only their structure was indicated, that is, their argument spaces were empty, but the relations between them were specified. Rieppel claimed that this type of structure description could be also illustrated as an arrow diagram (with arrows specifying the relations between the argument spaces), or by a list of number pairs, where numbers (or signs) represent objects. He went on to explain that the ordered pair “w {A; B}” could specify the relation between A and B as an arrow that ran from A to B, but not from B to A, no matter what we chose to substitute for w, A and B. Rieppel then claimed

413Carnap Der Raum 9. 414Carnap Der Raum 10.

194 that Hennig made a similar claim in a later work about cladograms corresponding to a “structure description” (“Strukturbild”) that Rieppel credited to Carnap.415

However, this particular connection to Carnap seems be a red herring. Carnap was mentioned in the bibliography of the Grundzüge, but not anywhere in the text. His name was dropped from the bibliography in later edition, in both English and German. The 1949 footnote was the most explicit connection Hennig made to Carnap, and it drew a connection between

Carnap’s idea of space, and not to this particular notion of relations and structure diagrams. More problematic, however, was that the concept of relations as Rieppel explained it, spoke to relations that held between sets and members, not parts and wholes. Hennig was clear in the

1947 discussion that he was talking about “Teilungshierarchie” or a “division hierarchy,” and the relations that defined a division hierarchy were part-whole relations. Henig was also clear about this in both editions of Grundzüge and Phylogenetic systematics. As it turns out, Carnap did discuss a type of part-whole relation, but that was during his constructivist programme in Der logische Aufbau der Welt (1928).

Carnap expanded on a constructivist theory and the idea of the structure descriptions, especially his concept of relations, in Der logische Aufbau der Welt (1928), in ways that would be relevant to Hennig’s notion of individuality and the part-whole relation. To be clear, Hennig did not list Der logische Aufbau der Welt in the bibliography of either edition of the Grundzüge or Phylogenetic systematics, but Carnap’s notion of multigrade relations built from the idea of relations discussed in Der Raum, and was part of the logical debate in the concept of individuality that Hennig discussed and used in his concept of a semophorant, as well as the works Hennig cited in his bibliography.

415The later work was Hennig, 1957: 55. Rieppel “Willi Hennig on transformation series” Taxon 55 ( 2006): 379-80. Rieppel made a similar argument about Carnap and structure diagrams in “Concepts.”

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Logicians in the late 1930s and 1940s knew that not all predicates and relations were well-behaved. Multigrade relations or predicates posed a problem for the predicate calculus

Carnap inherited from Russell and Whitehead. Normally, predicates have a fixed number of arguments that can be stipulated. For example, in the sentence that Rieppel used, “Desdemona loves Cassio.” the predicate took two arguments. However, certain relations or predicates are not so straight-forward. Logicians Alex Oliver and Timothy Smiley provided the following whimsical example of a multigrade predicate:

Imagine some cooperative new men. Tom and Dick cooked dinner. Harry and Roger cooked dinner. These two sentences share the predicate ‘cooked dinner’. How many arguments does it have? Easy answer: two. The ‘and’ which separates the names is a piece of punctuation, functioning like a comma to separate the arguments.

Collaborative cookery took off. Tom, Dick and Harry cooked dinner. Tom, Dick, Harry and Roger cooked dinner. On another occasion, Tom cooked dinner. If we say that we have three more predicates here, with three, four and one arguments respectively, we make ‘cooked dinner’ ambiguous and the occurrence of the very same words an incredible orthographic coincidence. Incredible because the ambiguity never ends, for although lists of names can only be finitely long, there is no bound to their length. We shall have distinct ‘cooked dinner’ predicates with five arguments, six and so on ad infinitum, multiplying senses beyond possibility. Moreover, a common predicate is needed to account for the validity of arguments. Here are three examples from many. Each of our sentences implies ‘some man or men cooked dinner’, a pattern that requires each premiss to have the same predicate as the common conclusion. ‘Tom and Dick cooked dinner’ and ‘Milly, Molly and Mandy did not cook dinner’ jointly imply ‘Tom and Dick did some-thing that Milly, Molly and Mandy did not’ by-how else? -existential generalization over the place occupied by a common predicate. ‘Jekyll and Hyde are Jekyll’ and ‘Jekyll and Hyde cooked dinner’ jointly imply ‘Jekyll cooked dinner’ via an extension of Leibniz’s law hinging on the common predicate ‘cooked dinner’.416

So, some relations or predicates are messy. You cannot be sure how many arguments they take.

It also becomes hard to express the relationship between the individuals. As Oliver and Smiley claimed (and they noted that many logicians before them had made similar claims) a new kind of calculus was needed, something different from that found in Principia Mathematica.

416Alex Oliver and Timothy Smiley “Multigrade Predicates” Mind, Vol. 113, No. 452 (Oct., 2004), pp. 609-681, pp. 609-10.

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In sections 67-93 of the Aufbau, as philosophers Henry Leonard and Nelson Goodman pointed out in “The Calculus of Individuals and Its Uses” (1940) Carnap toyed with a solution to this problem, but it became clear by the 1940s that the best solution to Carnap’s problem was a

“calculus of individuals”—a mereology. Leonard and Goodman discussed the usefulness of such a calculus in the following passage:

The ordinary logistic defines no relations between individuals except identity and diversity. A calculus of individuals that introduces other relations, such as the part-whole relation, would obviously be very convenient: but what chiefly concerns us in this paper is the general applicability of such a calculus to the solution of certain logico- philosophical problems.417

In the corresponding footnote, they claimed: “Since this paper was presented, the convenience of such a calculus of individuals has been well illustrated by Dr. J. H. Woodger’s Axiomatic method in biology (1937).”418 One of the philosophical problems with which they felt this mereological calculus was equipped to deal was multigrade relations of the sort Carnap grappled in the

Aufbau. They wrote “Besides supplementing the body of symbolic logic, the calculus of concepts of lowest type equips us to exhibit and deal efficaciously with certain relational properties which are often ignored or misunderstood, sometimes to the detriment of constructional undertakings like Carnap’s Logischer Aufbau der Welt.”419 They went on to explain multigrade relations in the following way:

Consider, for example, the relation “met with”; we cannot define the ordinary meaning of propositions to the effect that three or more people all met together by requiring that every pair met; for each pair may have met separately, without all three ever having met together. Or again, John and James may be lodge- brothers, and James and Arthur be lodge-brothers, and John and Arthur be lodge-brothers, without all three being brothers in any one lodge. Even the commonplace proposition that a color, C, is, as we customarily say, “at place P at time T” is not implied by the proposition that C is at place P and at time T.

417 Leonard Goodman “Calculus” 46. 418 Leonard Goodman “Calculus” 46. 419 Leonard Goodman “Calculus” 50.

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In each of these cases we encounter a relation which is significant in varying degrees; as dyadic, triadic, tetradic, and so on. The relation “met with”, for example, may obtain between two people, among three, among four, and indeed among any number. Such a relation without any fixed degree may be called a “multigrade” relation. 420

It is possible that one could assume this interpretation of Carnap on relations was what

Hennig had in mind, if Hennig listed Carnap’s Aufbau in his bibliography, but unfortunately

Hennig did not. For this interpretation not to be a stretch, a more detailed historical investigation into Hennig’s understanding of both Carnap’s later work and the logic of multigrade relations would be required.421 The best Rieppel had as a start was a quote from der Raum that does mention the examples of multigrade relations Carnap mentioned in the Aufbau. Rieppel quoted:

This is the basis of Carnap’s ‘‘structure description’’, which he sketched in his doctoral thesis as follows: ‘‘We call a ‘general system of order’ (‘allgemeines Ordnungsgefüge’) a system of relations not between certain identified objects … but between un-interpreted relational entities (‘unbestimmte Beziehungsglieder’); the only thing known of this system is that conclusions can be drawn from relations of one certain kind to relations of another certain kind … this is therefore a system of meaningless relational entities for which the most diverse things can be substituted (such as numbers, colors, degrees of relationships, circles, judgements, humans) in so far as there exist between them relations which satisfy certain formal requirements’’ (Carnap, 1922, p. 5f; emphasis added).422

Nevertheless, it is problematic to see Hennig’s diagrams as Carnapian structure description as

Rieppel described. If they were structure descriptions, then it would mean that they were set- theoretic representations, and thus summative representations, and that would be inconsistent with what Hennig had said in all his work thus far. Rieppel, of course, anticipated exactly this problem. He recognized his argument led straight to this tension in Hennig’s work, but was

420 Leonard Goodman “Calculus” 50. 421On the topic of mereology, it is perhaps of historical interest that Carnap was friends with Woodger during the 1930s, had a correspondence with Woodger, and had visited Woodger’s home in England with Max Black. See Pnina G. Abir-Am “The Biotheoretical Gathering, Trans-Disciplinary Authority And The Incipient Legitimation Of Molecular Biology In The 1930s: New Perspective On The Historical Sociology Of Science” Hist. Sci., xxv (1987). Woodger acknowledged Carnap’s help in his The axiomatic method in biology (Cambridge, 1937). 422 Rieppel “Concept” 477-8.

198 unable to resolve it.423 I suggest Hennig meant for a different reading of those diagrams. He meant for those diagrams to be understood as mereological hierarchies.

I further suggest reading Hennig as using Carnap’s ideas about space and nature in a way consistent with the German reaction to Kant which he cited. Alberto Coffa began The semantic tradition from Kant to Carnap: To the Vienna Station with the bold claim: “For better and worse, almost every philosophical development of significance since 1800 has been a response to

Kant.”424 Michael Friedman discussed the intellectual atmosphere at the time Carnap was writing Der Raum by noting the “tensions” between the geometry and the experience of nature, specifically what he deemed to be “the Kantian understanding” of the relationship between geometry, when it functioned as “an a priori “transcendental condition” of the possibility of the scientific experience of nature,” and space, when it functioned as a “pure form of our sensible intuition,” which seemed to be undermined by new mathematical-physical developments. The question then, claimed Freidman, for philosophers, mathematicians, and physicists, was what should be the relationship between geometry and our experience of nature.425

In a nutshell, Der Raum was Carnap’s neo-Kantian answer to that question. It was an attempt to resolve the apparent differences between philosophers, mathematicians, and physicists by distinguishing among three kinds of space—intuitive, mathematical or formal, and physical— by distinguishing among the corresponding discursive domains.426 Sarkar claimed:

. . . this move heralded what later became the most salient features of Carnap’s philosophical work: tolerance for diverse points of view (so long as they met stringent criteria of clarity and rigor) and an assignment of these viewpoints to different realms, the

423See Rieppel “Semaphoront” 424Coffa Sematic tradition 7 425 Michael Friedman “Carnap and Weyl on The Foundations of Geometry and Relativity Theory” Erkenntnis 42(1995): 247. 426See Der Raum. For more explanation on Der Raum see Friedmann, Sarkar,

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choice between which is to be resolved not by philosophically substantive (for instance, epistemological) criteria but by pragmatic ones.427 Hennig was sketching out a multidimensional multiplicity, and grappling with issues surrounding measurement, so there was certainly enough in Carnap’s Der Raum that spoke to those issues.

More importantly, those were the issues Hennig discussed when he mentioned Carnap explicitly.

The idea of a formal treatment of space that, among other things, conceived of space in a multidimensional fashion that would not be able to be captured in its totality in one description, appealed to Hennig.428 However, Hennig’s relationship with the philosophy of physics did not end there.

5.5.4 Torrey

Discussions of the space-time continuum were more than a little strange in a book about taxonomic method. On the topic of physics and its relationship to biology, Hennig introduced biologist Theodore Torrey (1945-1986). Like many of the other biologists Hennig cited on this topic, Torrey worked on developmental biology. In his history of Indiana University’s biology department, Frank Young described Torrey as starting up the intensive research in developmental biology and embryology with his appointment in 1932. Torrey’s research was mainly in the field of descriptive and experimental embryology of vertebrates, specifically the degeneration of nerves and sense organs, embryonic sense organs, and especially the embryology and physiology of vertebrate excretory organs. Young noted that he worked extensively on the early embryogeny of the human kidney and was among the first to recognize that bone preceded cartilage in the evolution of the vertebrate skeleton. 429 Torrey’s concern was regarding the

427Sarkar, Sahotra “Rudolf Carnap” edited by A. P. Martinich and David Sosa A Companion to Analytic Philosophy (Massachusetts: Blackwell Publishers Ltd, 2001) 95. 428Rieppel acknowledged this debt to Carnap in Olivier Rieppel “Willi Hennig’s dichotomization of nature” Cladistics 27 (2011): 108, but found it difficult to reconcile it with his previous argument. 429In addition to his research, Torrey was recognized as an outstanding teacher and administrator. Young said he was among the first to combine the then conventional comparative anatomy and embryology courses into an integrated

200 failure of biologists to recognize the importance of mathematics and physics to biology. Hennig noted this in all editions:

Trotz dieser heute nicht selten stark betonten Erkenntnis, daß die Unterscheidung zwischen Struktur und Prozeß nur konventionellen und anthropzentrischen Charakter habe (v. Bertalanffy I, p. 249) bleibt Torrey 1939 im Recht, wenn er es beklagt, daß der Biologe noch immer viel zu wenig mit dem dem Physiker und Mathematiker täglich vertrauten Begriffe des vierdimensionalen Kontinuums von Raum und Zeit arbeite.430

Although the insight, often strongly emphasized, that the distinction between structure and process has only conventional and anthropocentric character (von Bertalanffy) Torrey (1939) is correct when he complains that the biologist still works far too little with those concepts, familiar to the physicist and mathematician, of the four-dimensional continuum of space and time.431

In “Organisms in time” (1939), Torrey acknowledged biologists’ reluctance to consider mathematics and physics in their analysis, specifically their reluctance to consider the biological world in four dimensions:

It is most surprising how little attention has been paid to the significance of time by biologists. Here is a factor that has played an important part in the development of physical thought, and there is reason to believe its serious consideration would lead to consequences of equal importance in biology. Much of the tardiness on the part of biologists in thinking of organisms in terms of four dimensions seems to be based on a preconceived fear of the unknown or perhaps merely a stubborn literal adherence to Huxley’s tenets of objective science. In any event the conception of the ‘four dimensional continuum’ which makes up a part of the every day thinking processes of the physicist or mathematician is a mental stumbling block over which the biologist trips, and having tripped, despairs. Actually it requires no special kind of intellectual feat to think in terms of four dimensions; the task is only one of logically building upward from a basis of familiar spatial concepts.432

developmental course, and his textbook on developmental biology was highly successful and is still in print. Young wrote: As a departmental administrator Ted Torrey (“Terrible Ted” or “T-Square” to the students) had no superior and few peers. His management of Zoology’s menage of primadonnas was masterful. He should have written a book on the care and feeding of intellectual tigers. Yet throughout there was never any feeling of neglect among those of us who did not attain international reputations. He was Chairman of Zoology from 1948 until the fall of 1966 when he was succeeded by W. R. Breneman [306] Frank Young “A brief history of biology at Indiana University” Proc. Indiana Acad. Sci. 97 (1983): 297-312. 430Hennig Grundzüge 1950: 8; Grundzüge 1982:13. 431Hennig Phylogenetic systematics 6. 432Torrey “Organisms” 275.

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Not only did Torrey urge biologists to consider physics, but it became clear that when he said

“logically building upward from a basis of familiar spatial concepts” he meant that literally, using tools from formal logic. Torrey then turned his attention to how recognizing the multidimensional nature of organisms, treating the organism as an organized whole, and formally building time into the analysis helped solve some of the problem faced by biologists. Torrey’s solution was similar to what was proposed in a movement called “organicism,” to which both

Bertalanffy and Woodger devoted much effort:

Proceeding to the question of how this ‘time factor’ is applied in conjunction with living organisms, we are immediately brought face to face with the almost insurmountable difficulty of attempting to describe or define what we mean by a living organism. Analyzed chemically and physically, organisms reveal no characteristics serving to distinguish them from non-living entities. They are something more than static, three- dimensional objects differentiated by some structural peculiarity or featuring a particular kind of chemical make-up. Such physical and chemical heteronomy is simply not found. We know living things not by how they are built, but by what they do. The materials comprising an organism are engaged in a multitude of activities, all directed towards the maintenance of both the individual and the tribe to which it belongs. How these separate activities are integrated into an organized whole is a problem in itself not to be considered here. Rather, the point to be made is that living things are truly organized events, and events manifest themselves only in time.433

Torrey’s proposal, which involved building time into the concept of an organism, not only helped see the organism as an integrated, complex whole, but also as seeing it as being made up of “events in time.”

Torrey’s analysis of an organism was similar to what is found in Hennig’s concept of a semaphoront. Torrey’s organism, like Hennig’s semaphoront, was understood as an organized event manifested in time. Torrey continued in a fashion consistent with Hennig, including a discussion of abstracting stages from the organism’s multidimensional whole, coupled with

433Torrey “Organisms” 277-78.

202 understanding the organism (or in Hennig’s case, the semaphoront), as a “division hierarchy” as described by Woodger:

So far in our discussion, we have assumed a very comprehensive view of living things, looking upon any stage of an organism’s ontogenetic or adult history as only a part abstracted from a hyperdimensional whole. Sight must not be lost of the fact, however, that such abstracted parts are of themselves also wholes, albeit wholes of a lower order. Any cross section that one might choose, whether it be a twenty-five somite embryo or thirty-year-old adult, is also a unit, an organized, integrated going concern, it itself made up of parts subsidiary to the whole which in turn is a part of a greater whole. Thus an individual of any historical stage may be analyzed progressively downward into systems, organs, tissues, cells, and cell components which, although they exhibit a certain degree of ontogenetic and adult independence, are entities of a lower order than the whole and bent essentially upon the service of the whole. In this connection attention should be drawn to the logistic system developed by Woodger (1930) in a study of the relation between embryology and genetics. Woodger conceives of the organism as a system of separate entities, ranging from the lowest cell component to the complete individual, arranged in hierarchal order. Every part is a whole, in a sense, but each is only a part of the whole of the systemic level above it and includes the whole of the level below it. To illustrate, the endoderm of a gastrula is a whole of one level, but only a part of a greater whole, the gastrula itself. Likewise the cells making up the endoderm are parts of the part of the whole, the nucleus of one such cell a part of the part of the part of the whole and so on. Woodger also conceives of a greater whole, the “division hierarchy” which includes the entire ontogenetic history of the organism. A given embryonic stage of development, therefore, becomes a ‘short temporal slice’ of the division hierarchy. Though clothed in logistic language, Woodger’s notions would seem to be essentially comparable to my own.434

Hennig’s ideas about semaphoronts were similar, as he cited Torrey in this context in all editions:

Gerade in neuester Zeit ist diese Tatsache wieder besonders stark in den Vordergrund gerückt und eine extrem dynamische Auffassung nicht nur der Lebensvorgänge, sondern auch der lebendigen Form vertreten worden,”Jede beschreibbare Einzelform ist nur ein willkürlicher Ausschnitt, der durch den gewählten Zeitpunkt bestimmt wird” (Torrey nach dem Referat von Dabelow).435

. . . not only of the processes of life but also that of the living form: “each describable single form is only an arbitrary portion of the whole that is determined by the point in time chosen” (Torrey, from a review by Dabelow).436

434Torrey “Organisms” 279-80. 435Hennig Grundzüge 1950:8; Hennig Grundzüge 1982:13. 436Hennig Phylogenetic systematics:6.

203

According to Hennig, although semaphoronts were things, they were not organisms or a species.

They were “animated natural things” taken during a time-slice of their continuous existence.437

He provided the same definition in all editions of his book:

Wir bezeichnen dieses in der angegebenen Weise zu charakterisierende Element aller biologischen Systematik im folgenden der Kürze halber als Merkmalsträger- Semaphoront. Die Definition des Semaphoronten als des Individuums während einer, allerdings sehr kleinen, Zeitspanne (nicht “an einem Zeitpunkt”) seines Lebens hat den Vorteil, daß es dann leichter als handelnd und Lebensvorgänge zeigend gedacht werden kann. Wie lang die Zeitspanne praktisch zu bemessen ist, während der ein Semaphoront als konstante, systematisch brauchbare Größe existiert, darüber können keine allgemeingültigen Angaben gemacht werden. Sie hängt von der Geschwindigkeit ab, mit der sich seine einzelnen Eigenschaften verändern. Im maximalen Grenzfalle wird sie sich mit der Lebensdauer eines Individuums annäherungsweise decken. In vielen anderen Fällen, namentlich bei Organismen, die metamorphotische und cyclomorphotische Prozesse durchmachen, wird sie dagegen sehr deutlich kürzer sein.438 Translated in 1966 as: We will call this element of all biological systematics, for the sake of brevity, the character-bearing semaphoront. Definition of a semaphoront as the individual during a certain, however brief, period of time (not “at a point in time”) has the advantage that it may be thought of as acting and showing evidence of life processes. No generally applicable statements can be made about how long a semaphoront exists as a constant systematically useful entity. It depends on the rate at which it its different characters change. In the maximum extreme it would be approximately congruent with the duration of the life of the individual. In many other cases, particularly in organisms that undergo metamorphic and cyclomorphic processes, it would be notably shorter.439

Semaphoronts were the basic units used to carry the empirical character information, and the semaphoront could bear a variety of characters such as: morphological, ethological, ecological, physiological and geographical. Hennig built the individual organism by ‘fusing’ temporally successive semaphoronts of an individual life-cycle into a semaphoront complex, and he built individual species by logical reconstruction, that is, by fusion of semaphoront complexes.

According to Hennig the semaphoronts form a hierarchical complex, but not one based on similarity. He discussed this in detail in 1950:

437Hennig Grundzüge 1950: 9, Hennig Phylogenetic systematics 6. 438Hennig Grundzüge 1950: 9; Hennig Grundzüge 1982:14. 439Hennig Phylogenetic systematics 6.

204

Es wäre von allgemein erkenntnistheorestischem Interesse und auch für die Theorie der biologischen Systematik von Bedeutung, einmal zu untersuchen, inwieweit die Tatsache, daß sich bestimmte zwischen diskreten Naturdingen bestehende Ähnlichkeitsbeziehungen dadurch am besten zum Ausdruck bringen lassen, daß man die durch solche Ähnlichkeitsbeziehungen miteinander verbundenen Dinge in ein Hierarchisches System von Gruppen einordnet, für sich allein schon genügt, eine historische Entwicklung dieser Dinge von der Art, wie sie für die Arten der biologischen Systematik von der Deszendenztheorie angommen wird, zu beweisen, inwieweit also in solchen Fällen der Schluß „Hierarchie der Ähnlichkeitsbeziehugen = Teilungshierarchie” (WOODGER, siehe BERTALANFFY 1931, I, p. 265 ff.) berechtigt ist.440

It would be of general epistemological interest and also of great importance for the theory of biological systematics to examine the extent to which this fact – that certain relationships of similarity existing between discrete natural objects are best expressed by ordering things bound together by such relationships of similarity into a hierarchical system of groups – suffices in and of itself to prove a historical development of these things from the way in which this development is hypothesized for the types of biological classification by the theory of evolution. That is, it would be of interest to explore to what extent the conclusion “hierarchy of similarity relations = division hierarchy “(Woodger, see Bertalanffy, 1931, p. 265 ff) is justified in such cases.

Hennig simplified this claim in 1961, saying instead:

Wenn aber zwischen Naturkörpern Beziehungen bestehen, die offenbar nicht vom Menschen gesetzt sind, deren Struktur aber der eines hierarchischen Systems entspricht, so scheint sich als einzige annehmbare Erklärung für das Zustandekommen dieser Struktur die Annahme einer “Teilungshierarchie” (WOODGER, siehe v. BERTALANFFY 1931, p. 265 ff.) anzubieten.441

But if there are relationships between natural bodies that obviously were not instituted by man but whose structure corresponds to that of a hierarchic system, then the only acceptable explanation for the occurrence of this structure seems to be the assumption of a “hierarchy of partition” (Woodger, see von Bertalanffy, 1931).442

Key to this description was that Hennig did not think semaphoronts formed just any kind of hierarchy; they formed “Teilungshierarchie” or division hierarchy, which was often incorrectly translated in Phylogenetic systematics.

440Hennig Grundzüge 1950:20. 441Hennig Grundzüge 1982: 28. 442Hennig Phylogenetic systematics 21.

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5.5.5 Mereology

5.5.5.1 “Concept of an organism” (1930-31)

Hennig did not cite Woodger’s work in the bibliography of the Grundzüge, but mentioned Woodger’s name in the text, in conjunction with Woodger’s logical concept of a

“division hierarchy”—a part of his mereological calculus. Why would Hennig consider a division hierarchy in the first place? Consider again the authors that Hennig had cited in his papers so far. Those authors with an interest in cutting-edge physics and philosophy, and had a shared reaction to anti-mechanistic philosophy. This reaction to mechanistic philosophy had a counterpart in biology. According to historian and philosopher Nils Roll-Hansen:

The molecular biologist’s idea of the organism as a chemical machine, built from molecules of various shapes and sizes, appeared simplistic and outmoded in the context of the epistemologically sophisticated physics of the twentieth century. Why should biology hold onto a world view that had been discarded by physics? This was a standard argument used by a wide range of philosophers, physicists, and biologists . . . As late as 1949 the physicist and geneticist Max Delbrück used this argument against the analytical chemist’s approach to the problem of biological inheritance.443

So, Hennig was drawing from physicists and philosophers of physics who were challenging a mechanistic approach. He was also drawing from biologists in disciplines outside of taxonomy that were anti-mechanistic, such as Bertalanffy and Torrey, who were promoting holism, emergence theories, and for Bertalanffy, the general systems theory. Common for all these approaches was the principle that “the whole is more than the sum of its parts.” Bertalanffy, like

Woodger, defended an “organismic conception” of life such that an organism cannot be understood as a “machine” made of parts and having a definite structure. Instead, organisms were dynamic process. For Hennig, this amounted to building in a notion of time. By the time

Hennig had sat down to write the Grundzüge, he had developed a philosophical position, and

443Nils Roll-Hansen “E. S. Russell and J. H. Woodger: The Failure of Two Twentieth-Century Opponents of Mechanistic Biology” Journal of the History of Biology, 17 (1984):404.

206 settled on a hierarchical approach. He just needed the right type of hierarchy to use. Woodger had developed one that fit the bill, and Bertalanffy and others had already put it into practice.

When Woodger designed his mereological calculus in his account of biological hierarchies, he very clearly did not have taxonomy in mind. Woodger did not provide a mereological treatment of taxonomy in “The ‘Concept of an organism.’” According to Historian

Marshall Allen, when Woodger was writing these papers, he was reading Principia Mathematica in order to develop his biological axioms. While he was doing this, he met with Karl Popper,

Alfred Tarski, and Rudolf Carnap. Allen claimed that from all, especially Carnap, he absorbed the “logic of science,” a philosophical focus which followed so easily from his interests in the new logic.444 But that wasn’t all. Just as Ernst Mayr had read genetics, attended genetics lectures, met with geneticists, and included genetics in his publications, all in an effort to more effectively communicate with geneticists to work towards a common goal, so too did Woodger with logic. He met with and corresponded to Carnap—an influence on Hennig—as well as prominent logicians and philosophers Alfred Tarski, Karl Popper, and Max Black.445 Woodger included philosophy and logic in his series “The ‘Concept of an organism,’” but he also co- authored a formal logic paper with logician W. Floyd “A Simple Method of Testing Truth-

Functions” (1936).446 Woodger travelled to Poland in 1935 to meet with Tarski and the Polish

School of Logicians, as his mereology bore a striking resemblance to Polish logician Stanisław

Leśniewski’s system.447 Woodger’s efforts in logic were met with success. Frederic B. Fitch’s review of The Axiomatic Method in Biology in The Journal of Symbolic Logic was quite

444Marshall William Allen. “J. H. Woodger and the Emergence of Supra-Empirical Orders of Discussion in Early Twentieth Century Biology.” Master of Science, History, Oregon State University, Corvallis, OR, 1975. 445Woodger’s ability in logic was good enough that Tarski trusted him to edit and translate his (1956). Logic, Semantics, Metamathematics: Papers from 1923 to 1938. 446J. H. Woodger and W. F. Floyd “A Simple Method of Testing Truth-Functions” Analysis, 3 (1936) 92-96. 447 John R. Gregg and F.T.C. Harris, edited. Form and Strategy in Science: Studies Dedicated to Joseph Henry Woodger on the Occasion of his Seventieth Birthday (Dordrecht: Holland, D. Reidel Pub. Co. 1964), 4.

207 favourable. He ended his review with: “Dr. Woodger is to be commended for having written a book which not only is of sufficient scientific importance to be of interest to both the logician and the biologist but which also contains a reasonably adequate elementary introduction to the logic of Principia mathematica.”448 Likewise, E. S. Allen penned a favourable review in Bulletin for the American Mathematical Society:

We have here the first attempt to build a system of biology on the basis of abstract logic. The book will probably be harder reading than the author (reader in biology at the University of London) realizes—save for those few who are versed both in Russell’s symbolism and in fundamental biology. Nonetheless, its writing was a task well worth doing, and one which has been done excellently. It discusses biology with precision of statement and reliability of reasoning, and clearly shows the conceptual unity underlying a number of basic branches. It emphasizes the wisdom of R. A. Fisher’s remark: “I can imagine no more beneficial change in scientific education than that which would allow each (mathematician and biologist) to appreciate something of the imaginative grandeur of the realms of thought explored by the other.”449

The Axiomatic Method’s reception was mixed in biological circles, and in some cases proved a harder sell. For example, J. B. S. Haldane submitted a critical review to Nature.450 His specific objections mainly target biological inaccuracies he saw which challenged Woodger’s logical treatment of genetics, however, Haldane was clear that he had philosophical issues with almost anything he recognized as “biological positivism.” Bertalanffy, in contrast, included Woodger’s ideas in his own work.

When Woodger discussed taxonomy, he provided a very different hierarchical approach, one that was based on a set-member relation.451 Briefly, and with disclaimers, in Axiomatic

448Frederic B. Fitch “Review: The Axiomatic Method in Biology by J. H. Woodger; W. F. Floyd; Alfred Tarski” The Journal of Symbolic Logic, 3 (1938): 42-43. 449E. S. Allen “Review: The Axiomatic Method in Biology by J. H. Woodger; W. F. Floyd; Alfred Tarski” Bull. Amer. Math. Soc. 44 (1938). 450 J. B. S. Haldane “Biological Positivism” Nature 3563 (1938): 265. 451 See Woodger “Concept of an organism part 3”,199-200.

208 method Woodger discussed taxonomy again, applying the abstract definition of hierarchies. His abstract definition of hierarchies applied to sets and classes, not to individuals.

So, what Hennig did in Grundzüge, appeared not just radical, but remarkable. Rather than apply Woodger’s formal analysis of a taxonomic hierarchy, Hennig extended Woodger’s mereological notion of a division hierarchy to taxonomy, and applied it to species taxa. As seen from the previous discussion, the technical and formal logical discussion of hierarchies was not a strange formal footnote in the history of cytology that Hennig dusted off and popped in his book.

When Woodger presented his notion of a division hierarchy, authors such as Torrey and

Bertalanffy immediately snatched it up in cytology as part of a movement called “organicism.”

Hennig cited both these authors’ use of Woodger on this topic. Rieppel noted that Bertalanffy was one of the most often cited authors in the Grundzüge, and Rieppel also noted that Hennig cited Torrey in his discussions on space and time.452

From a logical perspective, Hennig built a semophorant in much the same way Woodger built cells. When Woodger introduced the notion of hierarchical order in his first series of three papers, it was to help distinguish between hierarchies, like the Linnaean hierarchy, that was fully nested displaying the summative property, and the kind of hierarchy he was proposing, a division hierarchy where the whole could be more than the sum of its parts.

Woodger (1937, 1952) defined an abstract hierarchy, such as the Linnaean hierarchy, where R is “relationship,” as follows:

R is a hierarchy if and only if R is one-many and if the converse domain of R is identical with the set of all terms to which the first term of R stands in some power of R.453

452Rieppel “Semaphoronts” 169-17, 172. 453Gregg defined hierarchical relations: (

) ( ̌ ̌ { })(1954: 26)

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This kind of hierarchy, the usual kind of set-theoretic hierarchy, was an organizational model that had three noteworthy features. First, the highest level of organization consisted of a single entity. Second, any entity at a lower level of organization was related to only one entity at the next higher level. However, it could be related to more than one entity at the next lower level.

Third, entities at all lower levels were related by extension to the single entity at the highest level of organization. A division hierarchy was different. Division hierarchies were not fully nested and nor was it the case that the sum of all entities or the relations at one level of organization was equal to the sum of all entities or the relations at some other level. In other words, division hierarchies did not necessarily display the property of summativity. Another way to think of this is consequence is ontologically, a division hierarchy implies a more fully fledged ontology—the whole is more than the sum of its parts.

In the second paper, Woodger provided a more detailed account of hierarchies, included a division hierarchy. He began by defining what he took to be the relevant concepts for biological organization in a logic of relations: symmetry, asymmetry, converse, transitivity, intransitivity, relative products and squares, dyadic, triadic relations, one-one, one-many, and many-one relations, as well as the domain and field of a relation. He provided an example of a hierarchy demonstrating a dyadic, asymmetrical, intransitive, aliorelative relation454 which would look like a hierarchy used to construct human pedigrees. He proceeded to explain the limits of such a hierarchy, especially in terms of biological organization. For Woodger, biological organization was more than just a geometrical relation. He claimed that if you scattered coins on the ground, they wouldn’t make an organized whole. Even if you arranged them in a pattern, the coins would

454Aliorelative is another word for irreflexive. An aliorelative relation is one in which a term cannot stand to itself. Woodger gave the example “greater than.”

210 not constitute the kind of whole, the kind of biological organization, Woodger had in mind.

Woodger explained:

What we have to do is to make clear the difference between, say, a mass of frog’s spawn and a frog blastula. Both are “analysable into cells” but there is clearly a difference between them which we express by saying that the latter is a single whole organism and the former is not. The example of the coins shows that it is not sufficient to say that in the case of the blastula there is some relation between the cells with respect to which they constitute a system and that in the case of the mass of frog’s spawn there is no such relation. This is evidently important but there is something more required. And one further requisite seems to be that this relation should be an internal relation in the sense that a given term (e.g. a cell) is different when it is in this relation to the other terms from what it is when it is not in this relation. The whole will then change in its properties when it is deprived of a part, and a part will have different properties when removed from the whole from what it has in its place as a part. The whole will have “Gestalt” properties in the sense of Kohler.455

Woodger wanted to impress upon his readers that the relations were different and the resulting hierarchy was different. The hierarchy that he used for whole-parts was the division hierarchy.

At the end of the day, what Woodger wanted to do was provide a language to describe this type of situation. Woodger sketched out a system in this paper and the next, but he needed a more detailed account. A few years later, Woodger did precisely that.

5.5.6 Axiomatic Method (1937)

In 1937, Woodger provided a more rigorous presentation of this system in his Axiomatic method. In this monograph, he provided a calculus for the different types of hierarchies he outlined, including his division hierarchies. He included a short chapter on taxonomy, where he outlined what he understood the Linnaean hierarchy to be, and briefly sketched out the resulting kind of hierarchal system. It is important to remember that Gregg’s presentation was an expansion of this chapter, not Woodger’s mereological calculus. There were five features of

Woodger’s mereological calculus that helped distinguish a hierarchy constructed in this type of

455Woodger “Concept 2” 449.

211 calculus, namely a division hierarchy, from a hierarchy constructed in set-theory.456 These features were: parthood, time, organized entities, beginners and enders, and division.

In the Appendix can be found a foray into logic may seem to be an unnecessary and somewhat painful digression, especially since Hennig did not cite these works by Woodger in his bibliography. However, Woodger had a longstanding friendship and correspondence with

Bertalanffy during this period, and Woodger translated Bertalanffy’s work into English.

Bertalanffy included Woodger’s work, especially his logic, in his own work, and Hennig cited

Bertalanffy profusely. Given Hennig’s emphasis on logic and formalism, and his use of the term

“division hierarchy,” it is not unreasonable to stop to underscore the importance of the formal difference between the two hierarchies—the abstract hierarchy and the division hierarchy—

Woodger presented.

What is significant about Woodger’s mereological calculus, and why Hennig would have picked a division hierarchy over an abstract hierarchy found in Woodger’s treatment of taxonomic hierarchies, is that Woodger’s division hierarchies include the features parthood, time, organized entities, beginners and enders, and division. As such there are fusions and overlaps, which would provide new entities. These were precisely the sort of features Hennig was looking for in a hierarchy for his new methodology. The traditional treatments of hierarchies and even

Woodger’s new set-theoretic account of taxonomic hierarchies was not consistent with the ontological picture Hennig was painting.

456Woodger used small letters from the beginning of the Greek alphabet for variables whose values are class-signs for one-termed predicates) and small Latin letters in bold type for the corresponding subject-matter signs or empirical constants. For variables whose values are relation-signs we shall use the letters P, Q, .R, S and T, and empirical constants (subject-matter signs) of this kind will be in bold type consisting of a single capital letter or a capital followed by one or more small letters.

212

Given Hennig’s appreciation of other aspects of technical philosophy (including Carnap’s daunting doctoral dissertation), it is also not unreasonable to assume he was aware of these important logical distinctions even if he did not burden us with the machinery. As it turned out,

Hennig was aware of these distinctions, even if he did not explain it in the detail I just did, and he made that clear in both the 1961 German manuscript and Phylogenetic systematics.

5.6 Conclusion

As early as 1947, and consistently through the Grundzüge einer Theorie der

Phylogenetischen Systematik (1950), Hennig argued that the structure that best represented the complex taxonomic relations was hierarchical. Specifically, he believed that structure was a mereological “division hierarchy,” not a traditional set-theoretic hierarchy.

In the late 1940s Hennig wrote two short papers in which he developed in his philosophical programme: “Probleme der biologischen Systematik” (1947) and “Zur Klarung einiger Begriffe der phylogenetischen Systematik” (1949). In “Probleme der biologischen

Systematik,” Hennig discussed the state of taxonomy, aiming to rid taxonomy of problematic dichotomies. Hennig believed that phylogenetic systematics was not only a descriptive science, but also explanatory. He also believed it was both nomothetic and ideographic science. He began developing concept of a semaphoront (although he did not use the term in this paper), and issued a promissory note for further discussion on these and other topics in his forthcoming manuscript.

In this paper, Hennig explored the idea of relations, in particular genetic relations and how they were connected to the concept of an individual. He argued such an individuality claim could only be made if the links connecting the different phases of a life could be uncovered—a genetic link could be made. Hennig went on to discuss metamorphosis of the common flesh fly as an illustration of his point. According to Hennig, this needed to be spelled out along more

213 formally. Hennig credited his insights along these lines to Zimmermann, another biologist who believed in cleaning up taxonomic methodology along more formal lines.

This led Hennig to a more general account of hierarchies in taxonomy that he would cover in this paper, and in “Zur Klarung einiger Begriffe der phylogenetischen Systematik”

(1949). He said that although there were other types of systems available to taxonomists, noting the “periodic system” for butterflies and the network structure of family relations, the most suitable system for representing the phylogenetic system was a hierarchical system. Hennig went on to specify the kind of hierarchical system he had in mind when he was sketching out the structure of genetic relationships in reproductive communities. He used the technical term

“Teilungshierarchie” which translated to “division hierarchy” in English to describe this type of hierarchy.

Hennig borrowed this technical term, along with the terms “Histosysteme” and “enkaptic structure” from Bertalanffy’s Theoretische Biologie (1931, 1942). What all these terms shared, and what made them significant to Hennig, was they assumed the whole as more than simply the sum of its parts. Heidenhain, for example, introduced his concept of the “enkaptic structure” of organism to explain how organic parts came together to form a complex whole, promoting a non- summative approach, and explained how organisms formed through division. Heidenhain discussed what he called an “enkaptic hierarchy” in cell biology, and according to Bertalanffy,

Woodger provided a calculus for such a hierarchy, including the part-whole relation and a notion of division.

In “Zur Klarung einiger Begriffe der phylogenetischen Systematik” (1949) Hennig did not use the term “Teilungshierarchie,” but he mentioned enkaptic systems twice, once in conjunction with figure 2, and once to distinguish between phylogenetic and morphological

214 relations. Hennig’s point was to draw a connection between enkaptic systems and phylogenetic systems. When species were arranged according to their phylogenetic relationships, the arrangement was equivalent to an enkaptic system, a system where the symbolic boundary lines of the stem species were drawn around their successor species, not to represent a system of nested sets.

(1931-2), and then developed it in more formal detail in Axiomatic method as part of a mereological calculus—a logic of parts and wholes—to help explain some of the finer points of cytology. Although Woodger did not appear in Hennig’s bibliography in the Grundzüge, his name appeared in the text, and he figured largely in Bertalanffy’s work and was discussed by

Torrey, both of whom were cited by Hennig. Hennig used “Teilungshierarchie” in “Probleme der biologischen Systematik” in a way consistent with Woodger’s use. Hennig explained that he was borrowing the term from cell biology and he too was using it as part of an account of individuality.

In “Zur Klarung einiger Begriffe der phylogenetischen Systematik,” Hennig also discussed the philosophical notion of space, referencing German philosopher Bernard Bavink, psychiatrist and philosopher Theodor Ziehen, and philosopher Rudolf Carnap. Hennig began

“Zur Klarung einiger Begriffe der phylogenetischen Systematik” by discussing problems with the morphological system, specifically that phylogenetic systematics was based on the conviction of the existence of real, natural species, but it was thwarted by problems with methodology and

215 attempts to determine the structure of phylogenetic relationships. He presented a graphic interpretation, explaining that morphological change can be represented by inserting a temporal dimension and a morphological dimension, but such an account ran into tremendous difficulty.

One problem Hennig encountered when constructing a solid foundation for taxonomy was one of space, time, and measurement. This lead Hennig to introduce philosophers who wrote on physics, specifically Bavink, Ziehen, and Carnap. There were at least two points Hennig wanted to drive home in this paper, with respect to space. First, according to Hennig, a good morphological system required a measurable foundation, and according to Bavink there was no mathematical basis to determine the exact measurements of similarities and differences in form, no mathematical basis for the morphological system. Second, when Hennig discussed space, he proposed an account of life as a “multidimensional diversity” following Ziehen and Carnap. On this account, Hennig claimed organisms differed in many different directions or dimensions, and as such, saw relations interconnecting the multidimensional diversity. Hennig expanded on his notion of space and multidimensional multiplicity in the Grundzüge, but it is important to note that the textual evidence seems to support Carnap’s influence on Hennig on this issue, rather than on a formal logic point about set-theory and species. If Carnap’s influence is taken on Hennig’s understanding of the relationship between logic and taxonomy, as Rieppel did in his investigation, Hennig is led into a series of contradictions, especially on his account of hierarchies.

Hennig’s philosophical programme was certainly daunting. On first glance, it might appear that Hennig might have broken things simply for the sake of fixing them. However, in retrospect (and from a philosophical perspective), it seemed instead that Hennig was ahead of his time. Although almost no taxonomist at that time, or for many decades to come, was sympathetic or even interested in the logical and ontological issues Hennig worked through and claimed were

216 essential to the reform, by the 1970s, many taxonomists had begun to move toward an analogous view.

217

Chapter 6 Beckner

6.1 Introduction

Gilmour had been accused of promoting logical positivism, but upon closer inspection it is clear that he had no such agenda. Simpson took an explicit quantitative turn, but had no accusations made with respect to logical positivism, even though he was sympathetic to treating species as groups, which would have unexpected logical and ontological consequences. Hennig’s work, in contrast, candidly dealt with logic, and he cited at least one author associated with logical positivism, but unlike Simpson and Gilmour’s work, Hennig’s book escaped the

American philosophical community’s attention in the 1950s.457

457 Mayr (1982), Hull (1988, 131) and Rieppel (2004) and others claimed that when Hennig published the Grundzüge, it escaped notice in the international taxonomic community and was not widely available, even though it was revolutionary. Russian entomologist Sergius G Kiriakoff highlighted this fact in “Phylogenetic Systematics Versus Typology” (1959): “Hennig’s book (1950) on the principles of phylogenetic systematics opened a new epoch in classification. Unfortunately, it is not generally available, hence Hennig’s later papers (1953, 1954, 1957) are mentioned.”[ Sergius G Kiriakoff “Phylogenetic Systematics Versus Typology” Systematic Zoology (1959):117] Unavailability was not the only problem the Grundzüge faced. Mayr, Hull, and Rieppel noted even when Grundzüge became available, Hennig’s style proved a significant obstacle. In a review of Phylogenic systematics, Walter Bock remarked: Perhaps the most important nonavailable book during the past two decades for English-speaking systematists was Hennig’s “Grundzüge einer Theorie der phylogenetischen Systematik.” Although its existence was widely known, this book was relatively unaccessible and when available, its difficult German style precluded extensive reference.[“Phylogenetic Systematics, Cladistics and Evolution Phylogenetic Systematics. by Willi Hennig; D. Dwight Davis; Rainer Zangerl” Review by: Walter J. Bock Evolution, 22 (1968) 646] Hull, for example, remarked on numerical taxonomist, Robert Sokal’s experience with the Grundzüge: As a result of Kiriakoff’s papers and Simpson’s footnote, Sokal obtained a copy of Hennig’s Grundzüge and worked his way through it. Even though German was Sokal’s native language, he found Hennig’s prose very tough going, but by the time that he had struggled through the book he was more than impressed by the sophistication of Hennig’s views.[ Hull Science as Process 131 ] Like Sokal, German was Mayr’s native tongue, and like Sokal he too found Hennig’s book a hard go. Mayr remarked unfavorably regarding Hennig’s style, in “Cladistic analysis or cladistic classification ?” claiming the Grundzüge was “written in a rather turgid style.” However, Mayr’s negative assessment escalated by the time he sat down to Growth of biological thought. Mayr wrote: Hennig’s work is written in rather difficult German, some sentences being virtually unintelligible. It nowhere refers to the writings of Huxley, Mayer, Rensch, Simpson, and other authors who have covered in part the same ground in the preceding decades. New terms and definitions are casually introduced, but there is no index that would guide one to the relevant pages. Not surprisingly the volume was at first rather universally ignored, except by a few German authors. It did not become more widely known until 1965 and 1966, when English versions of Hennig’s methodology were published. [Mayr, Growth of biological thought 226 ]

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Hennig’s absence in the literature aside, philosopher David Hull’s succinct 1964 statement in Systematic Zoology on the controversial topic of phylogenic taxonomy summed up the culmination of a few decades of debate:

The three factors in phylogenetic taxonomy are phylogeny, the taxonomic schema, and the relation between the two. Of the three factors in the phylogenetic program, only phylogeny is of an empirical nature. The structure of the taxonomic schema is entirely a matter of logic, and the relation which this schema is to have to phylogeny is primarily a concern of the purposes of taxonomy.458

Although Simpson and Gilmour disagreed on certain issues, they could both agree that while phylogeny may be an empirical matter, to make claims about phylogeny, inferences must be made. Gilmour, on the one hand, was critical of the types of inferences made when it came to evolutionary taxonomy. In “Taxonomy and Philosophy” (1940), for example, he provided instances of fallacious reasoning. Simpson, on the other hand, believed his pioneering work in statistics moved a step towards making better inferences in evolutionary taxonomy.

It wasn’t just striking that a philosopher was publishing in a biological journal in the

1960s, or that he was accurately summarizing the methodological debate. The origins of Hull’s statement regarding taxonomic schemata pointed to a subtly different and more complicated chapter of the story about logic and taxonomy. This chapter involved biologists and philosophers together examining debates that informed taxonomic schemata, for example the species debates that now included imposing a formal structure on what they took to be a conceptual mess that underpinned particular taxonomic schemata, such as the Linnaean hierarchy and phylogenetic

Mayr was not entirely fair, especially since Hennig cited all those authors (except Mayr) in his bibliography. In the text Huxley was mentioned at least once (on page 168), Rensch at least six times (pp 73, 83, 86), and Simpson at least twice (p 216). The paper shortage in post-war Germany explained the lack of an index. However, as Mayr mentioned, Hennig’s style was not the only difficulty with the book. There existed a further problem, namely Hennig’s use of concepts. Not only did Hennig introduce myriad of new terms (Rieppel identified terms such as “semaphoront,” “cladogram,” “symplesiomorphy,” “synapomorphy”), but he redefined existing terms (Rieppel identified terms such as “phylogeny,” “relationship,” “monophyly”) in ways many taxonomists felt could at best confused or at worst stirred unnecessary controversy in the midst of taxonomy’s reform. 458David L. Hull “Consistency and Monophyly” Systematic Zoology, 13 (1964): 1.

219 trees. The set-theoretic approach that attempted to capture the Linnean hierarchy provided a formal definition of the term “monotypic.” Within this conceptual tangle emerged another term, a rival term—“polytypic”—which would raise as many problems as it solved. Philosophy, and logic in particular, was more than window-dressing.

In 1959, young American philosopher Morton Beckner attempted to describe the kinds of methodological changes Gilmour, Simpson, and others addressed in more explicit logical terms in The biological way of thought, specifically those concerning taxonomic schemata. The biological way of thought was not the first attempt to capture taxonomic schemata in formal symbolic logic, but it was one of the first attempts to do so in a way consistent with one faction of the taxonomic reform, those who fell under the umbrella of Huxley’s “New systematics.”

Beckner described the “New Systematics” in the following way:

The New Systematics has arisen in the attempt to adapt intractable empirical matter to the ideal of a classification based on phylogeny, which is at the same time useful as a catalogue. I shall outline the theses of the New Systematics which will be of concern to us. The species is the taxon with the highest “degree of objectivity.” It differs in kind from all other taxa. The population, not the individual, is the basic taxonomic unit. “Biological” criteria of species are to be employed; morphological taxonomic characters do not have special theoretical significance. Wide use is to be made of quantitative techniques, especially of statistical methods.459

The logical framework Beckner constructed aimed to be consistent with these theses. One of the concepts central to his framework was the “polytypic species concept.” This concept appeared not only in the pure biological literature, but its counterpart, the monotypic species concept, proved a central and controversial concept in earlier attempts to formalize taxonomic schemata.

In some respects, Beckner’s attempt to formalize taxonomic schemata was more successful than previous attempts to conceptualize species as classes. In particular Beckner

459Morton Beckner The biological way of thought. (New York: Columbia University Press,1959): 58-59.

220 discussed an earlier attempt to formalize a taxonomic schema, specifically developmental biologist John Gregg’s attempt to use set theory to capture species in a monotypic classification in The language of taxonomy: an application of symbolic logic to the study of classificatory systems (1954). Gregg’s attempt to formalize the Linnaean hierarchy was an extension of

Woodger’s brief attempt to formalize the Linnaean hierarchy using set-theoretic tools. Gregg’s brief and elegant presentation of what a set-theoretic account of the Linnaean hierarchy would look like was, to say the least, provocative.

The response to Gregg’s work came in waves. At first, Gregg’s work seemed to slip under the radar, with not much enthusiasm and not much criticism. Simpson, for example, did not sing its praises, but didn’t think the whole endeavor was for naught. He wrote in Principles of animal taxonomy:

. . . these particular applications of set theory and symbolic logic to classification do not adequately take into account some relationships that are involved in actual classification and that do appear to be perfectly logical. That does not imply that these relationships could not be adequately incorporated in some system such as Gregg’s or that it would not be worthwhile to do so.460

In Systematic zoology, taxonomist Richard Blackwelder provided a lukewarm review:

It solves none of the problems of taxonomy; it will not answer the questions currently arising between systematists. Nevertheless, this book may well prove to be the clue to the solution of some of these important problems. Taxonomy is the study of kinds of organisms. This book is an attempt to develop a language for use in taxonomy. It is therefore not a book on taxonomy but on metataxonomy-the study of taxonomic statements. Taxonomy and metataxonomy differ in having different subject matters, in having different vocabularies, and in being unequally developed. This book is an attempt to develop one aspect of metataxonomy by illustrating the utility of set-theory concepts in the study of taxonomic classification.461

In other words, for Blackwelder, Gregg’s book had a limited audience—philosophers. It served no real purpose in taxonomic circles.

460 George Gaylord Simpson Principles of animal taxonomy (Columbia University Press 1961): 21. 461R. E. Blackwelder “The Language of Taxonomy” Systematic Zoology, 4 (1955): 41.

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Gregg used Simpson’s classification of mammals when he raised objections to monotypic classification, namely Mutica contained a single order, Cetacea (whales and their relatives) and the family Rhachianectidae contained a single genus Rhachianectes (gray whales). It was easy to see why Simpson felt Gregg did not adequately account for some relationships involved in actual classification that do not appear perfectly logical. Consider the Mutica/Cetacea example. In

“Classification of mammals,” Simpson provided the classification to which Gregg referred,462 but Simpson also provided a discussion of these groups. Mutica/Cetacea were special, claimed

Simpson, and “on the whole the most peculiar and aberrant of mammals.”463 Simpson struggled with where to place them in the hierarchy. Simpson wrote:

Their place in the sequence of cohorts and orders is open to question and is indeed quite impossible to determine in any purely objective way. There is no proper place for them in a scala naturae or in the necessarily one-dimensional sequence of a written classification. Because of their strong specialization, they might be placed at the end, but this would remove them far from any possible ancestral or related forms and might be taken to imply that they are the culmination of the Mammalia or the highest mammals instead of merely being the most atypical. A position at the beginning of the eutherian series would be even more misleading. They are, therefore, inserted into this series in a more or less parenthetical sense. They may be imagined as extending into a different dimension from any of the surrounding orders or cohorts.464

In terms of classification, Simpson claimed this group was a mess. Although it was clear that naturalists identified this group early on, they failed to identify them as mammals. Linnaeus classed them as mammals, but in the following century the Cetacea were usually confused with other aquatic mammals. Simpson claimed “[e]ven after the pinnipeds were associated with the

Carnivora, the Sirenia were long considered Cetacea, or an order closely allied to the latter. This idea is to be found as late as the 1890’s in the work of so able a man as Cope, but even then this

462Simpson “Classification” 100. 463Simpson “Classification” 213. 464Simpson “Classification” 213.

222 was old fashioned, and no competent student has since accepted it.”465 What went into the final classification, the sort that Simpson presented, involved a complex set of relationships, which might not seem to be clear on first glance. Nevertheless, Simpson’s balanced remarks reflected a sincere and genuine optimism about the applicability of set theory on the question of taxonomic schemata. The second wave of responses, however, was markedly different.

The second wave of responses came in conjunction with the rise of numerical taxonomy in the early 1960s, a methodological approach that endorsed a set-theoretical approach, so it comes as no surprise that Gregg’s book would now raise alarm bells in certain circles.466 The criticisms one might expect with the kind of interdisciplinary work to which Gregg engaged, such as difficulties satisfying two different sets of standards—biologists and logicians—were now leveled at Gregg. His highly technical approach suited neither camp. Philosophers Buck and

Hull claimed that: “[p]ast treatments of this kind in biology have not proved very influential, either because the logicians who have attacked the problem have not appreciated the biological principles and procedures involved or because their formalizations have proved incomprehensible to most biologists.”467 However, on certain points, Buck and Hull agreed with

Gregg. Specifically, they approved of Gregg’s basic logical relations between individual organisms, as well as taxa and categories. They thought that organisms should be viewed as members of the taxa to which they belonged, and taxa in turn as members of their appropriate categories.468 Buck and Hull found “no disagreement in viewing relations between taxa as

465Simpson “Classification” 214. 466See Sokal, R. R., and P. H. A. Sneath. Principles of numerical taxonomy. (W. H. Freeman and Co., London, 1963); Nicholas Jardine “A Logical Basis for Biological Classification” Systematic Zoology, 18, (1969): 37-52. 467Roger C. Buck; David L. Hull “The Logical Structure of the Linnaean Hierarchy” Systematic Zoology, 15 (1966): 97. 468Later Hull presents a different view when he argued that species are individuals.

223 involving inclusion, or its absence, never membership.”469 On where they departed from Gregg,

Buck and Hull had the following to say: “By and large, our analysis of the structure of the taxonomic hierarchy agrees with Gregg’s, although in one important respect we depart from him.

As a consequence of his formalization, Gregg is forced to disparage the current practice of monotypic [my italics] classification. Our treatment requires no such limitations.”470

Beckner’s The biological way of thought fell between these waves, making his work a relevant contribution to these debates. Although Beckner also used formal logic, his approach differed from Gregg’s on precisely this point—the current practice of allowing monotypic classification. Where Gregg presented an analysis of the Linnaean hierarchy critical of a monotypic approach, Beckner proposed a logical analysis of many of the conceptual changes proposed by biologists working within the confines of “the intent and practice of the New

Systematics,” and this included Gilmour’s and Simpson’s work during the 1930s and 1940s and the adoption of a thorough-going “polytypic” approach. Beckner defined polytypic concepts, which he argued stood in contrast to monotypic concepts. Beckner used polytypic concepts when fashioning a new taxonomic schema. From the “New Systematics” perspective, Beckner’s approach challenged aspects of the Linnaean hierarchy’s taxonomic schema in all the right places, as he included insights from debates (including the reality of species debate, specifically

Mayr’s influential distinction between “population thinking” and “typological thinking”) that fell under this umbrella and figured in his argument for his logical schema.

Revisiting Beckner’s discussion of Mayr’s distinction between “population thinking” and

“typological thinking” is historically significant not just because this distinction had come to characterize the transition from the old taxonomy to the new taxonomy, but because Beckner’s

469Roger C. Buck and David L. Hull “Reply to Gregg” Systematic Zoology, 18 (1969) 354. 470Buck and Hull “Logical Structure” 97.

224 investigation began before the motivation for the distinction became complicated. The same year

Beckner’s book hit the press, Mayr re-introduced these terms in his writing on Darwin, making explicit attempts to connect his new methodological approach to Darwin. When the terms

“population thinking” and “typological thinking” cropped up in the literature after 1959, they structured not only the new taxonomy, but the history of taxonomy Mayr had popularized.

Investigations of these terms after 1959 exposed even more intricacies, including difficulties detaching the work on methodological reform from the increasingly poisonous debates with numerical taxonomists, as the term “typological thinking became synonymous with

“essentialism.”471 This blurring of history and biology made the emphasis on and motivation for populations appear to come out of the blue. Because Beckner focused on Simpson’s work before

Simpson and Mayr enmeshed themselves in historical investigations about Darwin, and before they waged war on numerical taxonomy, Beckner proffered a clearer perspective into each taxonomist’s logical and philosophical agenda. In this respect, revisiting Beckner provides a valuable insight.

6.2 Beckner, Gregg, and the reality of species

The Biological Way of Thought was Beckner’s Ansley award-winning PhD thesis, which was completed in 1957 at Columbia (under the supervision of Ernest Nagel, Albert Hofsadter, and John Cooley) and published in 1959. Although his PhD was in philosophy, Beckner was well suited for this particular type of interdisciplinary work. He held a degree in philosophy and zoology from the University of California, Santa Barbara, in 1951, and before he started his doctoral studies, he began medical school at NYU.472 His book was a perfect fit in the

471For more on this, see David L. Hull “Contemporary Systematic Philosophies” Annual Review of Ecology and Systematics,1. (1970) 19-54. 472Holly S. Beckner “Morton O. Beckner, 1928-2001” Proceedings and Addresses of the American Philosophical Association, 75 (2002) 185.

225 philosophy of science during the 1950s in America. Stephen Toulmin, contrasting philosophy of science in America with Britain during the 1950s, claimed that in America “the philosophy of science was heavily influenced by the influx of ‘logical empiricists’ from Austria and Germany: notably, Carl Hempel and Herbert Feigl, Rudolph Carnap and Hans Reichenbach, John von

Neumann and Philip Frank” and found allies in American philosophers, such as Ernest Nagel.473

Toulmin identified their “‘positive’ program and method for philosophy-in-general” as wedding the logical techniques of Russell and Whitehead’s Principia Mathematica to an empiricist epistemology borrowed from Ernst Mach.474 He also observed that their actual perception of natural science was influenced by two external factors: they arrived at the philosophy of science generally from the philosophy of mathematics or formal logic, and the “longer-term intellectual goal of the program, building up a single, comprehensive axiom-system, should be capable in principle, of representing the totality of our positive scientific knowledge.”475

Perhaps given this background, it was not surprising Beckner began his investigation with a page from Woodger’s theoretical biology work. Like Woodger, Beckner asserted biology’s status as an autonomous science, not dependent on physics or chemistry. Like

Woodger, Beckner saw biologists swamped with data and mired by bias. Like Woodger, Beckner believed biologists had reached a point where it was necessary to “uncover and investigate the logical features that are characteristic of the biological way of thinking, and to determine whether these features are peculiar to biological theory.”476 In this respect Beckner was not alone. Gregg, also at Columbia, but working as a developmental biologist, held a similar set of beliefs when, in 1950s, he followed Woodger down the rabbit hole to a set-theoretic wonderland.

473Stephen Toulmin “From Form to Function: Philosophy and History of Science in the 1950s and Now” Daedalus, 106, Discoveries and Interpretations: Studies in Contemporary Scholarship, Volume I (1977): 146. 474Toulmin “From Form to Function” 146. 475Toulmin “From Form to Function” 146. 476Beckner Biological way 2.

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Like Woodger, Gregg promoted formal logic as a useful tool in his The language of taxonomy: an application of symbolic logic to the study of classificatory systems (1954). Unfortunately, this move landed Gregg, and those who behaved likewise, in hot water.

In the chapter titled “Systematics” in The biological way of thought, Beckner mixed

Gregg with the architects of what he referred to as the “New Synthesis” in taxonomy, including

Simpson, Mayr, and Gilmour, resulting in a collection of strange bedfellows. Beckner noted that before Gregg published The language of taxonomy, he discussed the role of formal symbolic logic, specifically on the question of whether species were objectively real, in “Taxonomy, language and reality” (1950). Gregg opened this article by drawing attention to the debate on the species concept in 1949 between paleontologist Benjamin Burma and zoologist Ernst Mayr, who was at the American Museum of Natural History in New York at the time, in evolutionary studies flagship journal Evolution.

Burma and Mayr presented opposing opinions on the question of whether species were real. Their debate curiously mixed philosophy of language, metaphysics, and biology, and Gregg pounced on the opportunity to use formal logic to clear up what he took to be the conceptual mess on which he believed the debate rested. So did Beckner. As it turned out, this was not just a problem of interest to philosophers. This particular group of taxonomists saw this as a problem as well. Simpson looked at Gregg’s assessment, and agreed that Gregg did precisely what he set out to do:

By a ponderous application of symbolic logic, Gregg sought to show that the issue raised by Burma and Mayr is not a genuine taxonomic problem or, at least, that if it does relate to a taxonomic problem it does so in the wrong words. It is, of course, important that words be used as accurately as possible and that they do not obscure properly taxonomic questions. Nevertheless, Burma and Mayr (as well as subsequent discussants) were considering a genuine taxonomic problem, in words perhaps not logically impeccable

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but, taken in context, adequately performing their main semantic function, that of communicating understandably among colleagues.477

Although Burma and Mayr’s discourse may not have been “logically impeccable,” Simpson believed they tackled a genuine taxonomic problem, and perhaps more importantly, they had effectively communicated among their colleagues. Simpson also believed that Gregg did not have the last word on the matter. Or the last symbol. For Gregg, however, this debate was the departure point for his logical analysis of the Linnaean hierarchy, and as such would figure into

Beckner’s story.

6.3 Burma, Mayr, and the 1949 Evolution debate

Before continuing, one might wonder, what would possess a developmental biologist provide a set-theoretic account of the Linnean hierarchy in the first place? As I had mentioned before, taxonomy was suffering from a significant image problem and other biological disciplines wasted no time weighing in when it came to directions for methodological reform.

Developmental biologists, it seemed, were no exception. In his research during the 1940s at

Columbia on amphibians, Gregg cited Joseph Needham’s work, a member of the Biotheorectical

Gathering, and friend of Woodger, which is likely how he became aware of Woodger’s work.478 He was a Rockefeller Foundation Fellow in London from 1953 to 1954, which was where Woodger was working. To underscore the role of relaxing notions of expertise in interdisciplinary groups, the person Gregg thanks for knowledge of taxonomy is not an established taxonomist, but Simpson’s Drosophilist Richard Lewontin.

Now, these facts all likely line up to explain why Gregg’s book turned out to be such a resounding flop in the eyes of the taxonomic community. However, there was a good reason why

477George Gaylord Simpson “The Species Concept” Evolution, 5 (1951) 285. 478 He cited Joseph Needham Chemical Embryology.(Cambridge: Cambridge University Press, 1931), and Biochemistry and Morphogenesis (Cambridge: Cambridge University Press, 1942).

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Gregg was able to get his foot in the door. As Simpson aptly pointed out, Burma and Mayr presented hopelessly bad philosophical arguments for their positions. Gregg capitalized on these bad ontological arguments and countered with his own, stronger philosophical arguments.

Gregg’s logical framework might have been deeply flawed, but his ontological arguments for species as sets were much better presented than Mayr or Burma’s. This was how Gregg was able to enter the debate. It was not until Hull and Ghiselin were able to formulate a sound rebuttal, with their philosophical argument for species-as-individuals thesis, that one could properly slam the door on Gregg.

Burma, who appealed more to philosophy than biology in this article, presented the following argument against the reality of species.479 Organisms and species needed to be considered in four dimensions. Burma began by asking his readers to consider a person named

John. At the start of his life, Burma considered John as John0, at the next instance, John1. Burma continued: “John is a succession of conformations of matter in time, and any meaningful study of

480 him will have to consider the four-dimensional John0+1+2+3+4+ . . . n.” Like the instances that made up an individual, the individuals that made up a species were never identical at any given moment, and constantly changed in character. From this understanding of species, Burma believed taxonomists ran into problems when they tried to reconcile their claim that species were real. If species were defined as the whole of any one breeding population, then, Burma argued, this definition “unfortunately puts all living and fossil animals in one species, since there is a continuity of germ-plasm back from John to the original primordial cell, and from it forward to

479For a much longer and more biological treatment of species, see his Benjamin H. Burma “Studies in Quantitative Paleontology: I. Some Aspects of the Theory and Practice of Quantitative Invertebrate Paleontology” Journal of Paleontology, 22 (1948) 725-761. In this article, Burma provided a very detailed, rigorous and comprehensive treatment of species from a paleontological perspective using the most current quantitative methods, notably Simpson and Roe, as well as Fisher, the latter being testament to his mathematical skills. 480Benjamin H. Burma; Ernst Mayr “The Species Concept: A Discussion” Evolution, 3 (1949) 369.

229 every living animal (not to mention plant).”481 Reworking the species definition, unfortunately does not avoid this problem. If species were defined as “the whole of any one series of breeding populations as it exists at any one time,” then Burma claimed the “definition merely lands us in an exactly opposite difficulty, for we now have an infinity of species, time being infinitely divisible.”482 The act of delineating species, he concluded, was purely arbitrary, making species a mental construct without objective existence. Mayr thought otherwise.

Mayr’s argument appealed more to biology than philosophy, and began with a series of bold assertions. Mayr believed the natural world had gaps. Nature could be carved at her joints.

Mayr also maintained he was not alone in this belief: “The arrangement of organic life into well- defined units is universal, and it is this striking discontinuity between local populations which impressed the naturalists Ray and Linnaeus and led to the development of the species concept.

There can be no argument as to the objective reality of the gaps between local species in sexually reproducing organisms.”483 According to Mayr, naturalists observed gaps, this was a fact. If the natural world had gaps, claimed Mayr, then there was no reason to think that the groups of organisms that made up species were arbitrary. Mayr’s response to Burma’s objection, however, did not stop with just this claim.

Mayr agreed with Burma that if species were understood as an absolute concept, then it was virtually impossible to divide a breeding population in any way that was not arbitrary.

However, according to Mayr, this was not a problem for taxonomists because taxonomists did not think of species in this kind of absolute fashion. As far as Mayr was concerned, taxonomists treated the species concept as a relational concept, and as such taxonomists were concerned with

481Burma “The Species Concept” 370. 482Burma “The Species Concept” 370. 483Mayr “The Species Concept” 371.

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“delimiting a breeding population of one species against a sympatric synchronous breeding population of other species.”484 Consequently, taxonomists had no problem when it came to this kind of delineation, claimed Mayr, because taxonomists tested for reproductive gaps only when populations were in contact.485 So, claimed Mayr, the gap between this kind of species concept was well-defined and had objective reality. Mayr argued that “the essence of the species concept is the non-interbreeding of a population with other populations, a phenomenon which can be tested only where such populations are in contact. No matter how different certain individuals might be (polymorphs, larval stages, etc.), as soon as it is established that they are members of a single breeding population, they are considered conspecific.”486 Mayr’s strong ontological claim about the reality of species applied to what he called “non-dimensional species concepts.” Non- dimensional species concepts, he claimed, were the standard of the species concepts, as originally conceived by Ray and Linnaeus. Mayr claimed “[t]he objective reality of this species is beyond doubt. The difficulties which Dr. Burma sees are not those of the original, non- dimensional species concept. Rather they are clue to an expansion of this species concept in space and time.”487 What did Mayr mean by a “non-dimensional species concept”?

A few years earlier, Mayr defined a “non-dimensional species concept” in the following way:

To use an analogy from the field of geometry, we can say that the Linnaean species had no dimensions, since it dealt with the delimitation of natural populations at a single locality and at a single time level. The scientific exploration of the whole world in the post-Linnaean period resulted in the addition of longitude and latitude to the domain of the taxonomist. Taxonomy thus became two-dimensional and it became necessary to

484Mayr “The Species Concept” 371. 485Mayr “The Species Concept” 371. 486Mayr “The Species Concept” 371. 487Mayr “The Species Concept” 371.

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replace the simple binomial species of Linnaeus by the polytypic, trinomial species of recent authors.488

Non-dimensional species concepts involved taxonomic descriptions that focused only on the morphological features of local flora and fauna at a particular time. Note that Mayr also included the term “polytypic” in his discussion, a term he discussed in greater detail in Systematics and the origin of species, but a term he used often in his taxonomic writing during this time.489 For

Mayr, a polytypic species was a technical term that took species as aggregates of geographically variable populations, not as a set of necessary and jointly sufficient morphological characters (a definition used later). Mayr used the term “polytypic species” almost interchangeably with

“multi-dimensional species,” and this term became central to his biological species concept.

Although he did not use the term “polytypic,” Mayr introduced Kinsey’s and Rensch’s work on this kind of species concept, in “Speciation phenomena in birds” (1940) and built their ideas (ideas he later referred to in his discussions of polytypic concepts) into his “biological or zoogeographical” species concept:

A species consists of a group of populations which replace each other geographically or ecologically and of which the neighboring ones intergrade or hybridize wherever they are in contact or which are potentially capable of doing so (with one or more of the populations) in those cases there contact is prevented by geographical or ecological barriers.490

Note again that Mayr made no reference to necessary or sufficient morphological properties, just claims about species composed of populations, ecological and geographical replacement,

488Ernst Mayr “The Naturalist in Leidy’s Time and Today” Proceedings of the Academy of Natural Sciences of Philadelphia, 98 (1946) 273. 489For example “Evolution in the Family Dicruridae (Birds)” Ernst Mayr and Charles Vaurie: Evolution, 2 (1948): 242; “New Species of Birds described from 1941 to 1955” Ernst Mayr Journal of Orn. 98, (1957) 25; “Geographic Speciation in Tropical Echinoids” Ernst Mayr: Evolution, 8 (1954) 1-18. “New Species of Birds Described from 1938 to 1941” John T. Zimmer and Ernst Mayr The Auk, 60 (1943):260; “Notes on Nomenclature and Classification” Ernst Mayr Systematic Zoology, 3 (1954): 86, 87; “Notes on the Birds of Northern Melanesia. 31 Passeres” Ernst Mayr American Museum Novitates 1707(1955): 4. 490 Ernst Mayr “Speciation Phenomena in Birds” The American Naturalist, 74 (1940): 256.

232 intergrading and hybridizing. A few years later Mayr traced the term “polytypic” as far back as 1902, and mainly in the German literature. Mayr wrote:

Geographic variation among marine animals and the occurrence of polytypic species has been recorded by various authors. Döderlein, in particular, applied the polytypic species concept consistently from 1902 on. Rensch (1929, 1933, and 1947) summarizes much of the literature, which indicates that polytypic species are of widespread occurrence among marine animals. The only attempt, known to me, to analyze a whole family or genus systematically is that of the Schilders (1939) who show that more than 50 per cent of the species of cowries (Cypraea) are polytypic.491

Mayr’s most comprehensive discussion of the term “polytypic” was in Systematics and the origin of species. Here Mayr delved into the history of the species concept and why taxonomists, ornithologists and entomologists in particular, required a new type of species concept, one substantially different from the Linnaean species concept.

The Linnaean species concept, as well as Ray’s species concept, according to Mayr, was a non-dimensional species concept. In other words, this species concept did not take into account space or time, and such species were always separated from sympatric species.492 This had peculiar philosophical consequences:

In its purest form it is clear-cut and has objective criteria, because it is defined by the gap that separates it from other sympatric species. This local species is the yardstick by which all other situations are measured. Lacking the dimensions of space and time, such a species is not evolving, it is static. It is for this reason that the nondimensional species [sic] has a great deal of objectivity and can be defined unequivocally. (Mayr 1949)493

In Systematics and the origin of species, Mayr suggested two reasons for this change in the species concept: “the discovery of variation and the drowning of the system in minute

‘species.’”494 On the one hand there were naturalists, such as Darwin and Wallace, who noticed

491Ernst Mayr “Geographic Speciation in Tropical Echinoids” Evolution, 8 (1954) 2. 492 Mayr defined sympatric species as “two or more populations which occupy identical or broadly overlapping geographical areas.” Mayr Methods 323. 493Mayr Methods 26. 494Mayr Systematics 109.

233 that “‘good’ species were found to be connected by intermediates or in which one species had slightly different attributes in different parts of the range” and this observation challenged the traditional “static” species concept and demanded a more “dynamic” one.”495 On the other hand, there were those who followed the static species concept by the book and characterized each population, “even those that differed merely in their means or extremes.”496

Mayr went on to say that by the middle of the nineteenth century, ornithologists were eager to change the methodological approach. The revolution began with trinomials, but these ornithologists also toyed with the idea of a “polytypic” species concept, that is, a new species concept that united two or more formerly separate species. Mayr identified Kleinschimdt (1900) as the first to realize the implications of the “polytypic” species concept, and as a result

Kleinschimdt baptized the concept “Formenkreis.” Riddled with problems, “Formenkreis” was rethought and renamed “Rassenkreis” by Rensch in 1929. Unlike “Formenkreis,” Rensch’s new term enjoyed the spotlight. Huxley discussed Rensch’s “Rassenkreis” in The new systematics:

Rensch has proposed the term Rassenkreis for a group of subspecies which replace each other “geographically.” In order to conform to accepted usage and to terms of international applicability, it is perhaps better to call such groups polytypic species; in contradistinction to the monotypic species (for which Rensch reserves the term Art), which show no subspeciation.497

Despite initial appeal, Huxley called for the use of the term “polytypic” rather than

“Rassenkreis.”

Although Mayr’s claim in his response to Burma concerned non-dimensional species concepts, he tentatively extended his ontological claim to multidimensional species concepts,

495Mayr Systematics 110. 496Mayr Systematics 110. 497Huxley New Systematics 10.

234 and discussed paleontology as his example. Specifically he discussed Simpson’s “Criteria for

Genera, Species, and Subspecies in Zoology and Paleozoology” (1943):

In all multidimensional situations an inference has to be made (Simpson, 1943) on the basis of the objective species of the non-dimensional system. The subjectivity of this expanded species concept by no means invalidates the species concept per se. The species of the local naturalist or of the paleontologist within a given horizon is clearly delimited against other species and can thus be considered as having objective reality.498

At first glance, drawing on another biologist, especially one of Simpson’s caliber, seemed like a strong closing for Mayr’s argument. However, on closer inspection, Simpson’s article was an odd choice for Mayr to cite in an argument for the reality of species. Not only would Simpson’s paper helped show just how conceptually murky this debate actually was, Simpson’s claim about the reality of species was connected to his claim about inference.499

6.4 Simpson, species, populations, and logic

Like Mayr, Simpson did not doubt the reality of species in nature. In fact, he believed that he was toeing the taxonomic party line when he claimed that species existed in nature. He differed from Mayr in that he doubted the assumption that the taxonomist’s concept of a species was identical to real species in nature. At best, claimed Simpson, the taxonomist’s species concept was an approximation or estimate of species in nature. As early as 1929, he expressed this idea:

498Mayr Systematics 372 499In Methods and principles of systematic zoology Mayr et al had a section titled “The Subjective Element in Classification” where it appeared Simpson’s differing stance might be acknowledged. They produced the following quote from Simpson: From a series of concrete specimens in hand an inference is made as to the nature of a morphological group from which the sample came, and an endeavor is made to frame the morphological concept in such a way that the inferred morphological group will approximate a genetic group. The thing that is actually classified is an inference, a purely subjective concept, which approximates a real but unobservable, morphological unit, which is in turn approximates an equally real but even less observable genetic unit. [25] They agree the “philosophical basis” of Simpson’s stance was right, but they believe in practice the scope should be narrowed to just paleontological specimens.

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It may be urged that this is a polyphyletic view of mammalian origin and that it logically necessitates either referring monotremes and multituberculates to the Reptilia (or to a new class) as distinct orders, or referring the cynodonts to the Mammalia. This, however, would be a mere quibbling over terms. Whatever the ultimate logical aim of classification, the first necessity is that it should be practical. It is used as a means to express truths or what are believed to be truths, but it has no objective reality. Whether we conceive of mammals as derived through three different lines from a circumscribed group of advanced reptiles or by the same three lines from a similar group of earliest mammals, the essential unity of the Class Mammalia is not questioned. To transfer the cynodonts to the Mammalia would simply increase our difficulties by necessitating that a line be drawn at the beginning of the cynodont group, at present much less sharply limited than the cynodont-mammal line, and to place the cynodonts and their allies in a new class, as has been done by at least one student, increases the difficulties exactly two- fold without any practical gain. Walter Granger and “A Revision of the Tertiary Multituberculata”500

Whatever the ultimate logical aim of classification, Simpson believed first and foremost taxonomy should be practical, a means to express truths or what are believed to be truths, and that it had no objective reality. As a rule, ontological issues played second fiddle to practical issues in Simpson’s work. In addition, his reason for maintaining his ontological position on species was connected to his position on inference. Simpson’s position on inference, as he demonstrated in his work on quantitative methods, was connected to his definition of a population and the role populations played in taxonomic methodology.

Simpson maintained a consistent position in the 1940s. He expressed this scepticism in

“Types in Modern Taxonomy” (1940) and “Criteria for Genera, Species, and Subspecies in

Zoology and Paleozoology” (1943) respectively:

The usual theory, often questioned but believed by me and by most taxonomists, is that this concept corresponds more or less with a real thing in nature, a group of individual animals that are truly related in a way that makes them a natural unit of a certain approximate scope. This thing in nature may be considered the real species, but it is not and cannot be the species of taxonomy. The mental concept that is the species of taxonomy cannot be shown to be coextensive with the real species and even if by chance

500Walter Granger and George G. Simpson “A Revision of the Tertiary Multituberculata” Bulletin of The American Museum of Natural History Vol. LVI., Art. IX (1929) 673.

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the two were coextensive, it would be an error to suppose them identical. One, the taxonomist’s species, is an estimate of the other, the real species.501 and

One of the points that I want to emphasize is that the species in nature is something different from the species in classification.502

With regard to the relationship between taxonomic species and species in nature, Simpson reminded his readers a lesson most taxonomists knew since at least the days of Linnaeus.

For Simpson, just as for Gilmour and Linnaeus, taxonomic species were created by naturalists, rendering them subjective, mental concepts. Simpson stated this explicitly in both papers: “A species as it is actually defined or diagnosed and used in the literature is a subjective concept”503 and “The taxonomic species is a subjective concept . . .”504 Simpson differed from the traditional approach to species and to Mayr’s polytypic species concept when it came to the criteria for determining the species concept, and how that criteria required a new methodology.

As Simpson demonstrated in his late 1930s papers and in Quantitative zoology, his taxonomic species concept was based on a statistical notion of populations, rather than on a traditional type concept. This statistical notion required a change in how specimens were collected, what collections should look like, and how information was organized and analyzed from these collections. To keep current, according to Simpson, taxonomists had to rethink the role of type concepts in taxonomic methodology.

Simpson confronted the problem of types in “Types in Modern Taxonomy” claiming that the biggest problem with the type concept was its scope. It was as if the type concept had been

501George G. Simpson “Types in Modern Taxonomy” American Journal of Science Vol. 238, No.6, June, 1940. 414. 502George G. Simpson “Criteria for Genera, Species, and Subspecies in Zoology and Paleozoology” Annals of the New York Academy of Sciences, 44(1943): 145-6. 503Simpson “Types” 414. 504Simpson “Criteria” 148.

237 plucked off the shelf and dusted off for use in every taxonomic task. From a historical point of view, Simpson believed that the type concept had been exploited in taxonomic methodology.

Taxonomists used it as a basis for taxonomic definitions, as standards of comparison, and as fixed points to which taxonomic names were attached. With the new approach to variation coming out of a Darwinian theory of evolution by natural selection, and new statistical techniques to help ensure better reasoning about taxonomic groups and evolutionary claims,

Simpson believed it was time to revamp the relationship between the type concept and taxonomic aims. Simpson wrote:

Most taxonomy has hitherto assumed that the same specimens, the “types,” adequately serve all three of these functions. Some, perhaps most, taxonomists apparently feel not only that the single set of specified “types” can do this triple duty but also that it must do so. The newer theory of taxonomy as a system of group concepts based on inferences about populations from samples, a theory that is rapidly gaining ground and to which I strongly adhere, is decisively incompatible with this use of “types.” According to this theory the specimens used as “types” in the three different ways not only need not be, but also cannot be, the same if proper scientific methods are followed.505

In other words, Simpson believed type concepts should continue to have a role in taxonomic methodology, just a more restricted one.

Simpson took a more epistemological turn at this point. With respect to the first two functions of “types,” Simpson replaced the old term “type” with a new term—”hypodigm”—that referred to the set of specimens from which the inference to the population or species was made.

His use of the term “hypodigm” not only underscored the idea that the taxonomic species was a mental concept, but brought to light the epistemological limitations of real species. Simpson reminded his readers that real species could not be directly observed or compared because they were not literally available to taxonomists. It was the epistemological limitations of real species that rendered taxonomic species a mental concept derived from observations, “not a thing subject

505Simpson “Types” 417.

238 to observation.”506 The best a taxonomist could do was to employ the term “hypodigm,” which provided “an indirect means of comparing with the real species that it represents.”507

Simpson’s methodological proposal found in the papers building up to Quantitative zoology and in Quantitative zoology shed light on what he thought a taxonomic species was. For

Simpson, taxonomic species were estimates based on observations taken of specimens grouped on the belief, irrespective of whether such a belief was well-founded or not, that they belonged to a biologically real group that existed in nature. All the resulting taxonomic descriptions could be said to do was imply that the group of specimens (if selected unbiasedly, statistically speaking, and even though it usually comprised relatively small part of that species) represented the real group, and one could use this implication to justify an inference from the specimen set the probable characters of other organisms that belong to the group.508 In Simpson’s own words, specimens comprised “a sample from which group or population characters are estimated and this is the only proper sense in which they are the basis of a species in taxonomy.”509 But the problems with types were only the tip of the iceberg.

Underneath the semantic debate on species festered the concern about taxonomy’s place in the new biology. Taxonomy still faced the possibility of becoming obsolete. Simpson addressed this more political problem by drawing attention to the fact that the different approaches to species in the twentieth century reflected different kinds of explanations, from causal explanations to descriptive explanations, and recognizing this was the first step in helping taxonomy’s find her place in the new order.

506Simpson “Types” 419. 507Simpson “Types” 419. 508Simpson “Types” 415. 509Simpson “Types” 415.

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On that note, Simpson began “Criteria for Genera, Species, and Subspecies in Zoology and Paleozoology” (1943) paper in an uncharacteristic way, with a brief philosophical (and mildly metaphysical) account of species to help diffuse the debates regarding the different species concepts, and charted a course for a new methodological approach. He wrote:

A species in nature is a group of organisms. It is not a process, as some geneticists say; or an infinite mathematical abstraction, as some statisticians maintain; or a collection of individual specimens, as no one is likely to say but as many, perhaps most, working taxonomists seem unconsciously to assume. The group arises by dynamic genetic processes, it can be described and interpreted by statistical methods, and it is composed of individuals, but it is the group itself that is a species.510

In effect, Simpson connected the different species concepts with different kinds of explanations.

In order to ensure a place for taxonomy, he reminded his readers that real species were still groups of organisms, and taxonomic species were descriptions of those groups. Like Gilmour,

Simpson believed that the morphological species concept remained the most useful.511 Simpson defined morphological species as: “a group of individuals that resemble each other in most of their visible characters, sex for sex and variety for variety, and such that adjacent local populations within the group differ only in variable characters that intergrade marginally.”512

However, in contrast to Gilmour, Simpson believed that the morphological species concept could be much better if some significant changes were made.

Simpson started his argument by acknowledging the importance of the genetic species concept to real species, and saw this as where taxonomists began to run into trouble. Simpson redefined the problem of identifying species boundaries—a problem that had motivated centuries of debates between taxonomists regarding whether a group was a single species or two different

510Simpson “Criteria” 146. 511Simpson wrote “The neozoologist, by custom and for practical reasons, and the paleozoologist, from necessity, both define their species by morphology and not by the transmission of heredity or breeding habits and potentialities.” Pg 147. 512Simpson “Criteria” 147.

240 species—in genetic terms. He wrote: “[i]n modern taxonomy it is a basic concept that the species in nature is a genetic group. The kind of genetic group that should be called a species grades into kinds that are given other names and this gradation, sometimes denied, is the most fruitful source of misunderstanding and disagreement.”513 The relationship between genetics and taxonomy,

Simpson claimed, was only recently captured in a species concept largely by the combined efforts of Mayr and Dobzhansky. Simpson summarized their species concept (which Simpson called “genetic” and Mayr called “biological” as: “[A] genetic species is a group of organisms so constituted and so situated in nature that a hereditary character of any one of these organisms may be (possibly, but not necessarily) transmitted to a descendant of any other.”514 But, said

Simpson, a serious problem remained with this species concept, and it became clear when put it into practice.

Regardless of how well the genetic species concept may capture the true relationships that bind species, claimed Simpson, it failed as a concept if it could not be effectively put into practice. Paleozoologists, for example, could not apply this species concept to vertical species or dynamic temporal sequences, both of which figured largely in their work. Although in theory the zoologist could apply this species concept, in practice she also could do no such thing. Simpson observed that, when it came to what species concept was used in practice; both the zoologist and the paleozoologist defined their species morphologically, rather than “by the transmission of heredity or breeding habits and potentialities.”515

Like Gilmour, Simpson maintained that the morphological species concept was “a description of the usual result of the situation involved in the genetic definition” and like

513Simpson “Criteria” 146. 514Simpson “Criteria” 146. 515Simpson “Criteria” 147.

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Gilmour, qualified his claim, by stating that the “morphological species tend to correspond closely to genetic species, although it cannot be expected that the correspondence will be exact and universal.”516 Like Gilmour, Simpson reminded his readers of a little taxonomic history, specifically that:

. . . the objective effect of the genetic situation was observed long before there was any clear idea of that situation or of phylogenetic processes in general. Species were defined morphologically before the concept of a phylogenetic species was achieved, but just because the species are real groups and because the phylogenetic situation does have definite morphological effects, it turns out that essentially the same groups are called species under both definitions.517

Charge past taxonomists with ignorance of genetics and phylogenetics, but their groups still reflected these ideas. Simpson’s claim was not new, and he knew it. This insight was made by

Darwin almost a century earlier, when Darwin claimed that his theoretical framework should have no real effect on taxonomic practice. So, why did Simpson call for a reform?

Again, for Simpson, the current morphological species concept differed from tradition species concepts on at least one significant logical point, having to do with inference. What the taxonomist observed and described was a series of individual specimens, and these specimens do not constitute the species. The set of specimens was only a sample taken from a natural population (where the natural population is assumed to be a species) and because it was only a sample, it could never represent completely that population. But this failure to completely represent the natural population need not be a problem. If the sample was unbiased, a taxonomist armed with the appropriate statistical tools could infer confidently from the sample the characters and limits of the morphological species from which the sample was drawn.

516Simpson “Criteria” 146. 517Simpson “Criteria” 146.

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Simpson’s point with regard to the morphological species concept was two-fold. First, the taxonomist had no direct access to species. At best, she had only indirect access via statistical tools. Second, it was this inference that was the species concept actually used in taxonomy. So, for Simpson, the taxonomic species was a subjective concept not equivalent to the natural population, but one that approximated that population “more or less closely according to the adequacy of the sample and the skill of the taxonomist.”518 So, for Simpson, a taxonomic species was: “an inference as to the most probable characters and limits of the morphological species from which a given series of specimens has been drawn.”519 In other words, taxonomists employed a subjective estimate of a natural population (that can be defined as a genetic species), based on a series of specimens.

In “Types in modern taxonomy” Simpson explained how his new population thinking drew attention to three different functions for the type concept. As mentioned earlier, according to Simpson’s history of taxonomy, types had been used in taxonomic methodology as a basis for taxonomic definitions, as standards of comparison, and as fixed points to which taxonomic names were attached. Population thinking, Simpson argued, made it impossible for the type concept to serve all three functions. In Quantitative zoology, Simpson and Roe began to address this problem for taxonomists when they noted that:

[i]n somewhat better defined usage, one as common in science as in popular language, the typical condition is taken to be that most frequent. Typical then signifies in more technical language belonging to a modal group. This usage, proper but requiring definition, is in often confused with the strictly technical use of types in zoology. The type of a taxonomic group is the basis and standard of comparison for that group, but it need not necessarily be and very frequently is not in a modal class in the frequency distribution for the taxonomic division. It may be far removed from any average and is quite likely to be since it is usually the first specimen that came to hand by chance. The

518Simpson “Criteria” 148. 519Simpson “Criteria” 148.

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type of a species is thus not, or not necessarily, typical in any of the more usual senses of the word.520

In “Types in modern taxonomy” Simpson explained how a statistical account of populations that not only enabled inferences from particulars to generals, but was also involved in definition and comparison, now needed to be based on all available specimens (or a group) and not a single specimen selected as primary. This group of specimens Simpson called a “hypodigm,” and he reserved the term “type” for the function of name bearer.

Mayr’s appeal to Simpson on the reality of species was odd. While Simpson would agree that nature had joints, it was not clear he believed naturalists were in possession of a blueprint to carve her up effectively. Simpson’s notion of species did not assume Mayr’s polytypic concept, but a statistical notion he developed in the decade before. The relevant aspect of logic for

Simpson in this debate was inference, not compositionality relations in a hierarchy.

6.5 Gregg and logic

When Gregg entered the debate, he thought he could clear up some of the misunderstandings seen in these discussions by revealing them as a misuse of taxonomic language. This was exactly what he tried to do in “Taxonomy, language and reality” (1950)— explore some of the problems with the misuse of taxonomic language, for example those that gave rise to what he called the “pseudo-problem of existence.”521 He asked whether taxonomic groups should be thought of as “abstract” entities or whether they could be discovered in nature, like organisms. Gregg’s response was that if species were thought of as classes of organisms,

520Simpson & Roe Quantitative Zoology 104. 521This was a puzzle Gregg introduced to highlight what he took to be a pseudo problem around claims such as: “Species exist” or “Genera exist.” He claimed statements of the form “F's exist” where “F” stood for any taxonomic category was represented as “There is an A such that A is an F.” Such statements he claimed were true whenever "F" was substituted by any taxonomic category-name. He wrote “In such statements, ostensible reference to existence as a characteristic of taxonomic groups does not occur. Certainly, no problems worthy of many decades of heated debate are posed by assertions such as this.” This was why he saw this as a pseudo-problem. Gregg “Taxonomy” 424.

244 then the question of whether or not taxonomic groups were abstract entities would be part of a more general question of whether classes were abstract or spatiotemporal entities. Gregg would argue classes could not be spatiotemporal entities, here is why.

Gregg claimed that classes of organisms, such as species, cannot be spatiotemporal entities in nature because it violated the notion of the class-member relation and led to nonsensical statements—objects cannot be members of other objects. It just does not make sense.

Objects are parts of a whole, and members, of a class. Gregg recognized that some taxonomists objected to this claim, asserting that this was nothing more than word games. He wrote:

Objections that it is not nonsense to say this seem based upon the notion (advanced independently by two different taxonomists reading an earlier version of this paper) that species are composed of organisms just as organisms are composed of cells: according to this argument a species is just as much a concrete, spatiotemporal thing as is an individual organism, though it is of a less integrated, more spatiotemporally scattered sort. This argument sounds fairly plausible, until one reflects that it contains an equivocation upon two common meanings of “is composed of.” It is true that an organism is composed of cells; it is also true, but in a different sense, that species and other taxonomic groups are composed of organisms. The relation of a cell to the organism in which it is located is the relation of part to whole. But the organism-species relation is that of member to class; and these are entirely different sorts of relations.522 Was Gregg just putting too fine a point on a semantic quibble? Is it not the true that species are composed of organisms just as organisms are composed of cells?

Gregg attempted to use formal logic to answer this objection. Using transitivity, Gregg argued for the difference between the two relevant compositionality relations. Gregg argued that given a cell, an organ, and an organism, the following could be said: a cell is a part of an organ, and an organ is a part of an organism. It follows that the cell is part of the organism. The part- whole relation is a transitive relation, like “less than.” The class-member relation, however, is

522John R. Gregg “Taxonomy, Language and Reality” The American Naturalist, 84 (1950) 424. Mayr claimed he was one of the two taxonomists Gregg cited. He was unsure if the other was A. J. Cain or T. Dobzhansky. See p 152 Mayr “The Ontological Status of Species: Scientific Progress and Philosophical Terminology” Biology and Philosophy 2 (1987) 145-166.

245 not a transitive relation.523 Gregg explained: “It should be noted here that given “x = y” and “y = z,” it is always correct to infer “x = z”; but given “x A” and “A F” it is not correct to infer “x

F.” For example, given “Jones Homo sapiens” and “Homo sapiens Zoological Species,” it is not correct to infer “Jones Zoological Species.”” This was because for Gregg there was a relevant ontological difference among the following objects: Zoological Species, Homo sapiens, and Jones. Homo sapiens was a class of organisms that consequently may contain the organism

Jones as a member, while Zoological Species was a class of classes of organisms of which Homo sapiens was only one, and consequently did not contain as a member the organism Jones, who was not a class of organisms. According to Gregg, one way membership differed from identity and from part-whole was that it was a non-transitive relation. 524 Although his contemporaries did not call him out on it, this particular objection rested on shaky logical ground. On this logical point, he stood in opposition to most logicians at the time, as well as Woodger, who generally took the relevant difference between the part-whole relation and the set-member relation

(specifically on the notion of a proper part in set theory) to be not transitivity, but reflexivity.

Nevertheless, for Gregg, species were classes, not wholes. They were sets, not individuals. With this idea in hand, Gregg began a much more comprehensive logical treatment of species and classification systems. The The language of taxonomy was an ambitious work, since taxonomy was not exactly Gregg’s field. He made note in his foreword that his instruction

“in the rudiments of modern taxonomy” he owed to his friend Richard Lewontin. In addition, he received a Rockefeller Foundation fellowship which he took in London in 1953-54, and in the

Foreword he acknowledged the Foundation’s fellowship in the writing the book. In The language of taxonomy, Gregg wrote: “The purposes of this book are two. First, it has been written to

523Gregg “Taxonomy” 425. 524Gregg “Taxonomy” 429.

246 suggest that the symbolic methods of modern formal logic are useful and appropriate tools for the prosecution of methodological research in the foundations of taxonomy.”525 In particular,

Gregg chose set-theory because he believed it provided “a systematization of some highly general ideas centering on the notion of set, class, aggregate, manifold, or collection that seem made to order for use in the methodological treatment of taxonomic classificatory systems.”526

As it turned out, many taxonomists did not share Gregg’s assumption that this particular application of set theory was tailored to taxonomic classificatory systems.

Second, Gregg hoped to illustrate “the methodological utility of set-theoretical methods by using them to reconstruct the neo-Linnaean concept of taxonomic classificatory system.”527

Gregg was motivated by what was now a common concern among taxonomists, namely the lack of suitable methodological terminology. Rather than develop new terms, Gregg embarked in what he took to be a necessary conceptual clean-up mission, arguing that “the available descriptions of such systems are nearly all deficient in clarity and rigor.”528 The last three sections of the book were offered as a first step to improve this situation. At first glance, this goal appeared to be in line with what many taxonomists were aiming to do. For many taxonomists, however, Gregg’s execution left much to be desired.

The first two chapters of Gregg’s short book outlined the basics of set theory. In chapter three Gregg introduced the formal notion of a hierarchy, which he borrowed from Woodger.

Woodger discussed two types of hierarchies in his work: abstract hierarchies and division hierarchies, the latter applied to individuals. Gregg defined a hierarchy as:

525Gregg Language viii. 526Gregg Language viii. 527Gregg Language ix. 528Gregg Language ix.

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A hierarchical relation or HR: HR = the set in which any relation z is a member iff (z One-

529 many) (ž “UN = žp0 “{B ‘z}).

In other words, a hierarchy was any one-many relation z whose converse domain was identical

530 with the set of all first constituents of žp0-paris whose second constituent is the beginner of z.

Gregg then provided the following definition of a taxonomic classificatory system:

A relation z is to be regarded as a taxonomic classificatory system just in case these four conditions are satisfied: 1. The field of z is included in G; 2. There exists a member of the field of z in which every member of the field of z is included 3. Given any members x and y of the field of z, x bears z to y iff y is included in but not identical with x and there exists no third member of the field of z in which y is included and which is included in x; and 4. Given any members x and y of the field of z, either x bears z to y or else y bears z to x or else the overlap of x and y is identical with the empty set.

According to Gregg, if the postulate was adopted that the empty set was not a member of G, then ( IC(u)) & (y w) ((y w) =EM)) was a logical consequence of the above four conditions together with the definitions of “IC(u)” and “HR,” where each were defined respectively as:

529Gregg Language 26. 530Assume the following notation: EM = the empty set = notion for ordered pairs530 {x,y} = notion denoting a set TCS = taxonomic classificatory system SCM = Simpson’s entire classificatory system CA = Category associated with a taxonomic system FIELD = field of (the relation) membership & = and = union  = inclusion conditional “ = image relation. The image of a set x by a relation z, briefly z “ x is the set of all first constituents of pairs in z whose second constituents are members of x: (z “ x = the set in which any y is a member iff there is a w such that ( z) & (w x)). E.g. if z is the relation between parasite and host, and x is the set of all mammals, then z”x, the z-image of x, is the set of all parasites of mammals. ‘ = image relation of {x} when {x} has exactly member.

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“IC(u)” designates a relation that appeared in such contexts as ‘( IC(u)),’ which translated to ‘the set x immediately contains the set y, with respect to the set u,’ or more briefly, ‘the set x immediately u-contains the set y.’ The use of the sign is fixed by the following rule: ( IC(u)) (x u) & (y u) & (yx) & (y x) & z (z u) & (z x) & (yz) & (zx)

HR = the set in which any relation z is a member iff (z One-Many) & (ž “ UN = žp0 “{B’z})

zp0 = the relation in which any pair is a member iff ( z) (z ⎸z)) ( z⎸z ⎸z)) ( z⎸z ⎸z ⎸z)) . . . )

For example, if z is the relation of parent to child, then ( zp0) if and only if x is a parent of y, or else x is a grandparent of y, or else x is a great-grandparent of y, or else x is a great-great-grandparent of y, or . . . 531

With this definition of a taxonomic classification system, Gregg presented his analysis of the

Linnaean hierarchy.

6.6 Gregg’s paradox

After careful construction of axioms and postulates, Gregg was ready to address the bugs in his system. The last chapter of Gregg’s Language addressed a paradox that arose when a taxonomic group from one category contained a single subgroup in another category that, according to the axioms Gregg provided, was identical. If they were identical, then it would seem that both groups belonged to each category. Using an example Gregg borrowed from Simpson’s

“The principles of classification and a classification of mammals”(1945), if the cohort Mutica had a single order Cetacea, then given Gregg’s axioms, Mutica was both a cohort and an order and Cetacea was both a cohort and an order.532 This landed Gregg in a problem: No taxonomic group in the field of a given system could be a member of more than one category associated with that system.533 Gregg explanation went something like this:

531Gregg Language 23. 532Simpson’s classification of Mutica began on page 100. 533Gregg Language 64.

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Postulate 1: No taxonomic group in the field of a given system is a member of more than one category associated with that system: For all z, all y, and all w, if (z TCS) and (y CA “{z}) and (w CA “{z}) and (((y w) FIELD ‘z) EM), then (y = w)

Following from postulate 1 was postulate 2: For all z, all y, and all w, if (z TCS) and (y CA “{z}) and (w CA “{z}) and (y w), then (((y w) FIELD ‘z) EM)

Gregg’s paradox arose when he applied his system to Simpson’s example of a monotypic case, the Mutica and Cetcea. He began by making the following four assumptions: 1. (Cohort CA “ {SCM}) 2. (Order CA “ {SCM}) 3. (Mutica Cohort) & (Mutica FIELD ‘z) 4. (Cetacea Order & (Cetacea FIELD ‘z)

Although no passage was provided, Gregg believed Simpson held the following in “Classification of mammals”: 5. (Cohort Order)

Gregg also believed the indentations Simpson employed in his graphic representation of the classification of mammals implied both: 6. (Cetacea  Mutica) 7. (Mutica  Cetacea)

From 6 and 7 and an earlier claim he made, namely: 8. x y ((x  y) z(z x) (z y))

Gregg arrived at the claim that Mutica and Cetacea were identical taxonomic groups (have the same members): 9. (Mutica = Cetacea)

According to the following axiom of set theory: 10. (x = y) & (y z) (x z)

As well as 3, 4 and 9, Gregg arrived at: 11. (Cetacea Cohort) 12. (Mutica Order)

It can be inferred from another axiom, namely:

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13. (x y) = the set in which any z is a member iff (z x) and (z y)

And 11 and 4, that Cetacae is both a cohort and an order in the field of z: 14. (Cetacea (Cohort Order) FIELD ‘z)

A similar claim, namely that “Mutica is both a cohort and an order in the field of z,” can be made using that same axiom, in addition to 12, and 3: 15. (Mutica (Cohort Order) FIELD ‘z)

Gregg assumed that 14 and 15 should seem strange to many taxonomists, but he continued. From 14 and 15, the claim that cohort and order are overlapping categories can be inferred: 16. ( (Cohort Order) FIELD ‘z) EM

Now, claimed Gregg, using the following assumption: 17. (SCM TCS)

And bundling it with 1, 2, 5, 16, 17, we arrive at:

18. (SCM TCS) & (Cohort CA “{SCM}) & (Order CA “{SCM}) & (Order CA “{SCM}) & (Cohort Order) & (((Cohort Order) FIELD ‘SCM) EM)

This claim was significant, according to Gregg, from this claim we can infer:

19. There is a z, a y, and a w, such that (z TCS) and (y CA “{z}) and (w CA “{z}) and (y w) and (((y w) FIELD ‘z) EM)

And 19 is a logical contrary of: 534 20. For all z, all y, and all w, if (z TCS) and (y CA “{z}) and (w CA “{z}) and (y≠w), then (((y ∩ w) ∩ FIELD ‘z)= EM)

Hence, the set is inconsistent resulting in the paradox.

Buck and Hull suggest that Gregg ran into this paradox because he defined taxa extensionally, that is, by enumeration.535 Buck and Hull raised a couple of preliminary problems

534Propositions are contraries when they cannot all be true, and they are not contradictories because they may all be false. For example “Every girl is happy” and “No girl is happy” are contraries and both are false, that is, it is false that every girl is happy, since some girls are not happy, and it is also false that no girl is happy, since there are some happy girls. However, because they cannot all be true, that is enough to render the set of propositions inconsistent and generate the paradox. 535They provide two passages suggestive of this:

251 with an extensional approach, namely it conflicted with current and past taxonomic theory and practice, in addition to it not being possible to enumerate all the members of any given taxon.

These problems aside, they believed this paradox arose because enumeration revealed nothing about the common properties of the entities that were members of the class. An enumeratively defined class was basically just a list of its members’ proper names, and that provided no connotations as to common properties inferable from those names. Buck and Hull argued

“[w]hen there is no basis for classification, no qualifications for membership; one entity’s name is as good or as bad as that of any other in defining a class name. One of the reasons why Gregg says so little about the relation of individual organisms to taxa may easily be that with enumeratively defined taxa names there is virtually nothing to say.”536 According to Buck and

Hull, two classes with the same membership were necessarily identical, that is, they were

“really” not two classes but one. Buck and Hull suggested an “intensional” definition to resolve this problem.

Taxonomist James S. Farris replied to Buck and Hull’s objection with an attack on the type of intensional definition Buck and Hull proposed, namely problems with defining properties

Simply by way of convention, let us agree to call a statement of the properties which an organism x must have in order to be a member of a particular taxonomic group A, the group-description; for example, a list of properties which an organism must have in order to belong to the genus Daphnia, is a group-description. [Gregg “Taxonomy”1950] and It is frequently advantageous to be able to construct a designation for a given set by enumerating its members. In fact this is an excellent method of defining sets that are otherwise difficult to define. We shall construe taxonomic group names—‘Insecta,’ ‘Primata,’ ‘Homo sapiens,’ ‘Arthropoda,’ and the rest—as set names, one and all, i.e., as names of sets of organisms. Now this decision is not made on the grounds that taxonomic groups ‘really are’ sets of organisms; it is made solely for the reason that by making it we can bring statements about taxonomic groups within the scope of the systematized and precise idioms of set theory, with all the advantages this carries. Those who wish to put forward other interpretations of taxonomic group names are, of course, free to do so . . . . [Gregg Language 1954] 536Roger C. Buck; David L. Hull “The Logical Structure of the Linnaean Hierarchy” Systematic Zoology, 15 (1966) 106.

252 must be arrived at by abstraction from known members of the taxa being defined. Farris began by stating that:

[i]f we define Cetacea one way today, we may find a new whale tomorrow that does not fit the definition, but belongs in the Cetacea nonetheless. But if the definition of Cetacea is made broad enough so that we may be assured that no whales will be unjustly excluded from the order, other forms that do not belong in the Cetacea may be embraced by the definition. This difficulty is intensified in the monotypic case. The defining properties for the set of non-cetacean muticans, for example, would necessarily be conjectural; and there could be no assurance that a newly discovered form belonging in the Mutica would correctly be placed there by a preconceived definition of the cohort. . . . Intensional definitions of taxa can indeed be used to resolve Gregg’s Paradox, but in order to overcome the difficulties outlined above, it is necessary to base the definition on overall similarity (either phenetic or evolutionary), rather than on a limited set of defining properties.537

Farris’s problem with Buck and Hull’s solution to the monotypic case was tied to the notion of intensional definition that seemed to depend on a set of defining properties. Farris’s solution, in contrast, was an intentional definition based on “overall similarity” rather than a set of defining properties. Farris’s was a notion that looked more like the polytypic sort we will see in Beckner’s work. At this point it easy to see that these biologists and philosophers were caught in a terminological tangle: was it intensional monotypic concepts and intensional polytypic concepts versus extensional monotypic concepts and extensional polytypic concepts? Or did monotypic speak properties or position on a hierarchy? Exploring this line of objection to Gregg is helpful because it pointed to the start of an ambiguity with the terms “polytypic” and “monotypic” that would also appear in Beckner’s work. It was becoming unclear whether the problem, when it came to polytypic concepts, was with rank or with properties.

6.7 Beckner and polytypic species

Although Beckner’s work was fraught with daunting formal symbolic logic like Gregg’s, the taxonomic community greeted it with less hostility, perhaps because Beckner consciously

537James S. Farris “Definitions of Taxa” Systematic Zoology, Vol. 16, No. 2. (Jun., 1967), pp. 174-175.174.

253 positioned his approach in what was becoming the dominant position within the taxonomic reform—the work coming out of Huxley’s book The new systematics. Beckner described three types of logical concepts he would use in his analysis: polytypic, historical, and functional. The relevant logical concept for his analysis of taxonomy was the “polytypic concept.” One of the reasons why this concept was significant to Beckner’s analysis was because one of the claims

Beckner believed was central to the “New Synthesis” was the idea that a population, a rather than a type, was the basic unit of classification, and that that was a central claim held by proponents of what he called the “New Synthesis.”

Simpson and Mayr both argued vigorously for this claim, but Beckner confessed he found their position difficult to grasp. He wrote: “In the old systematics, the specimen was the basic unit. It is difficult to see exactly what is intended here, in so far as populations classified, the members of the population are classified as well. In what sense, then, is the population “more basic”?”538 Beckner proceed by saying that according to the New Synthesis, reliable species descriptions could not be gained through an examination of single or few specimens. Species descriptions, then, were reliable insofar as the specimens on which they were based represented an adequate sample of the population of the species. In order to be adequate, on this account, a sample needed to be large. This type of species description, Beckner claimed, followed from a polytypic character of species, rather than a monotypic, character of species. How? Becker explained.

To use a character in a species description, claimed Beckner, the character must have been known to be widely distributed in the species, though it need not be universal. So, even though the species description referred to properties possessed only by specimens, if the

538Beckner Biological way 69.

254 description was effective, there must exist populations in which the properties were distributed in the ways entailed by the notion of a polytypic concept.539 Beckner defined polytypic concepts in the following way:

Polytypic concepts. A class is ordinarily defined by reference to a set of properties which are both necessary and sufficient (by stipulation) for membership into the class. It is possible, however, to define a group K in terms of a set G of properties f1, f2, . . . , fn in a different manner. Suppose we have an aggregation of individuals (we shall not yet call them a class) such that: 1) Each one possesses a large (but unspecified) number of properties in G 2) Each f in G is possessed by large numbers of these individuals; 3) No f in G is possessed by every individual in the aggregate

By the terms of 3), no f is necessary for membership in this aggregate; and nothing has been said to either warrant or rule out the possibility that some f in G is sufficient for membership in the aggregate. Nevertheless, under some conditions the members would and should be regarded as a class K constituting the extension of a concept defined in terms of the properties on G. If n is large, all the members of K will resemble each other, although they will not resemble each other in respect to a given f. If n is very large, it would be possible to arrange the members of K along a line in such a way that each individual resembles his nearest neighbour very closely. The members near the extreme would resemble each other hardly at all, e.g., they might have none of the f’s in common.540

Polytypic concepts stood in contrast to monotypic concepts. Beckner defined monotypic concepts by reference to a property that was necessary and sufficient for membership by extension; that is, monotypic concepts were equivalent to the traditional common-feature definition of a class.541

Beckner argued that this polytypic species definition was well-suited for the kind of quantitative techniques Simpson proposed. Beckner claimed that an increasing number of taxonomists knew that organisms subjected to continuous variation demonstrated a range in

539Beckner Biological way 69. 540Beckner Biological way 22-23. 541Beckner wrote: “In the case of monotypic concepts (concepts defined by reference to a property which is necessary and sufficient for membership in its extension), purely syntactical criteria guarantee the existence of an extension. . . The satisfaction of syntactical requirements does not, however, guarantee the existence of a polytypic class.” Beckner Biological way p 23.

255 variation in a population and as such a taxonomist might want to use an interval rather than a specific taxonomic character in her species description. Beckner claimed his species concept would allow for this, because “[p]ossession of a magnitude within the interval may simply be regarded as one of the properties in the G-class of the polytypic-species-definition.”542

Beckner continued his definition of polytypic concepts by emphasizing the importance the logical character had on these concepts in ordinary language, specifically to the semantic concepts such as “meaning,” “reference,” and “description.” He suggested that all the members of such classes have a “family resemblance” to one another, drawing a connection to the recent work of controversial analytic philosopher Ludwig Wittgenstein. Wittgenstein died in 1951, and the Philosophical Investigations from which the term “family resemblance” came, was published posthumously in 1953. Although Wittgenstein did not discuss taxonomy in the Investigations,

Wittgenstein’s notion of family resemblance held two attractive features for Beckner: a rejection of the idea of the centrality of necessary and sufficient conditions to the concept of definition, and the proposal of a new analogy for definition that characterized different uses of the same concept without boundaries or exactness. Wittgenstein described this dynamic approach to properties using a games metaphor and a thread metaphor, and then used the “family resemblance” terminology to drive his point home. Consider his explanation in its full form:

66. Consider for example the proceedings that we call “games”. I mean board-games, card-games, ball-games, Olympic games, and so on. What is common to them all?— Don’t say: “There must be something common, or they would not be called ‘games’ “— but look and see whether there is anything common to all.—For if you look at them you will not see something that is common to all, but similarities, relationships, and a whole series of them at that. To repeat: don’t think, but look!—Look for example at board- games, with their multifarious relationships. Now pass to card-games; here you find many correspondences with the first group, but many common features drop out, and others appear. When we pass next to ballgames, much that is common is retained, but much is lost.—Are they all ‘amusing’? Compare chess with noughts and crosses. Or is

542Beckner Biological way 71.

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there always winning and losing, or competition between players? Think of patience. In ball games there is winning and losing; but when a child throws his ball at the wall and catches it again, this feature has disappeared. Look at the parts played by skill and luck; and at the difference between skill in chess and skill in tennis. Think now of games like ring-a-ring-a-roses; here is the element of amusement, but how many other characteristic features have disappeared! And we can go through the many, many other groups of games in the same way; can see how similarities crop up and disappear. And the result of this examination is: we see a complicated network of similarities overlapping and criss- crossing: sometimes overall similarities, sometimes similarities of detail.

67. I can think of no better expression to characterize these similarities than “family resemblances”; for the various resemblances between members of a family: build, features, colour of eyes, gait, temperament, etc. etc. overlap and criss-cross in the same way.— And I shall say: ‘games’ form a family. And for instance the kinds of number form a family in the same way. Why do we call something a “number”? Well, perhaps because it has a—direct—relationship with several things that have hitherto been called number; and this can be said to give it an indirect relationship to other things we call the same name. And we extend our concept of number as in spinning a thread we twist fibre on fibre. And the strength of the thread does not reside in the fact that some one fibre runs through its whole length, but in the overlapping of many fibres. But if someone wished to say: “There is something common to all these constructions—namely the disjunction of all their common properties”—I should reply: Now you are only playing with words. One might as well say: “Something runs through the whole thread— namely the continuous overlapping of those fibres.”543

Beckner wanted to paint a similar picture for species in the “New Synthesis.” Like Wittgenstein, he argued that taxonomists believed must be something common to the organisms that made up a species or they would not be called “species,” but upon investigation, no feature was shared by all, no common thread that ran the length of the species. What taxonomists did observe was a complicated network of similarities overlapping and criss-crossing, like the continuous overlapping and criss-crossing of fibers in a thread.544 Beckner finished his definition of polytypic concepts by claiming a concept C “polytypic with respect to G” if and only if it is E- definable in terms of the properties in G; its extension K meets conditions 1) and 2); and the E- defining test-procedure is intended to discover whether or not condition 1) is met. If the

543Wittgenstein Philosophical Investigations 31-32. 544Although Beckner used Wittgenstein here, philosopher Paul Thompson (in correspondence) quite rightly points out the strong connection, and in my mind arguably better connection between the definition of polytypic Beckner presents and Mill’s logic.

257 extension K in fact also meets condition 3), the concept will be said to be “fully polytypic” if G is understood.545

Unfortunately, Beckner’s explanation did not stop here. Beckner’s discussion of polytypic concepts included Mayr’s familiar examples and Mayr’s use of the term, which proved not an easy fit with the formal definition and Wittgensteinian analysis he provided. For example, after Beckner claimed that species are polytypic, he provided A. C. Kinsey’s gall wasp example, just as Mayr did, do help illustrate polytypic species. Kinsey claimed that Cynips were often found in long chains of local populations. These wasps were unusual because that they could interbreed with neighbouring populations, but not with more distant links. Beckner followed

Kinsey in claiming that on a “monophyletic chain assumption,” every group of interbreeding would be a species, and the problem would be that some wasps would belong to several species.

On Kinsey’s account, Beckner said, the wasps would belong to one species, a Rassenkreise or polytypic species. However, this use of the term “polytypic” did not fit exactly the formal definition Beckner proposed.

Recall that according to Mayr, a polytypic species was a technical term that took species as aggregates of geographically variable populations, rather than a set of necessary and jointly sufficient morphological characters (as in Beckner’s monotypic concept) or a set of some properties (as in a polytypic concept). Recall also that Mayr suggested it was developed in response to “the discovery of variation and the drowning of the system in minute “species.” So, instead of having numerous distinct species, ornithologists had a large variable species and what were would have been species were now subspecies. With Gregg, a similar problem arose with taxonomic rank—what happened if the extension of a class was identical on two different levels

545Beckner Biological way 22-3.

258 of the hierarchy and the set only had one subset? It seemed that Mayr had something philosophically different in mind with his notion of polytypic concept than Beckner, especially if

Mayr’s 1940s polytypic concept was considered in light of his 1987 statement:

Indeed I do not know the writings of a single evolutionary taxonomist in the period from the 1930s to 1970 who did not reject the class concept of the species. But this went entirely unnoticed by the philosophers. Evidently they did not read the writings of the biologists and vice versa. It was not until a biologist (Ghiselin) translated the views of the biologists into philosophical language that the conflict was discovered; and even then not at once. In 1966 Ghiselin clearly stated biological species are, in the logical sense, individuals ... a species name is a proper noun” (1966:208-209). But this went unnoticed, and Hull in 1967 still treated the species as a class. Not until Ghiselin had amplified his thesis (1974a, b) and had pointed out that it was by no means a new proposition, but went back at least to Buffon, did Hull (1976) take notice and become converted.546

The mudslinging tenor of this passage aside, Mayr claiming not to know a single evolutionary biologist who did not reject the class concept of the species was a pretty bold claim to make. For

Mayr’s 1940s polytypic concept to avoid being labeled as “class,” he would need to claim that he avoided or suspended an investigation into compositionality relations entirely, and the crux of his logical interest was on taxonomic rank. It was also not clear that assuming taxonomic groups were classes was controversial. Mayr did object to Gregg’s claim “species as spatio-temporal entities is nonsense.”547 However, at the time, Simpson suggest something to the effect that species were classes in 1961 when he wrote “Classification involves only groups; no entity possible in classification is an individual.” 548 That being said, at best Beckner’s use of the term polytypic was vague as to whether is refers to taxonomic rank, and his formal definition was wide enough to allow for either interpretation.

546Mayr “Ontological status,” 153. 547See Gregg “Taxonomy” 424-425, and 426. 548I do not mean to suggest that Simpson was endorsing species as a class defined by a set of necessary and jointly sufficient conditions, but he certainly was not promoting a species-as-individuals thesis. That Simpson was claiming species as a class, loosely speaking, was not surprising, given that for Simpson, some abstraction and inference making was needed from the individuals to the population in order for classification to occur. Hull quoted Simpson on this in “Consistency and Monophyly” (1964) p1.

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However, no matter how much Mayr would like to claim no evolutionary biologist he knew claimed species were a class, it was not clear that the compositionality problem was as distinct from the problem of taxonomic rank at this time as Mayr would have people believe. It is without question that Ghiselin brought the problem to the fore, and introduced the problem in clear and unambiguous terms.549 Undoubtedly, Ghiselin was the first to suggest a solution in terms that made sense both to biologists and philosophers in America, a solution that understood species as individuals. This was no small feat. Despite Mayr’s claim, this problem caught on in the literature. Farris demanded the biological community to look at the relationship between logic and taxonomy on the question of taxonomic schemata on problem of polytypic concepts in his discussion of Gregg’s paradox and Buck and Hull’s solution. Indeed, Sokal and Sneath raised this problem after reading Beckner’s book, and presented a similar sort of solution to the problem of taxonomic schemata. In both cases, these biologists saw the type of concept they were presenting as logically consistent with Beckner’s polytypic concept.

Sokal and Sneath drew attention to what they took to be an ambiguity in Beckner’s account, and renamed the concept “polythetic.” In 1963, Sokal and Sneath called attention to this confusion in a small article in Nature. They wrote: “Natural taxonomic groups are of the class of concepts which Beckner has called “polytypic” (better termed polythetic), in which no single attribute is in theory sufficient and necessary for membership in the group so long as the members share a high proportion of characters.”550 In a footnote, they cite an earlier paper in which Sneath discussed the issue with the term “polytypic” in a bit more detail. In “The construction of taxonomic groups” (1962) Sneath began by defining “monotypic” classifications, which he would then distinguish from “polytypic” classifications. He wrote:

549Rieppel made a similar claim in “Species are individuals—the German tradition” Cladistics 27 (2011) 1–17. 550Robert R. Sokal and P. H. A. Sneath “Numerical taxonomy” Nature 193(1962): 856.

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Special classifications are usually based on single character, or in a series of single characters, such that the possession of a unique set of these is both sufficient and necessary for the membership in the group which is thus defined. For example, the group of black limbless animals comprises all animals which are black and limbless, and no others. Beckner (1959, pp. 14-31) calls such groups monotypic, because the defining set of features is unique.551

Before he defined polytypic classifications, Sneath acknowledged that the term monotypic came with baggage: “. . . but since monotypic has other meanings, monothetic is a better term (from the Greek mono ‘one’ and thetos ‘arrangement’).”552 When Sneath discussed polythetic classifications, he did so in the context of phenetic groups. The term “phenetic,” he said, was introduced by Cain and Harrison in a 1960 paper to refer a relationship that was based on overall similarity or affinity, rather than ancestry. On polythetic groups, Sneath wrote:

Phenetic groups, in the other hand, are composed of organisms with the highest overall similarity, and this means no single feature is either essential to the group membership or is sufficient to make an organism a member if the group. The organisms 1, 2, 3, and 4, possessing respectively the features A, B, C; A, B, D; A, C, D; and B, C, D might form a phenetic group, where each organism possesses three of the four features A, B, C, and D; however, none of the four is found in all the four organisms. Such groups, in which several sets of characters occur, are called ‘polytypic’ by Beckner, but are better called polythetic.553

Sneath, it seemed, proposed a similar definition to Beckner’s formal definition. Sneath went on to say:

Phenetic taxa are always in theory polythetic. In practice it usually possible to find some characters which are constant, but there is always the possibility that an individual will be found which is aberrant in one or more of these respects. This is why any monothetic system . . . will always carry the risk of serious misclassification; an organism which is aberrant in the feature used to make the primary division will be inevitably moved to a category far from its phenetic position.554

551P. H. A. Sneath “The construction of taxonomic groups.” Symp. Soc. Gen. Microbiol. 12 (1962):290. 552Sneath “Taxonomic groups” 290. 553Sneath “Taxonomic groups” 290. 554Sneath “Taxonomic groups” 291.

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Perhaps one reason why Sokal and Sneath made such a fuss about the term “polytypic” was because their term “polythetic” was tied to their notion of a natural classification, a notion they borrowed from Gilmour. When Sneath looked at the debate surrounding the term “natural classification” and the implication that a phylogenetic classification was synonymous with natural classifications, he became concerned. Like Gilmour, he wanted to distance the term

“natural” from “phylogenetic.” When it came to classifying viruses, Sneath argued “the idea of phylogenetic classification is practically useless, yet we recognize groups of viruses which we feel as ‘natural’ in the sense of being very similar overall.”555 Following Gilmour and claiming that a natural classification system was one from which the most generalizations could be made, it made sense that Sneath would want to replace the term “polytypic” which carried with it a great deal of phylogenetic baggage, with the more neutral term “polythetic” which only implied characters.

6.8 Conclusion

From a historical perspective revisiting Beckner’s discussion of Mayr’s distinction between “population thinking” and “typological thinking” that has come to characterize the transition from the old taxonomy to the new taxonomy is valuable because Beckner’s investigation pre-dates the acrimonious debates between Mayr and the numerical taxonomists that complicated the motivation for the distinction. In Beckner, a cleaner, less political, more grounded distinction can be found, and it is easier to see how it is tied to his ideas regarding methodological reform. However, even Beckner ran into difficulties when he tried to define polytypic.

555Sneath “Taxonomic groups” 290.

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The relationship between logic and taxonomy, as it unfolded in the construction of taxonomic schemata, was complicated. Biologists and philosophers who examined the debates that informed taxonomic schemata, for example the species debates, and imposed a formal structure on what they took to be a conceptual mess that underpinned particular taxonomic schemata, such as the Linnaean hierarchy and later phylogenetic trees, found themselves ensnared in a conceptual tangle. One of the terms that caught them was “polytypic”—a term, it seemed, that raised as many problems as it solved.

Mayr had used the term with success in his biological writing, and later claimed it free of reference to logical notions of classes. Although Gregg had not employed the term, he was critical of its counterpart, monotypic, which he felt had an uncontroversial connection to the notion of classes. Beckner provided a new definition of polytypic that involved understanding species as classes, but not as a set of necessary and jointly sufficient conditions. Although

Beckner aimed to build Mayr’s position into his polytypic approach, it is not clear that he was successful on that front. Simpson, given his statistical approach to species, did not seem adverse to a class conception of species, as long as species were not defined in terms of a set of necessary and jointly sufficient conditions. In light of this, Beckner’s approach seemed up Simpson’s alley.

This debate did expose certain deep philosophical questions about taxonomic schemata, and the relationship between logic and taxonomy that Hennig had explored was now in the spotlight, and the idea of species as classes, whether understood as monotypic or polytypic, was about to come under attack.

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Chapter 7 Conclusion

The way taxonomists saw it, they had done nothing wrong. For centuries taxonomists inhabited a hive of activity, but now they were suddenly dodging insults hurtled at them as they found themselves ushered to the periphery of the biological arena, and embattled in a civil war.

Certainly there were taxonomists who remained firmly fixed in their ways, defending their territory at all costs. However, for those taxonomists who reached out and joined transient interdisciplinary groups, their tales challenged usual story. As these taxonomists attempted to rethink their methodology, their relationship with logic developed and changed in surprising and productive ways.

Gilmour was part of the Association for the Study of Systematics in Relation to General

Biology and tinkered with Mill’s logic. He borrowed at least three ideas from Mill’s logic that he believed would help resolve the methodological debates: Mill’s nominalist notion of classes and kinds, Mill’s approach to classification systems, and Mill’s empiricism. With respect to nominalism, like Mill, Gilmour rejected the notion of shared essences, Aristotelian, Platonic or otherwise, and instead embraced common attributes. According to Gilmour, classification involved grouping individual objects in a way that enabled taxonomists to infer something about a particular object by virtue of it belonging to a particular group defined by a certain collection of attributes. Gilmour did not hesitate to logical terms such as “inductive process” to make his point in the Nature paper. Another Millian thread that ran through Gilmour’s philosophy of classification was the idea that all classification systems served a particular purpose. With respect to his empiricism, according to Gilmour, classification systems did not reflect a true

264 order of nature or something inherent in the universe, but instead were “conceptual orders” people imposed on their experience in ways that suited their purposes. This idea framed his notion of “natural” and “artificial.” Rather than employing the terms “natural” and “artificial” systems in a normative way, describing natural systems as better than artificial systems because they reflected the true order of nature, Gilmour implied the difference between natural and artificial systems was a difference in kind rather than a difference in degree. Gilmour’s story is significant because it serves as a reminder that taxonomists have appealed to logic in the past, in particular inductive logic like Mill’s, and have favoured nominalism. Gilmour was not the only taxonomist who promoted a nominalist position, driven by a desire to keep epistemological issues separate from ontological issues. Hints of nominalism can also be found in Simpson. It also raises interesting philosophical questions about the applicability of Mill’s logic, versus

Wittgenstein’s logic, to these issues.

Simpson had his fingers in many pots. He found himself a participant in many transient interdisciplinary groups, and courtesy of his wife, psychologist Anne Roe, a promoter of inductive statistics as part of a quantitative methodology in his reform movement. Like Gilmour, during the 1930s, Simpson believed that many of the methodological problems taxonomists faced were not rooted in ontology, but logic and flawed arguments. That is to say, Simpson did not think taxonomists held misguided ontological claims, but their arguments did suffer from serious logical and epistemological problems. Over the course of a long and tremendously influential career, Simpson helped develop solutions to those problems. Both Gilmour and

Simpson recognized that there was a gap between how taxonomists viewed nature and what they could realistically build into their methodology. And like Gilmour, Simpson was concerned with the types of arguments presented in evolutionary classifications. However, Simpson presented a very different kind of solution.

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Around the time Gilmour was presenting a new philosophy of classification that he hoped would diffuse the raucous methodological debate in botany, Simpson fashioned a new methodology, one that took the usual taxonomic evidence collected, and pumped it through a new statistical machine that enabled taxonomists to make better inferences that would help answer evolutionary questions. Simpson’s methodological approach had extensive impact. From a paleontological perspective, the flaws in traditional taxonomic methods were exposed early in

Simpson’s career when he tried to use traditional taxonomic methods to make inferences to support evolutionary claims. As a paleontologist, Simpson faced different challenges than his zoological and botanical counterparts, but like his counterparts, he found traditional methods would not permit the inferences necessary to make justifiable evolutionary claims. Part of his response to this problem involved proposing a quantitative, statistical methodological approach.

Although it focused on morphological attributes, it took populations, rather than individuals, as the basic methodological units. In this sense, he called his approach an evolutionary approach.

His notion of a population was informed by a new branch of statistics tailored to biological work.

By focusing on populations, this approach, argued Simpson, not only better captured Darwinian intuitions, but avoided the fallacious reasoning common to earlier, traditional evolutionary approaches. One of the logical features of his statistical approach about which he was pleased its inductive approach, moving from particulars to generals.

Simpson’s quantitative proposal sounded good on paper, but how it would pan out in practice was an entirely different story. Taxonomists had a long history of being cautious when applying techniques from other disciplines. One of Simpson’s goals was to convince taxonomists that statistics could be applied to taxonomy in a way that would not privilege formal tools over biological fact. This type of worry rang familiar to Simpson. Early in his career he raised suspicion and scepticism over a priori claims he read in the literature, so any methodological

266 move that ran counter to established biological fact would not bode well for Simpson. Simpson’s work serves as a good reminder how one argues for the limits, checks and balances of a strong quantitative programme.

Beckner’s academic background straddled two disciplines, biology and philosophy. His

The biological way of thought was an interdisciplinary work that aimed to use philosophy and logic to solve problems in biology. Beckner’s work on species began with Gregg’s controversial attempt to apply Woodger’s account of hierarchies to taxonomy in The language of taxonomy

(1954). Like Woodger, Gregg explicitly characterized taxonomic groups as logical “sets” or

“classes” and introduced the problem of “overlapping categories” in his system. The problem of applying this kind of set-theoretic approach was taken up in the 1960s by biologists, and although biologists such as Leigh Van Valen and A. Sklar supported an account of taxonomic groups as sets, one only has to glance through Mayr’s presentation of evolutionary systematics to find repeated warnings against adding formal tools like set-theory to the taxonomist’s methodological toolbox. Like the graphic warnings labels on a cigarette package, Mayr showcased Gregg’s set theoretic account of the Linnaean hierarchy as a vivid reminder that applying formal to taxonomic methodology was hazardous to taxonomy’s health. In addition to biologists, philosophers Roger Buck and David Hull, joined the fight, rejected a set-theoretic account of taxonomic groups. Later Hull and Ghiselin called for replacing it with an account of species as individuals.556

556See A. Sklar “Category Overlapping in Taxonomy” in Form and strategy in science; studies dedicated to Joseph Henry Woodger on the occasion of his seventieth birthday. J. R Gregg and F.T.C. Harris (ed), (Dordrecht: D. Reidel Pub. Co. 1964): 395-401; Leigh M. Van Valen “An Analysis of Some Taxonomic Concepts” in Form and strategy in science; studies dedicated to Joseph Henry Woodger on the occasion of his seventieth birthday. J. R Gregg and F.T.C. Harris (ed), (Dordrecht: D. Reidel Pub. Co. 1964): 402-415.; R. C. Buck, David L Hull. “The Logical Structure of the Linnaean Hierarchy” Systematic Zoology 15 (1966): 97-11; Michael T. Ghiselin “An Application of the Theory of Definitions to Systematic Principles” Systematic Zoology 15(1966): 127-30; Michael T. Ghiselin “Further Remarks on Logical Errors in Systematic Theory” Systematic Zoology 16(1967): 347-48.

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Beckner’s solution was to draw a connection between the “Rassenkreise” or “polytypic species”

Mayr discussed in his pioneering Systematics and the origin of species and polytypic classes.557

In the early 1960s, Simpson picked up Beckner’s discussion and explored polytypic classes in his Principles of Animal Taxonomy. Likewise, Hull’s presentation of disjunctive definitions amounted to a discussion of polytypic classes in “Effect of Essentialism.”558 Also in the early

1960s Sneath talked briefly about polythetic classes in “The construction of taxonomic groups.” where he discussed polythetic classes with a reference to phenetic groups.559 He claimed polythetic groups were “composed of organisms with the highest overall similarity, and this means that no single feature is either essential to group membership or is sufficient to make an organism a member of the group.”560 By 1969 Mayr was citing Beckner, Simpson, and Sneath on polytypic classes in Principles of systematic zoology, but he used Sneath’s term “polythetic.”

Mayr wrote: “Taxa characterized by a set of characters of which each member has a majority are called polythetic taxa. . . No single feature is essential for membership in a polythetically defined taxon nor is any feature sufficient for such membership.”561 He stressed the fact that many zoological taxa were “based on a combination of characters, and frequently not a single one of these characters is present in all members of the taxon.”562 In his glossary, Mayr defined

“polythetic” as: “Of taxa, in which each member has a majority of a set of characters.”563

Polytypic/polythetic classes came with their own sets of problems, not the least of which were they did not quite seem robust enough to capture what taxonomists wanted in a species concept.

One advantage to a mereological approach over these aforementioned approaches, Hull and

557Beckner Biological way 61-2. 558Hull “Essentialism” 13-18. 559Peter H. A. Sneath “The construction of taxonomic groups.” In Microbial classification (eds) (G. C. Ainsworth & P. H. A. Sneath Cambridge: University Press.) 1962. 560Peter H. A. Sneath “The construction of taxonomic groups.” 291. 561Mayr Principles of systematic zoology 83. 562Mayr Principles of systematic zoology 88. 563Mayr Principles of systematic zoology 409.

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Ghiselin argued, was the logic of individuals captured the way species operated in evolutionary theory, making it a better fit with an evolutionary account of species than set-theoretic approaches.564

Without a doubt, Hennig had a strange and complicated philosophical agenda. In terms of how he saw the relationship between logic and taxonomy, at least this much is clear. From as early as 1947 in “Probleme der biologischen Systematik,” consistently through the Grundzüge einer Theorie der Phylogenetischen Systematik (1950), and into Phylogenetic systematics Hennig argued that the structure that best represented the complex taxonomic relations was hierarchical.

Specifically, he believed that structure was a mereological “division hierarchy,” not a traditional set-theoretic hierarchy. As part of his philosophical and logical programme, in “Probleme der biologischen Systematik,” Hennig discussed the state of taxonomy, aiming to rid the discipline of problematic dichotomies, specifically the nomothetic and ideographic dichotomy. He argued that taxonomy was not only a descriptive science, but also law-like and explanatory.

Hennig began this logical programme by developing concept of a semaphoront, and explored the idea of relations, in particular genetic relations and how they were connected to the concept of a biological individual. He argued such an individuality claim could only be made if the links connecting the different phases of a life could be uncovered—a genetic link could be made. According to Hennig, this needed to be spelled out more formally, and he felt he was in fine company, noting Zimmermann, another biologist who believed in cleaning up taxonomic methodology along more formal lines. Although there were other types of systems available to

564Hull and Ghiselin were the early champions of this idea that species were individuals. See David L. Hull “Are Species Really Individuals?” Systematic Zoology, 25(1976):174-191; David L. Hull, “The Ontological Status of Species as Evolutionary Units,” in Michael Ruse Philosophy of Biology (Prometheus Books, 1998): 146-155.; David L. Hull “A Matter of Individuality” Philosophy of Science, 45 (1978) 335-360. Michael T. Ghiselin “On psychologism in the logic of taxonomic controversies.” Systematic Zoology (1966): 207-215; Michael T. Ghiselin The triumph of the Darwinian method. (Berkeley: University of California Press. 1969); Michael T. Ghiselin “A Radical Solution to the Species Problem” Systematic Zoology, 23 (1974) 536-544.

269 taxonomists, Hennig argued that the most suitable system for representing the phylogenetic system was a hierarchical system. He went on to specify the kind of hierarchical system he had in mind when he was sketching out the structure of genetic relationships in reproductive communities was “Teilungshierarchie” which translated to “division hierarchy.”

A “division hierarchy” was a specific type of hierarchy used in mereology. Woodger coined the term in cell biology to explain the organization of cells, where cells were treated as logical individuals that exhibited the part-whole relation, and hierarchies were generated by divisions and were not necessarily summative. Hennig used “Teilungshierarchie” in “Probleme der biologischen Systematik” in a way consistent with Woodger’s use. Hennig explained that he was borrowing the term from cell biology and he too was using it as part of an account of individuality. Although Woodger and Gregg discussed division hierarchies, division hierarchies were not part of their vision of a taxonomic system.

For Hennig, it was clear that division hierarchies were equipped to deal with the biological relations he had in mind, time and ancestry, all of which are necessary features of a phylogenetic relationship. If Hennig’s deviation rule was followed, a stem species ceased to exist when it split into two daughter species, just as a cell ceased to exist when it divided. When the two descendant daughter species formed a new entity at a higher level of complexity (just as the daughter cells formed part of an organ) this new entity “encapsulated” the two daughter species, making it a monophyletic taxon at its lowest level of complexity. So, in Hennig’s familiar figure, he was not showing nested sets, but trying to reflect a mereological relation in a hierarchical way. In both the German and the English translation of the second edition of the Grundzüge,

Hennig discussed Woodger and Gregg, and the term “Teilungshierarchie” in conjunction with

270 this figure, because he wanted to make clear that this type of hierarchy was importantly different the usual set-theoretic interpretation.

Given the criticisms of set-theoretic treatments of hierarchies it might be puzzling why

Hennig would introduced Gregg in the first place—and why he cast Gregg in a reasonably favourable light—considering Gregg’s hierarchical system was not the system he would inevitably endorse. Remember, hierarchical systems were the sort of systems that best captured taxonomic relationships, including phylogenetic relationships, and according to Hennig,

Woodger and Gregg provided the most comprehensive formal treatment, to date, of hierarchies.

Given the equivocation present in taxonomic literature of terms such as “affinity,” Hennig felt it was important for taxonomists to now understand not just the equivocation, but the formal consequences of the equivocation in terms of hierarchies. Gregg and Woodger provide the language for that.

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Postscript Hennig’s Phylogenetic Systematics (1961/66) 7.1 Introduction

Zoologist Olivier Rieppel remarked that while the practical applications of Hennig’s

Phylogenetic systematics (1966) comprised familiar ground for taxonomists, Hennig’s philosophical programme remained uncharted territory. Rieppel rightly drew attention to the fact that when Hennig constructed a new methodological approach, he also fashioned new concepts and took great pains to outline the philosophical position that underpinned his new methodology.

When Hennig’s method of cladistic analysis finally reached an international audience, it was scooped up almost immediately. As Rieppel noted, after the Grundzüge’s eventual translation to

English, his method was transformed into “into easy-to-use desktop computer software packages.”565 In spite of the appeal of Hennig’s method, Rieppel observed that Hennig’s underlying theory and philosophy remained in the dark: “Instead, the philosophy of science worked out by Karl Popper (1976) was appealed to in support and defense of cladistics, a tradition that continues to the present.”566 Rieppel sought to remedy this. However, as Rieppel discovered, working through Hennig’s philosophical programme was no easy or small task.

565Olivier Rieppel “Semaphoronts, cladograms and the roots of total evidence” Biological Journal of the Linnean Society, 80 (2003):167. 566Rieppel mentioned Platnick & Gaffney, 1977, 1978a, b, as well as Kluge, 2001a, b. in Rieppel “Semaphoront” 167. This relationship between Hennig and Popper can be seen even earlier, for example, in a review of Hennig’s Die Stammesgeschichte der Insekten, entomologist R. A. Crowson wrote: In the view of Hennig, as of this reviewer, theories about the ancestry of taxa are hypotheses in the normal scientific sense of the term, and should be used as a basis for making predictions which might be verified or falsified, according to the principles of Karl Popper. There is of course a difference in this respect between the hypotheses of phylogeny and those of physics or chemistry; it is rare for a precise conclusion about characteristics of modem animals to follow with absolute certainty from a hypothesis about their ancestry. The failure of a single prediction made on the basis of a phylogenetic hypothesis is rarely sufficient to justify final rejection of the hypothesis, for which several falsified predictions would generally be needed. The fact that Hennig himself makes very few definite, falsifiable predictions on the basis of the phylogenetic theories propounded in his book is, from the point of view of his own theory, a legitimate criticism of it. Crowson “ Review of Die Stammesgeschichte der Insekten by Willi Hennig” Systematic Zoology, 19 (1970) 393-396.

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Although Hennig’s work has been successful in spite of everyone’s relative ignorance of his philosophy, I think Rieppel is right to investigate Hennig’s philosophy of biology. Hennig philosophy of biology is more than a matter of historical interest. As seen in the earlier chapter, in Hennig’s philosophy of biology is Hennig’s account of a hierarchy, which is a mereological account. As will be seen in this chapter, Hennig’s division hierarchy is tied to his account of biological individuality. This is significant, as it puts him in the same philosophical camp as Hull and Ghiselin, but years before them.

Complaints abounded regarding Hennig’s style when the Grundzüge circulated through the taxonomic community, and unfortunately, Hennig’s prose did not improve in the second edition, Phylogenetic systematics. According to Hull, when D. Dwight Davis agreed to translate the much revised second edition of the Grundzüge (1961), he struggled with Hennig’s words.

Hull claimed that despite Davis being fluent in German, he sought the help of one of his colleagues at the museum, Rainer Zangerl.567 Even with their changes, Rieppel commented that the English translation contained “sentences must have struck readers as ‘virtually unintelligible’, such as the definition of ‘order’ (Hennig, 1966: 3f).”568 Bock agreed: “The single greatest shortcoming of “Phylogenetic systematics” is that it is an extremely difficult book to read. Hennig uses an extensive and difficult terminology, writes in an involved style (which may have suffered from the problems of translation) and has used a poor organization for the structure of the book.”569 Bock also drew attention to the fact that despite it being a revised edition, in many respects, it was “an old book.” He raised concerns regarding the paucity of papers published after 1960 cited. Although Bock believed that many important current debates in systematics were overlooked in Hennig’s book, he acknowledged that “many important ideas

567 Hull Science as process 134. 568 Rieppel “Semaphoronts” 168. 569 Bock “Review” 646.

273 proposed during the 1960’s were reached earlier and independently by Hennig, thereby testifying to his profound analytic abilities.”570

A. J. Cain provided an even harsher assessment in his review of Phylogenetic systematics:

Much is hard reading, with obscurity of logical connexion between sentences, a flat and poor style, and frequent repetition of stylistic cliches. . . And the reader is left to struggle without any help towards elucidating the meanings of the terms. The reader is treated pretty cavalierly throughout; casual statements are made on important matters with no references or only an author’s name without further data, although the reader needs to be able to check the author’s assertions; legends for text-figures often fail to explain major features of the diagrams; proof-reading and checking are careless (for example, Fig. 66 refers to the Lepidoptera, not merely the butterflies; in Fig. 39, 3 and 5 should be transposed; Vertigo genesii is not a parasitic snail larva”, as the title of the reference quoted makes clear); and important discussions and statements of fact may appear not where they should logically be but in summaries-for example, that on sterility and crossability as means of defining biospecies. The author has the irritating habit of giving very short quotations from a large number of authors with no indication of context, a few words here or a phrase there which have struck him. Where so much divergence of terminology or emphasis exists, this is extremely dangerous, and the critical reader is left with the feeling that he ought to check every short quotation to make sure that the quoted author really meant it in the way that Hennig takes it. One at least certainly did not.571

When Hull described the translation of Hennig’s Grundzüge (1961), he made the following remarks:

However, these two men [Davis and Zangerl] did not just translate the manuscript. They also heavily edited it, eliminating what they took to be repetitive passages, simplifying Hennig’s Teutonic sentences, and clarifying his ideas. In this midst of this undertaking, Davis died, and Zangerl had to carry on alone. As fate would have it, both men who translated Hennig’s manuscript were trained in the very philosophical tradition that Hennig attacked in the book—idealistic morphology. Both Zangerl (1948) and Davis (1949) emphasized the necessary role that the hierarchies of morphological types of neoclassical morphology play in phylogeny construction, a position that Hennig himself adamantly opposed. Only a German scholar studying the relevant manuscripts can say how much the idealist presumptions of Davis and Zangerl influenced their translation. Hennig himself was unable to help much in the project because he was in the midst of

570 Bock “Review” 646. 571 Cain “Review” 412.

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fleeing from East to West Germany. An accurate translation of his manuscript was the least of his worries.572

Hull was right. One place where a significant confusion arose in Hennig’s work was on the question of hierarchies. The story seemed to be that in 1966 Hennig either made some sort of mistake in his discussion of hierarchies or was inconsistent in his treatment of hierarchies. It seems, however, your position on the matter depended on who you read.

Hull’s earlier quotation suggested that confusion regarding hierarchies, specifically morphological hierarchies, could be the result of editorial decisions. Later Hull claimed the following about Hennig on hierarchies:

One common error in the early years of cladistics was to read too much into cladograms, an error committed by all sides of the dispute, but eventually the distinction became clear. Scott-Ram claims that the “roots of this misconception can be traced back to Hennig’s own discussion of hierarchical systems, which is based on the Woodger- Gregg model” (p. 89). Scott-Ram is right that the Woodger-Gregg model of hierarchical structure is mistaken, but these errors did not influence Hennig because Hennig’s German book appeared before Gregg published and it contains no reference to Woodger’s analysis of hierarchical organization. Hennig added his discussion of Woodger and Gregg to his English version, possibly to make his system appear more quantitative and up-to-date. I doubt that he understood Woodger and Gregg’s set-theoretic reconstructions.573

Here Hull seemed to change his mind about Hennig and hierarchies, from a confusion on hierarchies as a result of editorial decisions to a confusion on Hennig’s part. Hull maintained that there was no reference to Woodger’s analysis of hierarchies in Hennig’s early work, and that he doubted that Hennig understood Woodger and Gregg’s set-theoretic reconstructions. However,

Hennig clearly referenced Woodger on division hierarchies in the Grundzüge (1950), and it will also become clear that Hennig not only understood Woodger and Gregg, but understood the

572 Hull Science as process 134. 573Review by: David L. Hull “The Descriptive Attitude: Transformed Cladistics, Taxonomy and Evolution. by N. R. Scott-Ram” Systematic Zoology, 39 (1990): 422.

275 differences between Gregg and Woodger’s respective positions regarding taxonomic hierarchies in the 1950s.

Patricia Williams argued in her paper “Confusion in cladism” that Hennig conflated two types of “hierarchy” in Phylogenetic systematics, which she called the Linnaean hierarchy and the “divisional hierarchy.” She claimed:

What seems to have happened is that Hennig carefully began with a particular concept of ‘hierarchy’, the divisional ‘hierarchy’, his interpretation of Gregg. Because Gregg was discussing the Linnaean hierarchy, Hennig thought his interpretation of Gregg to be a correct understanding of the Linnaean hierarchy. In this, he was wrong. The divisional ‘hierarchy’ in biology is a linear, temporal phylogenetic tree; the Linnaean hierarchy is an atemporal, inclusive hierarchy which can be constructed from a phylogenetic tree, but is not the same thing as one. Hennig shifted back and forth between the two ‘hierarchies’ and, in the process of doing so, developed a self-contradictory system of biological taxonomy. 574

In so doing, she concluded, Hennig made the school of biological taxonomy known as “cladism” philosophically confused.

Rieppel also drew attention to what he thought was a confusion in Hennig’s work.

Rieppel argued that by accepting Gregg’s Language of taxonomy (1954) exposition of what was presumably Woodger’s “From Biology to Mathematics” (1952) set-theoretical concept of hierarchies, Hennig was caught in a “conundrum.” On Gregg’s set-theoretic interpretation, sets imposed sharp boundaries that resulted in a classification system of nested sets. This had consequences on the logical understanding of a semaphoront. According to Rieppel, semaphoronts (semaphoront complexes) were not only the character bearers, but logically speaking they were members of sets, they instantiated their respective species (by instantiation of the characters that were the membership criteria for the respective sets). Herein lay the problem for Rieppel. On this reading, according to Hennig’s species concept, Rieppel claimed that “based

574 Patricia A. Williams “Confusion in Cladism” Synthese 91(1992):151.

276 on (lawful) continuity through time rather than on certain (necessary and sufficient) properties, species become individuals,” and consequently the hierarchy for species was a division hierarchy. Since species were parts of the genealogical nexus, they were not members of a set.

So, for Rieppel, according to Hennig, semaphoronts (semaphoront complexes) were not the objects of the investigation of phylogenetic relationships: “In order to answer the question of whether the hierarchic system is rightfully used in biological systematics we must investigate whether semaphoronts can be substituted” for the argument spaces in Gregg’s Language of taxonomy (1954) formal language.575 As Rieppel pointed out, Hennig responded: “Obviously they cannot.”576

Rieppel also had problems with Woodger and Hennig. Rieppel agreed with Hull’s assessment of Woodger as an ‘‘idealist morphologist’’ based on the account of homology in

Woodger’s “Theory of biological transformation” (1945).577 Given Hennig’s objections to idealist morphology throughout Phylogenetic systematics, Rieppel puzzled over reconciling that with Hennig’s overt praise of Woodger’s treatment of homology in terms of ‘‘symbolic logic’’ and his appeal to Woodger’s claim in 1952 that species and supraspecific taxa are real, and as such are individuals, individuated by their genealogical relations. Rieppel’s solution was that

Hennig ran together two arguments that should have been kept separate.578

Knox also worried about Hennig’s reading of Gregg in the revised edition of the

Grundzüge (1966), given Hennig’s position on genealogical groups. Knox wrote:

It is difficult to determine whether Hennig misunderstood the work of Woodger and Gregg, or simply misrepresented it, because their definition of a hierarchy is antithetical

575 Hennig Phylogenetic systematics 18. 576Hennig Phylogenetic systematics 18. 577Rieppel “Concept” 487. 578Rieppel “Concept” 487.

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to Hennig’s stated intention of developing a truly historical approach to systematics. In Gregg’s model, genera are sets of species, not genealogical groups.579

Knox also indicated that Woodger had changed his position from a set-theoretic account (the

Linnaean hierarchy) to a more “evolutionary phylogenetic scheme” by 1952, and he was not certain that Hennig was aware of that change either.580

It is not clear to me that Hennig was confused on the question of hierarchies and logic in

Phylogenetic systematics. By revisiting Gregg on hierarchies and ontology, Woodger’s work on hierarchies from the 1930s to the 1950s, noting Woodger’s change in position when it came to taxonomy, and then looking at Hennig’s 1961/1966 books, it should be clear that Hennig held the same position with respect to hierarchies as he did in his 1947, 1949, and 1950 works.

7.2 Gregg and Woodger

In “Taxonomy, Language and Reality” (1950) Gregg argued that if species were thought of as classes of organisms, then the question of whether or not taxonomic groups were abstract entities would be extended a more general question of whether classes were abstract or spatiotemporal entities, to which he responded classes could not be spatiotemporal entities. If classes of organisms, such as species, were spatiotemporal entities in nature, it would violate the notion of the class-member relation, and lead to nonsensical statements. The relation of a cell to the organism in which it was located was the relation of part to whole, whereas the organism- species relation was member to class; and logically, these were a relation of an entirely different sort.581

579 Eric B. Knox “The use of hierarchies as organizational models in systematics” Biological Journal of the Linnean Society 63(1998): 9. 580 Knox “Use of hierarchies” 9. 581Gregg “Taxonomy” 424. Mayr claimed he was one of the two taxonomists Gregg cited. He was unsure if the other was A. J. Cain or T. Dobzhansky. See p 152 Mayr “The Ontological Status of Species: Scientific Progress and Philosophical Terminology” Biology and Philosophy 2 (1987) 145-166.

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When Gregg wrote Language of taxonomy (1954), he attempted to provide a set-theoretic account of the Linnean hierarchy that was in keeping with his ontological claims. Gregg intended to present a reconstruction of Linnaean classification using set-theory to model species as sets of individual organisms and higher groups as more inclusive sets. The resulting hierarchies were fully nested and display the property of summativity. This approach worked well for numerical taxonomy, and although Simpson had some problems with the execution, he did not shun the idea entirely. Mathematician and philosopher Nicholas Jardine capitalized on Simpson’s

Principles of animal taxonomy (1961), where he seemed to promote a species taxa as sets position.582 Jardine, for example, included the following passage from Simpson, in his attempt to provide a set-theoretic account of a taxonomic hierarchy that would improve upon Gregg’s:

Nevertheless, an individual never is and cannot be classified. Classification involves only groups; no entity possible in classification is an individual. An individual may be referred to or placed in a given group. That is often called “classifying,” but that is a misnomer. That process is identification, which is not the same as classification. [Simpson’s italics]583

Jardine wanted to emphasize Simpson’s idea that groups were important in classification, hence a set-theoretic account would not be out of the question. In the chapter on hierarchies, Gregg claimed to provide Woodger’s “From Biology to Mathematics” (1952) definition of abstract hierarchical relations:

( (

) ( ̌ ̌ { }))

Gregg explained that according to this definition, a hierarchy is any one-many relation z whose converse domain was identical with the set of all first constituents of ̌ pairs whose second

582 Sokal and Sneath did as well in Sokal, R. R., and P. H. A. Sneath. Principles of numerical taxonomy. W. H. (London: Freeman and Co., 1963). 583Nicholas Jardine “A Logical Basis for Biological Classification” Systematic Zoology, 18 (1969): 38.

279 constituent was the beginner of z.584 However, there were a couple of problems with Gregg’s definition.

Gregg provided a definition and diagram of the relation z with respect to its one-many asymmetry, but his set-theoretic model of a hierarchy relies primarily on the converse relation ̌

This was problematic because in a fully nested hierarchy, that is, one that displays the property of summativity, this difference was inconsequential, however, in hierarchies that were not fully nested, the inapplicability of Gregg’s set-theoretic approach to modeling top-down organization falls apart. Knox also raised585 this objection and raised the example of a zygote as not an aggregate of all the cells that will develop from it, and knowing that a cell was a zygote told you nothing of its future development (e.g. some zygotes undergo meiosis).

In “From Biology to Mathematics” Woodger took a second look at taxonomic hierarchies because he was concerned with his comprehensive treatment in Axiomatic method (1937)—the departure point for Gregg’s Language of taxonomy (1954). Woodger noted where he provided his “purely abstract definition of hierarchy” that “[a]t one time I found myself applying the term

‘hierarchy’ to very diverse objects and without being able to state at all in words why I did so” and he went on to describe division hierarchies exemplified by zygotes dividing, and hierarchies composed of nesting sets of mutually exclusive subclasses exemplified the Linnean classification of animals and plants. He then provided the following definition:

R is a hierarchy if and only if R is one-many and if the converse domain of R is identical with the set of all terms to which the first term of R stands in some power of R.586

In the corresponding footnote, Woodger made a point of stating:

584 Gregg Language 26-27. 585Knox “Use of hierarchies” 8. 586Woodger “Biology to Mathematics” 11.

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It does not suffice to define ‘hierarchy’ as denoting the set of all one-many relations which have one and only one beginner. In the first of the above illustrations of the notion of hierarchy the generating relation is the relation in which a square stands to each of its four quarter squares [the division hierarchy]; in the second it is the relation D explained above (p. 9 ) [Woodger’s example of cell division], and in the third it is the converse of the relation of immediate inclusion of classes [Linnean hierarchy].587

Gregg only looked at the last type of hierarchy, and his definition was more restrictive. Woodger stipulated “if the converse domain of R is identical with the set of all terms to which the first term of R stands in some power of R” and Gregg “whose converse domain was identical with the set of all first constituents of ̌ pairs whose second constituent was the beginner of z.”

More importantly, in “From Biology to Mathematics,” Woodger distinguished between the Linnaean system and what he understood as an “evolutionary” system. The evolutionary system, Woodger suggested, required a different compositionality relation than the Linnaean system, since species under the evolutionary interpretation were not “atemporal.” Woodger distinguished between “evolutionary species” which he believed were concrete entities that had a beginning and end in time, and Linnean species, which were abstract and timeless.588 Woodger went on to propose a solution in terms of species-names, in WL, where species-names were treated like general names. So, only near the end of “From Biology to Mathematics” did

Woodger entertain the possibility that species could be logical individuals. Although he did not explore this concern in any more detail, he did have the logical calculus to provide such an analysis if he wanted to—the division hierarchy he outlined in Axiomatic method would provide a temporal account. Hennig was well aware that Woodger made this argument.

587Woodger “Biology to Mathematics” 11-2. 588Woodger “Biology to Mathematics” 19.

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7.3 Hennig on hierarchies 1961/66:

7.3.1 Part I

In the Phylogenetic systematics, Hennig shortened his historical account and argument for hierarchies in taxonomy. What remained was the argument that he began in 1947 about non- hierarchical systems. Hennig noted that in the history of biological systematics, many attempts were made to introduce non-hierarchical systems: Quinary systems such as Kaup, Oken,

MacLeary, Vigors; Quaternary systems, such as Reichenbach; combinative systems; and correlative systems such as the period table of elements or butterflies. Hennig claimed that it was no coincidence that those who proposed non-hierarchical systems in taxonomy also supported nonphylogenetic positions, and that none of them survived. Hennig supposed that the fact that none of them survived suggested that “the hierarchical system best expressed the structure of the complex relations” that interconnected all organisms.589

Hennig began his formal account of hierarchies by noting that formal investigation of the taxonomic hierarchical system had been done by Woodger, and results of this had been published by Gregg in the Language of taxonomy. Hennig was right about this. Woodger had mentioned in passing in “The “Concept of Organism” and the Relation between Embryology and

Genetics.” (1931-2) what a taxonomic hierarchy would look like and expanded on that in a brief chapter in Axiomatic method. In both these works, Woodger described the Linnean hierarchy in terms of classes that could be defined and arranged hierarchically in terms of nested sets. The most comprehensive formal treatment of the Linnean hierarchy was Gregg’s in the Language of taxonomy. Gregg put the flesh on Woodger’s bones.

589Hennig Phylogenetic systematics 16.

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Rieppel noted that Phylogenetic systematics was not the first place Hennig mentioned

Gregg and Woodger together on hierarchies and formal logic. Rieppel translated:

...the choice of the type of system has to correspond to the structure description [Strukturbild] of certain relations, which exist between the entities that are to be components of the system […] The hierarchical type of system has most recently been investigated by Woodger and Gregg […] We therefore have to ask the question whether there exist relations between animal species that satisfy the requirements invoked by Woodger’s definition of ‘hierarchy’; in addition, these relations that exist between animal species must exist objectively, i.e., independent of any human being that may or may not recognize them (Hennig 1957., pp. 55, 57).590

In addition, Rieppel recorded Hennig’s praise of their efforts: “In my view the work of Woodger and Gregg is enormously important […] every systematist should look into it’ (Hennig, 1957; pp.

55–56).”591 So, it should come as no surprise that Hennig mentioned them together, favourably, in Phylogenetic systematics. Hennig wrote:

We consider the investigations of Woodger and Gregg extraordinarily important because they clarify, with methods that exclude all confusion and contradiction, the peculiarities of the hierarchical system, and so create exact prerequisites for investigating questions of whether and why it deserves the favour it enjoys in biological systematics.592

Hennig was often misunderstood in this passage as endorsing Gregg’s position. Instead, as it would become evident as Hennig continued, Hennig wanted to provide a thorough formal account of hierarchies because of what he perceived as an equivocation in taxonomic systems and consequently formal hierarchical accounts. This becomes clearer in Part II of his book.

In the revised section on hierarchies in Phylogenetic systematics, Hennig began with

Gregg’s definition of an abstract hierarchy, and Gregg’s graphic representation of it.593

590Rieppel “Dichotomy” 108. 591Rieppel “Dichotomy” 108. 592Hennig Phylogenetic systematics 17. 593In the text Hennig ascribed the definition to Woodger, but that was because Gregg ascribed the definition to Woodger. It was not Woodger’s definition, it was Gregg’s as discussed earlier.

283

594 Hennig Figure 4.

Hennig explained the diagram in Figure 4 by saying that the elements represented by X0 through X9 were paired by relations that extended in only one direction and such relationships existed, for example “between mother and child, father and son, employer and employee.”595 Of course, claimed Hennig, there were relationships that could be organized non-hierarchically, such as those between brothers, but those would not be included in this Figure. Hennig then asked: what in biology could be substituted for X0 through X9?

Recall the type of hierarchy presented. It was Gregg’s set-theoretical hierarchy. Being a set-theoretical hierarchy, it was not designed to deal with objects, like semaphoronts, that exist in time and have relations (such as ontogenetic and genealogical relations) that were not defined in this type of hierarchy. Hennig was aware of this, so, in response replied, “obviously they cannot.”596 Hennig did not believe this kind of hierarchy could account for organisms in their ontogenetic development from zygotes to adults, because “the structure of these ontogenetic relations does not correspond to the conditions of a hierarchic system.”597 This type of hierarchy

594Rieppel “Semaphoront” 174. 595 Hennig Phylogenetic systematics 1966 17. 596 Hennig Phylogenetic systematics 1966 18. 597 Hennig Phylogenetic systematics 1966 18.

284 was not designed to deal with these kinds of objects. In fairness, these were not the types of objects Gregg intended this hierarchy to organize.

Given Hennig’s earlier work on hierarchies, his response should come as no surprise.

First, Gregg’s hierarchy was the wrong type of hierarchy. Hennig was clear that the kind of hierarchy he had in mind was Woodger’s “division hierarchy” which he called

“Teilungshierarchie.” Again, division hierarchies were not found in Woodger’s discussion of taxonomic hierarchies, but in his work on cell biology, and Hennig came across Woodger’s idea of division hierarchies when reading Bertalanffy, Torrey, and others. Also, Hennig promoted a radically different ontological picture than Gregg. Hennig argued for individuals and Gregg for sets or classes. Hennig’s position on this matter became clearer as he continued.

7.3.2 Part II

In Part II, Hennig explored in greater detail his ideas regarding hierarchies, and began by claiming phylogenetic relationships were arranged in terms of a different kind of hierarchy—a

Teilungshierarchie. Perhaps part of the reason for the confusion can be blamed on inconsistent translation. For example, in the next passage, where Hennig opened the floor again to a discussion of hierarchies, “Teilungshierarchie” was translated as “partitioning hierarchy” instead of “division hierarchy”:

In den vorstehenden Kapiteln ist der Nachweis geführt worden, daß die Gesamtheit aller Arten, die in der Gegenwart und Vergangenheit unterschieden werden können geordnet nach den phylogenetischen Beziehungen, die zwischen ihnen bestehen der Definition einer Hierarchie (Teilungshierarchie) im Sinne von WOODGER und GREGG entspricht. Die adäquate Darstellungsform ist dementsprechend das hierarchische System. Die Fragen, denen wir nun im einzelnen nachgehen müssen, ergeben sich aus der Struktur eines solchen hierarchischen Systems.598

598Hennig Grundzüge 1982:75.

285

In the preceding chapters it was shown that all species that have ever lived, when arranged according to their phylogenetic relationships, correspond to the definition of a hierarchy (partitioning hierarchy) in the sense of Woodger and Gregg. Accordingly the adequate form of presentation is the hierarchic system. The questions that we must now pursue in detail result from the structure of such hierarchic system.599

Woodger and Gregg do mention division hierarchies—they provided accounts of biological hierarchies—but division hierarchies were not part of their vision of a taxonomic system.

However, for Hennig, it was clear that division hierarchies were equipped to deal with the biological relations Hennig had in mind, time and ancestry, all of which are necessary features of a phylogenetic relationship. Hennig proceeded with a figure illustrating the hierarchical system he had in mind. It is this chapter that contained the figure that resembled a figure in Hennig’s earlier paper where he discussed “enkaptic systems” and Donoghue and Kadereit showed he reproduced from Zimmermann.

Rieppel was on the right track in “Hennig’s enkaptic system” (2009).600 If Hennig’s deviation rule was followed, a stem species ceased to exist when it split into two daughter species, just as a cell ceased to exist when it divided. When the two descendant daughter species formed a new entity at a higher level of complexity (just as the daughter cells formed part of an organ) this new entity “encapsulated” the two daughter species, making it a monophyletic taxon at its lowest level of complexity. So, in Hennig’s familiar figure, he was not showing nested sets, but trying to reflect a mereological relation in a hierarchical way. In both the German and the

English translation of the second edition of the Grundzüge, Hennig discussed Woodger and

Gregg, and the term “Teilungshierarchie” (or “partitioning hierarchy” as it was translated) in conjunction with this diagram, because he wanted to make clear that this type of hierarchy was importantly different the usual set-theoretic interpretation.

599Hennig Phylogenentic systematics 70. 600Olivier Rieppel “Hennig’s enkaptic system” Cladistics 25 (2009) 311–317.

286

Hennig introduced this figure right after he claimed that phylogenetic relationships corresponded to a “division hierarchy” and continued, explaining this diagram with reference to

Bigelow and using the term “Teilungshierarchie” which was translated into “partitional hierarchy”:

Ein Vergleich der beiden graphischen Darstellungsformen des phylogenetischen Systems (Abb. 18 I und II) zeigt weiterhin, daß als Maßstab für die (relative) Rangordnung, die Subordination der Taxa in der Hierarchie der höheren Gruppenkategorien, der Zeitpunkt ihrer Entstehung angesehen werden muß. Das erfolgt zwangslauftg aus dem Charakter des phylogenetischen Systems als “Teilungshierarchie” mit der Art als sich teilender Einheit. Wie BIGELOW (1956) richtig formuliert, beruht die Rangordnung (Subordination) der Taxa höherer Ordnung im phylogenetischen System auf der “recency of common ancestry.”601

Comparison of the two diagrams in Fig. 18 shows that time of origin must be regarded as the measuring stick for (relative) ranking, the subordination of the taxa in the hierarchy. This necessarily follows from the fact that the phylogenetic system is a “partitional hierarchy,” with the species as the unit that divides. Bigelow (1956) correctly states that the rank order (subordination) of the higher taxa in the phylogenetic system rests on “recency of common ancestry.”602

If the hierarchy in this quote were Gregg’s set-theoretic hierarchy and diagram 1 were treated like a Venn diagram, this quote would be puzzling indeed, given Hennig’s requirements.

At this point Hennig made an unambiguous statement about the differences between the two types of hierarchies and their place in taxonomic schemata. In the case of morphological systems, the usual hierarchy would suffice for representing the relations of morphological similarity, but for phylogenetic systems a different kind of hierarchy was required—a

“Teilungshierarchie” or in this case translated as “partition hierarchy.” He wrote: “Dieses hierarchiesche System entspricht aber keiner Teilungshierarchie wie das hierarchische der phylogenetischen Systematik.”603 “At any rate it is also possible to present relationships of

601Hennig Grundzüge 1982:76. 602Hennig Phylogenentic systematics 72. 603 Hennig Grundzüge 1982: 79.

287 morphological similarity in a hierarchical system, although this hierarchical system is not a partition hierarchy like that of phylogenetic systematics.”604 Hennig went on to explain that taxonomists often equivocated on the term “affinity” and this had consequences taxonomic schemata, specifically hierarchies. Again, when Hennig explained this equivocation with the term “affinity” and the corresponding confusion it had on hierarchies, the term

“Teilungshierarchie” was not translated as “division hierarchy” but “partition hierarchy.” Hennig wrote:

Zwischen dem Grad der morphologischen Ähnlichkeit (overall resemblance, static relationship Formverwandtschaft) verschiedener Arten und dem Grade ihrer phylogenetischen Verwandtschaft (nach der von uns oben gegebenen Definition dieses Begriffes) besteht, wie heute wohl allgemein zugegeben wird, kein festes Verhältnis. Das behauptet auch keiner von den Autoren, die sich mit der Messung morphologischer Ähnlichkeitet beschäftigt haben. Die Begriffe “phylogenetische Verwandtschaft” und “Ähnlichkeit” (Formverwandtschaft) müssen daher streng auseinandergehalten werden. Leider geschieht das auch .heute noch sehr häufig nicht. “In discussions of dendrograms and their construction, confusion between phyletic and static relationship pervades much of the literature (MICHENER 1957). “It is not always easy to determine, for example, whether a given author means ‘similarity’ or ‘recency of common ancestry’ when he uses the term ‘affinity’” (BIGELOW 1958). Diese Aequivocatio terminerum ist in der Verbindung mit der Tatsache, daß der hierarchische Systemtypus sowohl zur Darstellung der phylogenetischen Verwandtschaft, wie auch zur Darstellung der hiervon durchaus verschiedenen Formverwandtschaft benutzt wird, deshalb so gefährlich, weil sie bei Schlußfolgerungen, die ausder Struktur des Systems einer Tiergruppe gezogen werden, den logischen Fehler der Metabasis außerordentlich begünstigt. Aus Abb. 19 ist zu ersehen, wie das zu verstehen ist. Ein Systematiker, der selbst nach den Grundsätzen der phylogenetischen Systematik arbeitet, wird selbst stets geneigt sein, auch das hierarchische System eines fremden Autors, der versichert, daß er darin die “affinity” der Arten darstellen wollte im Sinne der phylogenetischen Systematik als Teilungshierarchie zu interpretieren. Daher wird er annehmen, daß die Arten A und B, die der Autor eines Systems in einer Gruppe vereinigt hat (Abb. 19 Ia), zusammen eine monophyletische Gruppe bilden. Tatsächlich aber hat der Autor des Systems durch die Einordnung der Arten A und B in einer Gruppe nur ihre Formverwandtschaft (affmity im Sinne der overall resemblance) ausdrücken wollen.605

It is generally agrees today that there is no firm relationship between the degree of morphological similarity (overall resemblance, static relationship, form relationship) of species and the degree of their phylogenetic relationship (as defined above). None of the

604Hennig Phylogenentic systematics 74. 605Hennig Grundzüge 1982 79

288

above authors who have occupied themselves with measuring morphological similarity have maintained that there is. Consequently the concepts of “phylogenetic kinship” and similarity (form relationship) must be kept strictly apart. Unfortunately, even today this is not always done. “In discussions of dendrograms and their construction, confusion between phyletic and static relationships pervades much of the literature” (Michener 1957). “It is not always easy to determine, for example, whether a given author means ‘similarity’ or ‘recency of common ancestry’ when he uses the term ‘affinity’” (Bigelow 1958). This equivocation of terms is connected with the fact that the hierarchic type of system is used for representing both phylogenetic kinship and the entirely different form of relationship. Such ambiguity is dangerous because it greatly favors the logical error of metabasis in conclusions drawn from the structure of the classification of an animal group. Fig. 19 shows what this means. A taxonomist who works according to the principles of phylogenetic systematics will always be inclined to interpret the hierarchical system of any author who says he intended to present the “affinities” of the species as a partition hierarchy in the sense of phylogenetic systematics. Consequently, he will assume that the species A and B (Fig. 19 Ia), which the author of the system united in a group, form a monophyletic group. But actually the author of the system only intended, by including the species A and B in one group, to express their form relationship (affinity in the sense of overall resemblance).606

It now becomes clear why Hennig would introduced Gregg in the first place—and why he cast

Gregg in a reasonably favourable light—considering Gregg’s hierarchical system was not the system he would inevitably endorse. Hierarchical systems were the sort of systems that best captured taxonomic relationships, including phylogenetic relationships. Woodger and Gregg did provide the most comprehensive formal treatment, to date, of hierarchies. Given the equivocation present in taxonomic literature with the term “affinity,” it is important for taxonomists to now understand not just the equivocation, but the formal consequences of the equivocation in terms of hierarchies. Gregg and Woodger provide the language for that.

After all the references to division hierarchies, Hennig paused for an explanation on the term. When Hennig talked about reconstructing groups, he made the analogy to the reassembly of families torn apart by war. Reassembly can be accomplished, claimed Hennig, but not by constructing a group by the logical abstraction of characters or by the construction of general

606Hennig Phylogenentic systematics 76.

289 concepts in a purely morphological systematics. Rather, it must be by determining their tokogenetic relationships. Phylogenetic systematics, argued Hennig, approached “family reassembly” in exactly this way. He emphasized the fact that Woodger’s recent modern logic drew attention to exactly this point.

There are a few things to note about the passage below. Hennig drew attention to the fact that Gregg recognized that Woodger’s division hierarchy was different from the set-theoretic system he (Gregg) presented, and it was Woodger’s system to which Hennig was referring. Also,

Hennig used Woodger’s standard illustration of dividing a square into smaller squares, the illustration Woodger generally used when discussing division hierarchies informally. Hennig wrote:

In einer solchen „Familienzusammenführung” besteht auch die Arbeit der phylogenetischen Systematik. Daß die Struktur der phylogenetischen Beziehungen von der tokogenetischen verschieden ist (Abb. 6), ändert nichts an dieser Tatsache. Sehr bemerkenswert ist es, daß auch Vertreter der modernen Logik (symbolische Logik, Logistik) diesen Unterschied ganz richtig erkannt haben. Leider hat THOMPSON davon ebensowenig Kenntnis genommen wie BLACKWELDER. WOODGER z. B. hat (nach der Formulierung von GREGG 1954) “a simple language” entwickelt “with a structure entirely different of that of the theory, in which taxonomic group names may be constructed as names of individuals”. WOODGER (1952) geht von dem Beispiel eines Quadrates aus, das man in kleinere Quadrate aufteilt. “If ‘X’ names each of these smaller squares then X names the larger square of which they are parts.” Hier liegt also eine Hierarchie (Teilungshierarchie) vor, wie im System der phylogenetischen Systematik. In einer solchen Hierarchie sind nach WOODGER die höheren Kategorien keine „sets of organisms”, sondern die untergeordneten Kategorien sind “parts” (im wahren Wortsinn) der höheren. Nach WOODGER sind die „evolutionary species and genera” keine Abstraktionen wie die Kategorien der logischen und der morphologischen (leider nennt sie WOODGER „taxonomischen”) Systematik, sondern „concrete entities with a beginning in time”. Zwisehen der Art und den höheren Kategorien (im phylogenetischen Sinne) besteht nach WOODGER in dieser Hinsicht kein Unterschied. Er weist die Auffassung zurück, daß man „species as real from genera as unreal” unterscheiden könne. Allerdings vermeidet :er, sich auf die Begriffe „real” und „Individuum” zur Kennzeichnung der Art und der höheren Kategorien festzulegen (wie das GREGG in seiner Bemerkung über WOODGERs Arbeiten tut). Er bezeichnet sie lediglich als

290

„concrete entities with a beginning in time” im Gegensatz zu den „abstract, timeless” Kategorien der morphologischen Systematik.607

The work of phylogenetic systematics consists of such “family reassembly.” This is not altered by the fact that the structure of the phylogenetic relationships is different from that of the tokogenetic relationships (Fig 6). It is noteworthy that even the representatives of modern logic (symbolic logic, logistics) have correctly recognized this difference. Unfortunately neither Thompson nor Blackwelder (1959) has taken note of this. Woodger (according to the definition of Gregg 1954) has developed a simple language “with a structure entirely different from that of set theory, in which taxonomic group names may be construed as names of individuals.” Woodger (1952) proceeds from the example of a square, which can be subdivided into smaller squares. . “If X’ names each of these smaller squares then X names the larger square of which they are parts.” Consequently, this is a hierarchy (division hierarchy), as in the system of phylogenetic systematics. In such a hierarchy, according to Woodger, in the higher categories are not “sets of organisms,” but the subordinate categories are “parts” (in the true sense of the word” of the higher ones. According to Woodger, the “evolutionary species and genera” are not abstractions like the categories of logical and morphological (unfortunately he calls them “taxonomic”) systematics, but “concrete entities with a beginning in time.” He says there is in this respect no difference between the species and the higher categories (in the phylogenetic sense). He rejects the view that one can distinguish “species as real from genera as unreal.” However, he does not commit himself on the concepts “real” and “individual” for characterizing species and higher categories (as Gregg does on his remarks on Woodger’s works). He simply calls them “concrete entities with a beginning in time,” in contrast to the “abstract, timeless” categories of morphological systematics.608

Not only did Woodger and Gregg take different ontological positions with respect to the status of taxonomic groups by the 1950s, Hennig did not consistently use them as a pair in his work as

Hull, Williams, and Rieppel seem to suggest. They were paired up in Hennig’s work insofar as they developed a language for discussing hierarchies, but in terms of their position on taxonomic hierarchies, Hennig recognized their differences.

After his discussion about Woodger, Hennig continued to discuss division hierarchies and individuals, this time citing Hartmann and Bertalanffy on individuals. Hennig’s objective in this section was to clarify his concept of individuality, especially as it pertained to phylogenetics and

607Hennig Grundzüge 1982: 84. 608Hennig Phylogenentic systematics 80-81.

291 division hierarchies.609 Hennig began by acknowledging that there was a difference between what Hartmann called “individual” and “supraindividual” categories. To explain the difference he used the example of division using a protozoan and a zygote from a metazoan. He claimed all the products resulting from a protozoan organism dividing could be classified as individuals and as “operational units” in Bertalanffy’s sense of the term. All of the descendants of that protozoa collectively formed a clone. While the clone satisfied the definition of a division hierarchy and the totality possessed individuality and reality in Hartmann’s sense, the clone did not satisfy the criteria for Bertalanffy’s “operational unit.” In contrast, when the metazoan divided, its division

609 Hennig wrote: In dieser Hinsicht besteht nun zweifellos ein deutlicher Unterschied zwischen dem, was man auch in der Systematik Individuen schlechthin nennt.und den „überindividuellen” Gruppenkategorien, denen man nach den Ausführungen von N. HARTMANN und anderen ebenfalls Individualität zusprechen muß. Am deutlichsten wird dieser Unterschied, wenn man von einem Zellenindividuum ausgeht, daß als „Wirkungseinheit” im Sinne von BERTALANFFYS ja alle Merkmale des Individualitätsbegriffes aufweist. Jeder zu den Protozoa gehörende Organismus ist ein solches Zellenindividuum. Teilt sich dieser Organismus, so sind die Teilungsprodukte und auch deren durch wiederholte Teilungen entstandene Nachkommen wiederum Individuen mit allen Merkmalen dieses Begriffes. Sie alle zusammen (ein „Klon”) erfüllen die Definition einer Teilungshierarchie [my italics]. In dieser Gesamtheit als „Klon” besitzen sie ebenfalls Individualität und reales Sein im Sinne von N. HARTMANN. Dem „Klon” fehlt aber das Merkmal der „Wirkungseinheit”. Andererseits ist auch die Zygote der Metazoa ein Zellenindividuum mit allen Merkmalen der Individualität, auch dem der Wirkungseinheit Auch sie teilt sich, und die Teilungsprodukte und schließlich deren Nachkommen, sind wieder Zellenindividuen, die mindestens in vielen Fällen alle Merkmale des Individualitätsbegriffes behalten. Auch sie bilden in ihrer Gesamtheit eine Teilungshierarchie [my italics]. Im Gegensatz zu den Individuen eines Klons bleiben sie aber miteinander verbunden und bauen zusammen einen Organismus auf. der seinerseits ebenfalls das Individualitätsmerkmal der kungseinheit neben den anderen Individualitätsmerkmalen besitzt. An diesem Beispiel wird der Unterschied zwischen den Individuen im Sinne und denjenigen Kategorien einer Teilungshierarchie [my italics] deutlich, deren Individutäts-Charakter das Merkmal “Wirkungseinheit” fehlt. . .Schwieriger ist der besondere Individualitätscharakter der Arten zu bestimm Nicht zu bezweifeln ist, daß sie wie die höheren Kategorien des Phylogenetischen stems beziehungsweise jeder Teilungshierarchie [my italics] „Stelle oder Dauer in der Zeit” Fraglich dagegen ist, ob die Arten innerhalb ihrer Umwelt als Wirkungseinheiten sehen sind. Daß. es aber Kräfte gibt, die „nach innen” auf den Zusammenhang Komponenten hinwirken, ergibt sich aus der Defmition der Art als „Fortpflanzungsgemeinschaft”, die im Besitz eines Bestandes harmonisch aufeinander abgestimmter Gene ist. Mindestens gilt das für die diejenigen Fälle, in denen eine Art eine wirklich geschlossene Population und Fortpflanzungsgemeinschaft ist. Jene, ebenfalls als Arten bezeichneten Kategorien aber, die aus Komplexen isolierter vikariierender Fortpflanzungsgemeinschaften bestehen, bilden den Übergang zu den Kategorien höherer Ordnung. . .Wenn wir im Vorstehenden zur Überzeugung gelangt sind, daß die Kategorien des phylogenetischen systems samt und sonders Individualität und Realität besitzen, so gilt das selbstverständlich nur unter der Voraussetzung, daß unser System die Teilungshierarchie[my italics], der seme Elemente in der Natur angehören, zutreffend abbildet, daß also die zwischen ihnen bestehenden genetischen Beziehungen richtig erkannt sind. Wir müssen uns daher jetzt der Frage zuwenden, ob, in welchem Umfange und mit welchem Grade von Genamgkeit die uns zur Verfügung stehenden Methoden es gestatten, die theoretisch gestellte Aufgabe der phylogenetischen Systematik zu erfüllen.[86-87]

292 products formed a division hierarchy, possessed individuality and reality in Hartmann’s sense, and formed an operational unit in Bertalanffy’s sense. For many, this was a puzzle—which was an individual?

Hennig’s point was that in his system, individuality was a much looser concept, much like Hartmann’s. It could apply to higher categories of the phylogenetic system or of any other division hierarchy that has “a place or duration in time.” In other words, for Hennig, all categories of the phylogenetic system were characterized by the individuality and reality, not the abstract and timeless categories. This was why the morphological system did not appeal to him, and why Gregg’s formal system did not appeal to him either. Hennig drove his point home when he claimed that we cannot “uncritically transfer all the criteria of individuality that characterizes one category rank to other ranks if we are to avoid faulty conclusions.”610

7.4 Conclusion

On the question of hierarchies and logic in Phylogenetic systematics, Hennig was not confused. Problems with translations may have led to some confusion, but it is clear that Hennig had division hierarchies in mind, and had developed a concept of individuality that built from it.

Hennig praised both Woodger and Gregg for their formal work on hierarchies, but was well aware of the differences in their systems by the 1952.

When species were viewed as sets or classes, the question was whether to define them in terms of a set of necessary and sufficient conditions or polytypically. Both of these options seemed to fit with the traditional picture of Neo-Darwinian evolution where genes mutate, organisms compete and are selected, and species evolve that had informed the paradigmatic biological hierarchy in which genes are parts of organisms, organisms are individuals, and

610Hennig Phylogenentic systematics 83.

293 species are sets of individuals. The relationship between logic and taxonomy, as it unfolded in the construction of taxonomic schemata, now had become more complicated. Within his methodological reform, Hennig had presented a system in which species behaved as individuals.

It would not be long before other biologists and philosophers, such as Michael Ghiselin and

David Hull, would also promote the “species-as-individuals” claim. Within the volatile taxonomic methodological reform and within relationship of logic and taxonomy, discussions and criticisms of this Neo-Darwinian inspired hierarchy forced taxonomists to rethink their ideas concerning hierarchies, as well as their concept of biological individuality.

294

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Appendix 1 Woodger’s notion of Parthood

In Axiomatic method, Woodger’s first axiom in his mereological calculus stated that the relation “part of,” where “xPy” was read as “x is part of y.” To appreciate to notion of parthood, it helps to remember (or to know) that there are two ways to understand sets, the usual set- theoretic way, which is to think of them as collections of things (for example, the set of all irrational numbers, or the set of all people who wear glasses), and the mereological way, which is to think of them as aggregates (fusions or conglomerates) made up of parts (for example, the fusion of minerals to make granite, or the fusion of bricks to make a wall). The difference between a collection with a set-member relations and an aggregate with a part-whole relation can be described by their respective calculi.

There were three main relations Woodger defined for parthood, and these relations helped distinguish between a part-whole relation and a set-member relation. 611 The first was transitivity for both spatial and temporal parts.612 So, for any part of any part of a thing is itself part of that thing. Woodger stated it formally:

̂ ̂ { ⃗⃗ ( ) ( ) ⃗⃗ ⃗⃗ }

For the sum of a class of parts, the sum of α (written S ‘α’), if α is contained in the parts of x, and if when y is any part of x there is always a z belonging to α having parts in common with the parts of y.613 He also stated that every class that was not null (provided that it was of the same type as the field of P) had a sum. Second, Woodger went on to stipulate that that P was reflexive, an object will be included among its parts (or everything is part of itself).614 Third, Woodger

611The idea the part-whole relation was transitive, reflexive, and asymmetrical was important as it is makes it importantly different from the proper part relation which was an irreflexive, asymmetrical, but transitive relation, as Leonard and Goodman pointed out. Henry S. Leonard; Nelson Goodman “The Calculus of Individuals and Its Uses” The Journal of Symbolic Logic, 5 (1940): 49. 612To say that something bears the transitive relation in logic means, if A bears some relation to B and B bears the same relation to C, then A bears it to C. In mathematics, for example, both equality and inequality are transitive: if A=B and B=C, then A=C, and if A B and B C, then A C . 613Woodger Axiomatic method 55. 614To say something bears the reflexive relation in logic means that it bears a relation that always holds between any object and itself, for example, everything is the same height as itself.

310 claimed that only the logical product of P with diversity (formally, ( ̇ )) was asymmetric, that is, no two distinct parts could be part of each other.615

Time

Another important feature of Woodger’s mereological calculus was time. The idea of time was important for Hennig. As will be seen in the next chapter, the reason a set-theoretic approach to taxonomy appealed to Gregg was because it did not include time, it was atemporal. Gregg provided an argument for why he believed it was correct to view species as sets, and not as mereological individuals. Although Woodger did not provide a rigorous argument like Gregg, he too believed that taxonomic hierarchy was governed by a set-member relation and not a whole- part relation. However, in terms of time, just as Woodger stipulated transitivity, reflexivity, and asymmetric properties for parthood, he also did so for time.

Woodger defined the relation ‘T’, where ‘T’ denoted the relation “before in time.” He stated that T was asymmetrical, and the statement “the sum of α is before the sum of β in time” was equivalent to the statement “α and β are not null, and that if x is any member of α and y any member of β then x is before y in time.”616

1.2.2 ( ) ( )

This axiom restricted the application of the relation “before in time” to those cases where every part of the earlier term preceded every part of the later one. Woodger also provided axioms that stipulated the following cases: if no part of x is after y then x precedes everything that y precedes (in time): ( ) ⃗⃗ ⃖⃗⃗ ⃖⃗⃗ ⃖⃗⃗

And

If no part of x precedes y in time then everything that precedes y also precedes x:

( ) ⃗⃗ ⃗⃗ ⃗⃗ ⃗⃗

615To say a relation is asymmetric the relation always holds, if you have two object, in at most one direction between those two objects. For example, the relation “mother of” is asymmetric, since if x is the mother of y, it follows that y is not the mother of x. Likewise, the mathematical relation “ ” is also asymmetric, because if x y, it follows that y x. 616 I will keep Woodger’s numbering system for his axioms.

311

Together these axioms showed that T was transitive.

Woodger also defined “the class of momentary things” as those in which no part is before in time to another:

̂{( ) }

According to Woodger, everything has momentary parts, and proved transitivity for this as well. If xTy and yPz and z is momentary then xTz (1.3.3); if xPy and y is momentary and xTz then yTz (1.3.4); if x is part of y and y is momentary then the predecessors of x with respect to time are identical with those of y, and the successors of x with respect to time are identical with those of y (1.3.5); and the relation of being neither before nor after, if its field is limited to momentary things, was transitive (1.3.6).617 Finally, it can be proved that if z is the sum of a class α of momentary things such that no member of α is before any other member of α in time, then z itself was momentary:

1.3.7. ( ) ( )

Organized entities

Now Woodger had to start building, but he had to be careful. Not only did Woodger have to piece together things in a temporal sequence, but recall that the goal for Woodger’s programme was to make sure that he could eventually build hierarchies that would enable him to claim “the whole is more than the sum of its parts.” Woodger introduced the concept of organized entities or “org” to denote the class of all organized unities throughout their “temporal extent.” In the spirit of Bertalanffy and Heidenhain, for Woodger, a cell, or a whole organism, throughout its life was a member of this class. He began by defining a “time-slice” or “slice” of an organized unity (e.g. a “momentary” cell): x is a slice of an organized unity y (written xSly) if x is momentary and a part of y, and if there is no momentary part of y distinct from x of which x is a part:

1.4.1 ̂ ̂( ⃗⃗ ( ) ⃗⃗ ̇ )

617 Woodger Axiomatic method 57.

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He defined “Sl” as a relation between x and y, and wrote “Sly” for “the slices of y.” At this point, should start to become a little clearer why Woodger’s ideas, as they came through Bertalanffy and others, might be attractive to Hennig who was coming up with a concept of a semaphoront.

Woodger had a great deal to say about organized entities and time slices. For example, according to Woodger, if x and y were slices of z, they were either identical or they had no parts in common.618 He also maintained that any two distinct slices of a member of org one must precede the other in time, and between any two distinct slices of a member of org there was always a third, distinct from both.619 Any member of org was identical with the sum of its slices (i.e. ( ) ⃗⃗⃗ ).620 It could also be proved that the relation T with its field limited to the slices of any member of org was a series. Every member of org had a first slice preceding all the others, and a last slice succeeding all the others with respect to time. Basically, Woodger was formally setting up a dynamic process account of organisms. Hennig, by adopting this account, found himself in what would become a complicated subject, especially in debates about Phylogenetic systematics (1966)—the idea of beginners and ends.

Beginners and enders

Woodger used B’y to denote the first or beginning slice of y, and E’y to denote the last or ending slice of y with respect to time, and ⃗⃗ ⃗ ’y to denote the intermediate slices of y with respect to time, that is, those between the first and last slices. With these definitions and the previous axioms, it followed that for any member x of org, the B’x existed, the E’x existed and was distinct from the B’x, the ⃗⃗ ⃗ ‘x was not null, and x must have more than three slices.621

Biological relations—division and fusion

Woodger used ‘U’ to denote what he called the “characteristic biological relation” between parts of an organized entity, for example, in cell division or cell fusion. According to Woodger, one characteristic feature of this relation was that identity seemed to be preserved with both division and fusion, so, for example, if x was a cell and xUy, then y was also cell, or if x was a

618 Woodger Axiomatic method 58. 619 Woodger Axiomatic method 58. 620 Woodger Axiomatic method 58. 621 Woodger Axiomatic method 58.

313 chromosome and xUy, then y was one as well. He made a point of claiming that this relation was different from both disintegrating division (e.g. when a cell dies) and synthetic union when two or more things come together to form a new entity.622

To help illustrate the relation U, Woodger provided the following diagram, where he discussed two kind of branching: branching forward with respect to time (which he called division) and branching backward with respect to time (which he called fusion).

Woodger Figure 1623

Woodger explained the relation U was the relation between two pieces on continuum, when each piece extended from one fork to the next, and one immediately preceded the other. At each fork in the forward direction with respect to time (downward on the page) a slice was identified and labeled. To be clear, starting with the part marked x on the left of the figure as a reference point, all the slices before x occur before the fork, and all slices later than it occur after the fork, and the last slice of x (E’x) is marked “d.” Woodger also noted that slice d was part of it the first slice of y (B’y) and another part the first slice of z (B’z).624

Woodger went on to explain that in the case of each fork in the backward direction with respect to time, slice taken, such as that marked “u” in the figure, after the fork but all slices before it are before the fork. The slice u was taken as the first slice of y and part of it as the last slice of x and another part as the last slice of z. In both cases, x stood in U to y, since U embraced both division and fusion. Woodger also showed that the slices of parts of such a continuum fell

622 See Woodger Axiomatic method 58. 623 Woodger Axiomatic method 59. 624 Woodger’s full explanation can be found on pages 59-60.

314 into five mutually exclusive classes: (1) intermediate slices in the sense defined in 1.5.3; (2) slices like d which occurred at divisions, (3) slices like u which occur at unions or fusions; (4) slices like b which are the first slices of parts of the continuum and which do not belong to the converse domain of U (this class is null in the case of cells); and finally (5) slices like e which are the last slices of parts of the continuum and which do not belong to the domain of U.625 So, if x stands in U to y, then x and y are both members of org and either the first slice of y is part of but not identical with the last slice of x, or the last slice of x is part of but not identical with the first of y:

1.6.1 ( ) ̇ ̇

Also, if xUy and the first slice of y is part of the last of x, then x is the only term standing in U to y, and there is at least one z distinct from y such that xUz and the first slice of z is part of but not identical with the last of x:

1.6.2 ( ) ̇ ( ) ̇

Lastly, if xUy and the last slice of x is part of but not identical with the first slice of y, then y is the only term standing in converse U to x, and there is at least one z such that z is not identical with x, zUy and the last slice of z is part of the first of y:

1.6.3 ( ) ̇ ̆ ( ) ̇

From these axioms and definitions previously given, Woodger proved the following theorems:626

1. If xUy, x and y cannot be identical.

2. If xUy and u is any slice of x except the last and v is any slice of y, then u is before v in time (1.6.6).

3. If xUy and u is any slice of x and v any slice of y except the first, then u is before v in time (1.6.7).

626Woodger Axiomatic method 60-61.

315

4. If xUy and u is the last slice of x and v the first of y, then u and v cannot be identical but one is part of the other (1.6.8).

5. If x stands in U2 to y, x is before y in time (1.6.9).

6. If x stands in any power of U (excluding identity and U itself) to y, then x is before y in time (1.6.10).

7. If xUy we cannot have xPy (1.6.11).

8. U is intransitive and asymmetrical (1.6.12).

9. Upo is transitive and asymmetrical (1.6.13).

10. If xUy the last slice of x is the only slice of x which has parts in common with y, and the first of y is the only slice of y which has parts in common with x (1.6.14).

11. If xUy there is one and only one z such that z is a slice either of x or of y and a part of both x and y (1.6.15).

With these theorems, axioms, and definitions in place, Woodger was able to distinguish formally between division (Dv) and fusion (Fs). According to Woodger, x stands in Dv to y if xUy and the first slice of y is part of the last slice of x. He also claimed that x stands in Fs to y if xUy and the last slice of x is part of the first of y. It followed that U was identical with the logical sum of Dv and Fs (1.7.3), that Dv was one-many and asymmetrical (1.7.4), and that Fs was many-one and asymmetrical (1.7.5).627

Hierarchies

Woodger claimed that if x was any member of the domain of Dv, then Dv with its field limited to the terms to which x stood in Dv* including x itself was a hierarchy (1.7.1l). This resulted from the fact-that Dv was one-many and asymmetrical. Such hierarchies can be called Dv-hierarchies and defined as follows:

1.8.1 ̂{( ) ⃖⃗⃗⃗ ⃗⃗ }

627Woodger Axiomatic method 61.

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It followed that if R was a Dv-hierarchy no member of its field could stand in Fs to another.628

Woodger explained that in the case of xUy, there was at most one slice of z which was part of y, which prompted him to define another relation between members of org, namely the relation in which x stands to y when there was more than one slice of x which was a part of y, but x was not identical with y, and when, if u was any slice of x and v any slice of y such that u was neither before nor after v, then u was part of v. He called this other biological relation ‘Pt’, the definition being:

⃗⃗⃗ 1.9.1 ̂ ̂( ⃗⃗ ( ) ̆ )

From this, Woodger drew the following conclusions. It followed that U and Pt were mutually exclusive. A term x was said to begin in y (xBegy) if it stood in Pt to y and its first slice was part of but not identical with some slice of y (Woodger’s theorem (1.9.5)). A term x was be said to end in y (xEndy) if it stood in Pt to y and its last slice was part of but not identical with some slice of y (Woodger’s theorem (1.9.6)). A term x was said to divide in y (xDivy) if it ended in y and belonged to the domain of Dv (Woodger’s theorem (1.9.7)). A term x was be said to extend through y if it stood in Pt to y but did not begin in y and if to every slice z of y there was a slice w of x such that w was part of but not identical with z (Woodger’s theorem (1.9.8)). So, according to Woodger, it followed that if xPty, and no slice of x was a slice of y, then x must begin or end in or extend through y (Woodger’s theorem (1.9.9)). Also, if x both divided in and extended through y, the last slice of x must be part of the last slice of y (Woodger’s theorem (1.9.10)).629

Woodger needed to distinguish also between “cell”, which denoted the class of cells, and the class of momentary whole organisms. The first he considered as temporally extended things having a first and last slice from the class of instantaneous or momentary cells, which will be Sl”cell, whereas the latter, Sl”wh, the undefined sign ‘wh’ denoted the class of whole organisms considered as time extended with a first and last slice. The first axiom of this set stated that every cell belonged to the converse domain of U with its field limited to cell (1.10.1).630 The next was the corresponding axiom for whole organisms, stating that every member of this class was a

628 Woodger Axiomatic method 62. 629 These can all be found on Woodger Axiomatic method 63. 630 Woodger Axiomatic method 63.

317 member of cell or has a member of the latter class as a part (1.10.2).631 These two axioms together constituted the thesis of “abiogenesis.”

Woodger continued with the next axiom stated that every member of cell was a member of wh or stood in Pt to a member of wh (1.10.3).632 Axiom 1.10.4 stated that if x was a member of wh and its first slice was the first slice of a cell belonging to the converse domain of Fs (e.g. if x began with a zygote), then x did not belong to the converse domain of Dv.633 Axiom 1.10.5 stated that every member of cell or wh was a member of org; and axiom 1.10.6 stated that if x and y were any two cells there was a finite cardinal number λ such that for every v, if x stood in the v the power of U to y, then v was equal to or less than λ. Because Woodger envisioned this system for cells and not for taxonomy, he defined three other sub-classes of org. First, the class of cell-parts (cp): x was a member of cp if it was a member of org but not of cell, and if to every slice y of x there was a slice z of some member of cell such that y was part of but not identical with z (1.10.7). This class would thus exclude secretions and accretions of cells which were not cell-parts throughout their temporal extent. He defined the class of cellular-parts (c1p) as follows: x was a member of clp if it was a member of org but not of cell or of wh, and if there was a member of cell standing in P to x and a member of wh to which x stood in P (1.10.8). Lastly, he defined the class of social organized unities as those members of org which did not belong to wh but have members of this class standing in P to them. This class was denoted by ‘soc’ (1.10.9). The last axiom of this section (1.10.10) stated that if α is any member of the class of four classes cp, cell, clp, wh and if x and y were any two members of α having a slice in common, then x and y were identical.

631 Woodger Axiomatic method 63. 632 Woodger Axiomatic method 64. 633 Woodger Axiomatic method 64.