Philos Theor Biol (2010) 2:e105 ESSAY REVIEW Is Evolutionary Biology Infected with Invalid Teleological Reasoning? A Review of Not by Design: Retiring Darwin’s Watchmaker by John O. Reiss, University of California Press, 2009 David J. Depew§ In Not by Design: Retiring Darwin’s Watchmaker (2009), John Reiss claims that thinking of organisms as analogous to artifacts, and so thinking of natural selection as naturalized design, is not the only point at which invalid and unsound teleological reasoning has affected evolutionary biology. Teleological errors persist whenever evolutionary biologists turn the observation that an organism would not exist unless it possessed a certain trait into the claim that the trait in question came into existence because it had this salutary effect. Since he thinks fitness itself is often measured in ways that commit this fallacy, Reiss infers that the only good measure of fitness is the continued existence of populations or species, a principle he traces back to the anti-evolutionary 18th century comparative anatomist George Cuvier. In this essay, I explicate Reiss’s reasons for coming to this conclusion and offer challenges on several points. Among these is Reiss’s perhaps too hasty dismissal of the consequence etiological or selected-effects account of adaptedness. I conclude by suggesting that Reiss’s work exemplifies one way in which evolutionary developmental biology (Evo-devo) is currently affecting the consensus form of genetic Darwinism that has prevailed for many decades under the name of the Modern Synthesis. KEYWORDS Alberch (Pere) ● Conditions of (for) existence ● Consequence etiology ● Cuvier (George) ● Darwin-Wallace principle ● Evo-devo ● Fitness ● Functions (biological) ● Natural selection ● Teleology 1. An Ambitious Critique John Reiss is a practicing evolutionary biologist (herpetology) who by his own account happened to be in the right place (Harvard’s Museum of Comparative Zoology) at the right time (the 1980s) to hear echoes of the debate about sociobiology that had been raging there between E. O. Wilson and, on the other side, Stephen Jay Gould and Richard Lewontin (xiv). Reiss is not concerned with sociobiology, at least in this book, but with the adaptationism that Gould and Lewontin saw in the sociobiologists’ approach to cooperative behavior. At Harvard, Reiss was guided by Pere Alberch, in whose laboratory Gould’s stress on § Project on the Rhetoric of Inquiry, Bowman House, University of Iowa, Iowa City, IA 52240, USA ✉ E-mail: [email protected] Received 18 July 2010; Revised 29 November 2010; Accepted 4 December 2010 OPEN ACCESS - Freely Available at philosophyandtheoryinbiology.org DEPEW, D. — EVOLUTIONARY BIOLOGY AND TELEOLOGY 2 developmental constraints was being transformed into a now influential version of the Evo-devo movement (xiv, 327). On Alberch’s view, which Reiss accepts, variation in the rate, timing, placement, and intensity of gene products during the ontogenetic process, rather than mutation in structural genes, constitutes the proximate source of the phenotypic variation on which natural election works (327-29). Reiss does not think that Evo-devo, at least as he construes it, does away with natural selection. Rather, he seeks to identify the role played by selection in retaining or eliminating the variation generated in the developmental process. Selection, he argues, enables organisms, populations, species, and other lineages to maintain the presumptively adapted conditions of existence to which their very persistence already testifies. “Adaptedness,” Reiss writes, “is not a product of evolution; it is a condition for evolution” (22). He thinks that this fact, as he takes it to be, belies the adaptationist assumption that organisms are collections of independently optimal adaptations that arise by way of concerted spurts of directional selection. “It is a mistake,” he writes, “to atomize organisms and to explain each part as the solution of a problem raised by the environment” (295). But this is only the beginning. It is not just adaptationists of the sort upbraided by Gould and Lewontin whom Reiss criticizes. He argues at considerable length that Darwin himself retained elements of the intelligent design model that he attacked; that the same assumptions lurk within the Modern Synthesis; and that even as ardent an anti-adaptationist as Gould himself was not entirely free of them (295). Why Reiss comes to these startling conclusions is surely the main thing that readers of this book or this review essay will want to know. So answering this question will be my focus. I will, however, pose some questions along the way. Reiss’s intended audience is primarily his fellow biologists and students of biology, who on his view need to know just how contaminated by the argument from design their interpretive habits are before they can change them. Philosophers and historians of biology are sometimes brought in as witnesses, but more often than not they, too, are said to fall into the fallacy that is Reiss’s topic from beginning to end. This is the fallacy of inferring from the fact that a given sort of organism would not exist unless it possessed a certain set of traits to the conclusion that these trait come into existence just because they contribute to the actual or probable existence of the organisms that have them. This inference assumes that organisms are assemblies of traits. Having done so, it repairs its invalid slide from treating traits as necessary conditions for organic functioning to claiming that they come into being for this purpose by supplying a tacit premise that the l8th century philosopher Gottfried Leibniz called “the principle of sufficient reason.” The principle that everything that happens has to happen and for that reason must be a Good Thing served Leibniz as an all- purpose warrant for giving deductive-sounding, but value-laden reasons for the existence of entities, properties, and states of affairs of the sort satirized in Voltaire’s Candide. This high-handed and high-minded premise does make what Reiss calls “deterministic teleology”—I would prefer to call it deductive or demonstrative teleology—valid. But it also makes it unsound, question-begging, and empty in ways that Gould and Lewontin, channeling Voltaire, ridiculed in their famous polemic “The Spandrels of San Marco and the Panglossian Paradigm” (Gould and Lewontin 1979). Most of Darwinism, Reiss argues, still shows signs of this fundamentally theological fallacy. The book is divided into four parts. The first sets out the propositions I have summarized and lays the groundwork for Reiss’s contention that hard-to-recognize forms of unsound teleological reasoning continue to dog contemporary biology, especially in how fitness is measured, biological functions are defined, and selection is conceived. The second part is a detailed intellectual history of “How We Got Into This Mess.” The third is an attempt to show that traces of the unsound teleology whose history is reconstructed in the second part are still found in concepts dear to the heart of the Modern Synthesis: adaptive landscapes, genetic loads, and genetic drift. The fourth part applies Reiss’s proposal to micro- and macro-evolutionary problems. In it Reiss (i) defends continued existence as the only tractable measure of fitness; (ii) treats the continued existence of populations, species, or other lineages as sufficient evidence that they are fulfilling their conditions for existence; (iii) conceives of “broad-sense” natural selection as maintaining rather than creating adaptedness and so as equivalent to the principle of conditions of existence; and, (iv) regards developmental responses to environmental shifts as the most important source of the new forms that natural selection broadly construed evolves. OPEN ACCESS - Freely Available at philosophyandtheoryinbiology.org DEPEW, D. — EVOLUTIONARY BIOLOGY AND TELEOLOGY 3 2. A Surprising Hero Since I am not a practicing evolutionary biologist, I am not in a good position to comment on how well received Reiss’s criticisms of current interpretive practice in his field might or should be. As a philosophically minded historian of evolutionary theory, however, I can say that I found his tour through the history of biological teleology’s misalliance with natural theology in his chapters on “How We Got Into This Mess” informative and for the most part persuasive. I agree that the design inference that Darwin criticized in William Paley and the Bridgewater Treatises was in fact first proposed in its modern form by Leibnizians such as the influential textbook philosopher Christian Wolff (1679–1754). Wolff explicitly held that the cosmos is structured in accord with the old “principle of plentitude” according to which being is inherently good. Since being is good, Wolff argued, it is maximized and since it is maximized it comes in a continuum that stretches from the purely rational down through various grades of the organic to the purely material. The principle of sufficient reason was an interpretive maxim that was supposed to help people apply the principle of plentitude to particular phenomena in this “great chain of being.” These phenomena might or might not have included finding purpose and design in apparently bad phenomena such as the Lisbon earthquake, whose singular fame among earthquakes springs from the fact that it occurred just when these theological-philosophical musings were being debated across Europe (see Neiman 2002). In the post-Newtonian, British uptake of the argument from design one can see both the principle of plentitude and the deductive form of the argument from design slowly disappearing into or rather hiding themselves behind a pseudo-empirical, inductive form of natural history whose culminating stage, but far from last gasp, was Paley’s Natural Theology (1801), which in his Autobiography Darwin confesses to having practically memorized when he was an undergraduate at Cambridge. Preachers like Paley could persuade people to see the fittingness of organic traits to the lives of organisms in specific environments as signs of God’s providence.