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Biological Atomism and Cell Theory

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Biological Atomism and Cell Theory Studies in History and Philosophy of Biological and Biomedical Sciences 41 (2010) 202–211 Contents lists available at ScienceDirect Studies in History and Philosophy of Biological and Biomedical Sciences journal homepage: www.elsevier.com/locate/shpsc Biological atomism and cell theory Daniel J. Nicholson ESRC Research Centre for Genomics in Society (Egenis), University of Exeter, Byrne House, St. Germans Road, Exeter EX4 4PJ, UK article info abstract Keywords: Biological atomism postulates that all life is composed of elementary and indivisible vital units. The activ- Biological atomism ity of a living organism is thus conceived as the result of the activities and interactions of its elementary Cell theory constituents, each of which individually already exhibits all the attributes proper to life. This paper sur- Organismal theory veys some of the key episodes in the history of biological atomism, and situates cell theory within this Reductionism tradition. The atomistic foundations of cell theory are subsequently dissected and discussed, together with the theory’s conceptual development and eventual consolidation. This paper then examines the major criticisms that have been waged against cell theory, and argues that these too can be interpreted through the prism of biological atomism as attempts to relocate the true biological atom away from the cell to a level of organization above or below it. Overall, biological atomism provides a useful perspective through which to examine the history and philosophy of cell theory, and it also opens up a new way of thinking about the epistemic decomposition of living organisms that significantly departs from the phys- icochemical reductionism of mechanistic biology. Ó 2010 Elsevier Ltd. All rights reserved. When citing this paper, please use the full journal title Studies in History and Philosophy of Biological and Biomedical Sciences 1. Introduction Rather than enumerating the successive recorded observations of cells from Hooke to Schleiden and Schwann, it may be instruc- Cell theory is generally regarded as one of the central unifying tive to consider the genesis of cell theory by examining the epis- ideas in biology. It is widely acclaimed in textbooks as a corner- temological motivations that led to its formulation, as these can stone of biological science (for example, Sharp, 1921, p. 9; Harold, help situate the subsequent criticisms of the theory in an appro- 2001, p. 17) and, alongside Charles Darwin’s theory of evolution, priate philosophical context. Of course, there is no single way of the most important generalization in biology (for example, Wilson, accomplishing this. E. S. Russell (1916), for instance, explained 1900, p. 1; Webster, 2003, p. 9). However, cell theory is far from the development of cell theory and the subsequent challenges to being an obvious, self-evident truth that is universally accepted it as an expression of the fundamental biological dispute over among biologists. In fact, ever since it was formally enunciated the causal primacy of form or of function. Georges Canguilhem by Matthias Schleiden and Theodor Schwann in 1838 and 1839 (2008 [1965]), on the other hand, interpreted the history of cell (Baker, 1948), the extent of its applicability, and even its internal theory as a dialectical battle between two opposing representa- coherence, have remained the subject of controversy in biology. tions of the anatomical constitution of organisms: one emphasiz- The main aim of this paper will be to uncover the rationale under- ing continuity, and the other emphasizing discontinuity. And lying the major objections that have been waged against cell the- Timothy Lenoir (1982) traced the steps that led to Schleiden’s ory since its formulation to the present day. To do so, it will be and Schwann’s enunciation of cell theory as part of a broader ‘tele- necessary to identify the philosophical foundations upon which omechanical’ research programme in biology, which he argued ar- cell theory rests. In turn, this will require going beyond the ‘official ose out of a materialistic interpretation of Immanuel Kant’s history’ of cell theory, on the grounds that there is, philosophically teleological conception of the organism advanced in his third speaking, no direct path connecting Robert Hooke’s first micro- Critique. scopical observations of cells in 1665 with Schleiden’s and Schw- In this paper, the perspective adopted to make philosophical ann’s articulation of cell theory 175 years later. sense of past and present disputes over the legitimacy of cell E-mail address: [email protected] 1369-8486/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.shpsc.2010.07.009 D.J. Nicholson / Studies in History and Philosophy of Biological and Biomedical Sciences 41 (2010) 202–211 203 theory is one I call biological atomism. I characterise biological not difficult to conceive that, when a certain number of these atomism as the doctrine which postulates a basic indivisible unit molecules are united, they form a living being: life being in of life and seeks to explain the morphological constitution and each of the parts, it can be in a whole, in any assemblage what- physiological operation of all living beings in terms of these funda- soever of these parts. (Buffon, quoted in Canguilhem, 2008, mental units. The activity of a living organism is thus conceived as p. 37) the result of the activities and interactions of its elementary con- To explain the confinement of the aggregation of organic molecules stituents, each of which individually already exhibits all the attri- in the organism, as well as the stable organization of the organic butes proper to life. It is important to distinguish from the outset molecules in three-dimensional space, Buffon introduced the con- what I call biological atomism from mechanistic1 efforts to reduce cept of ‘inner mould’ as a sort of principle of morphological con- biological entities (e.g., organisms) to physicochemical ones (e.g., stancy. With his theory of organic molecules, Buffon was able to genes), given that in theories of biological atomism the final units account for a number of fundamental biological processes, includ- of analysis are still living beings in their own right. ing heredity, reproduction, and development.2 Buffon’s friend, the By looking at cell theory through the prism of biological atom- geophysicist and mathematician Pierre-Louis Moreau de Maupertuis, ism, I want to suggest that we can reach a better understanding of published a similar atomistic theory in his Vénus physique (published the ideas which led to its formulation, and a fuller appreciation of in 1745), though the elementary particles of his theory were not just the rationale underlying the major objections that continue to be alive but were also endowed with psychic properties, such as desire, waged against it. I begin by surveying the major incarnations of aversion, and memory (Hall, 1969, pp. 18–28). In any event, the idea biological atomism prior to cell theory, and by illustrating the that living particles are the basic building blocks of plants and ani- philosophical continuity between them. I will then consider the mals was widely discussed and even generally accepted during conceptual development of cell theory itself and highlight its much of the eighteenth century. For instance, the article on ‘animal atomistic foundations. Following this, I will examine the main crit- economy’ in Diderot’s Encyclopédie described the constituents of icisms of cell theory, categorizing them according to whether they plants and animals as ‘living atoms or organic molecules’ (Diderot, represent efforts to locate the true indivisible unit of life above or quoted in Grene & Depew, 2004, p. 88). below the level of the cell. I will conclude by reflecting more gen- One of Buffon’s contemporaries, the Swiss physiologist Albrecht erally on the philosophical value of biological atomism and on the von Haller, advanced a rather different atomistic theory of the consequences of this perspective for biology. organism—one that persisted in various forms well into the nine- teenth century: the fibre theory. Building on earlier ideas ex- 2. Biological atomism before cell theory pounded by Francis Glisson, Nehemiah Grew, and James Keill, Haller postulated that the fibre is the elementary unit of all living The roots of biological atomism can be traced back to the pop- bodies, famously asserting in his Elementa physiologiae corporis hu- ularization of corpuscular theories of matter and light by Sir Isaac mani (published in 1757) that the ‘fibre is for the physiologist what Newton in the late seventeenth and early eighteenth centuries. In the line is for the geometer’ (Haller, quoted in Toulmin & Goodfield, the rare instances when Newton theorized about life, he referred to 1962, p. 391). According to Haller, there is only one kind of fibre to chemical transformations, especially fermentation, which he ex- form all organs. It is the manner in which the fibres are arranged, plained in corpuscular terms (Hall, 1969, p. 18). One of the chief the texture of the network they form, and the quantity of liquid re- exponents of Newtonian natural philosophy in eighteenth-century tained by the mesh, that gives each organ its distinctive character- France was Georges-Louis Leclerc de Buffon, and it is to him that istics. Haller conceived fibres as the fundamental units of life, we owe the first explicit formulation of an atomistic theory of life. arguing that sensibility and irritability, the two sources of all vital Though originally trained in physics and mathematics (he pub- activity, are themselves properties of the constituent fibres of the lished a French translation of Newton’s Method of fluxions in body. 1740), Buffon made his most important contributions in biology. At the end of the eighteenth century, the French anatomist Xa- As a true Newtonian, Buffon endorsed the corpuscular conceptions vier Bichat distanced himself from Haller’s fibre theory, and in so of matter and light, and argued by inference that living matter doing developed an atomistic theory of his own.
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