ABSTRACT
One of the points upon which there was widespread agreement among the idéologues is that ‘beautiful and great idea that all the sciences and all the arts constitute an ensemble, an indivisible whole, or form the branches of the same single trunk, united by a common origin’ (Cabanis 1956, I:124). Similarly, Tracy argued that the arts were, in principle, inseparable from the sciences in the sense that the arts must be based upon the sciences, the principles of which they were applications (Tracy 1817–18, III:3). But the theoretical unity of knowledge did not, for the idéologues, mean that all scientific investigations ought to be carried out as if there were no important distinctions between the way in which objects were considered in different areas of study (Cabanis 1956, II:184). The proper organisation of knowledge and, in particular, the appropriate distinction between the sciences became an important area of investigation for the idéologues, and was approached in the same manner as all other classificatory schemes were to be approached: worthwhile as long as useful, and best derived from careful observation of the subject matter itself (see Tracy 1817–18, III:3ff.; Cabanis 1956, II:509ff.; see Kaiser 1976:491– 504). François-Xavier Bichat (1771–1802), despite his premature death, was an
important contributor to the physiology of the idéologues, to the medical history of the nineteenth century and to Tracy’s psychology of human beings. He was also responsible for the neologism ‘biologie’ in 1801 (Bichat 1801: 11). Strongly influenced by Pinel and Cabanis, Bichat published Traité des Membranes and Recherches Physiologiques sur la Vie et la Mort in 1800, and Anatomie Générale Appliquée à la Physiologie et à la Médecine in 1801.1 If one places to one side those phenomena that are the objects of the
physical sciences, Bichat argued, and to the other, those phenomena that are the subject matter of physiology, one would see an immense difference between the two sciences and between the laws that govern each set of phenomena. Physical objects are invariable, and subject to constant laws: gravity varies according to the square of the distances between objects, for example, everywhere and always. By contrast, living beings are subject to all the laws of physics, but also to laws that vary beyond anything apparent in the physical world: living beings are subject to laws relating to sensibility and movement. If one attempts to express matters of physiology in terms of the language of physics, Bichat argued, rather than clarify matters, one would muddle them beyond al l measure (Bichat 1852:310–12). Mechanical explanations and physical determinism simply do not allow one to understand the domain of life, and using the words of physics as an approximation is, Bichat claimed, not helpful. In fact, Bichat went further. If physiology rather than physics had developed first, he argued, one would expect to find physical phenomena explained in terms more appropriate to living matter: crystals
would attract one another by means of the ‘excitation’ that they would exert on each other’s sensibilities, and planets would move because they ‘irritate’ one another across great distances. This, he noted, is no more, and certainly no less, exact than talking about ‘doses’, ‘quantities’, ‘sums’, or ‘gravitation’, ‘attraction’ and ‘repulsion’ in physiology (Bichat 1852:57–9). The sciences, then, must be kept distinct even though there is a theoretical
unity of knowledge, because the phenomena, studied by physics and those that are the subject of physiology are subject to different laws. This distinction provided the basis for Bichat’s definition of life: all objects are subject to forces that tend to destroy them, and life is distinguished from non-life to the extent that its organisation resists disintegration. Put differently, life is that which resists death (Bichat 1852:1).
