Epigenesis as Spinozism in Diderot’s Biological Project

Diderot’s natural philosophy, which emerges some decades prior to the appearance of the term ‘biology’ in the 1790s, is profoundly ‘biologistic’. Both the metaphysics of vital matter in D’Alembert’s Dream and the more empirical concern with physiology in his unpublished Elements of Physiology display a fascination with the uniqueness of organisms. This ‘biologism’ presents Diderot’s interpreter with some difficulties, notably regarding his materialism, for contemporary forms of materialism reject emergence, vitalism, teleology or other appeals to biological irreducibility. Here I examine a little-known aspect of Diderot’s proto-biological project: his association of epigenesis with Spinozism in the short article “Spinosiste.” Why defend a particular developmental theory in an entry on Spinoza (who was barely concerned with the specific properties of organisms)? My response also addresses the relation of Diderot’s biological project to biology as a science that appeared after his death. Indeed, Diderot’s ‘epigenetic Spinozism’ stands conceptually outside the history of biology.