Bonnet and Buffon: Theories of generation and the problem of species

Abstract

The theories of generation proposed by Georges Louis Leclerc, comte de Buffon, and by Charles Bonnet would normally be regarded as representative of the two extremes within the eighteenth-century debates concerning the generation of living organisms. Buffon's theory is often described as an "epigenetic" account of the development of the embryo, fundamentally opposed to Bonnet's system of "preformation." But these names are themselves confusing. Roger has noted that the latter term is quite inappropriate, suggesting that a more correct name for Bonnet's type of theory is the "pre-existence of germs." 1 In addition, Cole has observed that the term "epigenesis" is equally inappropriate when applied to Buffon's theory, since the latter explicitly rejected the original concept of epigenesis, in which the parts of the fetus are supposed to be produced one after another.2 The purpose of this present paper is to suggest that this confusion over names is merely symptomatic of an even deeper lack of appreciation of the real nature of the theories involved. It will be argued that Buffon and Bonnet were working within an essentially similar framework, and that this produced a surprising amount of similarity between their solutions to the problems which they envisaged. In particular, I shall examine the ways in which the two workers related their ideas on generation to their beliefs about the