The structure of developmental time: epistemology and metaphysics in the embryological theories of Harvey, Malebranche, and Buffon

Boris Demarest

Ghent University

This paper will argue that the differences between major embryological theories in the early modern life sciences are primarily due to major epistemological differences of opinion other than those on the acceptability of mechanical or vitalist explanation that are now commonly assumed to be the major issue at stake. To this end, it will show how the conflicting views of William Harvey, Nicolas Malebranche and Georges Buffon on explanation in embryology are largely due to their diverging views on the structure of time. The first section will discuss the relation between Harvey’s version of epigenesis and his cyclical view of time, as well as his views on observation in the sciences. It will argue that Harvey’s position is not so much vitalist as it is a position on the kind of structure exhibited by living systems, i.e. essentially reproductive systems that are best grasped through cyclic patterns. Additionally, it will attempt to explain his infamous denial of the usefulness of microscopes and telescopes in science by showing how this is prompted by his view on explanation. The second section will contrast Harvey’s perspective with Malebranche’s programmatic ovist preformationism, showing that their difference in opinion is not just on the merits of mechanical explanation, but on the nature of time and the structures observations acquaint us with. Malebranche clearly differs in Harvey in associating circular movement with vicissitude and chaos rather than with stability and eternity. Additionally, a closer look at his conceptions of time and space (and their peculiar connection) will allow for a re-evaluation of his praise for the microscope and the telescope. The third section will concentrate on the relation between Buffon’s embryological theories and his species concept. In this analysis, it will concentrate on (1) the empiricist background of Buffon’s arguments against preformation; (2) the conception of the temporal series behind his species concept (against Sloan’s identifying Harvey’s and Buffon’s views); and (3) the link with Buffon’s arguments surrounding the effects of microscopes in observation. The paper will conclude by showing how this picture sheds new light on the mechanism-vitalism debate in the early modern life sciences and its role in contemporary discussions on biological explanation.