 Shirley Roe’s discussion of the eighteenth-century debates is an excellent examination of the context. Enthusiasm for scientific study of natural phenomena of all sorts was combined with particular interest in natural history and changes over time and with newly available microscopic methods to stimulate interest in development (Roe 1981). Aristotelian epigenesis still provided the background assumptions about individual development as the eighteenth century began, and researchers sought to observe the gradual emergence of form from non-form. Yet Aristotelian accounts called for the efficacy of the causes, acting through the process of ensoulment. In effect, this interpretation of epigenesis depended on a life force within the organism driving its emergence of form. Those who accepted epigenesis also accepted a form of vitalism (see Detlefsen 2006, Zammito 2018 for more on early modern vitalism debates).