Jean Fernel and William Harvey on Seeds

Abstract. The analogy of the seed is an ancient and omnipresent feature of theories of generation in the history of philosophy. The basic idea is that animals emit seeds that are like those of plants, these seeds containing some power or force for development. In this essay, I compare and contrast the use of this analogy in two influential philosopher physicians: Jean Fernel (1497-1558) and William Harvey (1578-1657). I characterize Fernel’s account as compositional, focusing on the nature of seeds and what they contain, namely, the innate heat (calor innatus) and spirit (spiritus). While Harvey’s theory is similar in that he, too, thinks that this heat is key to understanding the process of generation, his use of the seed analogy is functional--he focuses less on what seeds contain and more on the fact that the ‘seed’ is a stage in the teleological process of reproduction. That is, while Fernel focuses on seeds as a vehicle for spiritus, Harvey concentrates on the fact that seeds are always paired with fruits, setting up a system of hypothetical necessities within a teleological system of directed development toward the creation of the living offspring. The two thinkers also differ on the nature of the power of the heat, Fernel evincing a Platonic position that requires the heat in the seed partake of a superior, Divine body (spiritus), while Harvey maintaining an Aristotelian position that locates the direct instrument of soul directly to the heat of the blood. While these differences are important, I also argue that there is a fundamental congruence between their theories of the seed insofar as both emphasize the need for seeds to act beyond their elemental natures. Both philosophers thus elevate the status of the vegetative soul, articulating how it is superior to the rational soul insofar as it can create the structure and function of a living being.