Abstract

This essay proposes to discuss the manner in which Jan Baptista van Helmont helped to transform the Neoplatonic notions of vital spirit and of ferment by giving these notions an unambiguously chemical interpretation, thereby influencing the eventual naturalization of these ideas in the work of late seventeenth century chymists. This chemical interpretation of vital spirit and ferment forms part of Helmont’s hybrid ontology, which fuses a corpuscular conception of minima naturalia with a non-corporeal conception of semina rerum. For Helmont, chemical alterations involve the minima as physical units but also depend upon ferments that are contained in the semina, which function as formative spiritual agents. Helmont’s nuanced ontology ultimately contributes to the development of modern corpuscularian theory by explaining many chemical reactions in fundamentally corpuscular terms, as the addition and subtraction of particles.