Abstract

Francis of Marchia (c. 1290-1344) is said to have challenged Aristotelian orthodoxy by uniting the celestial and terrestrial realms in a way that has important implications for the practice of natural philosophy. But this overlooks Marchia's vital distinction between bare potentiality, which is actualizable only by God, and natural potency, which is the concern of the natural philosopher. If due attention is paid to this distinction, Marchia's position no longer seems to be revolutionary.