Francisco de Toledo on Elemental Mixtures

How do uniform bodies like wine, oil, and flesh originate in nature from the four elements? This basic question about the constitution of physical substances was the object of a harsh debate that lasted for centuries. Its main issue was the process of mixing. When the four elements are put together under certain favourable conditions, they cause something ‘new’ that displays additional dispositional properties and a novel structure. Yet how is it possible? And what happens to the elements when they are mixed? In this chapter, I analyse how the Spanish philosopher Francisco de Toledo (1532–1596) engaged with these and further questions about mixtures. First, I examine Aristotle’s treatment of the problem in GC I.10 and four crucial clauses that he introduces to explain how mixing happens, which become the blueprints of Toledo’s own theory. Second, I analyse Toledo’s arguments in favour of the complete destruction of the elemental forms upon mixing, which allow him to maintain that the persisting factor required by mixing is expressed by (prime) matter. Third, I discuss Toledo’s arguments in favour of the persistence of the elemental qualities in the mixture as numerically identical. This stance provides a better fulfilment of the persistence clause established by Aristotle and relies on a neat distinction between prime and proximate matters. Finally, I draw my conclusions on Toledo’s theory of mixtures.