Abstract
Aristotelian philosophers have been always puzzled by the ambiguous status of essences: it is not clear whether an Aristotelian should admit that an essence, taken in itself, is real, even though essences do not exist over and above particular things, as Platonists posit; furthermore, it is not clear whether an Aristotelian should endorse the view that essences have a certain unity, even if they are taken in themselves, namely, by abstracting from the individuals of which they are essences. I tackle Thomas Cajetan’s analysis of this problem: this analysis is more sophisticated than that developed by Aquinas—whose texts had been commented upon by Cajetan. Cajetan distinguishes two senses of “real” and of “unity,” in order to speak of the reality and of the unity of essences, taken in themselves, though not endorsing a Platonist’s ontology. I suggest that his solution is appealing for the contemporary debate about this problem.