Thus, a determinate entity does not have two causes, one for its species and another for its individual being. Rather, the cause that necessitates its individual being suffices for its existence, just as with something whose species is confined to a single individual.

His statement, “There cannot, then, be two instances of blackness or two instances of whiteness in reality if the difference between them lies in the subject or something that serves the same function,” amounts to saying, “There cannot be two instances of blackness unless each inheres in a substrate.” Likewise, a single instance of blackness cannot exist without a substrate in which it inheres. If it is said that two instances of blackness require two substrates, just as a single instance also requires a substrate, this is because blackness must have a substrate. Two instances of blackness cannot be conceived without two substrates, just as blackness cannot be conceived as existing without a substrate. Whatever does not require a substrate does not require one for its multiplicity, just as a single instance of it does not require one. Individuation is like unity, and multiplicity is like plurality. Number and unity have no existence in external reality apart from the things that are counted and those that are one. Unrestricted number, unrestricted unity, and unrestricted individuation exist only in minds, not as concrete entities, just like all other unrestricted notions.

On this account, the determinate necessary existent has neither a cause nor a reason for its individuation, just as it has neither a cause nor a reason for its existence. Nor does there exist in external reality any individuation additional to its own determinate self, whether positive or negative, such that one could say that this