Rather, these are simply names applied to the one and same human being; each name points to one of his attributes, while the referent described by them is a single substance, not multiple substances.

It is therefore evident that your claim that the extra-mental human being is compounded of “this and that” is false, no matter how you frame it. And if you say that such composition exists only in the mind, we reply: a mental composition is nothing but what the intellect conceives and posits. Whoever fails to distinguish between entities that exist in the external world and notions fabricated by the mind stands outside the domain of knowledge, lost in the wilderness of ignorance and error.

This is precisely the condition of many of them: mental images have become confused with objective realities, so they imagine what is in their minds to be firmly established in the external world. Most of what you claim to be “intellectual truths”—universals and abstractions such as the Ten Intellects, prime matter, and the like—are mental constructs, not external existents.

In their so-called “higher science” and “first philosophy” they divided being into substance and accident, assigned nine genera to accidents—as their first teacher Aristotle stated—and called these the Ten Categories. They then made substance a genus comprising five species: (1) the Ten Intellects, (2) souls, (3) matter, (4) form, and (5) body. They even disputed whether the Necessary Existent should itself be called a substance, holding two divergent opinions on the question.

As for the four—Intellects, souls, matter, and form, the last two of which they regard as the constituent parts of body—when the matter is scrutinized, they prove to be merely conceptual notions devised by the mind, with no existence in external reality, unlike body itself, which truly exists.