From the way in which it has to account for what a human being is, since it has to make “body” or his “material parts” into a thing.
This is why I get rather bothered by the phrase “hylomorphic dualism”. If we say “HD and SD both believe man comes to be from two different things” we are equivocating badly on what is exactly the relevant point: that in hylomorphism matter and form are not material things, and if they were they would not solve the very problem that they were intended to solve. Saying that matter and form in hylomophism are two things is like saying that one is holding two things if he is holding a baseball and its roundness. Such a distinction does not give rise to an enumeration or multitude.
I think this lesson is crucial because matter is one of our first tutors of the idea that not every division or distinction gives rise to some multitude or enumeration. Substance and accident do not make two things; neither do matter and form, neither do creatures and God (though these things are not all “not many” in different ways – I’m not advocating pantheism but the sense that God cannot be simply enumerated among, say, existing things.)
If one had to use the term “dualism” when speaking of hylomophism, it would be better to call it hylomorphic non-dualism or even hylomorphic anti-dualism. It’s anti-monism too, so maybe we could call it anti-dualmonism, since hylomophic theory denies that one must choose between monism and dualism (or pluralism). This is one of the main points of Physics Book I – the problem was that until Aristotle principles were conceived as things, which led either to a monism that collapsed all things into one, or some other theory that couldn’t explain why things are one.
I believe that dualism and materialism are false. After all, materialism is only nineteenth century science and dualism is the belief that this is inadequate to explain mind – no surprises there. In the twenty first century we can now be certain that we know very little so do not need dualism, however, we can have faith that there is sense out there because we have found a little bit of it.