In 75.7, Thomas argues that the intelletual soul is not of the same species as an angel, because it is a substantial form of an animal.
He outlined a number of reasons why they were jointly opposed to describing the human mind as a substantial form.
Living corporeal substances are subject to death through the corruption of their substantial unity not so much the separation of soul from body, but the dissolution of the soul as the substantial form of the body.
A substantial form is the essence of a substance, and it corresponds to a species.
A substantial form, as a primary definable, is its own substance, for it is essentially predicated of itself alone.
He asserts that the substantial nature of the physical world is the unknown structure of atomic parts, not a substantial form which reflects our usual concepts.
Sibiani's colleague Prof Abdulrahim Rouzi said he knew of a case in which a newly married woman bled to death as a consequence of this more substantial form of FGM.
In that sense, any substantial form whatsoever will be immaterial, including the substantial form of an oak tree or the substantial form of a dog.
Thus, in On Light he holds the firmament or outermost heavenly sphere to be the most simple body, as it is composed simply of first matter and first form, but in his commentary on the Physics he speaks of the element fire as having in addition to first form the substantial form of fire.
According to one, Aristotle's substantial forms are not universals after all, but each belongs exclusively to the particular whose form it is, and there are therefore as many substantial forms of a given kind as there are particulars of that kind.
