How Are Form and Matter Related in Compound Material Substances?

Favoring as I do constituent ontology, I am sympathetic to that type of constituent ontology which is hylomorphic ontological analysis, as practiced by Aristotelians, Thomists, et al.  The obscurity of such fundamental  concepts as form, matter, act, potency, substance, and others is, however, troubling. Let's see if we can make sense of the relation between form and matter in an artifact such as a bronze sphere. Now those of you who are ideologically committed to Thomism may bristle at an exposure of difficulties, but you should remember that philosophy is not ideology. The philosopher follows the argument to its conclusion whether it overturns his pet beliefs or supports them, or neither. He knows how to keep his ideological needs in check while pursuing pure inquiry.  If the inquiry terminates in an aporetic impasse, then so be it.

1. Although it perhaps requires arguing, I will here take it for granted that form and matter as these terms are used by Aristotle and his followers are items 'in the real order.' 'Item' is a maximally   noncommittal term in my lexicon: it commits me to very little. Anything in whatever category to which one can refer in any way  whatsoever is an item. 'Real' is that which exists whether or not it is an intentional object of an act of mind. So when I say that form and matter are items in the real order I simply mean that they are not projected by the mind: it is not as if bronze spheres and such have  form and matter only insofar as we interpret them as having form and matter. The bronze sphere is subject to hylomorphic (matter-form) analysis because the thing in reality is made up of form and matter.   'Projectivism' is off the table at least for the space of this post. I am thus assuming a version of realism and am viewing form and matter as distinct ontological constituents or 'principles' of compound   substances.

2. The foregoing implies that the proximate matter of the bronze sphere,  namely, the hunk of bronze itself, is a part of the bronze sphere.  After all, 'ontological constituent' is just a fancy way of saying  'ontological part.'  But an argument I now adapt from E. J. Lowe ("Form Without Matter" in Form and Matter: Themes in Contemporary  Metaphysics, ed. Oderberg, Blackwell 1999, p. 7) seems to show that  the notion that the proximate matter of a compound material substance is a part of it is problematic.  The argument runs as follows.

A. If the hunk of bronze composing the sphere is a part of the sphere, then either it is a proper part or it is an improper part, where an improper part of a whole W is a part of W that overlaps every part of   W.

B. The hunk of bronze is not an improper part since it is not identical to the bronze sphere. (One reason for this is that the persistence conditions are not the same: the piece of bronze will still exist if the sphere is flattened into a disk, but the sphere cannot survive such a deformation. Second, the two are modally discernible: the hunk of bronze is a hunk of bronze in every possible world in which it exists, but the hunk of bronze is not a sphere in every possible world in which it exists.)

C. The hunk of bronze is not a proper part of the bronze sphere since there is no part of the bronze sphere that it fails to overlap.

Therefore

D. The hunk of bronze is not a part of the bronze sphere.

Therefore

E. The composition of form and matter is not mereological. (Lowe, p. 7)

This raises the question of how exactly we are to understand form-matter composition. If the proximate matter of a substance cannot  be a part of it in any sense familiar to mereology, the form-matter composition is 'unmereological,' which is not necessarily an objection except that it raises the question of how exactly we are to understand this unmereological type of composition. This problem obviously extends to essence-existence composition.

3. Now let's look at the problem from the side of form. Could the spherical form of the bronze sphere be a part of it? A form is a principle of organization or arrangement, and it is not quite clear how an arrangement can be a part of the thing whose other parts it arranges. Lowe puts the point like this: ". . . the arrangement of certain parts cannot itself be one of those parts, as this would involve the very conception of an arrangement of parts in a fatal kind of impredicativity." (p. 7)

4. In sum, the difficulty is as follows. Form and matter are real 'principles' in compound substances. They are not projected or supplied by us. We can say that form and matter are ontological constituents of compound substances. This suggests that they are parts of compound substances. But we have just seen that they are not parts in any ordinary mereological sense. So this leaves us in the dark as to just what these 'principles' are and how they combine to constitute compound material substances.