 There is an exegetical problem with ascribing this final way of understanding composition to Aristotle, and that is that it apparently conflicts with the view that he expresses in Metaphysics viii 6, 1045a7–10, and vii 17, 1041a26, that a form is what unifies a compound. The problem is how to understand the role of the time in the unification of the compound by the form: it cannot be just another element to be unified, for the time at which the matter exists does not figure as a part of the resulting unity. If we try to make the form unify a given portion of matter into many different things, depending on what time the unifying takes place at, we also run into the difficulty that such a process no longer seems worthy of the title “unification”, since the result is many objects, not just one. Indeed we can reformulate the problem without mentioning composition at all: if a common form must unify common matter into one and the same thing, and Socrates and Callias have the same form and the same matter, they are one and the same. Since Aristotle (and many neo-Aristotelians) would surely be unwilling to give up the unifying role of form, this does not look like a viable solution.