Here I engage in a questing argument. It is in the form of an argument, yet through it I seek to provisionally delineate how to respond more forcefully to those who suppose that matter “contains” its structure such that talk of “form” is bogus non-sense.
If one explains unity (form/identity/structure) in terms of material immanence, then we may ask what generates that unity. It must be either something within or without (outside) that thing. If it is without, is it a singular source or multiple? If it is singular, we are on the way to a form of Platonism. Either that source emanates form (one direction of causality) or the matter yearns for form (the other direction). If the source is multiple, then we may be on our way to process philosophy of some sort. If the source is within, then then we may ask if there is some internal potentiality that generates it. This leads to a problem, if the source of something's unity or form is always within, then everything must be atomic and autonomous. But that means that either everything contains within itself the potentiality to be all things, or that each thing is unique in its potentiality. In either case, problems result since explaining the source or differentiations of these potentialities or "seeds" is problematic. Finally, if we try to split the difference between these two and suppose a combination of internal and external causality, then we still have the problem of unity. I hold this last view, wherein the focal problem is to explain “emergence,” e.g., how potentialities and then actualities come to be without positing a mechanistic account.
If possibility is real and primordial, then there must be some limitation on pure possibility else all would be chaos and persistent structure would be impossible. This limitation can be understood to be in some sense external to the thing. (I border on the fallacy of simple location merely to be better understood.) The source of cosmic order must be in some way external to the thing, else we must suppose that every singular thing contains these principles. By the abductive criterion of simplicity, I dismiss that. Sorry, Leibniz. What is internal to the thing, in some sense, if its cosmic limitations are not? Its principle of generativity, its "powers." Hence, we see here that there is a diremption of the source of cosmic order and generativity. If we do not separate these two, then philosophies of necessity and mechanism appear to be the result.
After establishing all of this, we can loosen the binaries that I have presented; I have presented it as binaries merely for ease of communication. As we slowly move away from this provisional structure and into a fuller articulation, I would note that unity (form/identity/structure) is a habit in my view. The structural and characteristic tendencies that the cosmos places upon any particular event are just that—strong tendencies. A local event can violate natural laws on this view, which is another way of saying that chance is real and primordial. There is a level of discussion above describing cosmic structure, and that is asking the question of cosmogenesis, which is a special case of ontogenesis. That is something that I am still thinking through and for which I recommend reading Matt’s work at Footnotes2plato.