"Bonald" comments (link via the Western Confucian) on the same article by Stephen Barr which I wrote on here: "The example he gives is the band structure in metals. This is certainly formal, although metals don’t have the intrinsic teleology or indivisible unity of biological substantial forms. What we need is a sort of weaker idea of form for this lower order of being, one without teleology."

Is a pure body of water, or a metal lattice a substance? Or just a group of individuals? Or something in between?  Associations other than substantial unities have form, but it is an accidental form, not a substantial form. But an accidental form will have some sort of teleology. But it should also be said that discerning the end of something can be difficult for us, especially if we are trying to determine remote ends rather than proximate ends. But I do not think that is the problem we have with electronic band structure, since we are looking at potencies and actualities of parts of a whole. How much can a part be actualized before it is no longer a part of that whole? It seems to me that electronic band structure is just the quantification of those actualities. (James Chastek has this relevant post: Quantitative and logical parts.)