In chapter 3 of The Powers Metaphysic, Neil Williams presents a nice problem for dispositionalists: the "problem of fit".
Dispositionalists hold that there are fundamental dispositional properties. Now consider a particular rock and a particular glass. The rock might have a disposition to break the glass when thrown at it. And the glass might have a disposition to survive impact of the rock. These dispositions are incompatible: if the rock is disposed to break the glass, the glass can't be disposed to survive the impact. But if dispositions are fundamental, then what prevents the rock and the glass from having the incompatible dispositions? The dispositionalist seems to require a mysterious ban on recombination.
Necessitarian and dispositionalist accounts of laws of nature have
a well-known problem with "global" laws like the conservation of
energy, for these laws don't seem to arise from the dispositions of
individual objects, nor from necessary connections between fundamental
properties. It is less well-known that a similar, and arguably more
serious, problem arises for dynamical laws in general, including
Newton's second law, the Schrödinger equation, and any other law
that allows one to predict the future from the present.
So I was given a replacement computer now until the other one arrives. If you're waiting for a sign of life from me, I'll probably contact you soon.
But first some philosophy. I want to argue that necessitarianism is compatible with Humean recombinatorialism because powers aren't intrinsic in the sense relevant to this. I also want to suggest that in an ontology of powers, what's fundamental aren't really the powers, but the causal or nomic relations.
Necessitarianism is the view that properties like mass and spin have their causal or nomic role essentially: if a property doesn't behave like mass, it isn't mass. It follows that the laws about mass are metaphysically necessary. (There are many different views in the vicinity here, maybe more about this later.)