Spurious Causal Kinds: A Problem for the Causal-Power Conception of Kinds

There is an assumption common in the philosophy of mind literature that kinds in our sciences—or causal kinds, at least—are individuated by the causal powers that objects have in virtue of the properties they instantiate. While this assumption might not be problematic by itself, some authors take the assumption to mean that falling under a kind and instantiating a property amount to the same thing. I call this assumption the “Property-Kind Individuation Principle”. A problem with this principle arises because there are cases where we can sort objects by their possession of common causal powers, and yet those objects do not intuitively form a causal kind. In this short note, I discuss why the Property-Kind Individuation Principle is thus not a warranted metaphysical assumption.