 One account of (weak) emergent dependence is just this sort of functional realization. A concomitant of such a functionalist approach is that any token power (i.e., particular instance of it) associated with a weak emergent feature will be identical to a token power of its realizer (Wilson 1999, 2015). This will render emergence compatible with the physicalist thesis of physical causal closure. However, if properties have non-causal quiddities—primitively individuating aspects that are the property equivalent of individual haecceities—additional to their causal powers, then token identity of powers will not necessarily guarantee that a functionally realized emergent property is dependent on its lower-level base in a way compatible with physicalism (Melnyk 2006). (It has become common in recent metaphysics to invoke a primitive notion of “grounding” relating the more fundamental to the less fundamental, so the reader may be surprised not to see it listed as a distinct option here. The reason is two-fold: it is not often used by theorists of emergence, and it is a generalized notion that encompasses the present, more specific notion of functional realization. For discussion of the relative merits of deploying more specific notions or a more general unifying notion in discussions of forms of ontological dependence, see the exchange between Wilson 2014 and Schaffer 2016.)