Abstract
Philosophers look to the realization relation as a way to make sense of the possibility that special science kinds are physical, yet not reducible to kinds in physics. A realized property fails to reduce because it can be realized in multiple ways, thus blocking its identification with lower-level properties. One prominent analysis of realization, subset realization, distinguishes multiple realizers on the basis their “left-over powers,” that is, those that don’t contribute to the individuative powers of the realizer. However, I argue, the subset analysis of realization fails to mark an important distinction between different ways that a property might be realized, and also makes questions about the reducibility of kinds—presumably an empirical issue—tractable from the armchair. I offer as an alternative mechanistic multiple realization, which avoids both these problems.