The naturalistically inclined philosopher of mind faces two related challenges: (1) show how mental content could be part of the natural world, and (2) show how content can be one of the factors responsible for producing (causing) behaviour, that is, show that content is not epiphenomenal. One might pursue the first goal with the intent of showing that mental content is epiphenomenal, but it is more likely that the philosopher concerned with showing how content can be naturalized also expects content (...) to be causally efficacious. Indeed, why pursue the first challenge while holding that content is epiphenomenal? Thus these two challenges overlap: show how content can be naturalized without making content epiphenomenal. (shrink)