Epistemology & Philosophy of Science

Volume 44, Issue 2, 2015

Blockers: A Reply to Hawthorne

Physicalism is roughly the thesis that everything is physical. The two most popular ways of formulating physicalism rigorously are the ways given by Frank Jackson and David Chalmers. The best objections, in turn, include John Hawthorne’s ‘blocker’ objections. Hawthorne argues that, if it is possible for there to be non-physical beings or properties that prevent certain mental phenomena from existing (i.e., non-physical blockers), Jackson’s and Chalmers’ formulations will be inadequate. Jackson’s formulation will be inadequate by virtue of not capturing all of the right physical dependence principles. Chalmers’ formulation will be inadequate in so far as, when modified to define ‘restricted physicalisms’, such as physicalism of the mental, the restricted formulations will not capture all of the right physical dependence principles. By contrast, I argue that Hawthorne’s blocker arguments are misguided on the grounds that non-physical blockers are impossible; I argue that his critique of Chalmers’ formulation is unsound by virtue of falsely presupposing that restricted physicalisms require restricted formulations of physicalism (I argue that it is only necessary to define physicalism of a world); and I argue that Jackson’s and Chalmers’ formulations capture all of the right physical dependence principles.