Though there is yet no consensus on the right way to understand ‘physicalism’, most philosophers agree that, regardless of whatever else is required, physicalism cannot be true if there exists fundamental mentality. I will follow Jessica Wilson (Philosophical Studies 131:61–99, 2006) in calling this the 'No Fundamental Mentality' (NFM) constraint on physicalism. Unfortunately for those who wish to constrain physicalism in this way, NFM admits of a counterexample: an artificially intelligent quantum computer which employs quantum properties as part of its (...) cognitive operations. If one of these quantum properties serves a proper functional role in the artificial intelligence, then that property counts as a mental under the physicalism-friendly theory of mentality called “realizer functionalism”, which says that a lower-order property is mental if it satisfies an appropriate higher-order functional description. Further, if this quantum property is both fundamental and mental, then NFM must rule that it is not physical. Yet the existence of such an artificially intelligent quantum computer, which possesses mental properties solely in virtue of the functional roles those properties play, is surely consistent with the truth of physicalism. This ought to motivate NFM proponents to reformulate their view. (shrink)

Extensional articulations of physicalism define what it means to be physical relative to the properties of a set of entities, such that physicalism is true if the fundamental properties which compose the entities in this set are the same sorts of fundamental properties which compose everything that exists. Here I present a novel problem for these articulations of physicalism: they are consistent with phenomenal idealism, which is the view that only phenomenal properties exist. Under this view, paradigm physical objects such (...) as tables and chairs are constructed out of more basic phenomenal properties. Since this view says that everything—including paradigm physical entities—is ultimately constituted by phenomenal properties, it follows that this view is consistent with extensional definitions of physicalism, since such definitions only require that there be no fundamental difference between paradigm physical entities and everything else. Yet a good definition of physicalism should not be consistent with phenomenal idealism. (shrink)