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)

Regardless of whatever else physicalism requires, nearly all philosophers agree that physicalism cannot be true in a world which contains fundamental mentality. I challenge this widely held attitude, and describe a world which is plausibly all-physical, yet which may contain fundamental mentality. This is a world in which priority monism is true—which is the view that the whole of the cosmos is fundamental, with dependence relations directed from the whole to the parts—and which contains only a single mental system, like (...) a brain or computer. Because some properties of the whole are fundamental under priority monism, it follows that that the mental properties of a cosmos-encompassing brain or computer system may be fundamental in a priority monist world. Yet such a world need not contain anything physically unacceptable: the mental properties of the cosmos-encompassing brain or computer can be characterized in a physicalism-friendly functionalist or identity-theoretic way. Thus, as I see it, physicalism need not be false in such a world. This constitutes a challenge to those who hold the view that physicalism is inconsistent with the existence of fundamental mentality. (shrink)

Jaegwon Kim maintains that his ‘exclusion argument’ forces us to accept reductive physicalism, which identifies mental and other high-level properties of the world with lower-level properties, over nonreductive physicalism, which avoids such identifications. According to Kim, the exclusion argument shows that any nonreductive view leads to either epiphenomenalism or unacceptable overdetermination of physical effects by physical causes. However, a popular nonreductive physicalist approach called ‘compatibilism’ aims to show that physicalism need not collapse high-level properties into lower-level physical. Compatibilism attempts to (...) block the exclusion argument by attending to the tight modal relationship between higher and lower properties required by nonreductive physicalism. Unfortunately, a similarly tight modal relationship will be embraced by any dualists who hold that natural laws are metaphysically necessary. Despite its increasingly widespread popularity among nonreductive physicalists, it thus seems that the compatibilist’s proposed solution cannot be upheld without removing the barriers to dualists of this sort. (shrink)

How could physicalism be true of a world in which there are no fundamental physical phenomena? A familiar answer, due to Barbara Gail Montero and others, is that physicalism could be true of such a world if that world does not contain an infinite descent of mentality. Christopher Devlin Brown has produced a counterexample to that solution. We show how to modify the solution to accommodate Brown’s example: physicalism could be true of a world without fundamental physical phenomena if that (...) world does not contain an infinite descent of mentally constituted mentality. This solution is independently plausible and is available to physicalists of virtually all significant varieties. (shrink)

Physicalism should be characterized in a way that makes it compatible with the possibility that the physical world is infinitely decomposable. Some have proposed solving this problem by replacing a widely accepted No Fundamental Mentality requirement on physicalism with a more general No Low-Level Mentality requirement. The latter states that physicalism could be true if there is a level of decomposition beneath which nothing is mental, whereas physicalism is false otherwise. Brown argues that this solution does not work. He devises (...) an infinitely decomposable possible world in which physicalism should come out as true even though there is mentality all the way down. I propose a solution that circumvents his argument. The key is to specify the sort of mentality that physicalism cannot abide at any level, namely, mentality that does not consist solely in a structural-dynamic arrangement of entities. I also argue that the problem Brown identifies has significant implications for what is at stake in the debate over physicalism’s truth or falsity—implications he undersells. (shrink)

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)