Online research in philosophy

This paper is about the causal exclusion argument against non-reductive physicalism. Many philosophers think that this argument poses a serious problem for non-reductive theories of the mind — some think that it is decisive against them. In the first part I will outline non-reductive physicalism and the exclusion argument. Then I will distinguish between three versions of the argument that address three different versions of non-reductive physicalism. According to the first, the relation between mental and physical events is token-identity. According to the second, mental events are distinct from physical events, but the latter metaphysically include and determine the former. And on the third version, mental and physical events are entirely distinct. I will argue that the causal exclusion argument is not decisive against non-reductive physicalism in any of the three versions. According to non-reductive physicalism, mental events are dependent on physical events. Causal exclusion and overdetermination, however, requires distinct and independent causes. I will argue that the burden of proof lies with the opponents of non-reductive physicalism, who have to explain how metaphysically dependent events can possibly overdetermine an effect or exclude each other from being causally efficacious.

The importance of the exclusion argument for contemporary physicalism is emphasized. The recent attempts to vindicate reductive physicalism by invoking certain needed revisions to the Nagelian model of reduction are then discussed. It is argued that such revised views of reduction offer in fact much less help to reductive physicalism than is sometimes supposed, and that many of these views lead to trouble when combined with the exclusion argument.

This paper is a defence of Terence Horgan’s claim that any genuinely physicalist position must distinguish itself from (what has been traditionally known as) emergentism. I argue that physicalism is necessarily reductive in character -- it must either give a reductive account of apparently non-physical entities, or a reductive explanation of why there are non-physical entities. I argue that many recent ‘nonreductive’ physicalists do not do this, and that because of this they cannot adequately distinguish their view from emergentism. The conclusion is that this is the real challenge posed by Joseph Levine’s ‘explanatory gap’ argument: if physicalists cannot close the explanatory gap in Levine’s preferred way, they must find some other way to do it. Otherwise their view is indistinguishable from emergentism.

In this paper I compare two versions of non-eliminative physicalism (reductive physicalism and supervenience physicalism) with four of the five theses of classical theism: divine non-contingency, divine transcendence, divine simplicity, and the aseity thesis. I argue that:1. Both physicalism (either version) and classical theism require intuition-transcending identifications of some properties or possibilities.2. Among other identifications, both reductive physicalism and classical theism need to identify psychological with functional properties.3. Both reductive physicalism and classical theism have a problem with consciousness.4. Both reductive physicalists and classical theists should distinguish fine and coarse grained theories of properties.

I outline reasons for the recent popularity, and lingering suspicion, about 'emergence' by examining three distinct concepts of property emergence, their purposes and associated obligations. In Part 1, I argue 'Strong' emergence is the grail for many emergentists (and physicalists), since it frames what is needed to block the 'Argument from Realization' (AR) which moves from the truth of physicalism to the inefficacy of special science properties. I then distinguish 'Weak' and 'Ontological' emergence, in Part 2, arguing each is a way one may fail to establish the possibility of Strong emergence. But I also show Weak emergence can help the full-blown reductionist and Ontological emergence helps those opposed to physicalism. Lastly, in Part 3, I argue that the Completeness of Physics (CoP) is incompatible with Strong emergence and that rejecting CoP provides hope for the possibility of Strong emergence in a physical world. The result is a notion of Strong emergence offering much to non-reductive physicalism. My final conclusion is that concepts of emergence, when properly understood, have important contributions to make to philosophical debate.

Can physicalism (or materialism) be non-reductive? I provide an opinionated survey of the debate on this question. I suggest that attempts to formulate non-reductive physicalism by appeal to claims of event identity, supervenience, or realization have produced doctrines that fail either to be physicalist or to be non-reductive. Then I treat in more detail a recent attempt to formulate non-reductive physicalism by Derk Pereboom, but argue that it fares no better.

This paper is an attempt to understand the content of, and motivation for, a popular form of physicalism, which I call ‘non-reductive physicalism’. Non-reductive physicalism claims although the mind is physical (in some sense), mental properties are nonetheless not identical to (or reducible to) physical properties. This suggests that mental properties are, in earlier terminology, ‘emergent properties’ of physical entities. Yet many non-reductive physicalists have denied this. In what follows, I examine their denial, and I argue that on a plausible understanding of what ‘emergent’ means, the denial is indefensible: non-reductive physicalism is committed to mental properties being emergent properties. It follows that the problems for emergentism—especially the problems of mental causation—are also problems for non-reductive physicalism, and they are problems for the same reason.