Online research in philosophy

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.

In this paper I want to discuss the way in which physical science has come to claim a particular kind of hegemony over other subjects in the second half of this century. This claim to hegemony is generally known by the name of "physicalism". In this paper I shall try to understand why this doctrine has come to prominence in recent decades. By placing this doctrine in a historical context, we will be better able to appreciate its strengths and weaknesses.

In this paper we distinguish two issues that are often run together in discussions about physicalism. The first issue concerns levels. How do entities picked out by non-physical terminology, such as biological or psychological terminology, relate to physical entities? Are the former identical to, or metaphysically supervenient on, the latter? The second issue concerns physical parts and wholes. How do macroscopic physical entities relate to their microscopic parts? Are the former generally determined by the latter? We argue that views on these two issues are independent of one another and should not be conflated.

Some claim that Non-reductive Physicalism (NRP) is an unstable position, on grounds that NRP either collapses into reductive physicalism (contra Non-reduction ), or expands into emergentism of a robust or ‘strong’ variety (contra Physicalism ). I argue that this claim is unfounded, by attention to the notion of a degree of freedom—roughly, an independent parameter needed to characterize an entity as being in a state functionally relevant to its law-governed properties and behavior. I start by distinguishing three relations that may hold between the degrees of freedom needed to characterize certain special science entities, and those needed to characterize (systems consisting of) their composing physical (or physically acceptable) entities; these correspond to what I call ‘reductions’, ‘restrictions’, and ‘eliminations’ in degrees of freedom. I then argue that eliminations in degrees of freedom, in particular—when strictly fewer degrees of freedom are required to characterize certain special science entities than are required to characterize (systems consisting of) their composing physical (or physically acceptable) entities—provide a basis for making sense of how certain special science entities can be both physically acceptable and ontologically irreducible to physical entities.

Recent discussions of physicalism have focused on the question how the physical ought to be characterized. Many have argued that any characterization of the physical should include the stipulation that the physical is non-mental, and others have claimed that a systematic substitution of ‘non-mental’ for ‘physical’ is all that is needed for philosophical purposes. I argue here that both claims are incorrect: substituting ‘non-mental’ for ‘physical’ in the causal argument for physicalism does not deliver the physicalist conclusion, and the specification that the physical is non-mental is irrelevant to the task of formulating physicalism as a substantive, controversial thesis.

How should physical entities be characterized? Physicalists, who have most to do with the notion, usually characterize the physical by reference to two components: 1. The physical entities are the entities treated by fundamental physics with the proviso that 2. Physical entities are not fundamentally mental (that is, do not individually possess or bestow mentality) Here I explore the extent to which the appeals to fundamental physics and to the NFM (“no fundamental mentality”) constraint are appropriate for characterizing the physical, especially for purposes of formulating physicalism. Ultimately, I motivate and defend a version of an account incorporating both components: The physics-based NFM account: An entity existing at a world w is physical iff (i) it is treated, approximately accurately, by current or future (in the limit of inquiry, ideal) versions of fundamental physics at w, and (ii) it is not fundamentally mental (that is, does not individually either possess or bestow mentality).

The physicalist thesis that all entities are nothing over and above physical entities is often interpreted as appealing to a supervenience-based account of "nothing over and aboveness”, where, schematically, the A-entities are nothing over and above the B-entities if the A-entities supervene on the B-entities. The main approaches to filling in this schema correspond to different ways of characterizing the modal strength, the supervenience base, or the supervenience connection at issue. I consider each approach in turn, and argue that the resulting formulation of physicalism is compatible with physicalism’s best traditional rival: a naturalist emergentism. Others have argued that supervenience-based formulations of physicalism fail. My aim here, besides addressing the full spectrum of supervenience-based approaches, is to show how certain philosophical and scientific theses concerning naturalism, properties, and laws give us new reasons to think that supervenience-based formulations of physicalism are untenable.

We provide a formulation of physicalism, and show that this is to be favoured over alternative formulations. Much of the literature on physicalism assumes without argument that there is a fundamental level to reality, and we show that a consideration of the levels problem and its implications for physicalism tells in favour of the form of physicalism proposed here. Its hey elements are, fast, that the empirical and substantive part of physicalism amounts to a prediction that physics will not posit new entities solely for the purpose of accounting for mental phenomena, nor new entities with essentially mental characteristics such as propositioned attitudes or intentions; secondly, that physicalism can safely make do with no more than a weak global formulation of supervenience.

Physicalism is the claim that that there is nothing in the world but the physical. Philosophers who defend physicalism have to confront a well-known dilemma, known as Hempel’s dilemma, concerning the definition of ‘the physical’: if ‘the physical’ is whatever current physics says there is, then physicalism is most probably false; but if ‘the physical’ is whatever the true theory of physics would say that there is, we have that physicalism is vacuous and runs the risk of becoming trivial. This article has two parts. The first, negative, part is devoted to developing a criticism of the so-called via negativa response to Hempel’s dilemma. In the second, more substantial, part, I propose to take the first horn of Hempel’s dilemma. However, I argue for a broad construal of ‘current physics’ and characterize ‘the physical’ accordingly. The virtues of the broad characterization of ‘the physical’ are: first, it makes physicalism less likely to be false; and second, it ties our understanding of ‘the physical’ to the reasons we have for believing in physicalism. That is, it fulfills the desideratum of construing our theses according to the reasons we have to believe in them.