Problems with the ‘physical’ in physicalism

Hempel's Dilemma is a challenge that has to be met by any formulation of physicalism that specifies the physical by reference to a particular physical theory. It poses the problem that if one's specification of the physical is ‘current’ physical theory, then the physicalism which depends on it is false because current physics is false; and if the specification of the physical is a future or an ideal physics, the physicalism based on it would be trivial as it would be tautologously true, or because very little (if anything at all) can be inferred from or about a physics that does not yet exist. I review the reasons for thinking that the dilemma is a perpetual problem for currentist specifications of the physical, then introduce the argument that the standard positions on the specification question are wanting because they lack a generality which physicalism is generally accepted to have. I end with a suggestion for a way forward for physicalism.     

PHYSICALISM, SUPERVENIENCE AND THE FUNDAMENTAL LEVEL

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 key elements are, first, 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 propositional attitudes or intentions; secondly, that physicalism can safely make do with no more than a weak global formulation of supervenience.     

Two Kinds of Completeness and the Uses (and Abuses) of Exclusion Principles

I argue that the completeness of physics is composed of two distinct claims. The first is the commonly made claim that, roughly, every physical event is completely causally determined by physical events. The second has rarely, if ever, been explicitly stated in the literature and is the claim that microphysics provides a complete inventory of the fundamental categories that constitute both the causal features and intrinsic nature of all the events that causally affect the physical universe. After showing that these claims are distinct, I argue that they can be used to solve a difficulty with existing responses to the exclusion problem—namely, that these existing responses also undermine the powerful causal argument for physicalism. Recognizing that there are two kinds of completeness opens up room for the nonreductive physicalist to solve the exclusion problem while also endorsing a modified, cogent causal argument for a kind of physicalism compatible with her position.     

Physicalism as an attitude

It is widely noted that physicalism, taken as the doctrine that the world contains just what physics says it contains, faces a dilemma which, some like Tim Crane and D.H. Mellor have argued, shows that “physicalism is the wrong answer to an essentially trivial question”. I argue that both problematic horns of this dilemma drop out if one takes physicalism not to be a doctrine of the kind that might be true, false, or trivial, but instead an attitude or oath one takes to formulate one’s ontology solely according to the current posits of physics.     

Conceptual mastery and the knowledge argument

According to Frank Jackson’s famous knowledge argument, Mary, a brilliant neuroscientist raised in a black and white room and bestowed with complete physical knowledge, cannot know certain truths about phenomenal experience. This claim about knowledge, in turn, implies that physicalism is false. I argue that the knowledge argument founders on a dilemma. Either (i) Mary cannot know the relevant experiential truths because of trivial obstacles that have no bearing on the truth of physicalism or (ii) once the obstacles have been removed, Mary can know the relevant truths. If we give Mary the epistemological capabilities necessary to draw metaphysical conclusions about physicalism, she will, while trapped in the black and white room, be able to know every truth about phenomenal experience.     

Physicalism, Nothing Buttery, and Supervenience

I consider the position (which I call'the triad') according to which physicalism is a reductive claim which is capturable in terms of the idea (the ' nothing buttery ' idea) that there is nothing but/nothing over and above the physical, an idea which, in its turn, is meant to be capturable in terms of a determinate form of supervenience . (Physicalism is then meant to be capturable in terms of the form of supervenience in question.) I argue that there is a tension in the triad. The notion of 'nothing buttery' required has features which can't be captured by the supervenience of the triad. Hence, one cannot have both physicalism as nothing-buttery-reductive and physicalism as supervenience of the kind in question. If one wants to hold onto the idea of physicalism as nothing-buttery-reductive, one must be prepared to identify physicalism with a much stronger claim than one might have originally thought, a claim that can't be captured by the supervenience of the triad.     

On characterizing the physical

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 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 will explore the extent to which appeals to fundamental physics and to the NFM (no fundamental mentality) constraint are appropriate for characterizing the physical, especially for purposes of formulating physicalism. I will motivate and defend a version of an account incorporating both components.     

How to be a type-C physicalist

This paper advances a version of physicalism which reconciles the “a priori entailment thesis” (APET) with the analytic independence of our phenomenal and physical vocabularies. The APET is the claim that, if physicalism is true, the complete truths of physics imply every other truth a priori. If so, “cosmic hermeneutics” is possible: a demon having only complete knowledge of physics could deduce every truth about the world. Analytic independence is a popular physicalist explanation for the apparent “epistemic gaps” between phenomenal and physical truths. The two are generally seen as incompatible, since the demon’s deductions seem to presuppose analytic connections between physical and phenomenal terms. I begin by arguing, in support of the APET, that implications from the complete truths of physics to phenomenal truths cannot be a posteriori. Such implications are (according to the physicalist) necessarily true. But they cannot be Kripke-style a posteriori necessities, since (according to the physicalist) the complete truths of physics fix any relevant a posteriori facts about the reference of terms. I then show how the physicalist can turn the tables: the demon can exploit the physical fixing of reference to bridge the gap between the vocabularies, by deducing when phenomenal and physical terms co-refer. This opens the way for a “type-C” physicalism, which accepts in-principle deducibility while still appealing to analytic independence to explain why we (who are not demons) find it impossible to see phenomenal-physical connections a priori.     

WHAT IS PHYSICALISM?

Although 'most contemporary analytic philosophers [endorse] a physicalist picture of the world' (A. Newen; V. Hoffmann; M. Esfeld, 'Preface to Mental Causation, Externalism and Self-Knowledge', Erkenntnis , 67 (2007), p. 147), it is unclear what exactly the physicalist thesis states. The response that physicalism is the thesis that everything is physical does not solve the problem but is a precise statement of the problem because 'the claim is hopelessly vague' (G. Hellman; F. Thompson, 'Physicalism: Ontology, Determination, and Reduction', Journal of Philosophy , 72 (1975), p. 552). I argue that physicalism in fact should be the thesis that every existing particular essentially exemplifies properties the exemplification of which does not conceptually entail the existence of conscious beings. Physicalism thus is a purely philosophical thesis with no intrinsic relation to physics. ¹     

Causal Compatibilism – What Chance?

Orthodox physicalism has a problem with mental causation. If physics is complete and mental events are not identical to physical events (as multiple-realisation arguments imply) it seems as though there is no causal work for the mental to do. This paper examines some recent attempts to overcome this problem by analysing causation in terms of counterfactuals or conditional probabilities. It is argued that these solutions cannot simultaneously capture the force of the completeness of physics and make room for mental causation.     

On the Causal Completeness of Physics

According to an increasing number of authors, the best, if not the only, argument in favour of physicalism is the so‐called ‘overdetermination argument’. This argument, if sound, establishes that all the entities that enter into causal interactions with the physical world are physical. One key premise in the overdetermination argument is the principle of the causal closure of the physical world, said to be supported by contemporary physics. In this paper, I examine various ways in which physics may support the principle, either as a methodological guide or as depending on some other laws and principles of physics.     

The Constraint Interpretation of Physical Emergence

I develop a variant of the constraint interpretation of the emergence of purely physical (non-biological) entities, focusing on the principle of the non-derivability of actual physical states from possible physical states (physical laws) alone. While this is a necessary condition for any account of emergence, it is not sufficient, for it becomes trivial if not extended to types of constraint that specifically constitute physical entities, namely, those that individuate and differentiate them. Because physical organizations with these features are in fact interdependent sets of such constraints, and because such constraints on physical laws cannot themselves be derived from physical laws, physical organization is emergent. These two complementary types of constraint are components of a complete non-reductive physicalism, comprising a non-reductive materialism and a non-reductive formalism.     

Neural Synchrony and the Causal Efficacy of Consciousness

The purpose of this paper is to address a well-known dilemma for physicalism. If mental properties are type identical to physical properties, then their causal efficacy is secure, but at the cost of ruling out mentality in creatures very different to ourselves. On the other hand, if mental properties are multiply realizable, then all kinds of creatures can instantiate them, but then they seem to be causally redundant. The causal exclusion problem depends on the widely held principle that realized properties inherit their causal powers from their realizers. While this principle holds for functional realization, it fails on a broader notion of realization that permits the realization of complex qualitative properties such as spatial and temporal patterns. Such properties are best seen as dependent powerful qualities, which have their causal roles in virtue of being the qualities they are, and do not inherit powers from their realizers. Recent studies have identified one such property—neural synchrony—as a correlate of consciousness. If synchrony is also partially constitutive of consciousness, then phenomenal properties are both multiply realizable and causally novel. I outline a version of representationalism about consciousness on which this constitution claim holds.

     

Physicalism and Ontological Holism

The claim of this paper is that we should envisage physicalism as an ontological holism. Our current basic physics, quantum theory, suggests that, ontologically speaking, we have to assume one global quantum state of the world; many of the properties that are often taken to be intrinsic properties of physical systems are in fact relations, which are determined by that global quantum state. The paper elaborates on this conception of physicalism as an ontological holism and considers issues such as supervenience, realization of higher-order properties by basic physical properties, and reduction.     

The Relativity Of Color

C. L. Hardin led a recent development in the philosophical literature on color in which research from visual science is used to argue that colors are not properties of physical objects, but rather are mental processes. I defend J. J. C. Smart's physicalism, which claims that colors are physical properties of objects, against this attack. Assuming that every object has a single veridical (that is, nonillusory) color, it seems that physicalism must give a specification of veridical color in terms natural to physics, independently of our interests. Hardin argues that since physicalism doesn't give us any such specification of veridical color, this view is false. However, this argument assumes a mistaken account of veridical color. I show physicalism can appeal to an alternative account, according to which veridical color is characterized in terms of favored conditions of perceptual access, independently of any specification of the physical nature of color.     

Physicalism and strict implication

The aim of this paper is to determine the plausibility of Robert Kirk’s strict implication thesis as an explication of physicalism and its relation to Jackson and Chalmer’s notion of application conditionals, to the notion of global supervenience and to a posteriori identities. It is argued that the strict implication thesis is subject to the same objection that affects the notion of global supervenience. Furthermore, reference to an idealised physics in the formulation of strict implication threatens to make the thesis vacuous. Third, Kirk’s claim that the strict implication thesis does not entail reduction of the mental to the physical (excluding phenomenal properties) is untenable if a functional model of reduction is preferred over Nagel’s classical model. Finally, Kirk’s claim that the physical facts entail in an a priori way the fact that certain brain states feel somehow seems to be unfounded.     

Spinoza's Thinking Substance and the Necessity of Modes

How should ‘the physical’ be defined for the purpose of formulating physicalism? In this paper I defend a version of the via negativa according to which a property is physical just in case it is neither fundamentally mental nor possibly realized by a fundamentally mental property. The guiding idea is that physicalism requires functionalism, and thus that being a type identity theorist requires being a realizer‐functionalist. In §1 I motivate my approach partly by arguing against Jessica Wilson's no fundamental mentality constraint. In §2 I set out my preferred definition of ‘the physical’ and make my case that physicalism requires functionalism. In §3 I defend my proposal by attacking the leading alternative account of ‘the physical,’ the theory‐based conception. Finally, in §4 I draw on my definition, together with Jaegwon Kim's account of intertheoretic reduction, to defend the controversial view that physicalism requires a priori physicalism.     

Good News for Moral Error Theorists: A Master Argument Against Companions in Guilt Strategies

Moral error theories are often rejected by appeal to ‘companions in guilt’ arguments. The most popular form of companions in guilt argument takes epistemic reasons for belief as a ‘companion’ and proceeds by analogy. I show that this strategy fails. I claim that the companions in guilt theorist must understand epistemic reasons as evidential support relations if her argument is to be dialectically effective. I then present a dilemma. Either epistemic reasons are evidential support relations or they are not. If they are not, then the companions in guilt argument fails. If they are, then a reduction of epistemic reasons to evidential support relations becomes available and, consequently, epistemic reasons cease to be a viable ‘companion’ for moral reasons. I recommend this structure of argument over existing strategies within the literature and defend my claims against recent objections from companions in guilt theorists.     

Causal Closure,Causal Exclusion,and Supervenience Physicalism

This article considers the recent defense of the supervenience approach to physicalism due to Jaegwon Kim. Kim argues that supervenience supports physical causal closure, and that causal closure supports physicalism – indeed, a kind of reductive physicalism – and thus that supervenience suffices for physicalism. After laying out Kim's argument, I ask whether its success would truly vindicate the role of supervenience in defining physicalist positions. I argue that it would not, and that insofar as Kim's defense of supervenience physicalism succeeds, it does so by showing that supervenience physicalism is not a unique, nonredundant way to be a physicalist.     

Physicalism and phenomenal concepts

Frank Jackson’s famous Knowledge Argument moves from the premise that complete physical knowledge is not complete knowledge about experiences to the falsity of physicalism. In recent years, a consensus has emerged that the credibility of this and other well-known anti-physicalist arguments can be undermined by allowing that we possess a special category of concepts of experiences, phenomenal concepts, which are conceptually independent from physical/functional concepts. It is held by a large number of philosophers that since the conceptual independence of phenomenal concepts does not imply the metaphysical independence of phenomenal properties, physicalism is safe. This paper distinguishes between two versions of this novel physicalist strategy—Phenomenal Concept Strategy (PCS)—depending on how it cashes out “conceptual independence,” and argues that neither helps the physicalist cause. A dilemma for PCS arises: cashing out “conceptual independence” in a way compatible with physicalism requires abandoning some manifest phenomenological intuitions, and cashing it out in a way compatible with those intuitions requires dropping physicalism. The upshot is that contra Brian Loar and others, one cannot “have it both ways.”