Torin Alter

In Explanatory Optimism about the Hard Problem of Consciousness, Josh Weisberg tries to debunk the hard problem of consciousness. In his view, although consciousness appears to have DISC (directly accessed, indescribable, simple, contingently connected) properties, it does not: the appearance is better explained by automation, ‘a quick and seemingly spontaneous kind of cognitive processing, one whose underlying mechanistic activity is subjectively inaccessible to us’ (p. 92). I raise two problems for Weisberg’s argument. First, even if automation explains why consciousness appears DISCy, that is not enough to explain the hard-problem intuitions. Second, neither methodological naturalism nor the impressive track record of scientific explanations suffices to justify ascribing presumptive status to the claim that consciousness can be fully explained in structural-dynamic terms.

: Phenomenal knowledge usually comes from experience. But it need not. For example, one could know what it’s like to see red without seeing red—indeed, without having any color experiences. Daniel Dennett (2007) and Pete Mandik (forthcoming) argue that this and related considerations undermine the knowledge argument against physicalism. If they are right, then this is not only a problem for anti‐physicalists. Their argument threatens to undermine any version of phenomenal realism— the view that there are phenomenal properties, or qualia, that are not conceptually reducible to physical or functional properties. I will argue that this threat is illusory. Explaining why will clarify what is and is not at issue in discussions of the knowledge argument and phenomenal realism. This will strengthen the case for physically and functionally irreducible qualia. 2 Phenomenal knowledge usually comes from experience. For example, I know what it’s like to see red because I have done so. Does knowing what it’s like to have an experience with phenomenal character X require having an experience with X? No. A famous counterexample is Hume’s missing shade of blue, in which one can extrapolate from phenomenally similar experiences (A Treatise of Human Nature, Bk. I, Pt. I, Sec. I).1 One might think that a weaker version of the no‐phenomenal‐knowledge‐without‐experience thesis remains tenable, e.g., that knowing what it’s like to see in color requires having or having had color experiences. But this thesis also seems doubtful. Peter Unger (1966) devised plausible counterexamples over four decades ago, and since then others (e.g., Lewis 1988, Alter 1998, Stoljar 2005) have done the same. One could have phenomenal knowledge of color experiences without having such experiences. Indeed, one could have such knowledge without having experiences that are remotely like color experiences. What is the significance of this observation for contemporary debates about consciousness and physicalism? Daniel Dennett (2007) and Pete Mandik (forthcoming) suggest that it undermines the knowledge argument against physicalism.2 That is because they take the claim that someone who has never seen in color could not know what it’s like to see in color to be the basis of the knowledge argument’s main epistemic premise: the premise that (roughly put) 3 no amount of physical knowledge is sufficient for phenomenal knowledge of color experiences. If they are right, then this is not only a problem for anti‐ physicalists. Many physicalists (e.g., Loar 1990/97, Papineau 2002, 2007) accept the knowledge argument’s epistemic premise. Dennett’s and Mandik’s arguments threaten all versions of what David Chalmers (2003) calls phenomenal realism, the view that there are phenomenal properties, or qualia, that are not conceptually reducible to physical or functional properties.3 I will argue that this threat is illusory. Explaining why will clarify what is and is not at issue in discussions of the knowledge argument and phenomenal realism. The net result will be to strengthen the case for physically inexplicable qualia.

Zombies make trouble for physicalism. Intuitively, they seem conceivable, and many take this to support their metaphysical possibility – a result that, most agree, would refute physicalism. John Hawthorne (2002) [Philosophical Studies 109, 17–52] and David Braddon-Mitchell (2003) [The Journal of Philosophy 100, 111–135] have developed a novel response to this argument: phenomenal concepts have a conditional structure – they refer to non-physical states if such states exist and otherwise to physical states – and this explains the zombie intuition. I argue that this strategy fails. The considerations Hawthorne and Braddon-Mitchell adduce in support of their analysis in fact do no such thing. Further, their main argument for the analysis is self-defeating: exactly similar reasoning would undermine the view it is meant to establish. Finally, on closer inspection the conditional analysis is incompatible with the zombie intuition. Thus, not only is the analysis incapable of explaining the intuition: the intuition’s plausibility indicates that the analysis is incorrect. I also suggest that the allure of the conditional-analysis strategy may derive from a questionable view about what explaining the intuition would require.

The knowledge argument aims to refute physicalism, the view that the world is entirely physical. The argument first establishes the existence of facts about consciousness that are not a priori deducible from the complete physical truth, and then infers the falsity of physicalism from this lack of deducibility. Frank Jackson gave the argument its classic formulation. But now he rejects the argument . On his view, it relies on a false conception of sensory experience, which should be replaced with representationalism , the view that phenomenal states are just representational states. And he argues that mental representation is physically explicable.

Russellian monism offers a distinctive perspective on the relationship between the physical and the phenomenal. For example, on one version of the view, phenomenal properties are the categorical bases of fundamental physical properties, such as mass and charge, which are dispositional. Russellian monism has prominent supporters, such as Bertrand Russell, Grover Maxwell, Michael Lockwood, and David Chalmers. But its strengths and shortcomings are often misunderstood. In this paper we try to eliminate confusions about the view and defend it from criticisms. We present its core and distinguish different versions of it. We then compare these versions with traditional theories, such as physicalism, dualism, and idealism. We also argue that the knowledge argument and the conceivability argument are consistent with Russellian monism and that existing arguments against the view, such as the argument from weirdness, are not decisive. We conclude that Russellian monism is an attractive view that deserves serious consideration.

Ideal for courses in consciousness and the philosophy of mind, Consciousness and The Mind-Body Problem: A Reader presents thirty-three classic and contemporary readings, organized into five sections that cover the major issues in this debate: the challenge for physicalism, physicalist responses, alternative responses, the significance of ignorance, and mental causation. Edited by Torin Alter and Robert J. Howell, the volume features work from such leading figures as Karen Bennett, Ned Block, David J. Chalmers, Frank Jackson, Colin McGinn, David Papineau, and many others.

This chapter explains how the knowledge argument works and describes various physicalist responses to the knowledge argument. Frank Jackson first presented the knowledge argument in his 1982 paper, “Epiphenomenal Qualia”. “Qualia” refers to phenomenal properties: properties such as those Mary is said to understand only after leaving the room. Not everyone shares Jackson's opinion that epiphenomenalism is the best option for knowledge argument proponents. And some argue that there are versions of physicalism that the knowledge argument does not rule out. The most widely discussed such view is physicalist Russellian monism. Russellian monism combines two ideas. First, basic physics tells us about spatiotemporal‐causal structure but is silent about what underlies that structure. Second, there are intrinsic properties that both underlie that structure and constitute consciousness. Physicalist Russellian monism adds that those intrinsic properties are physical, even though they are not described by physics.

This book defends Frank Jackson’s knowledge argument against physicalism. According to physicalism, consciousness is a physical phenomenon. The knowledge argument stars Mary, who learns all objective, physical information through black-and-white media and yet acquires new information when she first sees colors for herself: information about what it is like to see in color. Based partly on that case, Jackson concludes that not all information is physical. The book argues that the knowledge argument succeeds in refuting all standard versions of physicalism: versions on which consciousness is grounded by what objective science reveals. It also argues that given further, plausible assumptions, the knowledge argument leads to Russellian monism, on which there are intrinsic properties that both constitute consciousness and underlie properties physics describes, such as mass and charge. It explains how the knowledge argument establishes those two conclusions and defends the argument against numerous objections.

Physicalism is standardly construed as a form of monism, on which all concrete phenomena fall under one fundamental type. It is natural to think that monism, and therefore physicalism, is committed to a supervenience claim. Monism is true only if all phenomena supervene on a certain fundamental type of phenomena. Physicalism, as a form of monism, specifies that these fundamental phenomena are physical. But some argue that physicalism might be true even if the world is disorderly, i.e., not ordered by supervenience relations in the way commonly supposed (Montero in J Philos 110:92–110, 2013; Leuenberger in Inquiry 57:151–174, 2014; Montero and Brown in Topoi 37(3):523–532, 2018; Zhong in Philos Stud 178(5):1529–1544, 2021). Unless these authors intend to challenge the claim that physicalism is a type of monism—a claim so central to the dialectic in philosophy of mind that rejecting it risks changing the subject—they are committed to challenging a supervenience requirement for monism. We argue that monism entails that there are substantial supervenience relations among concrete phenomena: relations that would not obtain in a disorderly world. Our argument thus has implications for debates about physicalism and supervenience, and sheds light on an under-discussed issue: what is implied by classifying a theory in the philosophy of mind as a form of monism? We also argue that physicalism’s commitment to monism creates problems for _via negativa_ physicalism, on which the physical is characterized negatively.

Anti-materialist arguments such as the knowledge argument, the conceivability argument, and the explanatory gap argument do not establish the existence of brute phenomenal facts about consciousness. First, those arguments work by exploiting specific features of the physical, which some nonphenomenal entities might lack. Even if the arguments establish an ontological gap between the physical and the phenomenal, they do not establish a gap between the nonphenomenal and the phenomenal. But they would have to establish such a gap to show that there are brute phenomenal facts. Second, the arguments do not rule out certain views on which there are no such facts. The chapter’s conclusion leaves open the possibility that combining the anti-materialist arguments with other considerations would establish the existence of brute phenomenal facts. However, whether that strategy can succeed is unclear. That and other considerations are used to support agnosticism about the existence of brute phenomenal facts.

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.

The supervenience requirement on physicalism says roughly that if physicalism is true then mental properties supervene on fundamental physical properties. After explaining the basis of the requirement, I defend it against objections presented by Lei Zhong (“Physicalism without supervenience,” Philosophical Studies 178 (5), 2021: 1529–44), Barbara Gail Montero (“Must physicalism imply supervenience of the mental on the physical?” Journal of Philosophy 110, 2013: 93–110), and Montero and Christopher Devlin Brown (“Making room for a this-worldly physicalism,” Topoi 37 (3), 2018: 523–32).

It is often claimed that Russellian monism carries a commitment to a structuralist conception of physics, on which physics describes the world only in terms of its spatiotemporal structure and dynamics. We argue that this claim is mistaken. On Russellian monism, there is more to consciousness, and to the rest of concrete reality, than spatiotemporal structure and dynamics. But the latter claim supports only a conditional claim about physics: _if_ structuralism about physics is true, then there is more to consciousness and to the rest of concrete reality than physics describes. Given the fundamental nature of their position, Russellian monists can, we argue, deny the antecedent without inconsistency. We also draw out two significant consequences of that result. One is that it provides a response to some recent objections to Russellian monism, by Alyssa Ney and Eric Hiddleston. The other consequence concerns a line of reasoning known as _the structure and dynamics argument_—reasoning that is thought to motivate Russellian monism. In David J. Chalmers’s version, which is regarded as canonical, structuralism about physics is implied by a premise. If our main thesis is true, then that version is problematic, at least from the perspective of Russellian monists who take the argument to motivate their theory. However, we argue, the argument can be reformulated without relying on structuralism about physics.

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.

According to Russellian monism, phenomenal consciousness is constituted by inscrutables: intrinsic properties that categorically ground dispositional properties described by fundamental physics. On Russellian physicalism, those inscrutables are construed as protophenomenal properties: non-structural properties that both categorically ground dispositional properties and, perhaps when appropriately structured, collectively constitute phenomenal properties. Morris and Brown (Journal of Consciousness Studies 2016, 2017) argue that protophenomenal properties cannot serve this purpose, given assumptions Russellian monists typically make about the modal profile of such properties. Those assumptions, it is argued, entail that protophenomenal properties are ‘experience specific’, that is, they are individuated by their potential to constitute phenomenal properties, and are thus not genuinely physical. However, we argue, that reasoning assumes that physical inscrutables must be individuated in terms of their (actual or possible) grounding roles. Not only is that assumption questionable: it is antithetical to Russellian monism.

According to Russellian monism, consciousness is constituted at least partly by quiddities: intrinsic properties that categorically ground dispositional properties described by fundamental physics. If the theory is true, then consciousness and such dispositional properties are closely connected. But how closely? The contingency thesis says that the connection is contingent. For example, on this thesis the dispositional property associated with negative charge might have been categorically grounded by a quiddity that is distinct from the one that actually grounds it. Some argue that Russellian monism entails the contingency thesis and that this makes its consciousness‐constituting quiddities epiphenomenal—a disastrous outcome for a theory that is motivated partly by its prospects for integrating consciousness into physical causation. We consider two versions of that argument, a generic version and an intriguing version developed by Robert J. Howell, which he bases on Jaegwon Kim's well‐known “exclusion argument.” We argue that neither succeeds.

I examine the notion of knowing what an experience or emotion it is like. What kind of knowledge is this? Is it, for example, a species of factual knowledge? If so, what sort of fact is known by someone who possesses this kind of knowledge? ;Knowing what it is like plays a central role in a recent, influential argument, which runs : complete knowledge of the physical facts would fail to provide one with knowledge of what it is like to taste a lemon or see red; therefore, there must be more to such experiences than the events involving only physical phenomena, and so materialism must be false. I argue that this argument involves an ineliminable illicit inference from epistemological premises about how we know about mental and physical events to a metaphysical conclusion about the nature of these events, and that materialism is compatible with the argument's epistemological underpinnings. ;Failure to appreciate this point has led materialists to advance reductionist theories of knowing what it is like, including the theory that it is a species of "ability knowledge" and the theory that it is a species of "acquaintance knowledge". I argue that all such reductionist theories are untenable: someone who does not know what it is like to see red is missing some bona fide factual knowledge about that experience. Given plausible assumptions, it follows that this factual knowledge cannot be acquired by discursive means alone. ;There is a prima facie tension between this "discursive unlearnability" thesis and the plausible idea that the representational resources of our language enable us to speak about that with which we are not directly acquainted, but others with whom we communicate are directly acquainted--an idea that gains support from recent work in semantics by Kripke, Kaplan, Donnellan, and others. I argue that the conflict is only apparent. However, the discursive unlearnability thesis does contradict the widely held view that all facts can be expressed in the language of objective science, and are in principle accessible to any rational creature with an intellectual capacity sufficiently powerful to understand that language.