Online research in philosophy

In 1995, in my book, Ten Problems of Consciousness (Bradley Books, MIT Press), I proposed a version of the theory of phenomenal consciousness now known as representationalism. The present book, in part, consists of a further development of that theory along with replies to common objections. It is also concerned with two prominent challenges for any reductive theory of consciousness: the explanatory gap and the knowledge argument. In addition, it connects representationalism with two more general issues: the nature of color and the location of the phylogenetic dividing line between those creatures that are phenomenally conscious and those that are not.

I argue that the explanatory gap is generated by factors consistent with the view that qualia are physical properties. I begin by considering the most plausible current approach to this issue based on recent work by Valerie Hardcastle and Clyde Hardin. Although their account of the source of the explanatory gap and our potential to close it is attractive, I argue that it is too speculative and philosophically problematic. I then argue that the explanatory gap should not concern physicalists because it makes excessive demands on physical theory.

It is argued that the explanatory gap argument, according to which it is fundamentally impossible to explain qualitative mental states in a physicalist theory of mind, is unsound. The main argument in favour of the explanatory gap is presented, which argues that an identity statement of mind and brain has no explanatory force, in contrast to "normal" scientific identity statements. Then it is shown that "normal" scientific identity statements also do not conform to the demands set by the proponent of the explanatory gap. Rather than accept all such gaps, it is argued that we should deny the explanatory gap in a physicalist theory of mind.

Michael Tye has recently been a vocal defender of color realism or, as I shall call it, color objectivism. Objectivism about color is the view that color properties are identical to intrinsic physical properties of the surfaces of objects. Subjectivism about color is the denial of color objectivism. Objectivists argue that color claims must be taken at face value. In this paper I forego the usual bickering about whether there are surface reflectance properties that can be identified with colors as the objectivist theory requires. Supposing that some such properties could be found, I argue that if objectivism about color were correct it would have the unsavory consequence that we are rarely if ever right—perhaps never right—about the particular colors of particular things. So objectivism does not bear out common attribution of colors to the surfaces of things, after all.

_Consciousness, Color, and Content_ is a significant contribution to our understanding of consciousness, among other things. I have learned a lot from it, as well as Tye.

Larry Hardin has been the most steadfast and influential critic of physicalist theories of color over the last 20 years. In their modern form these theories originated with the work of Smart and Armstrong in the 1960s and 1970s1 and Hardin appropriately concentrated on their views in his initial critique of physicalism.2 In his most recent contribution to this project3 he attacks Michael Tye’s recent attempts to defend and extend color physicalism.4 Like Byrne and Hilbert5, Tye identifies color with the reflecting properties of objects (“reflectance physicalism”). Specifically, the determinate and determinable colors are identified with types of reflectances. (Setting some complications aside, the reflectance of an object is the proportion of light that it reflects at each wavelength in the visible spectrum.) These reflectance types are, in the terminology of Hilbert, anthropocentric—in the terminology of Lewis6, they are not very “natural”.

Consciousness, Color, and Content is a significant contribution to our understanding of consciousness, among other things. I have learned a lot from it, as well as Tye’s other writings. What’s more, I actually agree with much of it – fortunately for this symposium, not all of it. The book continues the defense of the “PANIC” theory of phenomenal consciousness that Tye began in Ten Problems of Consciousness (1995). A fair chunk of it, though, is largely independent of this theory: the discussion of the knowledge argument, the explanatory gap, and color. Tye says much of interest about these topics. But as most of my disagreement is with the PANIC theory, I shall concentrate on that. The PANIC theory is nothing short of ambitious. It is a reductive account of phenomenal consciousness in intentional/functional terms. Tye further gives, at least in outline, a broadly physicalistic account of intentionality (a “naturalized semantics”), in terms of causal covariation. Putting the PANIC theory and Tye’s naturalized semantics together, the result is a physicalistically acceptable theory of phenomenal consciousness. The two parts of this package are independent. A naturalized semantics can be combined with dualism about consciousness (a position close to this is in Chalmers, 1996). And a PANIC theorist is at liberty to endorse a rival physicalistic theory of intentionality, or indeed could take intentionality to be entirely irreducible. The plan is this. Section 1 briefly airs a concern about Tye’s naturalized semantics. The rest of the paper focuses on the PANIC theory, in particular the use it makes of “nonconceptual content”.1 Philosophical Studies 113: 261–274, 2003. © 2003 Kluwer Academic Publishers. Printed in the Netherlands. 262..

Confronted with the apparent explanatory gap between physical processes and consciousness, there are many possible reactions. Some deny that any explanatory gap exists at all. Some hold that there is an explanatory gap for now, but that it will eventually be closed. Some hold that the explanatory gap corresponds to an ontological gap in nature.

Larry Hardin has been the most steadfast and influential critic of physicalist theories of color over the last 20 years. In their modern form these theories originated with the work of Smart and Armstrong in the 1960s and 1970s1 and Hardin appropriately concentrated on their views in his initial critique of physicalism.2 In his most recent contribution to this project3 he attacks Michael Tye’s recent attempts to defend and extend color physicalism.4 Like Byrne and Hilbert5, Tye identifies color with the reflecting properties of objects (“reflectance physicalism”). Specifically, the determinate and determinable colors are identified with types of reflectances. (Setting some complications aside, the reflectance of an object is the proportion of light that it reflects at each wavelength in the visible spectrum.) These reflectance types are, in the terminology of Hilbert, anthropocentric—in the terminology of Lewis6, they are not very “natural”.

The claim that there is an explanatory gap between physical and phenomenal properties is perhaps the leading current challenge to materialist views about the mind. Tye tries to block this challenge, not by providing an explanation to bridge the gap but by denying that phenomenalphysical identities introduce an explanatory gap. Since an explanatory gap exists only if there is something unexplained that needs explaining, and something needs explaining only if it can be explained (whether or not it lies within the power of human-beings to explain it), there is no gap. (Tye ????, p. ???) Tyes strategy differs crucially from the claim that identities never stand in need of explanation because they constitute ultimate explanations; for he allows that identities such as water = H?O are explainable. Unlike WATER and H?O, which are descriptive concepts, phenomenal concepts are perspectival and hence irreducible to descriptive concepts, according to Tye. The fact that something picked out by a perspectival concept is identical to something picked out by a non-perspectival concept cannot be explained.1 So, he concludes, phenomenalphysical identities need not be explained.