«DON’T PANIC: Tye’s intentionalist theory of consciousness* Alex Byrne, MIT Consciousness, Color, and Content is a significant contribution to our ...»
Forthcoming in A Field Guide to the Philosophy of Mind symposium,
DON’T PANIC: Tye’s intentionalist theory of consciousness*
Alex Byrne, MIT
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.
* Many thanks to Michael Glanzberg, Ned Hall, Sally Haslanger, Jim John, Sarah McGrath, Jim Pryor, Mark Richard, Susanna Siegel, Robert Stalnaker, Ralph Wedgwood, and Steve Yablo.
2 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. One important component of Tye’s view, discussed in section 2, is intentionalism—roughly, the claim that the phenomenal character of an experience is fixed by its propositional content.
Intentionalism is controversial enough, but the PANIC theory (explained in section 3) is considerably stronger. The various additions the PANIC theory makes to intentionalism are discussed in sections 4, 5, and 6. Finally, section 7 sketches a couple of alternative suggestions for treating some of the problems raised in the preceding three sections.
Before getting down to business, some terminology needs to be clarified.
The phenomenal character of an experience can be introduced by examples: the experience of tasting sugar differs in phenomenal character from the experience of tasting lemon juice; the experience of seeing ripe tomatoes differs in phenomenal character from the experience of seeing unripe ones; your experience and the corresponding experience of your twin on Twin Earth have the same phenomenal character; if Invert is “spectrally inverted” with respect to Nonvert, then Invert’s tomato-experiences differ in phenomenal character from Nonvert’s; and so on. Note that on the usage adopted here, the phenomenal character of an experience is a property of the experience; sometimes ‘qualia’ is used equivalently, but sometimes not (see, for example, Lycan 1996, 69-70).
The propositional content—or, simply, content—of an experience captures the way the world perceptually seems to the subject of the experience. When one looks at a purple pentagon in good light, it seems that there is a purple pentagon before one.
Clearly the proposition that there is a purple pentagon before one falls short of completely characterizing the way the world seems, but pretend otherwise for illustration.
If there isn’t a purple pentagon before one, then the content of the experience is false, and the experience is some kind of illusion. If there is a purple pentagon before one, then the
The content of experience, or perceptual content, can be also introduced in a more familiar idiom. Perceptual experiences are species of propositional attitude: it visually (aurally/tactually, etc.) appears that p. If it visually appears that p (and if the proposition that p completely characterizes the way things visually appear), then the content of one’s experience is just the proposition that p.1 There are many hard questions concerning perceptual content. Imagine someone with normal vision looking at an object that is shaped and colored exactly like a yellow lemon. She might describe the scene by saying that there seems to be a yellow ripe lemon before her. Presumably the content of her experience at least concerns the color and shape of the object. But does it also specify the object before her as ripe, or as a lemon?
Is her experience some kind of illusion if the object is a yellow but unripe lemon, or if the object is made of papier-mâché? Would the content of her experience be different if a qualitatively identical but numerically distinct object were before her eyes? Connectedly, would the content of her experience be the same, or at least importantly similar, if she were hallucinating a lemon?
Evidently the notions just introduced—the phenomenal character and content of an experience—are not especially clear; however, I assume with Tye that they are clear enough to support some theorizing.
1 More exactly: if it visually appears that p at time t (and if the proposition that p completely characterizes
Finally, a cautionary-cum-apologetic note. Partly to make the discussion fit smoothly with various quoted passages, events (for instance, experiences, and episodes of thinking), and states (for instance, beliefs), will be lumped together as states.2
1. Tye’s naturalized semantics
Tye’s causal covariational account of intentionality is this:
[Sensory state] S represents that P =df If optimal conditions were to obtain, S would be tokened in [creature] c if and only if P were the case; moreover, in these circumstances, S would be tokened in c because P is the case. (2000, 136, note
“Optimal conditions” are explained as follows:
In the case of evolved creatures, it is natural to hold that such conditions for vision involve the various components of the visual system operating as they were designed to do in the sort of external environment in which they were designed to
It seems to me that Tye himself has supplied compelling counterexamples against this proposal, namely various perceptual illusions, in particular the Müller-Lyer illusion 2 I am not pretending that this policy is entirely harmless. For a useful critical discussion of “states” and other ontological categories in the philosophy of mind, see Steward 1997.
3 As he says (1995, 101) this account derives from Stampe 1977 and Stalnaker 1984. Tye later adds a
(1995, 102; 2000, 106). In the latter illusion, one’s visual experience represents (incorrectly) that the lines are of different lengths, even in conditions that are presumably optimal.
It might be replied that the two-dimensional Müller-Lyer diagram is not supposed to be included in the “sort of external environment” in which the components of the visual system were “designed to operate”. If so, we need much more of a story about the right kind of external environment than Tye supplies. And in any case, this reply does not work: illusions like the Müller-Lyer occur when viewing ordinary three-dimensional scenes (DeLucia and Hochberg 1991). If “optimal conditions” are to play a central role in a naturalized semantics, they need to be explained along quite different lines.4
2. Intentionalism Setting Tye’s naturalized semantics aside, let us begin our investigation of the PANIC theory. According to Tye, “necessarily, experiences that are alike in their representational contents are alike in their phenomenal character” (2000, 45), a thesis he calls
representationalism (2000, x, 45). If representationalism is correct, the phenomenal difference between experiences in different sensory modalities—between seeing and hearing, for example—is due to a difference in content. But one might be more cautious.
Tye distinguishes representationalism from a “modality-specific, weak representational
4 Essentially the same problem arises for Dretske’s (1995) theory of naturalized semantics (which leans
Necessarily, visual experiences that are alike with respect to their representational contents are alike phenomenally. (2000, 69) For present purposes the PANIC theory needs to be sharply separated from both representationalism and “thesis R”. To avoid confusion it is best to introduce some different terminology.
Intramodal intentionalism is the claim that, within a perceptual modality, the phenomenal character of an experience supervenes on its content. An intramodal intentionalist therefore holds thesis R and its analogue for the other senses (which may be taken to include uncontroversial examples like olfaction and audition). Intermodal intentionalism is the claim quoted at the start of this section: necessarily, experiences alike in representational content are alike in phenomenal character. Hence, intermodal intentionalism implies intramodal intentionalism, but not conversely. These two sorts of intentionalism are unrestricted just in case they encompass not just paradigmatic perceptual experiences, but also sensations, like pain and nausea.5 To illustrate the core of these intentionalist positions, imagine that Invert is “spectrally inverted” with respect to Nonvert. They are both looking at a tomato, and because of the inversion their experiences differ in phenomenal character. Despite this difference, might Invert’s and Nonvert’s experiences have exactly the same content (they both represent the tomato as red, etc.)? According to some philosophers—notably Block (1990, 2000)—the answer is yes, while intentionalists disagree.6 Again, some 5 Lycan (1996) is an example of an intramodal intentionalist (according to him, functional role, not content, accounts for the phenomenal difference between sensory modalities); McGinn (1991, ch. 2) is an example of a restricted intentionalist (he thinks sensations have no content). This terminology is taken from Byrne 2001.
philosophers argue that a “zombie” is possible: a creature intentionally identical to you or me, but whose “experiences” have no phenomenal character: it visually appears to her, say, that there is a pink circle ahead, but there is nothing it’s like for her to enjoy this experience.7 Intentionalists deny that any such zombie is possible.
Intentionalism is obviously controversial, and Tye’s brand—intermodal unrestricted intentionalism—is even more so. As it happens, I agree with Tye that intermodal unrestricted intentionalism is correct (Byrne 2001); ‘intentionalism’ will henceforth be used for this strong thesis, unless the context indicates otherwise.
Now some mental states have content, but do not have phenomenal character. For example, there is nothing it’s like to believe that today is Wednesday—or, at any rate, there need be nothing it’s like to have this belief (one may have it during one’s lunchtime nap). More controversially, there need be nothing it’s like to recall (consciously) that today is Wednesday, or to wonder (consciously) whether today is Wednesday. At any rate, wondering whether today is Wednesday is hardly, to borrow a phrase of Block’s, “phenomenologically impressive”.
So a question naturally arises: what is the difference between those intentional states that have phenomenal character and those that don’t? What is the ingredient X that makes an intentional state one with phenomenal character? This is a question for both the 7 In the usage of this paper, when a subject undergoes an “experience” with the content that p, it perceptually appears to her that p. If some sub-personal state of the subject has the content that p (and so it does not appear to her that p), then this state is not an experience. Therefore the perceptual states of certain blindsight patients are not experiences (it does not appear to the subject that there is an ‘O’ before her).
Note that this usage does not trivialize the claim that all experiences have phenomenal character. The zombie possibility mentioned above is supposed to be a case where the subject has an experience (in the sense used here), but with no phenomenal character.
I think this usage of ‘experience’ is (in this respect) pretty close to Tye’s, but it is certainly not universal in the literature. For a broader use of ‘experience’ that includes blindsight cases, see Carruthers 2000, ch. 6.
8 intentionalist and his opponent. An anti-intentionalist may say something entirely unhelpful (like “Qualia”), or he may offer something more substantive, for instance a theory of “sensational properties” (Peacocke 1983). It is important to emphasize that the intentionalist is not under any greater obligation: a substantive reply is desirable, but not mandatory.
Comparing intentionalism with other supervenience theses helps to reinforce the point. Take, for example, the claim that the mental supervenes on the physical (say, a global supervenience thesis of the sort in Braddon-Mitchell and Jackson 1996, ch. 1).