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WITTGENSTEIN AND QUALIA1 Ned Block New York University (Wittgenstein, 1968) endorsed one kind of inverted spectrum hypothesis and rejected another. This paper argues that the kind of inverted spectrum hypothesis that Wittgenstein endorsed (the “innocuous” inverted spectrum hypothesis) is the thin end of the wedge that precludes a Wittgensteinian critique of the kind of inverted spectrum hypothesis he rejected (the “dangerous” kind). The danger of the dangerous kind is that it provides an argument for qualia, where qualia are (for the purposes of this paper) contents of experiential states which cannot be fully captured in natural language. I will pinpoint the difference between the innocuous and dangerous scenarios that matters for the argument for qualia, give arguments in favor of the coherence and possibility of the dangerous scenario, and try to show that some standard arguments against inverted spectra are ineffective against the version of the dangerous scenario I will be advocating. The leading idea of the paper is that an argument for qualia based on spectrum inversion does not require that the inversion be behaviorally indistinguishable. At one crucial point, I will rely on a less controversial version of an argument I gave in Block (1999). Wittgenstein’s views provide a convenient starting point for a paper that is much more about qualia than about Wittgenstein. 1. Introduction Thecontent of an experiential state can often be described in public language partly in terms of qualities of objects that bear some salient relation to the state, for example, “looks red” or “feels like sandpaper” or “smells rotten”, but it is the contention of this paper that public language terms including terms for such properties of objects do not fully capture the contents. Qualia in my terminology are ways things look red or feel like sandpaper or smell rotten. If things can look red in more than one way—as I will be arguing—“looks red” does not fully capture the content of the state. Qualia can be referred to in public language, for example as the quale I get when I see green things. But that way of referring to74 / Ned Block the quale does not fully capture its content—it does not capture the individuating particularity about the way that I see green that is different from the way others may see green. Similarly, I can refer to the content of a thought as “the content of the thought I had at 11:33 AM” without fully capturing its content.2 We have a notion of the content of an utterance or thought which can be fully captured without specifying anything about modes of presentation. If I say “Napoleon is buried in Paris,” we can fully capture an important content of that utterance by saying it is the content that Napoleon is buried in Paris, even though that way of putting it does not attempt to specify my eccentric ways of thinking of Napoleon and Paris. But the experiential aspect of the content of an experience just is a kind of mode of presentation, so a notion of the content of an experience that left out the mode of presentation would be defective. Note that I am assuming color realism, i.e. that there are facts about the colors of things and those facts involve things having colors, for example that fire hydrants are often red and grass is often green. This position contrasts with error theories that say that nothing really is colored but rather color involves an erroneous projection of mental properties onto the world (Boghossian & Velleman, 1989, 1991). In other work, I have defined qualia as qualities of experience that cannot be defined in terms of their representational,3 functional4 or cognitive properties. And I have used the inverted spectrum hypothesis (Block, 1990, 1994, 1999; Block & Fodor, 1972) in those arguments. The word ‘qualia’ is often used to indicate a feature of our experience whose existence is disputed. Here the focus is on the ineffability of experience, and so it is convenient to use the term ‘qualia’ to denote features of experience that have the kind of ineffability just mentioned.5 2. Two Inverted Spectrum Hypotheses “Wittgenstein’s Notes for Lectures on “Private Experience” and “Sense Data”” (Wittgenstein, 1968) were written in English, apparently between 1934 and 1936 (Rhees, 1968). Wittgenstein is notoriously difficult to interpret, even to the extent that scholars cannot agree whether claims that are clearly formulated in his writings are being asserted or denied—or neither. I will put forward an interpretation of Wittgenstein’s view of the inverted spectrum hypothesis and of the nature of sensory experience, not as a proposal that meets the standards of Wittgenstein scholarship, but rather as a suggestion in a recognizably Wittgensteinian framework that is worthy of discussion (and refutation) on its ownmerits. When I attribute a view to Wittgenstein, you may wish to understand that as “Wittgenstein-according-to-one-non-expert”. The seeming endorsement of the possibility or at least coherence of one kind of spectrum inversion (theWittgenstein and Qualia / 75 kind I am calling “innocuous”) begins in this passage6: The normal use of the expression “he sees [red] where …” is this: we take it as the criterion for meaning the same by ‘red’ as we do, that as a rule he agrees with us in giving the same names to the colours of objects as we do. If then in a particular instance he says something is red where we should say that it’s green, we say he sees it different from us. Notice how in such a case we would behave. We should look for a cause of his different judgment, and if we had found one we should certainly be inclined to say he saw red where we saw green. It is further clear that even before ever finding such a [[284]] cause we might under circumstances be inclined to say this. But also that we can’t give a strict rule for… Consider this case: someone says “it’s queer/I can’t understand it/, I see everything red blue today and vice versa.” We answer “it must look queer!’” He says it does and, e.g., goes on to say how cold the glowing coal looks and how warm the clear (blue) sky. I think we should under these or similar circumst[ances] be incl[ined] to say that he saw red what we saw [blue].7 And again we should say that we know that he means by the words ‘blue’ and ‘red’ what we do as he has always used them as we do.” I will be arguing that the kind of inverted spectrum hypothesis that Wittgenstein endorses (as possible or at least coherent) in this passage commits him to something he would not agree with, so a defender of Wittgenstein might respond that after proper consideration, Wittgenstein would not have endorsed it.8 However, I think what Wittgenstein describes here is obviously coherent. Further, subsequent technological developments have shown that something near enough is possible, even technically feasible now. Colors are easily reversed in digital television. I myself have appeared, inverted in color, in an interview on a German television station. And it is feasible right now for virtual reality goggles to make use of such technology in producing that inversion experience in a subject. Witha relatively small investment, suchvirtual reality goggles could be produced now. I think most vision scientists would agree that the same transformations could in principle be accomplished by circuits embedded between the eye and the brain, although no one knows how to do this now. (I will describe this science fiction scenario as having “wires crossed” in the visual system, a terminology that I think derives from Putnam (1981, p. 80).) Later in these notes (p. 316 of Rhees, p. 285 of Stern), Wittgenstein confirms the endorsement and introduces the version of the inverted spectrum hypothesis that he rejects—what I will call the “dangerous” type. (This is my terminology, not Wittgenstein’s—I mean dangerous for a Wittgensteinian point of view.) …We said that there were cases in which we should say that the person sees green what I see red. Now the question suggests itself: if this can be so at all,76 / Ned Block why should it [not] be always the case? It seems, if once we have admitted that it can happen under peculiar circumstances, that it may always happen. But then it is clear that the very idea of seeing red loses its use if we can never know if the other does not see something utterly different. So what are we to do: Are we to say that this can only happen in a limited number of cases? This is a very serious situation.—We introduced the expression that A sees something else than B and we mustn’t forget that this had use only under the circumstances under which we introduced it.9 Consider the prop[osition]: “Of course we never know whether new circ[umstance]s wouldn’t show that after all he saw what we see.” Remember that this whole notion need not have been introduced. “But can’t I imagine all blind men to see as well as I do and only behaving differently; and on the other hand imagine them really blind? For if I can imagine these possibilities, then the question, even if never answerable makes sense.” Imagine a man, say W., now blind, now seeing, and observe what you do? How do these images give sense to the question? They don’t, and you see that the expression stands and falls with its usefulness. The idea that the other person sees something else than I, [[317]] is only introduced to account for certain expressions: whereas it seems that this idea can exist without any reference to expressions. “Surely what I have he too can have.”10 Note the words “Wesaidthatthere were cases…” suggesting that those cases are coherently describable and perhaps possible. What is the difference between the innocuous and dangerous cases? In the innocuous case, colors are inverted but certain properties of them—warm and cool—are not, and this happens suddenly to someone whose color experience has been normal before. So it is detectable because of two significant changes: (1) Things the subject knows to be red such as hot coals and blood look green and things the subject knows to be green such as grass look red and (2) blood suddenly seems cool colored and grass seems warm colored. The dangerous scenario is widespread and is not behaviorally detectable. There is an immediate problem in figuring out what is supposed to be happening in the dangerous scenario. The most straightforward way for the innocuous case to become widespread would be if the odd thing that happened to the subject of the innocuous inverted spectrum scenario simply happened repeatedly, the result being many inverted people who saw blood as green and cool-colored and grass as red and warm-colored and were aware of this fact about their vision. But that is not what Wittgenstein intends in the dangerous scenario, since he takes the dangerous scenario to be one that is behaviorally indetectable. He says about the dangerous scenario that “we can never know if the other does not see something utterly different.” Perhaps the odd thing that happened to the subject in the innocuous scenario is supposed to have happened at or before birth in the dangerous scenario. Then one might suppose that inversion is widespread but not detectable because the inverted people have not experienced a change and they have learned to use color words and the word ‘cool’ in conjunctionWittgenstein and Qualia / 77 with the color experiences they get on seeing, e.g. grass. So one might take the dangerous scenario to be one in which warm and cool are supposed to be inverted along with the colors themselves (Block, 1990, footnote 16; Levine, 1991), and in which the subject has no memories of things having looked differently in the past. 3. The Inner Arena Model This paper started life as a comment on a chapter of Paul Horwich’s book in progress on Wittgenstein (Horwich, in progress). Horwich—like Wittgenstein— contrasts a form of inverted spectrum involving experiential contents that can be captured in ordinary language with another form of inverted spectrum which cannot, and so, in my terms involves qualia. I am grateful to Horwichand his chapter for inspiring me to try to elaborate the case for qualia from considerations of inverted and shifted spectra—the subject of this paper. Horwich, interpreting and elaborating Wittgenstein’s ideas, argues that (what I would call) the dangerous inverted spectrum hypothesis presupposes a private arena model according to which experiences take place that are observed directly by the person whose arena it is, but only indirectly by others. And awareness of experience is not just a matter of having the experience. On Horwich’s account, the private arena model motivates a conception of experience as essentially subjective and ethereal and not constituted by anything objective and concrete. Hecontrasts these ideas unfavorably with the claim that the meaning-constituting use of “I am in pain” should be taken instead to be an expressive use in which those words are substituted for a natural expression of pain. On this account, the reference of ‘pain’ is not involved in fixing the meaning of the term. He also links the private arena model to the idea that there must be determinate answers to questions about the sensations of others, e.g. whether computers can have pains. A related view of the “Cartesian Theater” has been advocated by Dennett (1991). I will argue that an inner arena model has little to do with the argument for inverted or shifted spectra. It is not easy to find contemporary philosophers who have argued for the possibility of an inverted spectrum and who can also reasonably be said to accept a private arena model. D. M. Armstrong (1968; Bacon, Campbell, & Reinhardt, 1993, reply to Martin) accepts a perceptual model of introspection and something that might be called an inverted spectrum, but the issue is complicated by his eliminativism about experiential qualities. Sydney Shoemaker (1982) has argued strongly for the possibility of an inverted spectrum but equally strongly against an observational model of introspection (1994b; 1996b, including footnotes not in the journal version). As Shoemaker notes, it is not clear that even Locke accepted an observational model of perception, given that his theory of perception involves causal signals from external objects affecting sense organs so as to produce ideas78 / Ned Block in our minds that represent those external objects. This is a reliable but fallible process as contrasted with introspection, in which for Locke there is no gap between appearance and reality. Shoemaker gives a detailed analysis of what is wrong with various observational models of introspection. For example, perception involves an organ of perception but there is no organ of introspection; perception involves experiences of what is perceived but there are no experiences of experiences in introspection; there are not different introspective perspectives on the same experiences in the way that there are different perceptual perspectives on the same perceived object; the relation between the pain and the introspective belief about it is more intimate than an observational relation: the pain is more like a part of the introspective belief than a reliable cause of it; the objects of perception often exist completely independently of the perception of them and the perceivers who perceive them, but what is introspected cannot be independent of the introspection and introspector in this way. Shoemaker emphasizes a version of the self-intimating nature of experience in relation to introspection which has no analog in observation. His overall viewpoint provides a serious challenge to the idea that a dangerous inverted spectrum necessarily involves an observational model of introspection. I am another example of someone who argues for an inverted spectrum but does not accept the observational model of introspection. I agree with the points just mentioned about what is wrong with the observational model of introspection, but unlike Shoemaker, I think that one can attend to one’s own experiences. (And in that respect, my view is more like an observational model than Shoemaker’s.) Shoemaker’s view is shared by Fred Dretske (1995), Gilbert Harman (1990), Michael Tye (1995; 2000) and many others who advocate what G. E. Moore termed the diaphanousness (or sometimes the transparency) of experience. Harman (1990) puts the point by saying that the more one tries to attend to one’s experience of the tree, the more one attends to the real tree instead. Although Moore is sometimes cited as the originator of this point, he did not actually accept it. I have heard him quoted saying “… the moment we try to fix our attention upon consciousness and to see what, distinctly, it is, it seems to vanish: it seems as if we had before us a mere emptiness. When we try to introspect the sensation of blue, all we can see is the blue; the other element is as if it were diaphanous.” But these words are followed by what I regard as a more significant truth: “Yet it can be distinguished if we look attentively enough, and know that there is something to look for.” (See Amy Kind’s treatment in her 2003.) If we want to appreciate the case for the claim that we can attend to our own experiences, we would do well to avoid examples like Harman’s in which one is looking at a tree, trying to attend to one’s experience instead of the tree. An example I have used (1995): you are engaged in an intense conversation, realizing suddenly that for some time, you have been hearing street-drilling outside and have even raised your voice to compensate for it. At the moment of the suddenWittgenstein and Qualia / 79 realization, you switch at least some of your attention to the experience of the sound, and not just to the sound itself. For another type of example, consider the difference between blurry vision as of something, say a movie, whose lines may be clear and crisp, as contrasted withclear and crisp vision of a blurry movie (Block, 1996, 2003). There is an introspectible difference that cannot be appreciated without attending to the experience as well as to what the experience is of. What we experience is closely tied to what concepts we bring to bear in experience and introspective experience is no exception. Of course these examples are the beginning of an argument, not the end.11 Another way in which I differ from the private arena model as sketched by Horwichis that I do not take experience to resist objective concrete constitution. The view of qualia advocated here is, at least according to me, fully compatible with physicalism. I also doubt that the private arena model motivates the claim that experience resists objective concrete constitution. I take Dennett’s (1991) Cartesian materialist picture (a picture Dennett argues against) to be one that combines a private arena view withmaterialism. Still another way in which I differ from the private arena model at least in Horwich’s version is that I do not think that questions about other minds need have determinate answers. An example that I have given elsewhere (2002) is that belief in qualia does not require a determinate fact of the matter as to whether fishhave qualia. Horwichtakesthedifference between the innocuous and dangerous inversion hypotheses to be the difference between a case that can be described in public language withexpressions like “smelling a rose”, “painful” and the like, and a case that requires a private way of describing experience not expressible in public language. In my terms, the difference is qualia. He takes the rules of use for mentalistic expressions to dictate that your experience when you look at red things in normal circumstances is just like mine. There can be no further question of what it is like for you to see red as compared with me. To ask what looking red is like is like asking how long five feet is. Here, I disagree, as will become clear in the sections below on shifted spectra and inverted spectra. Horwich argues that the dangerous form of the inverted spectrum hypothesis derives from the internal arena model, especially the conflation of first person sensation reports—which he construes as expressions of sensation (on the model of natural expressions of pain)—withobservations. Certainly I and other contemporary advocates of inverted spectra do not accept key tenets of the internal arena model and the observational view of introspection. Of course, what one explicitly advocates and what one presupposes are two different things. In introducing a materialistic version of the “Cartesian Theater”, Dennett (1991, p. 107) allows that “Perhaps no one today explicitly endorses” suchan idea. Indeed, “Many theorists would insist that they have explicitly rejected such an obviously bad idea”. But, he insists, the picture he has sketched nonetheless plays a behind-the-scenes role. And perhaps Horwich would suppose something of this sort too. But Horwich andDennettgive noreasons for thinking that actual contemporary arguments for80 / Ned Block the possibility of dangerous inverted spectra really do presuppose the mistaken models. In my view, Wittgensteinians who emphasize the observational model of qualia are barking up the wrong tree. The view of qualia that leads to the epistemic problems that exercise Wittgensteinians is that that there are determinate facts of qualia independently of our cognitive access to those facts. AWittgensteinian might call it the “inner light” model.12 4. Intrasubjective vs. Intersubjective Let us nowreturntotheissue of what the difference is between the innocuous and dangerous inverted spectrum scenarios. Philosophers have made much of the difference between an intrasubjective spectrum inversion—in which a person at one time is said to be inverted with respect to the same person at another time— and an intersubjective spectrum inversion in which one person is said to be inverted with respect to another. (See (Putnam, 1981; Shoemaker, 1982, 1996a).) The key dialectical difference can be explained as follows. Suppose we have a pair of identical twins at birth, one of whom has had the wires crossed in his visual system. The twins are raised normally and acquire color terminology in the normal way. On the point of view that I favor, we may suppose that it is possible that the way red things (which they agree are red) look to one twin is the same as the way green things (which they agree are green) look to the other. Now a vulnerability in this line of thought stems from the following objection (Block, 1990, 1994; Harman, 1990). Notice that it is not possible that the brain state that one twin has when he sees things that both twins call “red” is exactly the same as the brain state that the other twin has when he sees things that they both call “green”. At least, the total brain states can’t be the same, since the first causes the subject to say “It’s red”, and to classify what he is seeing as the same color as blood and fire hydrants, whereas the second causes the other twin to say “It’s green”, and to classify what he is seeing with grass and Granny Smith apples. Here is an example. Suppose that the color-relevant brain state that one twin (the one who had no operation) has when he sees red things and that the other has when he sees green things is R-oscillations in area V4, whereas the color-relevant brain reaction in the first twin to green and to the second twin to red is G-oscillations in area V4. If the proponent of the possibility of an inverted spectrum says this is evidence for inversion, the objector can say that phenomenal properties should not be thought to be based in brain states that are quite so “localized” as R-oscillations in V4 or G-oscillations in V4, given that R oscillations lead to different reports in the different twins. Rather color experience should be seen as based in more holistic brain states that include the brain bases of reporting and classification behavior. (I am assuming agreement on an extremely weak form of physicalism.13) Thus the objector whom I am thinking of will want to say thatWittgenstein and Qualia / 81 one twin’s holistic brain state that includes R-oscillations and the other twin’s holistic brain state that includes G-oscillations are just alternative realizations of the same experiential state: that experiential state has a disjunctive realization. So the fact that red things cause R-oscillations in one twin but G-oscillations in the other doesn’t show that their experiences are inverted. Of course the local G to R transition is a transition in the way things look. However, that experiential difference has only been demonstrated intrasubjectively, keeping constant the larger brain state that specifies the roles of R and G-oscillations in classifying things. The R/G difference in each subject is a color experience difference, but this gives us no knowledge of cross-person comparisons. The objector can insist on typing brain states for inter-personal comparisons holistically. And most friends of the inverted spectrum are in a poor position to insist on typing experiential states locally rather than holistically, given that they normally emphasize the “explanatory gap”, the fact that there is nothing known about the brain that can adequately explain the facts of experience. So the friend of the inverted spectrum is in no position to insist on local physiological individuation of qualia. At this stage, the debate seems a standoff, and that is where the intrasubjective inverted spectrum comes into the picture.14 The intrasubjective inverted spectrum scenario can be seen as a way for the defender of the inverted spectrum to evade this objection, for if the change happens in the life of an individual person, we have introspective and behavioral evidence of an inversion and so can avoid the issue of whether brain states should be thought of in a localistic or holistic manner (Block, 1990, 1994; Shoemaker, 1982). I agree with this superiority of the intrasubjective inverted spectrum scenario, and will be pursing it in detail later. But for now, my point is that the intra vs. inter difference is not directly involved in the difference between the innocuous and the dangerous inverted spectrum. What is involved, as I will be arguing, is whether the inverted pair are both normal, since that is what is relevant to the expressibility of phenomenal character in public language.