Sunday, April 24, 2011

Troubles with the zombie argument in philosophy of mind

First of all it is important to keep in mind my initial disambiguation of intentional states and phenomenal states. It is already established that intentional states, since they are supervenient on physical states, can only be categorized operationally. Phenomenal states, as the friend of qualia has characterized them, cannot be categorized operationally (since they are beyond the reach of language). Of course an android could distinguish color surfaces without recourse to qualitative experience. We don’t think that there is “something that it’s like” for welder-directing robots in automobile factories to locate the seams with lasers. So when we are told that we can conceive of zombies it must be that we are meant to be conceiving of beings that are physically identical to humans but have no conscious experience. That functional descriptions can supervene on multiple physical descriptions has no bearing on the ontological status of qualia at all. I will make two arguments that are variations on the larger set of arguments presented here. First that the zombie counterfactual assumes something that it purports to show, and second that the zombie argument is an example of skepticism and is vulnerable to some counter-skeptical arguments.

The zombie counterfactual turns out to be question-begging: the friend of qualia has included qualia-body dualism as one of the premises. The claim is that we can conceive of beings that are physically identical to humans but that do not have immaterial phenomenal mental properties, unlike, presumably, the actual humans. To see this, try the same thought experiment only with the initial assumption (the most reasonable one, on the principle of parsimony) that qualitative experience will ultimately be explicable in wholly physical terms (that is, assume materialism as the default metaphysical position). The thought experiment now looks strikingly different.

Now (assuming materialism to be axiomatic, instead of dualism) the zombie argument is not question-begging: our initial assumption is that both the “blueness” of the surface of the plastic chair and the “blueness” of the phenomenal experience of the surface of the plastic chair are qualities had by virtue of the physical properties of the perceived chair and the perceiving body respectively. Now try this assertion on for size: “I can conceive of the plastic chair as having the identical physical properties that it now has (including its light-absorbing and –reflecting properties) but not having any color at all.” This is definitely inconceivable. When I try to conceive of an object with no color I for one try to imagine that the objects are transparent - I’m not sure if that counts as an object that has no color but it’s the best I can do. I cannot conceive of a physical object that is physically identical to an object that is colored but that has no color. This is just an application of the argument that to the extent that what I know, I know through “experience,” it makes no sense to draw a distinction between the phenomenal and the physical.

A second line of argument is suggested by the way Wittgenstein’s linguistic arguments can be deployed against skepticism. “Philosophical skepticism” is any argument to the effect that you don’t know something that you’re certain that you do know. Modern skepticism is closely connected to rationalism: Descartes thought that logical proof was the paradigm of “knowledge,” and it turned out, perhaps unsurprisingly, that by that standard we know very little. “The Problem of Other Minds” is a skeptical argument: you’re certain that other people have experiences and thoughts like yours but it seems that you can’t prove it. The Zombie problem is a variant on the problem of other minds: can’t you just see that other people are conscious? What would it be to doubt this? If the Zombie argument is an example of skepticism then we should be able to extend Wittgenstein’s treatment of skepticism to the Zombie argument.

A famous back-and-forth between Wittgenstein and G. E. Moore is good for illuminating this. In his essay “Proof of an External World” (1939) and elsewhere Moore is arguing in much the same philosophical spirit as Wittgenstein (they both think that skepticism is a pseudo-problem with roots in a faulty understanding of language), but Wittgenstein’s remarks on Moore’s arguments (included in On Certainty) make a crucial difference clear. Moore, presaging the “Ordinary Language” movement, wanted to show that “common sense,” by which he meant, roughly, ordinary talking and thinking about our physical selves in our physical world, was better defended with reasons than the speculative bases of skepticism and the “idealism” (really a kind of phenomenalism) still powerful in English philosophy at the beginning of the 20th century. Moore thought that our perceptions of our own bodies in the environment were instances – paradigmatic instances - of knowledge, not belief. Holding up his hand he would say, “I know I have a hand.” From the plain fact that I know I have a hand there arises similar knowledge of, ultimately, the external world: the keyboard is a reason for (believing in) the hand, the hand is a reason for the keyboard; the desk is a reason for them both and so on.

Wittgenstein’s response to skepticism is altogether different. Drawing on his premise that language must have operational criteria for determining appropriate conditions of use, Wittgenstein challenges the skeptic’s use of the verb “to know.” Take an ordinary (non-philosophical) instance of using that verb: “Do you know where your keys are?” The question makes sense because one might know or might not know, and “knowing” can be defined operationally: one can put one’s hands on one’s keys or one cannot. The question, “Do you know that the external world exists?” has no criterion for use: nothing could count as demonstrating that the external world either does or does not exist. That is, we neither “know” nor do we “not know” that the external world exists. The word “knowledge” has no place here. Where Moore proposed a kind of normative epistemology that would, if accepted, constitute an argument for the existence of the external world, Wittgenstein denies that there could be any argument one way or the other: Moore has taken the bait and tried to play a game that can’t be played.

Here we can see Wittgenstein’s “soft” arguments about language and his “hard” argument called “solipsism” come together. It is important also to see that Wittgenstein is much closer to Hume than Moore is. Hume (like Berkeley) stresses that the assertion that the external world “exists” is just as untenable as the assertion that it might not. Both sides of the disjunction are nonsense, if either side is.

The problem of other minds is exposed to the same treatment as a pseudo-problem. PI 246:

In what sense are my sensations private? – Well, only I can know whether I am really in pain; another person can only surmise it. – In one way this is wrong, and in another nonsense. If we are using the word “to know” as it is normally used (and how else are we to use it?), then other people very often know when I am in pain. – Yes, but all the same not with the certainty with which I know it myself! – It can’t be said of me at all (except perhaps as a joke) that I know I am in pain. What is it supposed to mean – except perhaps that I am in pain?
Other people cannot be said to learn of my sensations only from my behavior, - for I cannot be said to learn of them. I have them.
The truth is: it makes sense to say about other people that they doubt whether I am in pain; but not to say it about myself.

If I say “I know he’s conscious” and you challenge me by excluding all operational criteria from counting as justification for my claim, all you will do is change the ordinary meaning of the (public) word “conscious.” But then I’ll just have to start using another word for the same purpose, because what I have to say will remain exactly the same. PI 403:

If I were to reserve the word “pain” solely for what I had hitherto called “my pain”, and others “L. W.’s pain”, I should do other people no injustice, so long as a notation were provided in which the loss of the word “pain” in other connexions were somehow supplied. Other people would still be pitied, treated by doctors and so on. It would, of course, be no objection to this mode of expression to say: “But look here, other people have just the same as you!”
But what should I gain from this new kind of account? Nothing. But after all neither does the solipsist want any practical advantage when he advances his view!

As for “consciousness,” its meaning will now be anything you care to stipulate – in other words nothing - since you’ve stipulated that one can’t hear, see, smell, taste or touch anything that could even possibly indicate its presence: much like the word “god.” Thinking about the semantics of the word “god” brings us back to the first argument about the question-begging nature of the Zombie counterfactual. If the claim is that an operational theory of mind such as functionalism, specifically, has a problem with qualia, it must at least be a tacit assumption that there could be some non-operational theory of mind (a traditional one? a popular one? a philosophical one?) that does not: one that actually incorporates information about “what it’s like” into psychological descriptions and explanations. But there is no theory of mind like that, and if the arguments rehearsed in this chapter are correct there cannot be one.

Even after all of this, though, Nagel’s point still stands: there is “something that it’s like” for me to have a qualitative experience, and mine might very well be different from a Martian’s, or a dog’s or even yours. Although language cannot express these “qualia,” much less produce coherent claims that they are “properties” distinct from physical properties, our progress here has not been wholly destructive. I am now in a position to say a few things, after all, about the metaphysics of phenomenal experience.

Sunday, April 17, 2011

Turning the Inverted Spectrum on its Head

The inverted spectrum argument is first found (remarkably full-blown) in Locke’s Essay Concerning Human Understanding (II, xxxii,15, “Of True and False Ideas”):

"Neither would it carry any Imputation of Falshood to our simple Ideas, if by the different Structure of our Organs, it were so ordered, That the same Object should produce in several Men's Minds different Ideas at the same time; v.g. if the Idea, that a Violet produced in one Man's Mind by his Eyes, were the same that a Marigold produces in another Man's, and vice versâ. For since this could never be known: because one Man's Mind could not pass into another Man's Body, to perceive, what Appearances were produced by those Organs; neither the Ideas hereby, nor the Names, would be at all confounded, or any Falshood be in either. For all Things, that had the Texture of a Violet, producing constantly the Idea, which he called Blue, and those that had the Texture of a Marigold, producing constantly the Idea, which he as constantly called Yellow, whatever those Appearances were in his Mind; he would be able as regularly to distinguish Things for his Use by those Appearances, and understand, and signify those distinctions, marked by the Names Blue and Yellow, as if the Appearances, or Ideas in his Mind, received from those two Flowers, were exactly the same, with the Ideas in other Men's Minds."

Locke composed this counterfactual as part of his effort to show that “tertiary” properties (the properties of mental “ideas”) were different from secondary (the causal properties of the object of perception to cause ideas) and primary (the physical properties of the objects themselves). This was the property dualism repudiated by Berkeley and Hume. In the 20th century the inverted spectrum has had a strong career as a demonstration of the failure of functionalism to handle qualitative properties and, more to the point, as a supposed demonstration that there are such properties (in substance this is very much the same as Locke’s original application).

Imagine someone whose color spectrum was inverted (the “invert”): where normal people saw red, the invert saw blue, where blue, red. Such a person, raised among normal, English-speaking people, would be functionally indistinguishable from anyone else: asked to go out to the car and get the blue bag, say, they would perform this task exactly as anyone else would. Neither they nor anyone else would have any way of knowing that the invert’s experience of seeing the blue surface of the bag was the same experience that everyone else had when they saw a red surface, since the invert, like everyone else, would refer to such a surface as "blue." Since the invert would be functionally identical to a normal person, a functionalist is committed to the position that there is nothing different about their mental state. But (the argument goes) of course there is something different about their mental state: the quale, or phenomenal quality of the experience, is different. Thus functionalism is false.

Wittgenstein argues that the absent qualia argument demonstrates just the opposite of what the friend of qualia claims: since it is not even in principle possible for public language (the only kind of language there is) to pick out private sensations, phenomenal properties are not a problem for operationalist approaches. No theory of mind (or science of mind or description of mind) will ever include any actual discussion of the specific quality of any specific private sensations, because they cannot be discussed. As for the alleged discussion of phenomenal experience we find in philosophy, this is an instance of confusing mention with use - just as one can mention “all sentences that have never been expressed,” but cannot cite one. Outside of (misguided) philosophical conversation there is no context for use of indexically subjective language such as “blue-for-me” as opposed to the intersubjective “blue” which, like all words, necessarily has public criteria for appropriate contexts of use. This is why even the very best of the phenomenologists (Husserl, Merleau-Ponty) never seem to get beyond a sort of “Prolegomena to Some Future Actual Practice of Phenomenology”: after the manifesto there is nothing more that can be said.

So far this is a version of what I am calling the soft argument: the argument is about language, not about the ontological furniture of the world. It has conclusions that perhaps all non-philosophers would find definitive. Qualia do not constitute any sort of obstacle to the naturalization of psychology from the point of view of the scientist because science never could be expected to go beyond the limits imposed on language by its public nature in the first place. Nor is there anything inadequate about our ordinary, colloquial speech about qualitative experience (about, that is, the flavor of the sauce or the hue of the sunset), notwithstanding our individuality, for the same reason. But what about that ontological furniture?

The metaphysical argument will be about the identification of consciousness with experience. The Kantian will say (confining ourselves to the terms of the present discussion) that consciousness is a necessary precondition for the possibility of experience, hence not identical to it. This argument might gain some traction if we concede to the Kantian the point that “experiencing” an object entails bringing the object under a concept (although see the discussion of Kant in Chapter Two), but that very distinction between sensation and perception in the case of objects itself entails that sensation (phenomenal experience) is something prior to the formation of a Kantian “representation.” (If the reader is thinking of Aristotle’s nous at this point I beg your indulgence until Chapter Four.)

I have been using the word “consciousness” as synonymous with phenomenal experience, but the word is also sometimes used in regard to intentional states. Used in its intentional sense, to be “conscious” of an object is, on the traditional view, to form a representation of it or, on the view that I advocate, to be in some sort of relationship to it. But it is incoherent to say that to be conscious of pain, say, is to form a representation of pain or to be in a relationship to pain. In its phenomenal sense the word “consciousness” just refers to the sum of phenomenal experience: pain is a constituent of consciousness, not one of its objects. I may be intentionally conscious of pain at some higher level of psychological organization (one that can be picked out with operational criteria), but it makes no sense to say that I have to form a representation of pain or be in a relationship to pain to have an experience of pain.

The same is true for color qualia or for any qualitative experience. Kripke famously pointed out that the word “pain” just refers to the sensation of pain. “Blue,” in its phenomenal sense, just refers to the sensation of blue. It is one of the components of experience, not some object of experience. Experience is qualia; qualia are experience. So (to get back to the supposed metaphysical implications of the inverted spectrum) it makes no sense to say that experience has properties. Only the objects of experience have properties.

Where this leaves us is at the point of distinction between Frank Jackson’s “What Mary Didn’t Know” essay and Thomas Nagel’s equally famous essay “What is it Like to Be a Bat?” In that article Nagel makes an argument very close to but not identical to Jackson’s. No matter how much we come to know (physiologically) about the echolocation organ of the bat, Nagel argues, we will never know “what it is like” to experience the world in the way the bat does. The difference between Nagel and Jackson is that, granting the present argument that (qualitative) experience itself has no properties, experience itself does not constitute any sort of information (experience is rather the ground of information). We can concede that different conscious beings have different experiences without conceding that this entails any ontological implications.

Some writers have argued that the invert cannot, in fact, be conceived (Douglas Hofstadter holds this view, for example). I do not take that position. Since I do not see how to refute the Wittgenstein/Buddhism non-duality version of “solipsism,” I have no motive to try to prove that we do, in fact, grasp the qualitative nature of the experiences of others. Even if we could do so we could not express this “grasp” linguistically. However there is a different application of the “absent qualia” argument, one that holds that we can conceive of beings functionally (“behaviorally” is a more appropriate word here) equivalent to humans that have no qualitative experiences: “zombies.” David Chalmers’ entire argument for qualia-matter dualism hangs on this claim. I do not believe that we can “conceive” of any such thing.

Sunday, April 3, 2011

Buddhism and Qualia

“Buddhism” is the name of an ancient tradition (with roots in the older Hindu tradition) that includes both philosophical and spiritual ideas and practices. After 2,500 years it is no surprise to find that classical Indian and Chinese philosophy, including Hindu and Buddhist philosophy, encompass a gamut of positions at least as diverse as those found in the European philosophical tradition. There are, in the philosophical senses of the terms, materialist Buddhists and idealist Buddhists, foundationalist Buddhists and relativist Buddhists. By titling this section “Buddhism” I do not mean to suggest that the arguments discussed here are characteristic of all of Buddhist thought. However these particular arguments do constitute a persistent and venerable thread and I will discuss several different sources. These arguments have roots in some of the most basic elements of Buddhist teaching. While I have chosen to concentrate on the Mahayana tradition that is not meant to suggest that other traditions and schools may not include similar arguments.

There is a complex mix of philosophical, psychological, spiritual and social motivations informing the life of Siddhartha Guatama and his ultimate focus on the nature of the self. The severe caste structure of Indian Hindu society was tightly tied to traditional Hindu concepts of karma and reincarnation. Souls rose and fell over the course of thousands of lifetimes, and humans were low on the scale of karmic life: overall the effect was fatalistic and conservative. At the same time the sixth century BC in India was a period of transformation when a vernacular Sanskrit brought cultural upheavals that included the beginnings of the Epic Hindu literature and the flowering of diverse Hindu sects, Jainism and other movements besides Buddhism.

The basic Buddha Dharma is the most well-known piece of Buddhist philosophy. These are the “Four Noble Truths”: All life is suffering (“duhkha”), says the Buddha; we suffer because we are caught in a cycle of sensual satisfaction and craving; this suffering can be alleviated and even brought to an end altogether; and the “Eightfold Path” of right attitudes and practices will lead to the cessation of suffering. From this starting point Buddhism developed, among other things, a philosophical tradition with a sustained interest in the nature of consciousness, experience and the relationship between the self and the world. The idea that the “ego”-self, the self that arises through the cycle of duhkha, is the encumbrance that the “bodhisattva,” or enlightened self, needs to lose in order to achieve nirvana is prominent in the earliest teachings attributed to Siddhartha.

It is a somewhat dangerous business bringing a discussion of Buddhism into a book focused on contemporary philosophy of mind. I want to stick closely to the line of argument that has brought us to this relatively exotic territory. The overall claim is that the metaphysical problem of the alleged existence of phenomenal properties as distinct from physical properties is a pseudoproblem. I have presented arguments of Hume and Wittgenstein that I think are persuasive versions of this claim. In the case of Wittgenstein I argue that the “solipsism” argument common to the early and late works entails that phenomenal properties do not exist (are not part of this world). The view that the self is “emptiness,” and that the overcoming of the duality between the self and the world constitutes nirvana (enlightenment) is extremely similar, if not identical, to Wittgenstein’s solipsism argument. I will describe the Mahayana version of the argument and then present some textual evidence for my interpretation from classical sources.

The earlier Abhidharma School taught that “dharmas” were individual, autonomous atoms of experience; something akin to Leibniz’s infinity of monads. This is idealist ontology: primary being was dharma which was understood as consciousness (more or less: the bulk of Abhidharma metaphysics consists of discussions of just what “dharma” is after all). Although the arising ego-self, on this view, dissolves into infinitude of discrete dharmas, these dharmas are constitutive of the world. Mahayana Buddhism attempted to go further and collapse the duality between the mental and the non-mental: a kind of ultimate erasure of the self from the world that resulted in freedom from the bonds of the karmic cycle, the traditional goal of both Hinduism and Buddhism. Their formula was


One must resist the Cartesian instinct to interpret this formula as stating that the world collapses into the mind (as it does on the idealist view). The idea is that each consciousness is a universe. That universe at the middle of which you are sitting is you: it/you came into existence when it/you became conscious. When you pass away the universe you inhabit will pass away: for that universe is you. This is a line that could be defended by Hume: he might point out, for example, that if all any talk about “the world” could possibly be referring to is experience, then it makes no sense to refer to “a world” beyond experience, and thus it is incoherent to speak of a common world for all of the “microcosms” – a pseudoproblem.

An account of nirvana as the realization of the non-duality of mind and world can be found in Mahayana Buddhism and its descendents. The Prajna-paramita, or Wisdom Sutra, was traditionally taken to be the word of the Buddha, but scholars trace its origins to the first century AD and it appears that it was composed over the next several centuries. In a chapter titled “Mara” (a malevolent deity who lays traps for spiritual seekers), we find:

Subhuti: Is it then possible to write down the perfection of wisdom?
The Lord: No, Subhuti. And why? Because the own-being of the perfection of wisdom does not exist, nor that of the other perfections, the emptinesses, the Buddhadharmas or all-knowledge. That of which the own-being does not exist, that is nonexistence; what is nonexistence cannot be written down by the nonexistent.

The spiritual goal here is to free the self from the cycle of satisfaction and craving, and that is accomplished by showing that the self is not part of the world (I am not claiming that our present question about phenomenal properties is what Mahayana Buddhism is all about!). The Wisdom Sutra emphasizes the nonexistence of “own-being,” the being of oneself in one’s world. I chose this passage because the topic is language, and the message conforms to Wittgenstein’s treatment of the alleged problem that arises when we think of phenomenal language, say the word “blue,” as referring to something internal (mental) versus external (physical). Here the predicate “exists” is understood as meaning “exists in this world,” the world of experience: but the experiencing subject is not in this world. This also conforms to Hume’s argument that it makes as little sense to speak of the physical as distinct from the mental as it does to speak of the mental as distinct from the physical. Both sides of the distinction drop away simultaneously.

In the chapter titled “The Exposition of the Nonexistence of Own-Being” the point is more explicit that karma (one’s involvement with duhkha, the cycle of satisfaction and craving) is based on “own-being” and “own-marks,” worldly characteristics of persons. “Dharma” means something in the area of “consciousness,” “self” or “view.”

Subhuti: If, however, these dharmas are empty of own-marks, how can with regard to dharmas which are empty of own-marks a difference or distinction be apprehended (to the effect that one says) “this one is a being of the hells, this one an animal,…this one a god, this one a human….” And as these persons cannot be apprehended, so likewise their karma or its karma result.
The Lord: So it is, Subhuti, so it is, as you say. In respect of dharmas which are empty of own-marks no karma or karma result can be apprehended....But when those too ignorant to cognize dharmas as empty of own-marks manufacture a karma…then, through badly done karma they are hurled into the three states of woe, through what is well done they are reborn among gods and men….Here the Bodhisattva, who courses in perfect wisdom, does not see those dharmas in such a way that, when seeing them, he apprehends any dharma whatever. Not apprehending them he sees that “all dharmas are empty.”

Hundreds of years later and thousands of miles away Eihei Dogen (1200-1253), the classic avatar of Japanese Zen Buddhism, had refined the teaching of the non-duality of mind and world into a meditation practice (“zazen”) and a literary genre (“koan”) that were more minimalist and practice-oriented than the ritual-encrusted, syncretic and generally more baroque Sanskrit and Tibetan traditions, although like Tibetan Tantric Buddhism, Zen and Chinese/Japanese Buddhism in general are descendants of the Mahayana tradition. In his Shobogenzo (“Treasury of the True Dharma Eye”) the solipsistic view has crystallized considerably. Here are quotations from the section “Actualizing the Fundamental Point” (written around 1230):

As all things are buddha-dharma, there is delusion and realization, practice, and birth and death, and there are buddhas and sentient beings.

As the myriad things are without an abiding self, there is no delusion, no realization, no buddha, no sentient being, no birth and death.

The buddha way is, basically, leaping clear of the many and the one.

To carry yourself forward and experience myriad things is delusion. That myriad things come forth and experience themselves is awakening.

When you see forms or hear sounds fully engaging body-and-mind, you grasp things directly.

To study the buddha way is to study the self. To study the self is to forget the self. To forget the self is to be actualized by myriad things, your body and mind as well as the body and mind of others drop away.

Enlightenment is like the moon reflected on the water. The moon does not get wet, nor is the water broken.

When the fundamental truth of mind=experience=world is realized things are grasped directly. The idea that there are qualitative experiences that are distinct from the objects of experience reflects the same Cartesian duality of mind and world that underlies representational theories of mind; the Buddhist aim in criticizing this duality as a misconception is essentially spiritual. The Wittgensteinian position is clearly echoed in the Zenrin kushu, a 15th century Zen text, which describes consciousness as “Like a sword that cuts, but cannot cut itself; Like an eye that sees, but cannot see itself”: what is constitutive of the experienced world cannot be considered as part of, or as in, that world.