7. Physicalism and Experience
7.1 The Phenomenal Quality of Experience
In discussing Kripke’s objection to the identity theory we encountered the idea that it is in the nature of some mental states that they feel a certain way to those who have them. Pains hurt. If something doesn’t hurt, it’s not a pain. There is something that looking at ripe tomatoes and strawberries in good light have in common, which is different from our usual visual perception of spinach and grass. If you don’t have an experience of seeing red when looking at an object, it doesn’t look red to you. For many mental states, such as sense perception or experiences, there is ‘something that it is like’ to have them. They possess phenomenal or phenomenological characters, sensory qualities or qualitative aspects. These are also referred to as raw feels and qualia.
Only conscious mental states, like seeing red or feeling nauseous, possess qualia. Unconscious states like repressed memories do not have phenomenal qualities. Epistemic states like knowledge, doubt and belief do not have qualia either. You don’t experience your beliefs or doubts, you just have them. Whether a mental state is knowledge has nothing to do with what it might feel like. Other mental states may be accompanied by qualia, but they are not essential to them. Maybe being angry, happy or jealous feels a certain way, but what you feel can vary. There may be a kind of feeling that accompanies some desires, but desire in general is not accompanied by any specific feel. Some desires are accompanied by some qualia, others by different ones, some by none at all. Being accompanied by qualia is not essential for something to be a desire. A desire is an intentional state: it is directed towards an object. Other intentional states are hopes, wishes and of course intentions. They, too, do not seem to feel a certain way. Epistemic and intentional states can also be subconscious or we may not be aware of them, and in that case they do not feel like anything at all.
Various mental states appear to possess qualia essentially. Qualia are central to how we identify certain mental states. Whether something is a pain depends solely on what it feels like. We identify pains by the way they feel. To discover whether something appears red to you, you’ll look at it. Mental states that are not essentially accompanied by qualia are not identified by how they might feel. To figure out whether you believe, know or doubt a proposition, you don’t inspect how entertaining it feels.
Thomas Nagel has argued that this also applies to the consciousness of an organism as a whole. Bats, for instance, experience the world through echolocation. Bats have a specific kind of phenomenal consciousness when they perceive moths. The world appears to bats in a certain way through their sense organs. There is something it is like to be a bat. All bats share this way of perceiving the world. The experiences of conscious organisms have a certain subjective character. They have a point of view.
7.2 Problems for Physicalism
The qualitative aspect of conscious experience is often felt to be problematic for reductive physicalism and functionalism. What place a state has in a causal network or what brain state it is seems irrelevant to what it feels like. No matter how similar a functional state or brain state is to ones that have previously occurred when people reported to be in pain, if it doesn’t hurt it’s not pain. If pains are essentially the kinds of things that are identified by the way they feel, then how can they be identical to functional states or brain states, which are not identified in this way? Brain states and functional states, it is sometimes claimed, don’t feel a certain way, and thus the identity theory and functionalism cannot account for qualia. This claim by itself is easily denied, but to make the point more forcefully, it has been argued that qualia are in some way or other independent of brain states or functional states.
Recall Turing’s test of whether a computer can be said to exhibit intelligence: it suffices for the computer to convince human interlocutors in a sufficient number of cases that they are conversing with another human being rather than a machine. But is there is no gap between the simulation of a conversation and a conversation, or between a simulation of intelligence and intelligence? Suppose we implant transmitters into the skull of a human body without a brain and control its movements externally, be it either by a human controller or a computer. That body plus whatever manoeuvres it is functionally equivalent to a human being, but would we also agree that it has mental states? In this case, there seems to be a clear difference between a simulation and the real thing that functionalism may not be able to account for.
The identity theorist can deny that simulations have consciousness, as they don’t have brains. But couldn’t there be a physical duplicate of you, a molecule by molecule copy, which lacks consciousness and experiences no qualia? This duplicate of yours is often called a Zombie: it seems plausible that Zombies could exist. If so, qualia cannot be identical to brain states. This is another version of the modal argument. Descartes himself considered the possibility that a human body may not be connected to a soul, without this manifesting itself in any kind of behaviour.
Less dramatically, isn’t it possible that there are people who see green whenever we see red, orange whenever we see blue, purple whenever we see yellow and conversely, and that this difference never comes to light? We agree on any judgement about colours: whenever we say ‘This is red’, they agree, and conversely, and similarly for all the other colours. Or might it not be that some people are in fact colour blind, but nothing in their behaviour ever shows this? The inverted spectrum or absent colour qualia appear to be genuine possibilities. People with inverted or absent qualia are functionally equivalent to us. If so, functionalist cannot account for qualia, as they cannot be identified with any functional states. The identity theorist can answer these objections by denying that Zombies or absent or inverted qualia are possible.
There are also problems qualia pose for both kinds of physicalism. It has been argued that no amount of physical information suffices to establish which qualia are associated with the physical occurrences that take place when organisms experience their environment. Nagel has argued that we can study the physiology of bats as much as we like, it will not tell us what it is like to be a bat. This is argument applies to consciousness as a whole. Frank Jackson has devised a thought experiment that is supposed to show that the same already applies to individual experiences. Suppose some poor girl, Mary, has been raised in an entirely black and white environment (or she wears contact lenses that allow her to perceive only light and dark, but not colours). She has been taught everything concerning human behaviour and their environment that can be explained in terms of physics. Nonetheless, we are inclined to say she's missing out. One day she is released (or has her lenses removed) and is presented with a ripe tomato in good light. Jackson argues that she learns something new, something she didn’t know before: what red looks like. She has acquired knowledge of a new fact, namely that certain physiological processes in humans, when ripe tomatoes are presented to them in good light, are connected to the experience of a quale, of what red looks like. Thus not all facts are physical facts and physicalism therefore must be false.
Before her release, Mary has got only a third person perspective on colour perception: she knows what is going on in people’s brains when light of certain wavelength hits their retinas. She lacks the first person perspective of what seeing coloured objects is like. She acquires this knowledge when she is released and presented with a ripe tomato. Similarly, we have only a third person perspective on bats and what is going on in them, but the first person perspective of a bat on its environment may be forever beyond our grasp, as we can only ever know what it is like to be human, but not what it is like to be a member of a different species.
Maybe one day neuroscience is able to explain how various physiological states perform functional roles in organisms. This still leaves a question: why is it that some physiological states feel a certain way to the organism? Physicalism faces an explanatory gap of how brain states give rise to qualia. Closely related is what is called the ‘hard problem of consciousness’: why are there any qualia at all? There is a gap, it seems, between the first person perspective of an organism and the third person perspective on the organism that physicalism cannot bridge, but must take for granted. When neurophysiology investigates the brain states associated with pain, it presupposes subjects’ reports of the phenomenological qualities of their experiences. We can describe what is going on in human beings in two ways: the qualia we experience and the physiological processes occurring. Neuroscience aims to describe humans in purely physical terms, whereas we describe our mental life in purely phenomenological terms. For a full account of what it is to be human, we would have to put these two together, but how are we to do that, as they seem so entirely disparate? This is another facet of the mind-body problem.
7.3 Physicalist Replies
The classic response by identity theorists to the problem that phenomenal consciousness appears to pose to physicalism is that we shouldn’t take qualia-talk at face value. Place and Smart suggested that instead of puzzling over sentences like ‘I see an orange after-image’, which seemingly commit us to the existence of irreducible mental properties, we should rephrase such reports in topic-neutral fashion, along the lines of ’There is something going on which is like what is going on when I see an orange’. The advantage of topic-neutral reformulations is that they show that reports about our mental lives do not commit us to any specific position on the nature of phenomenal consciousness. Dualists and materialists reports have the same meaning, but they are at liberty to fill in what it is referred to in terms of their preferred ontologies.
Other physicalists have argued that reports of what it is like to undergo certain experiences should be taken as what they are. The proposal is that phenomenal concepts have a genuine role to play in the way we report on our mental lives, which distinguishes them from concepts of neuroscience. Nonetheless, both kinds of concepts describe brain states. Some physicalists like Brain Loar and David Papineau propose a conceptual dualism of first person, phenomenal concepts and third-person, physical concepts. Phenomenal concepts are recognitional: they are acquired and applied essentially through the way we perceive the world with our sense organs. Physical concepts are theoretical and not tied to perception in this way. The two kinds of concepts are genuinely different in content, but refer to the same things, namely brain states. Any ‘gap’ is conceptual, not ontological: the world decides what properties there are, not our concepts.
This goes hand in hand with the observation that conceivability may not be a reliable guide to possibility. The dualist, be it of the substance or property kind, claims to be able to conceive that the mind is different from the brain or that mental properties are different from physical properties. The identity theorist must deny that whatever has been conceived here is a possibility, contrary to appearance. The conceptual dualist can give a diagnosis of where this impression of possibility comes from and where the dualist’s reasoning has gone wrong. Because there are two genuinely different ways of speaking, we can fail to realise that they both refer to the same things. The dualist arguments against the identity theory show only that we have dualist intuitions, grounded in our two ways of speaking, but do nothing to refute the identity theory.
Dualists argue that Jackson’s Mary gets to know a new fact when she sees colours for the first time: what goes on in people’s minds when they looks at coloured things and which qualia are connected to the brain processes she already knows about. Certainly something changes in Mary when she first sees colours. Light with a certain wavelengths enters her eyes and falls on her retina for the first time. The question is whether this really gives her knowledge of any facts she did not know about before. David Lewis has argued that seeing red things only gives her a new ability: to single out red things by looking at them. Before her release, she was able to distinguish which things look red to people with normal colour vision only with the help of experiments. This new capacity does not give her new knowledge that something is the case, although she gains knowledge how to do something on the basis of what has changed in her when she first experienced a red object.
7.4 Higher Order Theories of Consciousness
The difference between conscious and unconscious mental states can be characterised as one of awareness: we are aware of our conscious states, but not of our unconscious states. When I have the conscious experience of seeing a red thing, for instance, I am aware that I see something red. Thus it is plausible to say that consciousness consists in having higher order mental states, that is having mental states about one’s mental states. One option is that consciousness is higher order perception, another that it is higher order thought. According to both views, consciousness is not an intrinsic feature of mental states such as seeing orange, being in pain, wondering whether I’m being deceived by an evil demon, but, being essentially a relation to them, consciousness is extrinsic to mental states. Neither version is necessarily tied to physicalism. However, in as much as neither thought nor perception pose a special problem for physicalism, the theories lend themselves to give physicalist accounts of consciousness.
An interesting aspect of higher order theories of consciousness is that they aim to explain the nature of conscious mental states in terms of concepts that do not themselves presuppose consciousness. Contrast this with the arguments against physicalism based on the subjective quality of experience. They are framed in terms of notions of consciousness and conscious experience that are taken for granted and are likely to be treated as so basic and of their own kind that it is impossible to elucidate them any further.
The view of consciousness as higher order perception is often traced back to a passage in Locke’s Essay Concerning Human Understanding: ’consciousness is the perception of what passes in a man’s own mind’ (Book II, chapter 1, §19). According to this view, put forward by David Armstrong and William Lycan, in addition to having sense organs to perceive their environment, conscious beings also have an inner sense that perceives the perceptions of their sense organs or their experiences of the world. The subjective quality of experience or the first person perspective derives from the inner sense being aware of perceptual and other mental states.
One problem with this view, and a reason for thinking that consciousness is intrinsic to certain mental states, is that we appear to be immediately conscious of our experiences, rather than our consciousness of them being mediated via something else. We perceive the pain, not the perception of pain. Perceptions can misrepresent what we perceive. Things that are oval may look round, others look bigger than they are. What would it be for the inner sense to misrepresent what it perceives? Suppose I look at a purple flower in good light and perceive it as purple, but my inner sense misrepresents my perception as being one of looking blue. What does the flower look like to me? On the one hand, the immediacy of experience suggests that it looks purple to me, on the other the malfunction of the inner sense suggests it should look blue to me. We can’t have it both ways.
The alternative view is that consciousness consists in having thoughts or beliefs about one’s own mental states. For a mental state to be conscious, the subject judges itself to be in that state. Thus, consciousness is a cognitive state or has a conceptual component. As beliefs are not experiences, consciousness is not an experience either. Actualist higher order thought theories of consciousness require a conscious mental state to be the object of an actually occurring thought. For dispositionalist higher order thought theories of consciousness it suffices that the mental state is available to be the object of a thought, without that thought actually having to occur.
A reason to favour a dispositional account over an actualist account is that our conscious experiences may well be too complex and detailed for us to have thoughts about all the aspects of which we are conscious. Consider listening to a piece of music, looking at a painting, experiencing the taste, smell and texture of wine. The actualist theory appears to require that you have a distinct thought about each aspect of which you are conscious. That’s a lot of thoughts to have. You may not be able to conceptualise your experience in all or even any detail. What would it mean to have a thought about your experience if you cannot conceptualise it? By contrast, the dispositional account makes only the much weaker claim that we could have such thoughts under suitable circumstances.
Actualists, however, argue against dispositionalists by pointing out that they cannot in fact account for our awareness of our own mental states and thus cannot account for consciousness. Being able to have a thought about a mental state in suitable circumstances, or being disposed to have such a thought, cannot make anyone aware of that mental state. Only an actual thought can do so.
A problem for either higher order thought theory is that it appears to demand too much of conscious creatures, namely that consciousness requires cognitive or conceptual capacities. If the theories are supposed to account not only for the nature of individual conscious mental states, but also for consciousness as a whole, or the first person perspective that each conscious being has on the world, it would appear to require that conscious beings have a concept of the self or at least the first person: I am experiencing this. Nonetheless, we ascribe consciousness or conscious experiences to creatures we do not think have the capacity for thought, let alone the concept of the self.
A final problem for higher order theories is that, as they characterise consciousness not as an intrinsic aspect of our experiences, but an extrinsic, relational one, it should be possible that we undergo unconscious experiences, e.g. unconsciously seeing red or unconsciously feeling pain. The apparent immediacy of experience makes this sound problematic. It has been argued, however, that this feature is actually an advantage of higher order theories, as it can explain phenomena such as blind sight.
7.5 Eliminativist Physicalism
The difficulties encountered in aligning our concepts of the mental and the merely physical have pushed some philosophers to draw the conclusions that our mental concepts are flawed. Nothing in the world corresponds to them. Eliminativist physicalism holds that the project of finding a place for the mind in the physical world is deeply misguided. There are no such things as minds and mental states, if by these we mean what our ordinary, everyday concepts purport to refer to.
Eliminativist physicalism must be distinguished from reductionist physicalism. The difference is vital. According to reductionism, mental phenomena are identical to certain physical phenomena. As those physical phenomena exist, mental phenomena exist. This is precisely what eliminativist physicalism denies.
An analog from the history of science clarifies the motivation behind eliminativism. According to 18th century chemists, the processes of corrosion and combustion occur when a substance they called ‘phlogiston’ is released. Combustion is the release of relatively large quantities of phlogiston over a shorter period of time, corrosion the release of relatively small quantities over a longer period of time. Wood burns because it is made up of ashes and a good amount phlogiston, and maybe other stuff that is carried off in the vapours produced when wood burns. Iron rusts because it is made up of rust and a bit of phlogiston, which is slowly released during corrosion. In general, metals that corrode are made up of what phlogiston theorists called the ‘calx’ of the metal and phlogiston (plus possibly other stuff). Stones contain no phlogiston, which is why they neither burn nor corrode. This a unified theory that explains the two processes and why some substances corrode or combust and others don’t. 18th century chemists also used it to explain other phenomena, such as why metal ores, thought of as metals mixed with different elementary earths, have fewer properties in common than their metals and the formation of acids by combustion of carbon and sulphur.
Unfortunately, phlogiston theory is flawed and does not stand up to empirical scrutiny. Lavoisier carried out experiments involving careful measuring of the substances released and left over by corrosion and combustion which contradicted the results predicted by phlogiston theory. When wood is burnt, phlogiston theory predicts that the sum of the weight of the vapours released and the ashes remaining should equal the weight of the wood. Lavoisier found out that the sum is larger. As iron corrodes, it gets heavier. In other words, rather than something being released by corrosion and combustion, something is being absorbed. This is oxygen. (My account of phlogiston theory follows Kuhn, T. S. The Structure of Scientific Revolutions (Chicago: Chicago University Press, 2012))
Phlogiston theory is flawed in that it does not accord with empirical findings. Even worse than that, it looks as if there could not be any phlogiston. Phlogiston is supposed to be a substance the release of which brings about corrosion and combustion. Experiments show that both phenomena are brought about by something being absorbed. Thus there cannot be such a thing as phlogiston. The concept ‘phlogiston’ is incoherent. When confronted with Lavoisier’s experiments, some phlogiston theorists like Priestly, who ironically played a vital role in the discovery of oxygen, continued to believe in phlogiston and tried to adjust the theory by adding more and more absurd epicylces, for instance that phlogiston has negative weight or that it is not a substance but a principle. But creating illusions of coherence does not create coherence, and so phlogiston theory was dismissed. Lavoisier did not reduce phlogiston to oxygen. He showed that there is no such thing. The term ‘phlogiston’ is not even a term of chemistry any more: it has been eliminated from science altogether.
To give another example, 18th century physicists thought that heat is caused by absorption of a substance they called ‘caloric’: the hotter something is, the more caloric it contains. There is no such substance. Heat is mean molecular kinetic energy, which is not a substance. Caloric was not reduced to anything, but eliminated from physics, although heat was reduced to mean molecular kinetic energy.
Eliminativists argue that our mental concepts face a similar fate. They are part of a theory, folk psychology, that one day will be discredited by advances in neuroscience. Even though most of us may not be aware of this, the eliminativist insists that the interconnections between our mental concepts are systematic enough for them to form a theory. We use them in predictions and explanations of the behaviour of humans and other creatures. Theories, no matter how successful they may appear to be to practitioners, can turn out to be wrong. Eliminativists claim that folk pychology is successful in the same sense in which phlogiston theory was once successful. It will prove to be less successful than neuroscience. Neuroscience will do away with mental concepts, just as chemistry did away with ‘phlogiston’ and ‘caloric’. Mental concepts will be eliminated from neuroscience.
Theories comprise laws or at least regularities. Paul Churchland has proposed that folk psychology accepts the following regularities involving propositional attitudes:
1. If x fears that p, then x desires that not p.
2. If x hopes that p and x discovers that p, then x is pleased that p.
3. If x believes that p and believes that (if p then q), then, barring confusion, distraction, etc., x believes that q.
4. If x desires that q and x believes that (if p then q) and is able to bring about that p, then, barring conflicting desires or preferred strategies, x brings it about that p.
We could go on formulating further regularities or systematic interconnections between our mental concepts that we implicitly subscribe to. Being a theory, even should no one have explicitly formulated it in much detail, folk psychology can turn out to be as mistaken as phlogiston theory was shown to be.
Notice that the eliminativist does not hold that our mental talk makes no sense or is somehow meaningless. This is so even if the eliminativist makes the very strong claim that our mental concepts are incoherent, so that nothing could possibly correspond to them. The claim is only that when we use mental terms, we are not referring to anything. We can indulge in fictions, without being committed to the existence of fictional entities. In a way the eliminativist takes our dualist intuitions very seriously and perhaps more so than the reductive physicalist.
In as much as it relies on future advances in neuroscience, eliminativism is a fairly programmatic position. Neuroscience may take a course in which respectable referents for our folk psychological terms are found, which is what the reductive physicalist claims. In as much as experiments in neuroscience rely on the reports of ordinary subjects who will couch them in folk psychological terms, it may be the case that neuroscience presupposes folk psychology. The eliminativist needs to make a strong case that mental language can and will be eliminated from neuroscience.
Another question is whether our mental concepts really form part of a theory, and if they do, whether this theory has the same status as a scientific theory. Phlogiston theory was refuted on the basis of experiments. What kind of experiments could refute folk psychology? Acquiring knowledge of folk psychology, no matter whether it is a theory, is rather like acquiring knowledge of a first language (and may be inextricably linked to it). It is difficult to make sense of the claim that English, say, radically misrepresents the world. Similarly, it has been claimed that it makes no sense to assume that folk psychology misrepresents what is going on in our lives. It is so entrenched in our understanding of the world that we could not even begin to make sense of the world, if we had to assume that our ordinary conception of mentality is as radically mistaken as eliminativists claim it is.
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