Is that you, James?

Thomas Nagel

  • Philosophy and the Brain by J.Z. Young
    Oxford, 241 pp, £12.95, January 1987, ISBN 0 19 219215 9
  • Freedom and Belief by Galen Strawson
    Oxford, 353 pp, £27.50, January 1987, ISBN 0 19 824938 1
  • The Oxford Companion to the Mind edited by Richard Gregory
    Oxford, 874 pp, £25.00, September 1987, ISBN 0 19 866124 X

Your nervous system is as complex a physical object as there is in the universe, so far as we know: 12 billion cells, each of them a complex structure with up to sixty thousand synaptic points of connection with other cells. It is also the one piece of physical real estate of which you have an inside view, so to speak, since the events of your inner life, and the experiences through which you learn about the external world, are all immediate manifestations of what is going on in there. Since you can also study your central nervous system by external observation and experiment as you study other physical systems – by exposing its outer edges, such as the retina, to bombardment by suitably produced and therefore informative physical impulses – there arises a problem about how to bring these two views of yourself together.

The problem is as far from solution today as it was when Descartes tried to prove the distinction between mind and body 350 years ago – in spite of a widespread sense, fostered by the popular culture of science, that with the aid of computer analogies and advances in molecular biology we are on the verge of a breakthrough. The more we learn about the brain the clearer it is how little we understand its embodiment of the mind.

Here is a typical passage from Philosophy and the Brain by the eminent neurophysiologist J.Z. Young:

The pressure waves falling upon the ear from the sound of ‘Hullo’ are first transferred by the eardrum, then by the chain of three ossicles, next by fluid in the cochlear chamber and so into a travelling wave on the basilar membrane. From here they activate the hair cells to modify the trains of nerve impulses in the auditory nerve. These are then in turn re-coded several times before arriving at the auditory cortex. Here there are cells that respond only to certain patterns of these already much transformed versions of the original air waves. This is by no means the end of the process. The cortical cells continually exchange signals among themselves, which represent the patterns that have been learned in the past. Modification of the action of some of the cells by the incoming signals from the ear will produce appropriate outputs towards motor centres. The first response to the sound ‘Hullo’ may be a sharpening of attention and then, if it is repeated, perhaps a pattern of motor activity by the larynx and muscles of the throat that sends the response ‘Yes – is that you, James?’

There are evidently some gaps in the physiological story, but they get filled in with nothing more than the psychology of the man in the street dressed up as remarks about the brain.

The truth is that while a good deal is known about the outer boundaries of the nervous system – the initial effects of sensory stimulation and the last stages in the initiation of muscle contractions – we are largely ignorant about the central processes essential for hearing and seeing, let alone recognising the voice of your obnoxious colleague James who has to say ‘Hullo’ twice before you will answer him.

This darkness at the centre is emphasised by Young again and again, though there are interesting fragments of information: at least six ‘maps’ of the visual field in the cortex, in the form of patterns of cells activated by the irradiation of particular points on the retina; cells that respond to particular features of the visual stimulus, such as the directional orientation of a light-dark boundary; cells that are activated specifically by the look of human faces, and not by other types of patterns. A good deal has been learned about how individual neurons operate, how they interact with others in their neighbourhood, and how electrical nerve impulses are propagated. And a certain amount of crude geography has been inferred from the deficits produced by injury: lose Broca’s area and you can’t produce coherent speech; lose Wernicke’s area and you can’t understand language, though you can produce words; lose the hippocampus and you can’t form any new memories; lose the secondary visual association area and you can’t recognise what you are looking at, though you can see the shapes. But the understanding provided by such information is so far very limited. It is like trying to understand how the US political system works by locating the public buildings on a map of Washington DC.

Psychological theories formulated in terms of mental operations – theories of perception, learning, memory, motivation – do seek and often provide an understanding of how the mind works which transcends common sense and introspection. Some of those theories are represented in Young’s book, but though they are embellished with references to programmes in the cortex or activity in the basal forebrain areas, they are no more about the brain (and no less) than is my belief that Picasso had a remarkable imagination. The capacities described by those theories, or by that belief, are somehow or other due to the activity of the billions of cells beneath the skull or of particular large subsets of those cells, but we know remarkably little beyond that.

Young’s book is a clear, concise guide for the layman to what we do know, and he is scrupulous in pointing out the speculative character of any contemporary theory of the physical basis of central mental processes. The factual material is often fascinating, though I was disturbed by the statement, in a discussion of Sperry’s well-known split-brain cases, that the left eye communicates only with the speechless right cerebral hemisphere. In fact, it is the right half of each retina – which scans the left half of the visual field – that communicates with the right hemisphere, while information from the right half of the visual field goes to the left hemisphere. I have to assume that Young thought his simplification of the anatomical facts would be easier on the reader, but it makes me wonder whether other inaccuracies were introduced with a similar purpose – particularly since he seems concerned throughout to keep things very simple.

That aside, the book provides easy access to much information about current brain research that non-specialists should want to know, and bibliographical reference to more detailed treatments. But it is also presented, however diffidently, as a contribution to philosophy, and in this respect I am afraid it is not a success. Young believes that the information he has to offer about the brain can be useful in dealing with some of the big philosophical questions about knowledge, meaning, value and free will that have been around for a long time, but the trouble is that he has a tin ear for philosophy. He thinks information about the brain will help answer these questions because he doesn’t understand them well enough to see how easily they can be re-introduced once the facts have been heard.

It seems ungrateful to reject an offering of this kind from a scientist of Young’s distinction – made, I might add, with extraordinary humility and lack of pretension. But some outstanding intellects are simply not susceptible to philosophical problems, and apparently Young is one of them. He has sampled a number of prominent contemporary English and American philosophers and dutifully quotes Hare, Davidson, Mackie, Dennett, Ayer and so forth, as well as other, more traditional figures, in order to provide a context for the scientific information. But his comments on what he quotes, and his attempts to establish the philosophical relevance of facts about the brain, usually reveal that he doesn’t really know what is bothering these people. Evidence that the brain is active rather than merely passive in perception is hardly surprising, and does nothing to answer philosophical questions about the justification of belief. Information about punishment and reward centres in the brain or about homeostatic mechanisms that control body temperature, hunger and thirst is of no help with questions about the objectivity of value, nor does the suggestion that the basal forebrain areas are involved in learning social norms shed any light on ethics or political theory.

To take just one example, Young says:

For Descartes’s Cogito, ergo sum – ‘I think therefore I am’ – we might substitute the more biological proposition: ‘I am certain that I am alive.’ This has many advantages as a starting-point.

Well, it has the advantage of starting with the assumption that I am a biological organism, so that we can dispense with the need for asking how I know that. But Descartes, in his intellectual journey of relentless pre-emptive doubt, was trying not to avail himself of any assumptions about his nature or the world that depended on experiential evidence until he had established that such evidence could be relied on. That he was a biological organism was precisely the kind of thing he could doubt till then, in a way in which he couldn’t doubt that he was thinking. That is why he thought the existence of his mind was more certain to him than the existence of his body, and why he thought adequate new foundations for all other knowledge would have to rest on the inner knowledge of his own mind, through which all his other beliefs were formed.

This is the kind of thinking that makes someone a philosopher and not a biologist. The empirically-based findings of biology are logically incapable of supplying the foundations of empirical knowledge. If I had to give a general characterisation of philosophy I should say it was the examination of whatever is so basic that we must simply take it for granted in almost every aspect of life in order to function at all – whether we are merely living, talking, perceiving and acting, or are engaged in sophisticated scientific inquiry. An ordinary citizen or a research scientist can’t constantly be asking himself: ‘What is a number?’ ‘What is thought?’ ‘What makes my words mean anything?’ ‘How do I know that my experiences provide any evidence whatever about a world outside my own mind?’ ‘Does anything have any value at all?’

It is, in fact, a mark of the philosophical nature of these questions that you can go through life without thinking about them: it shows how fundamental they are. What is examined and called into question by philosophy is simply used in ordinary life. This makes philosophy a peculiar activity: when you try to subject to critical examination your most basic forms of thought and grounds of action, there is very little left that you can use in conducting the investigation. All your accustomed tools and methods are under the microscope, and you may have to use some of them anyway.

It is usually fruitless to try to answer the most basic philosophical questions by referring to the results of an empirical science – either because these results are based on methods and concepts and forms of evidence that are themselves the objects of those questions, or because the questions remain even if the results are accepted, as with sociobiology and ethics. The exception is a scientific result that is itself based on the philosophical revision of a basic concept – as Einstein’s theory of relativity was based on philosophical reflections about time. But physiological psychology has not reached that stage, and the information Young gives us about the location of centres associated with the emotions, the structure of pain receptors, short and long-term memory, thirst centres and anger centres and the information carried by DNA simply fails to make contact with the central issues of ethics, epistemology and metaphysics.

It may not always be so, but something radical will have to happen first. Consider the central metaphysical example. We know that the true physical story about the brain is unbelievably complicated. But we have, I would maintain, not the faintest idea of how such a physical story, even if we could get it and hold it in our heads, might constitute a full explanation of the basis of our mental lives. This is because practically no progress has been made on the fundamental problem of the relation between the view from outside and the view from inside, which arises in this area of science and no other.

All other scientific questions, however basic, approach things from outside, through sensory perception and experiment: they concern the external world and the relations between different levels of perception or description of it. This applies to biology and neurophysiology as well as to physics and chemistry. Psychology is the only exception, although plenty of philosophers and psychologists have tried to physicalise or externalise the subject-matter of psychology by various forms of behaviourism – some quite open and some, like the currently fashionable functionalism, lightly concealed. (Young, to his credit, has none of these flattening reductionist tendencies. While he is firmly opposed to a dualism of body and soul, he leaves open the question of the logical relation between mental events and the physical events invariably associated with them.)

The first question for any scientific theory is ‘What is it that has to be explained?’ And while externally-observable behaviour is part of what a theory of the mind has to explain, it is not all of it – in fact, the only physical manifestations that are of psychological interest are those that have something mental behind them. The subject-matter of psychology comprises the lives of beings that not only can be observed from outside but also have a point of view of their own. And while we can imagine, even if we do not possess a neurophysiological theory of the basis of their externally-observable physical behaviour – the model being that of enormously complex processes analysed into their minute physical parts – we have no comparable conception of what a purely physiological theory of the inner life could be, since it would have to anatomise the inside view in terms of what can be observed from the outside, and we have no models for that. We are still stuck, in other words, with the philosophical mind-body problem. It may eventually be transformed by work in physiological psychology, but only if it is acknowledged and addressed directly.

Another of the big old problems which might seem to be susceptible to illumination from facts about the brain is the problem of free will. But Young seems to think that this is merely the problem of describing how choices are made.

The act of making a choice is the product of the whole person, including his brain. We may follow the processes that might be involved in a trivial case: ‘I feel restless’ (the reticular system is in action); ‘I want a drink’ (the hypothalamus is signalling thirst and some centres conditioned by alcohol are at work); ‘Let’s see what he has in the cupboard’ (scanning activities by the eyes); ‘Ah, here are some bottles and glasses’ (comparison of visual input with stored representation); ‘I’d rather have gin than whisky’ (selection according to stored system of values).

Using these techniques, it would be easy to rewrite ‘Goldilocks and the Three Bears’ in neurophysiological terms. But the problem of free will is not addressed by descriptions of the process of choice: it can be raised against the background of any such description, since it is the problem of whether our natural sense of responsibility for what we do knowingly is intelligible, whatever naturalistic account of the process can be given.

By ingenious experimental techniques Benjamin Libet has shown that when a person decides to make a small physical movement of his finger at an arbitrary time of his choice, a characteristic electrically-detectable change in his brain, called a readiness potential, occurs slightly less than half a second before he becomes aware of his intention to move (and of course still longer before he actually moves the finger.) The brain appears to have made the choice before the person is aware of it. A philosopher to whom I described this experiment said wryly that the implication was clear: ‘Our brains have free will but we don’t.’ Young cites the result to show that it is futile to think of oneself as distinct from one’s brain. But the question remains, whether the initiation of decision prior to conscious awareness of it should undermine the belief that we are responsible for the decision (after all, no one would maintain that we are responsible for everything our body does – or even for everything our brain does). The question can be answered only through an analysis of what our natural sense of responsibility for actions amounts to. But an experiment like this seems to raise the disquieting possibility that what we take to be free actions are just things that happen to us, and that our conscious sense of choice is an illusion of control after the fact.

Perhaps this conclusion can be resisted on the grounds that consciousness from the start is not necessary for free choice. But behind the question whether the sense of freedom is an illusion there lurks a larger question. Even if we don’t have it, what would real control, or freedom, or responsibility be? Is there any naturalistic account of the generation of choice and action by the brain that would allow us to avoid the conclusion that the acts of which, as we do them, we take ourselves to be the originators are really, in the final analysis, things that merely happen to us – that we are so to speak carried along by our brains and by the world of which they are a part?

This is another of those mind-bendingly basic philosophical questions, and it is the subject of Galen Strawson’s Freedom and Belief, an often interesting and very involved exploration of the positive content and internal incoherence of our natural sense of ourselves (from the inside) as free and responsible agents. No one could accuse Strawson of insensitivity to philosophical problems: he has the essential capacity to be mystified by the utterly familiar, and to explain clearly both what is so puzzling about it and why the obvious moves of demystification that come first to mind will not work.

The problem of free will has more lives than a cat: after each attempted burial it will usually be found perched complacently on its freshly planted tombstone. Strawson’s position is that we naturally believe ourselves to possess a kind of freedom that we could not possess, because its conditions are incoherent. In the Western world, at least, people naturally believe themselves to be responsible for their actions in a way that makes them truly deserving of praise and blame for the character of those actions. But this, Strawson argues, requires that humans be truly self-determining – that their actions and all the features of character that influence their actions be determined by themselves – and this is impossible. It is impossible, not because of the way the world happens to be, but because it doesn’t make any sense, as the idea of a round square doesn’t make any sense.

But if it doesn’t make sense, what is it that we believe? Well, it’s not gibberish; its incoherence has to be uncovered. Even the idea of a round square, as Strawson points out, has a perfectly clear content: ‘a rectilinear, equilateral, equiangular, quadrilateral plane figure all points on the periphery of which are equidistant from a single point within it’. Just as this is geometrically impossible, philosophical argument shows both that true responsibility requires a strong form of self-determination, and that such self-determination is logically impossible. The difference is that we don’t have an irrepressible tendency to believe in round squares.

True responsibility is impossible not because everything we do is causally-determined far in advance: it is impossible whether what we do is causally-determined or not. Determinism is irrelevant to the question of free will because to be truly self-determining, one has to have determined how one is in such a way that one is truly responsible for how one is. But that requires having chosen how one is, and one can’t have done that unless the choice issues from one’s character and motives – i.e. from how one is. Responsibility for this in turn depends on one’s having chosen it, and so forth. ‘True self-determination,’ says Strawson, ‘is logically impossible because it requires the actual completion of an infinite regress of choices of principles of choice.’ This is impossible whether all our choices are causally-determined or not.

Strawson begins the book with a forceful exposition of this simple argument and responses to multiple attempts to refute it. While he doesn’t claim originality, he makes the case as effectively as I have ever seen it made. What is distinctive about his approach is that, having argued that strong free will is impossible, he has a great deal more to say about the positive content of the idea. A concept may be rich and complex although incoherent. For example, he believes there is considerable partial truth in the view of compatibilists, who think responsibility is compatible with determinism because responsibility requires only that our actions be causally-determined in certain ways that allow them to be regarded as the products of unconstrained choice. The truth in compatibilism reveals part of our conception of ourselves as free, even though it does not reveal the incoherent whole of it.

Strawson introduces the significant idea of a potential free agent. The issue of free will arises not just at the level of particular actions, but also with respect to the kind of being whose actions can be free, provided other conditions are met in the particular case. Thus on the ordinary conception, a human being completely tied up is a potential free agent, but an unfettered trout that can swim anywhere it wants is not. Certain capacities, in addition to the capacity for motivated movement, are necessary, and Strawson emphasises particularly the capacity for self-conscious thought: about one’s own desires, beliefs and reasons.

However, he does not believe that self-consciousness is enough, and this is not just because it does not guarantee full self-determination (nothing could do that), but because self-consciousness would be compatible with various forms of detachment from one’s own actions which would in themselves be incompatible with freedom and responsibility. Roughly, he claims that according to our natural idea of freedom, to be fully free one must believe oneself to be free – in making choices one must be convinced that they issue from oneself alone, in the light of one’s awareness of one’s desires and beliefs – and while this is a very hard conviction to get rid of, it is possible to imagine self-conscious beings who do not have it.

Certain forms of Eastern religious meditation may aim at overcoming this belief about oneself, but mere intellectual conviction that we do not have free will is not enough. By itself it will not change the overwhelming sense of responsibility one would feel if faced with the following choice (Strawson’s example): ‘If you agree to submit to twenty years of torture – torture of a kind that leaves no time for moral self-congratulation – you will save ten others from the same fate.’

Kant claimed that we cannot face such a morally-freighted choice without becoming directly aware of our own freedom. Strawson thinks that although it would be an alien and difficult condition to achieve, someone might really never feel free, and if that were so, then even if all the other conditions of freedom were met – even if, per impossibile, he were truly self-determined – he would still not have free will and would not be truly responsible. This is a difficult claim to assess, since it involves a counter-possible conditional: but it doesn’t seem right to me. If true responsibility were possible, couldn’t someone be deceived (even self-deceived) about whether he had it? Couldn’t he act with the illusion that all this was just happening to him, while actually it was his doing, and he was fully responsible for a choice which saved or failed to save ten other people from torture?

Strawson’s denial of this possibility leads him to conclude that the ordinary idea of free will is partly subjective: that is, it is not just the idea of an objective condition (even an impossible one) independent of the subject’s beliefs. (He spends an inordinate amount of time arguing that the extra condition of belief in one’s own freedom couldn’t be the indirect result of certain objective conditions.) But while he believes that a subjective condition is necessary for free will, he denies that it is sufficient: i.e. that a certain set of attitudes, on the part of the individual or of the community of which he is a member, would be sufficient for responsibility provided appropriate capacities for choice were present.

There is a strong temptation to think that our nearly unshakable conviction that we and others we know are sometimes responsible for what we do must be somehow self-guaranteeing, and that its content must be interpreted so as to make it come out either true or at least not refutable by very general information about the objective character and sources of human action. It has been argued, for example, that against the background of the powerful and natural system of ‘reactive attitudes’ connected with the idea of responsibility – such as resentment, gratitude, pride, shame and indignation, and the social practices connected with them – it makes no sense to call into question all claims of responsibility by means of a general rational argument that they are incompatible with our place in the natural causal order. Strawson believes, however, that ‘the fact that the incompatibilist intuition has such power for us is as much a natural fact about cogitative beings like ourselves as is the fact of our quite unreflective commitment to the reactive attitudes. What is more, the roots of the incompatibilist intuition lie deep in the very reactive attitudes that are invoked in order to undercut it.’ Whether or not the subjective conviction of free will is a necessary condition of free will, I agree that it does not appear to be a sufficient condition. It may be a basic experiential fact of life that we have such a conviction, but it is not self-fulfilling. Yet it is so powerful in most of us that we find it very hard to conceive that it is not just false but incoherent. Surely a conviction so strong and so central to our conception of ourselves must at least have an intelligible possibility as its object!

Strawson’s book has as one of its aims to describe the complex structure of the conviction in a way which will explain how it can be full of content and significance for us even though it is ultimately unintelligible. This is a valuable enterprise, and he pursues it with care and philosophical acumen. The book is too long, and it retains some of the unappealing features of the doctoral dissertation from which most of it derives: there are too many complicated détours to refute all possible counter-hypotheses, and countless arguments are shoved into footnotes. But it is a serious and intelligent work, written in an accessible style, on one of the hardest problems there is.

Anyone interested in these topics should acquire The Oxford Companion to the Mind, edited by Richard Gregory. The entries come from an outstanding group of 200 contributors, most of them psychologists, neuroscientists and philosophers. A substantial number were written by Gregory himself, and the book as a whole is of the quality one would expect from the author of Eye and Brain and The Intelligent Eye. His own essays are gems, and the general level of informativeness and economy of expression is high. There are short accounts of their own theories from figures such as Noam Chomsky, Roger Sperry, A.R. Luria and R.D. Laing, and articles on everything from neurotransmitters to the psychology of music to Capgras’s syndrome (the conviction that your nearest and dearest have been displaced by perfect replicas). The book gives a true picture of the fluid and complex character of thought about the brain in our time.