Am I My Brain?

The thought often strikes people when they are in their teens: it is most unlikely that the truth about the universe, or about the right way to live, is just what I happen to believe. It would be unbelievable good luck if the god my church taught me about actually existed, or if the ideas I have absorbed about democracy, feminism, or racism could not be improved on. Part of growing up is to see that, even if our beliefs are partly true, they do not correspond in a simple way to the world. Although I may aspire to make my beliefs as objective as possible, they are subject to the distortions of my particular perspective—my desires, interests, values.

There are two ways to respond to this thought, apart from ignoring it. One is to give up trying to be objective. Perhaps there is no objective truth, or if there is, we cannot know it. So one can say that my beliefs are as good as anyone else’s. This response is particularly common in the case of political beliefs. As George Orwell saw, it is a dangerous response, permitting every kind of propagandist his distortions. It survives only by deadening all critical thought. To hold views that we have no reason to think are more likely to be true than any others is hardly satisfying for most of us. And if you see your “beliefs” in this way, it is not clear that you really hold them.

The other response is to look for some way of correcting one’s beliefs through adopting a more objective perspective. We may try to look at the arguments for and against the existence of God with the eye of a logician. Or we may try to sift evidence about, say, the Nicaraguan conflict with the skeptical detachment of a historian. Perhaps most of all, we may absorb some of the methods of science, looking for evidence against a belief, and relating our confidence in it to the amount and quality of the supporting evidence.

In the search for more objective beliefs, science causes the greatest upheavals. We all know how far it has changed our understanding. As a route to increasingly objective beliefs, it is also the most hopeful, because of its inbuilt tendencies to connect statements with evidence. The development of more powerful instruments of analysis and observation, and the institutionalized pressure to see if results can be repeated, or better explained, make it harder for mistaken beliefs to survive.

But there is a deeper worry about objectivity: Kant’s thought that even science may not show us the world as it really is, because, as Thomas Nagel puts it, “we can conceive of things only as they appear to us and never as they are in themselves: how things are in themselves remains forever and entirely out of the reach of our thought.” Perhaps scientific observation is itself distorted by the nature of our sensory apparatus. It may be that we can correct for this. The observations of physicists, astronomers, or microbiologists transcend the limitations of the senses. Of course, we use our senses to interpret what radiotelescopes tell us, and some distortion may creep in. But as we understand more about the sensory systems of the brain, we can identify likely distortions and correct for them.

The more disturbing form of Kant’s thought concerns not our senses, but our intellectual apparatus. Our theories, and even our questions, have to be stated in concepts we can use. And perhaps the account of the universe that, from an objective point of view, is the most accurate one, cannot be reached by creatures with our intellectual limitations. Just as a dog cannot understand calculus, so perhaps we may be unable to grasp the concepts required for a more advanced physics.

Thomas Nagel’s stimulating book is, as he writes, “about a single problem: how to combine the perspective of a particular person inside the world with an objective view of that same world, the person and his viewpoint included.” The difficulty of reconciling these two standpoints, he argues, “is at the source of some of the most difficult problems of philosophy,” and is “the most fundamental issue about morality, knowledge, freedom, the self, and the relation of mind to the physical world.” In each of these subjects, he discerns a tension between objective and subjective perspectives. He also believes that the objective viewpoint usually gives an incomplete picture of things. Subjective features of the world—conscious mental process such as imagination or dreaming—are real, yet often cannot be incorporated as part of the objective account. As in the ambiguous figures used by psychologists, the two ways of organizing the picture are not reducible to each other, and there may be no way of eliminating a kind of rivalry between them.

The two perspectives are in conflict over the nature of the mind and of personal identity. Science gives us an objective picture of mental states as states of the brain, which is often thought of as the biological equivalent of a computer, although this is by no means an established view. Nagel objects that this picture of mental states leaves out the subjective side of experience. He once argued this in his well-known article “What Is It Like To Be a Bat?” We could know all about the brain mechanisms of a bat’s sonar system without having the slightest idea of what it is like to have the sonar experiences of a bat. In his new book, Nagel uses points of this kind to make two claims. We need to expand our idea of objectivity beyond physical objectivity. Here Nagel invokes the idea of “mental objectivity”: thinking of our experiences as only one kind among others, including kinds we may be unable to imagine. And we should accept that there is more to reality than objective reality since, as he writes,

the subjectivity of consciousness is an irreducible feature of reality—without which we couldn’t do physics or anything else—and it must occupy as fundamental a place in any credible world view as matter, energy, space, time, and numbers.

This line of thought conveys a brilliant diagnosis of why many people are uneasy about theories that reduce the mind to physical or functional states. A blind person who had studied the physiology and psychology of visual perception still would not know what it is like to see. If such a physiologist were operated on and given sight, the subjective quality of colors might come as a real surprise. This suggests that there is something about seeing that eludes description as a physical state or a function of such a state.

The question is whether we have to take this suggestion literally, and, as Nagel suggests, expand our picture of the world to include additional “subjective” items. Someone might study Paris in great detail without going there. He might know many facts about the proportions of the windows and shutters, the clothes people wear, the chemical composition of French bread and croissants, the way people drive, and so on. Yet he might never fully imagine what it feels like to be in Paris, and be surprised when he first goes there. But it seems excessive to conclude that we must expand our conception of reality to include an extra item: the subjective side of Paris. Nagel’s suggestive argument seems to prove too much. He must still face the question why it is that in some cases, but not others, our failure or inability to imagine something (such as the “subjective side” of Paris) should be taken as evidence of an additional property that eludes objective description. Nagel supplies no answer, and without one we may reasonably be skeptical of his argument in the case of the mind.

Nagel’s thoughts on personal identity can only be understood against the background of some influential recent thought experiments. If I ask what makes me the particular person I am, various things seem relevant. I have a particular body, which has relatively stable features and a continuous path through space and time. I have a mental life, which includes personal plans and projects, characteristic likes and dislikes, and which is linked to its own past by memory. Philosophers have made up thought experiments to discover which features are essential and which others are not.

Suppose my brain somehow has my memories wiped from it, and it is then programmed with “memories” of someone else’s past. And suppose the process is carried out in reverse on the other person’s brain. Do we say that I now inhabit his old body? Or do we say that I still inhabit my original body, with a set of delusive apparent memories?

Or consider Derek Parfit’s example, the teletransporter, which perhaps gets me from London to New York faster than the Concorde. I step into a booth in London, where a scanner destroys my brain and body, while signaling the exact states of all my cells to New York, where a replicator creates an identical body, including a brain with memories of my past. Have I traveled to New York? Or did I die in London, with only a copy of me being created in New York?

There are many rival answers to questions of this sort. Some theories stress bodily continuity, some psychological continuity. Some require that the relevant continuity is the result of known or familiar physical, biological, or social forces that act on my body and mind as I grow older (with the consequence that I cannot survive travel by teletransporter, which involves, among other things, the destruction of my body and the use of technologies that do not, and may never, exist). Others say that any reliable cause of continuity will do. The most radical view, expressed in Parfit’s Reasons and Persons,^* is reductionist. There is, he argues, nothing more to my continuing existence than certain kinds of psychological continuity, which can hold to varying degrees. On this view, there is no deep, all-or-nothing fact about whether a person is me. There may be no right answer to the question whether the person emerging from the teletransporter is me, and this question itself may be unimportant. What matters is just the degree of continuity of a particular kind of mental life.

Nagel rejects this. He thinks that what matters is not just psychological continuity, but what in the real world is its actual cause: the continuity of a particular brain. On his view, it is not quite true that I am my brain: I am larger and weigh more. But my brain is essential to me: it is the only part of me whose destruction I could not survive. This is a discovery that comes from a shift to a more objective point of view. We first identify gold by properties that are inessential, such as its color; only science reveals a particular atomic structure as its essential property. In the same way, we first identify people by inessential physical or psychological features such as bodily continuity or memory. Only the scientific discovery of the causal role of the brain in our psychology enables us to see the brain as our essential feature.

There is something intuitively appealing about this. Artificial hearts or kidneys do not make us worry about our identity. Yet if, at a more advanced stage of medicine, the neurologist tells you that your brain is functioning poorly, you may not be reassured to be offered a brain transplant. The brain seems more intimately me than the rest of the body is. But there is a problem of why we should stop where Nagel does. Could I survive the destruction and replacement of part of my brain? It is hard to see why the mechanisms in the cerebellum that control breathing, for example, are more intimately me than my heart and lungs. Perhaps what matters are the parts of the brain that are directly relevant to mental functions. But if so, why should we not say that the functions themselves are what count, rather than the piece of matter in which they are first embodied? This would allow the possibility of surviving teletransportation.

Nagel sees this problem and with typical candor says,

I don’t really have an answer to this, except the question-begging answer that one of the conditions that the self should meet if possible is that it be something in which the flow of consciousness and the beliefs, desires, intentions, and character traits that I have all take place—something beneath the contents of consciousness, which might even survive a radical break in the continuity of consciousness.

It is disturbing to give up the idea that I am something beneath the contents of consciousness. Part of our unease can be met by the thought that the continuity of our mental life also includes unconscious activity, and by the thought that it exhibits characteristic patterns. (The reductionist view, interpreted crudely, makes our experiences seem like a heap of stones, but it can accomodate the idea that they are organized to form a building.) But the possibly more satisfying alternative, showing that a particular physical region (whether the body, the whole brain, or part of the brain) is the location of the self, is not easy. The attempt seems doomed to arbitrariness.

Nagel has a special problem about the self. He thinks the self shows an important limitation of objectivity, conceived of as the impersonal view from nowhere. A complete impersonal description of the world would omit one important fact: that out of all the people in the world, this particular one is me. Nagel writes that an impersonal, objective conception of the world may include “TN, an individual born at a certain time to certain parents, with a specific physical and mental history.” But such a conception of the world cannot include, he argues, the “fact” that TN is “the locus of my consciousness, the point of view from which I observe and act on the world.” This is “a further truth, in addition to the most detailed description of TN’s history, experiences, and characteristics.” It is hard to state this point without sounding a bit like a character played by Woody Allen (Nagel might be heard saying: “I could have been Mozart, or Ingmar Bergman, or your mother, or anyone. Isn’t it just amazing that out of all those people I happen to be Thomas Nagel?”).

Statements made in the first person (“I am TN”) do seem irreducible to impersonal statements. But perhaps this is a semantic peculiarity rather than a deep metaphysical fact about perspectives. An objective description of the universe would not mention that this particular place is here, or that this particular moment is now. It is hard to keep up the sense of amazement that, out of all the millions of moments, “now” happens to be exactly ten past four this afternoon. Nagel sees the possibility of this problem being deflated by an analysis of demonstrative words such as “I” and “now,” but he rejects this approach. Yet persevering with such an analysis may be preferable to giving up the hope that the world can be described in a way both objective and complete.

Nagel does not claim to have solved either the problem of consciousness or the problem of personal identity. He is arguing against what he sees as premature “solutions.” He thinks we need a conceptual shift, of the kind physics had to make to accommodate electromagnetic phenomena. He thinks that when the new theory arrives (“probably not for centuries”), it “will alter our conception of the universe as radically as anything has to date.”

The recognition that our present theories will one day be transcended in important ways is a healthy corrective to parochial complacency. Current reductionist theories of the mind and of personal identity may well prove inadequate to describing ourselves in relation to the rest of the world. Nagel cites the unity of consciousness as a problem for the theory that mental states are states of something as complex as a brain, many of whose functions do not seem to work in a unified way. This is a problem, but serious exploration of it would require looking harder at the analogies Nagel thinks inadequate. How does the unified picture on the television screen emerge from such complex mechanisms? What is slightly exasperating about Nagel’s approach is his strong bias toward the view that such analogies will fail us, while he fails to give a detailed examination of them. It is also not quite satisfying that he offers as a possible solution the vague hope of future conceptual revolutions.

Nagel’s belief that no one now, including himself, has solutions to the great philosophical problems pervades his discussion. He says he does not feel equal to the problems treated in the book: “They seem to me to require an order of intelligence wholly different from mine.” When he writes that the scientific picture of man seems to leave no room for our subjective sense of freedom, he comments, “My present opinion is that nothing that might be a solution has yet been described.”

Nagel suggests that we hope to be autonomous, in a way that involves not just doing what we want to do, but having the kinds of desires we want to have. Our ideal is to be a particular kind of person, not through the luck of the genetic and environmental lotteries. Nagel thinks this ideal of total self-creation does not survive objective scrutiny. The

logical goal of these ambitions is incoherent, for to be really free we would have to act from a standpoint completely outside ourselves, choosing everything about ourselves, including all our principles of choice—creating ourselves from nothing, so to speak.

Our hope is incoherent, Nagel argues, yet it underlies all our judgments of personal responsibility, for when we regard others as “objects of admiration and contempt, resentment and gratitude, blame and praise,” we presuppose they are autonomous in this sense.

The idea of total self-creation is incoherent. But a more modest kind of self-creation is possible: we can to some extent shape what we are like in the light of our desires and values. If we try to do so, we have to start from somewhere, with values we simply take as given.

There seems to me a less pessimistic response to the problem. If we abandon the incoherent idea of total self-creation, we can then ask whether our ideas of responsibility really rest on such an inconceivable presupposition. Perhaps holding ourselves and others responsible for actions need only presuppose a more modest version of self-creation. We may have to give up some ultimate metaphysical idea of being absolutely responsible for our actions. But is it so clear that praise, blame, and related reactive attitudes are tied to this metaphysical idea? It seems at least worth exploring how far we can reconstruct these attitudes, or attitudes very close to them, while explicitly repudiating the idea that we are entirely responsible for what we are like. We have to choose between this kind of reconstruction or else accept that the attitudes are unjustifiable. Since there is no third choice, we should explore what is involved in each of these approaches. Either of them may yield more than Nagel’s pessimism suggests.

Nagel’s views on knowledge center on the process of liberating ourselves from distorting perspectives. To some extent we have the capacity to develop an “objective self.” We do so by stepping back first from the perspective we have as a particular person, and then from other limiting perspectives, such as those of our species. The wholly objective self would see the world from nowhere (or else from the perspective that would once have been thought of as God’s). It is a remarkable feature of human beings that we are able to understand our own perspective in objective terms, a perspective that Nagel thinks is unlikely to be explained by evolutionary theory. But we should not be complacent about how far we have come: “We are evidently just at the beginning of our trip outward, and what has so far been achieved in the way of self-understanding is minimal.”

The argument he gives against an evolutionary explanation of our intellectual power is simple. Evolutionary pressures might have selected genes for the ability to make a stone axe, but it is very implausible that such genes bring with them the capacity to develop modern physics.

“The capacity to form cosmological and subatomic theories,” Nagel writes, “takes us so far from the circumstances in which our ability to think would have had to pass its evolutionary tests that there would be no reason whatever, stemming from the theory of evolution, to rely on it in extension to those subjects.” He suggests that if we came to believe that our capacity for creating scientific theory were the product of evolution, “that would warrant serious skepticism about its results beyond a very limited and familiar range.”

I do not know what an adequate evolutionary account of the human intellect would be like. But this skepticism seems too strong, partly because it may underrate the generality of the capacities required for simple tasks. The man who needed to make a stone axe would be more likely to survive if he noticed that his neighbor’s axe, made of a different kind of flint, did not break so easily. He might have a brain programmed to adapt only to such information about axes. But he would be even more likely to survive if his brain were flexible enough to respond to such evidence about anything else he did and to ask questions that would lead him to look for such evidence. It does not seem absurd that the intellectual approach characteristic of science could have emerged in the struggle for survival.

Nagel emphasizes that we may not be able to understand the world fully. At times he seems to hold the (questionably intelligible) view that the universe is too pluralistic for any mind to form an adequate conception of it. (If it was created by an omniscient and omnipotent god, this arm of the paradox may cause some delighted chuckling: “I have created a world too complicated for Me to understand.”)

Whatever the truth about this, Nagel is surely right in stressing the Kantian possibility that our human brains may be inadequate to a full understanding of the world. Our perceptual limitations have been partly transcended by electron microscopes and so on. Perhaps computers more powerful than the brain will give us a parallel strategy for our intellectual limitations. This raises an issue about the kind of understanding we want. The computers would give answers we could use in our technology. But the understanding would not be ours. It would be like the “understanding” I have when I take a clock to be repaired. Part of our impulse toward a more complete and objective view of things is nontechnological. We are curious about the world, and take pleasure in expanding our own conscious understanding of it, in a way that suggests further questions. Computers alone will not give us all we want. We will, if possible, need to expand our own capacities. Perhaps direct neural links between brains and computers could open up ways of internalizing their understanding. If the Kantian limitations are real, the choice may be between Nagel’s pessimism and some such mental enlargement.

Why does it matter whether we hand over science to machines? We may care about ourselves being the ones who discover and understand. But from the objective point of view is anything we care about of the slightest importance?

Nagel sees instances of the conflict between objective and subjective in our values. He thinks there are objective values, in the sense that there are reasons for doing things that can be seen when we adopt an impersonal standpoint. There is also a conflict embedded in the values we hold, as Nagel thinks is shown when the “demands of impersonal morality are addressed to individuals who have their own lives to lead.” When we think of the misery in the world, there seems a strong case for devoting our entire lives to something like working for famine relief. But for most of us this would wreck our chances of doing most of the things we care about. Nagel hopes that social institutions can be designed to protect both personal life and impersonal good from the “ravenous claims” of each other. He thinks that being guided purely by the general good is not a plausible goal, at least at this primitive stage of our moral evolution.

The objective–subjective conflict may be most disturbing when we think of the objective unimportance of our own lives. The world would not have been a worse place if someone else had been born instead of me. But from my subjective perspective, to consider that possibility is to look back on a narrowly missed disaster.

And there is the same rivalry of perspective about the things within my life that I care about. We worry about our jobs, our children, our sex lives, or our reputations. But from a more detached point of view, Nagel argues, none of these really matter, any more than the concerns of a particular ant in an anthill. Nagel thinks we can eliminate neither our concerns nor this detached awareness of their objective unimportance. So our lives are absurd. And our problem has no solution, “but to recognize this is to come as near as we can to living in the light of the truth.”

A further question is how far there really is a single objective–subjective conflict underlying the very disparate issues discussed in Nagel’s book. I felt especially uneasy about this in the discussion of the meaning of life. When the problem is the nature of consciousness, or determinism, there seems a real tension between a plausible scientific account and how things seem from the subjective point of view. The tension is real partly because of the authority of science as the source of our most powerful understanding of what the world is like. But the authority of the detached perspective on our lives is much less clear. Here, the “objective” perspective seems to have been constructed by imagining away all our concerns and values. From that perspective, it does not matter whether a child falls in the fire, or whether a nuclear war breaks out. But such a perspective has no special authority. Unlike the scientific perspective, it has no plausible claim to be our best account of how things really are. Our lives do not become absurd because such a way of seeing things is possible.

At a time when so much philosophy is devoted to technical discussion of esoteric questions, Nagel has written an original book, accessible to any educated reader, on some of the largest questions about our knowledge of the world and our place in it. Often he does not answer those questions, and some of the answers he does suggest may not be right. But those who read it will be made to question many of their deepest beliefs, to consider new possibilities, and as a result to become more intellectually awake. So I hope it will have many readers. Unless, of course, it is absurd to care about such things.