Edge 142—June 30, 2004
(7,950 words)

"So, what are are you up to this summer? What new ideas are you exploring? What new questions are you asking yourself? How about emailing a postcard?" An ongoing, summer-long Edge event. We will publish Edge Summer Postcards as they are received through Labor Day.


To date: Esther Dyson, John Markoff, Bruce Sterling, Ned Block, Daniel C. Dennett, Marc D. Hauser

What I'm now thinking — though it certainly needs further work — is basically that the point of there being a phenomenally rich subjective present is that it provides a new domain for selfhood. Gottlob Frege, the great logician of the early 20th century, made the obvious but crucial observation that a first-person subject has to be the subject of something. In which case we can ask, what kind of something is up to doing the job? What kind of thing is of sufficient metaphysical weight to supply the experiential substrate of a self — or, at any rate, a self worth having? And the answer I'd now suggest is: nothing less than phenomenal experience — phenomenal experience with its intrinsic depth and richness, with its qualities of seeming to be more than any physical thing could be.

A Talk with Nicholas Humphrey

Nicholas Humphrey Edge Video Broadband | Modem

THE REALITY CLUB: Daniel C. Dennett responds to Nicholas Humphrey

"So, what are are you up to this summer? What new ideas are you exploring? What new questions are you asking yourself? How about emailing a postcard?" An ongoing, summer-long Edge event.


To date: Esther Dyson, John Markoff, Bruce Sterling, Ned Block, Daniel C. Dennett, Marc D. Hauser

Marc D. Hauser


Hey John,

As we logged in our 60,000th subject from our moral sense web site, and submitted a paper to Science showing that centuries of philosophers have been duped into thinking that conscious reasoning as opposed to intuition guides moral judgments, I headed off with my wife Lilan and 3 year old daughter Sofia to the heartland of logic and reason Greece. My wife had lived on the island of Naxos when she was a child. Naxos owes its fame to mythology, the location where Theseus [of philosophical fame in the Ship of Theseus paradox on individuality] abandoned Ariadne [who had fallen in love with the god of wine, Dionysus] after slaying the Minotaur. A small part of the trip was centered on a conference exploring the evolution of a tool using brain, a fitting meeting for a country that did so much for the technological revolution. The majority of our trip was spent soaking in the beauty of the archaeological sites as well as the gorgeous topography.

[photo: a natural crater with a church built into the rock face]

I am proud to report that I left my computer at home, never once checked email, and managed to finish two awful books on moral philosophy and Tom Robbins' terrific new novel "Village Incognito." A vacation sans email is highly recommended!

Daniel C. Dennett

Blue Hill, Maine (as usual)

Hi John,

After almost forty years of postponements for a tedious variety of reasons, I finally have my dream sailboat, a twenty-one-year old Beneteau First 42 that I found in Newport last October and sailed to Blue Hill, Maine, where my farm is.

Over the winter she was repaired, repainted, renamed (Xanthippe, after Socrates' notoriously shrewish wife). (John, I already sent you the video clip of me sailing her to Maine in snowy October. You could run it to contrast with the summer pix.) Here are a couple of shots of her. I'm training a racing crew of former students, and we'll try not to disgrace ourselves in Down East Race Week in August. And Susan—who won't race—is happy to cruise among the many islands and inlets, with friends or just us. Today we charged down Blue Hill Bay to Flye Point and anchored offshore to listen to the Flye Point Folk Music Festival wafting downwind to us, and then ran back up the bay, making 7 and 8 knots with just our genoa flying—Xanthippe is fast and agile.

But she's also a great thinking platform, a place to work out kinks in my book in progress on religion as a natural phenomenon. (The trick now is to keep the nautical metaphors out of the text. Let's see if I succeed.)


[Click for video clip: Broadband | Modem]

Ned Block

Villa La Pietra — Florence, Italy

I am at NYU's Villa La Pietra in Florence where a workshop I organized has just come to a close. Sir Harold Acton donated the 57 acre estate on Montughi Hill overlooking Florence with its 15th
Century villa and Acton's collection of paintings to NYU in 1994. (It is valued at $500 million.) It is now used as the NYU campus in Florence and as a conference center. The conference was on consciousness and intentionality with special attention to the following questions:

Is the phenomenal character of experience reducible to its intentional content? If not, is one more basic than the other? What kinds of properties do conscious states represent? Sensory properties only? Natural kind properties? Do the arguments for externalism apply to the representational contents of experience? Do experiences have their representational contents intrinsically? What does the transparency of experience show about its conscious content?

Can an unconscious state represent the same properties as a conscious state? Are the contents of experience Fregean? Are there constitutive connections between the content of perception and the explanation of action? If so, why, and what are they? How more generally should we conceive of the relation between the philosophy of perception and the philosophy of action?

In what respects are both conscious thought and perception phenomenal? What is the correct account (1) of a person's possession of concepts of his own conscious states? (2) of a person's knowledge of his own conscious states? What is the proper relation between a philosophical accounts of (1) and (2) and the developments accounts of empirical psychology? What is the nature of conscious thinking?

Back row: (left to right) Maja Spener, UC London; Rachel Bernstein, artist; Jesse Prinz, Chapel Hill; Gideon Rosen, Princeton; Anne Barnhill, NYU; Liz Harman, NYU; behind Liz Harman, partially obscured, Michael Tye, UT Austin; Beatrice Longuenesse, NYU; Alex Byrne, MIT, Dale Jamieson, NYU; David Velleman, Michigan; Benj Hellie, Cornell; Jessica Wilson, Michigan; behind Jessica Wilson, partially obscured, Charles Siewert; Jim Pryor, Princeton; Susanna Siegel, Harvard; Bob van Gulick, Syracuse; Scott Sturgeon, Birkbeck London, plus small Sturgeon; in front of Sturgeons, Veronique Munoz-Darde, UC London; Mike Martin, UC London, Paul Boghossian, NYU; Front row: David Chalmers, Arizona; Christopher Peacocke, Columbia; Ned Block, NYU; Bob Stalnaker, MIT

Bruce Sterling

Basel, Switzerland

Bruce Sterling, at the premiere of his designer objet "(C)lamp,"at the Art Fair in Basel, Switzerland. June 16, 2004.

John Markoff


QuickTime Movie (3.3MB)


A step forward into multimedia... It's from the start of the Canadian Grand Prix in Montreal last week... (turn up the volume for best results...)

These things are real Cyborgs....as close as fighter pilots....


Esther Dyson

Moscow, Tverskaya Street


I can't resist... this is from my Treo. I'll send you more. (of course, it wasn't summer yet.....)


What I'm now thinking — though it certainly needs further work — is basically that the point of there being a phenomenally rich subjective present is that it provides a new domain for selfhood. Gottlob Frege, the great logician of the early 20th century, made the obvious but crucial observation that a first-person subject has to be the subject of something. In which case we can ask, what kind of something is up to doing the job? What kind of thing is of sufficient metaphysical weight to supply the experiential substrate of a self — or, at any rate, a self worth having? And the answer I'd now suggest is: nothing less than phenomenal experience — phenomenal experience with its intrinsic depth and richness, with its qualities of seeming to be more than any physical thing could be.

A Talk with Nicholas Humphrey

Nicholas Humphrey Edge Video Broadband | Modem


Nicholas Humphrey is a research psychologist whose interests are wide ranging: He studied mountain gorillas with Dian Fossey in Rwanda; was the first to demonstrate the existence of "blindsight" after brain damage in monkeys; and is the only scientist ever to edit the literary journal Granta. Thirty years ago he breathed life into the newly developing field of evolutionary psychology with his theory about "the social function of intellect." His more recent ideas concern the nature of phenomenal consciousness.

Unlike Daniel C. Dennett, who sees the role of philosophers as disabusing people of their "primitive" ideas about the nature of consciousness, Humphrey believes that we should take these primitive intuitions at face value. If people say that the problem is what it "feels like" to be conscious, then the problem is indeed to explain "feeling." Humphrey and Dennett are a pair of bookends. Humphrey has been described as a "romantic scientist", who believes in the heuristic value of stories that go beyond the limits of established facts. But he would probably not agree that there is a hard and fast line between facts and stories. "I'm me," he says. "I'm living an embodied existence, in the thick moment of the conscious present. I'm trying to work out why."


NICHOLAS HUMPHREY, School Professor at the London School of Economics and Professor of Psychology at the New School for Social Research, is a theoretical psychologist, internationally known for his work on the evolution of human intelligence and consciousness. His books include Consciousness Regained, The Inner Eye, A History of the Mind, Leaps of Faith, and The Mind Made Flesh. He has been the recipient of several honours, including the Martin Luther King Memorial Prize, and the British Psychological Society's book award.

Nicholas Humphrey's Edge Bio Page

Daniel C. Dennett responds to Nicholas Humphrey


(NICHOLAS HUMPHREY:) Forty years ago I wanted to solve the problem of consciousness. It seemed to me it would be a shame to leave it for the next generation to get the prize. Consciousness presents the greatest ever challenge to science; so great, that unless we find an answer soon, science itself is in danger of being humbled. Consciousness — phenomenal experience — seems in many ways too good to be true. The way we experience the world seems unnecessarily beautiful, unnecessarily rich and strange.

I've had various goes at it: approaching the problem from different angles — through neurophysiology, through animal behavior, through social science, through philosophy of mind. My guess is we'll need all these approaches, and more, before we see what consciousness really is and what it's for.

Recently I've been toying with a rather grand idea about why we may need to have conscious qualia in our lives. My idea is that we need them in order to realize just how important we are. Our experience of being conscious encourages us as nothing else could to take ourselves seriously as selves. It dramatically affects our whole attitude to the kind of people that we think we are. We find new value in our lives and, just as important, in the lives of other people.

Humphrey, Minsky, Gould, Dennett, Brockman (August, 1995)

I've come to this on the back of my earlier ideas about the nature of sensation. Some time ago I proposed a theory of how sensations work and why they have their qualitative properties. I argued that sensations derive their characteristic phenomenology from the fact that they are — in evolutionary origin — a kind of bodily action, involving reaching back to the stimulus at the body surface with an evaluative response. Conscious feeling, I suggested, is a remarkable kind of "intentional doing". Feelings enter consciousness not as events that happen to us but as activities that we ourselves engender and participate in.

When a person smells a rose, for example, he responds to what's happening at his nostrils with a "virtual action pattern": one of a set of action patterns that originated far back in evolutionary history as evaluative responses to various kinds of stimulation at the body surface — wriggles of acceptance or rejection. In modern human beings these responses are still directed to the site of stimulation, and still retain vestiges of their original function and hedonic tone; but today, instead of carrying through into overt behaviour, they've become closed off within internal circuits in the brain; in fact the efferent signals now project only as far as sensory cortex, where they interact with the incoming signals from the sense organs to create, momentarily, a self entangling, recursive, loop. My theory was that the person's sensation, the way he represents what's happening to him and how he feels about it, comes through monitoring his own signals for the action patternas extended, by this recursion, into the "thick moment" of the conscious present.

Now, I still think this is a pretty good idea. Especially because of its potential to explain the underlying functional architecture — even the neurophysiology — of phenomenal experience: the "what it's like" to live in the subjective present of sensations. The sensory loops I identified could create an "as-if" time dimension, so that every moment of consciousness lasts — paradoxically — longer than it actually lasts in physical time.

But there was a puzzle that I had pushed aside. I'd produced a model of reentrant circuits in the brain which might possibly provide the basis for the phenomenology of consciousness. I'd proposed an evolutionary story about how these circuits originated as a kind of bodily activity. But, if truth be told, I'd done nothing to explain why evolution had taken this remarkable course, at least I certainly hadn't explained the crucial final stage when the activity in the sensory circuits became self-resonant.

Let's be clear: this final stage can hardly have been an accident. In fact it must have required very fine tuning of the circuits to produce just the right degree of feedback — which is to say, to produce just the right degree and quality of temporal thickening of consciousness. But what's the point? Why ever should natural selection have gone to so much trouble to create a thick subjective present? Why don't we let conscious time slip by like physical time does? What can be the biological advantage to us of experiencing our own presence in the world in this magically rich way?

So that's what I'm working on now. And what I'm now thinking — though it certainly needs further work — is basically that the point of there being a phenomenally rich subjective present is that it provides a new domain for selfhood. Gottlob Frege, the great logician of the early 20th century, made the obvious but crucial observation that a first-person subject has to be the subject of something. In which case we can ask, what kind of something is up to doing the job? What kind of thing is of sufficient metaphysical weight to supply the experiential substrate of a self — or, at any rate, a self worth having? And the answer I'd now suggest is: nothing less than phenomenal experience — phenomenal experience with its intrinsic depth and richness, with its qualities of seeming to be more than any physical thing could be.

Phenomenal experience, surely, can and does provide the basis for creating a self worth having. And just see what becomes possible — even natural — once this new self is in place! As subjects of something so mysterious and strange, we humans gain new confidence and interest in our own survival, a new interest in other people too. We begin to be interested in the future, in immortality, and in all sorts of issues to do with co-consciousness and how far consciousness extends around us.

This feeds right back to our biological fitness in both obvious and subtle ways. It makes us more lively, more fascinating and more fascinated, more determined to pursue lives wherever they will take us. In short, more like the amazing piece of work that humans are. Lord Byron said that "the great object of life is sensation — to feel that we exist, even though in pain." That's the raw end of it. But, at a more reflective level, what keeps us going, gives us courage, makes us aim high for ourselves and our children is the feeling that as human selves we have something very special to preserve.

None of this would have happened if it weren't for those sensory circuits in the brain developing their special self-resonance — a development that was pushed along by natural selection for metaphysics. As I once put it (imitating a famous passage of Rousseau): "The first animal who, having enclosed a bit of the world's substance within his skin, said 'This is me' was perhaps the true founder of individualized life. But it was the first animal who, having enclosed a bit of time within his brain, said 'This is my present' who was the true founder of subjective being."


I've had the good fortune to be involved as a researcher in opening three different doors onto the problem of consciousness: through neuropsychology, ethology and aesthetics.

When I was a PhD student in Cambridge in the 1960s, I was at the right place at the right time to make a wonderful discovery: the phenomenon that later became called "blindsight." There was a monkey in Larry Weiskrantz's lab, called Helen, who had had the primary visual cortex at the back of her brain completely removed in a surgical operation. The operation had been done a couple of years earlier, and during the two years since the monkey had seemed to be almost completely blind.

However, there were reasons to think this might not be the whole story. And so, one week when I had time on my hands and the monkey wasn't involved in Weiskrantz's research, I decided to find out more. We were both at loose ends. Over several days I just sat by her cage and played with her. And an extraordinary thing happened. I realized that this blind monkey was interacting with me with her eyes. I would hold up a piece of apple and wave it in front of her, and she would reach out and touch my finger and try to get it from me. Within a few days she was transformed from a monkey sitting around listlessly, gazing blankly into the distance, to a monkey who had suddenly begun to be interested and involved in vision again.

I persuaded Larry to let me go on working with Helen. Over the next seven years I took her with me from Cambridge to Oxford, and then back to Cambridge. And she and I developed a remarkable relationship. I was her tutor and she was my apprentice. I encouraged her and coaxed her, trying in every way to help her to realize that actually she wasn't blind. I took her for walks in the fields and woods near the laboratory at Madingley near Cambridge. And slowly but surely I taught her to see again. In the end she could run around the room picking up crumbs off the floor, she could catch a fly as it passed by. If you didn't know this monkey had no visual cortex, you would have assumed she had completely normal vision.

Yet I was pretty sure that actually her vision wasn't normal. I knew her too well; we'd spent hours and hours in this strange interaction, with me wondering what it's like to be her. And, though I found it hard to put my finger on what was wrong, my sense was that she still didn't really believe that she could see, that she herself was unaware of her capacity for vision. There were telling hints in her behavior. For example, if she was upset or frightened, she'd stumble about as if she was in the dark again. It was as if she could only see provided she didn't try too hard.

In 1972 I wrote a popular paper for the New Scientist, and on the front cover of the magazine they put the headline under Helen's portrait, "A blind monkey who sees everything." But that surely wasn't right. Not everything. My own title for the paper inside the magazine was "Seeing and Nothingness," and I went on to argue that basically this was a kind of seeing we'd never had any inkling of before. Could it be there was no phenomenal experience, no sensation accompanying it? With a monkey, who couldn't describe her inner world, there seemed no way of being sure.

Then, a couple of years later Weiskrantz, spurred on by what we'd found with Helen, moved the research to a new level by showing that a human patient with extensive damage to the visual cortex was equally capable of recovering some degree of vision. But now, with this human patient, it was possible to have him tell the researchers what it was like for him. And, to everyone's astonishment it turned out that, yes, this was indeed unconscious vision — blindsight. The patient believed he was blind, and reported no sensation, and yet he could still guess the position and shape of objects in the blind part of his visual field.

As I say, I was lucky. It was a remarkable break for a young student to have, and helped shape me both scientifically and personally. It was a transforming experience: day by day to watch in Helen the emergence of an "impossible" capacity. It was like being a midwife to a miracle. It made me feel good. But those seven years also left a different sort of mark on me. After such an unusually intimate experience, I no longer wanted to do research that involved brain lesions in monkeys. I still respect and admire those who continue to do this kind of work, but I myself wanted to go in a different direction.


In 1974 I had the chance to go and work with Dian Fossey, studying mountain gorillas in the Virunga mountains of Rwanda. Dian was working for a Cambridge PhD, under Robert Hinde at Madingley, and I was nominally in a position of some authority over her, because I was assistant director of the lab at the time. I went to stay in her camp for three months, to help her with her research, to answer some questions, and to give advice if I could (although of course it really wasn't my place to give advice to Dian Fossey).

I was in an unusual position: a lab-based experimental psychologist, now given the chance to observe the behavior of apes in the wild. Those were the days when everything was much more relaxed than it is today, when I could set off alone at dawn to track down a particular group, and spend the day, even sometimes the night, with them.

In the grandeur of the mountains, half-accepted into the gorilla family, watching and watched by a dozen black eyes, far from any other person, left with my own thoughts, I began musing about an issue that has fascinated me ever since: What's it like, for a gorilla, to be a gorilla? What does a gorilla know about what it's like to be me? How do we read minds?

When we're engaging with other human beings, we hardly notice the extent to which we are involved in mind-reading. We take it for granted. But the issue comes into much sharper focus when you find yourself doing the same with other animals who are similar to humans but perhaps not similar enough. It's a real challenge to know whether you're getting it right.

I was trying to understand what it was like to be a gorilla, living in a gorilla family in the forest. The gorillas were, maybe, trying to understand what it was like to be me. Puzzling about what was going on between us, I began to wonder about the special role of introspection and reflexive consciousness.

When we imagine what it's like to be another person, we project feelings, sensations, beliefs, and wishes into their minds. But of course we can only do this because we've experienced these very states of mind ourselves. Then, could this perhaps provide a clue as to why it's so important to us to be able to introspect? Could it be that the biological function of introspection — the reason the capacity evolved — is precisely that, by introducing us to how our own minds work, it helps us to read the minds of other people?

It dawned on me that this could be the answer to much that is special about human evolution. We humans — and to a lesser extent maybe gorillas and chimps too — have evolved to be "natural psychologists." The most promising but also the most dangerous elements in our environment are other members of our own species. Success for our human ancestors must have depended on being able to get inside the minds of those they lived with, second-guess them, anticipate where they were going, help them if they needed it, challenge them, or manipulate them. To do this they had to develop brains that would deliver a story about what it's like to be another person from the inside.

Later, I would call this new organ of reflexive consciousness the "inner eye".


Since student days, I've been interested in aesthetics, in value. In fact my next laboratory-based project after finishing the research with Helen was to investigate whether monkeys have aesthetic preferences. I had a hunch that somehow the study of value must be relevant to understanding consciousness — though I wasn't then sure how.

Here's something to think about. Suppose you were to be turned into a sensationless "zombie": someone who is in every respect exactly like a normal human being except for not having phenomenal consciousness (and all that follows from it) — someone for whom the subjective present never lights up. Would life be worth living any more?

Early on in my career I got involved in another remarkable case study, that threw unexpected, and tragic light on just this question. A 27-year-old woman came to London from abroad in 1972 to have an operation to remove cataracts from her eyes. She'd been blind since the age of three. The doctor who operated on her had promised her that there was a good chance of being able to see normally again. I met her several months after the operation and found her in a state of great despair. She was convinced the operation was a complete failure; she couldn't see any better than she could before.

Unfortunately, it seemed all too likely that, as the result of years of lack of use, her visual cortex had in fact atrophied, so that she was in effect in much the same condition as my monkey, Helen. And yet, if this were the case, perhaps not all was lost. Perhaps she would be capable of learning to see again as Helen had.

I decided to try some of the same things with her. I took her out into in St. James's Park and around London. We walked through the gardens while I described the sights and held her hand. And soon enough it became clear that she did indeed have a capacity for vision that she wasn't aware of. She could point to a pigeon on the grass, she could reach for a flower, she could step up when she came to a curb.

It seemed that, after all, the operation had not been a total failure: her eyes were working again, to a degree. But was this what she was hoping for? No, it only proved the more traumatic. For the awful truth, she let on, was that her vision — just as in blindsight (and very likely it was a kind of blindsight) — still lacked any qualitative dimension. She'd been living for 20 years with the idea of how marvelous it would be if only she could see like other people. She had heard so many accounts, stories, poetry, about the wonders of vision. Yet now here she was, with part of her dream come true, and now she simply couldn't feel it. She was desperately disappointed, almost suicidal. In the end she dealt bravely with her situation by putting on her dark glasses again, taking up her white cane and going back to her former status of being blind.

This case stayed with me — to remind me, if I should ever forget, how much consciousness matters. Even to the extent that mattering may be one of the main reasons why consciousness exists. What if it's consciousness that gives us a reason for waking up every day, and going out into the world —to experience the qualia of a rainbow, the sunset, music, interactions with our friends, sex, food? What if consciousness provides such an incentive for living that, as human beings, we would not — and probably could not — do without it?

Of course human beings find meaning on lots of other levels. But the more I try to make sense of it, the more I come back to the fact that we've evolved to regard consciousness as a wonderfully good thing in its own right — which could just be because consciosuness is a wonderfully good thing in its own right!


You asked me to explain how I've developed as a scientist. I'll confess I've long had the ambition to make a difference — so that I leave the world a different place than it would have been without me. But it's a funny thing: this kind of personal ambition can actually lead to an anxiety about being a scientist. The problem is that scientific truth is thoroughly impersonal. The answers to the questions scientists ask are in a sense already out there in the book of nature, waiting for someone — anyone — to find the key to reading them. If one particular scientist doesn't find the answer today, we can be pretty sure that another one will tomorrow or the next day — probably rather quickly given the way in which science is moving. So, if we're honest, we have to admit that even though we may have great fun in getting to the answer, and maybe great success and fame at having been the first to get there, in the end our personal contribution hardly matters. Even worse, perhaps what we are doing is to make some other scientist miserable — because we beat him to it.

This surely makes science a rather different enterprise from other great enterprises of our culture. Consider painting, or writing, or making music, where it's certainly arguable, that every creation is an individual work, which has the stamp of the person and the personality that made it. If Shakespeare hadn't written Hamlet, nobody would have written Hamlet. If Picasso hadn't painted the Demoiselles d'Avignon, nobody would have painted it. If Metallica hadn't composed their heavy metal music nobody would have done it.

Nonetheless, science does at least have this advantage over the arts: we need not doubt that the questions we are asking are important. Everybody wants to know the answer to the riddle of consciousness, or the origin of the universe. By contrast not everybody wants to know the answer to whatever it is that Metallica is trying to do. Or even, Picasso. Shakespeare? Well, perhaps Shakespeare's in a different league. Everyone does want to know the answers to the problems posed in Hamlet.

The ideal life, maybe, would be to create science, but in a style and with a way of presenting it which does have some of the qualities of great art, but which nonetheless has the security of providing verifiable answers to the big problems. Could someone be the Metallica of science? Maybe that's not the best model. But I'd say someone could certainly be the Dostoyevsky of science.

But, then, does it really matter whether your contribution has your personal stamp on it? I'd be the first to agree there are ways of making a difference — perhaps nobler ways — where who cares whether it's you or someone else. As scientists we have unrivalled opportunities to do things which, through their practical effects, make the world a better place to live in. And in my own work I'm afraid to say this practical element has been very much missing. I've made people interested and excited about ideas, but I can't claim to have done much to change people's lives for the better in any material way.

Maybe it's not too late. Recently I've been involved in research on the placebo effect, coming at it from a mixture of philosophical and evolutionary perspectives. The placebo effect is a very important aspect of all medicine. A large part of medical cures are effected by the patients themselves, when the medical procedure allows the patients to bring their own resources to bear to solve the problem. In the classical placebo case, you give a sugar pill and the patient uses this as an excuse to cure himself. But placebos are actually present in every kind of medical treatment. To the extent the patient believes the treatment is going to work, he allows himself to deploy his own healing resources in a way that he wouldn't have done otherwise.

How should we understand this? What questions should a science of the placebo effect be asking? Of course it's important to investigate the brain mechanisms that underlie these effects, and lots of researchers are already beginning to home in on the problem at the level of neurophysiology and immunology. But it's no less important to look at the bigger picture, and ask: Whatever is going on here, from a functional standpoint? If a placebo is releasing in people an ability to cure themselves, why don't they just get on with it? Why ever should anyone withhold self-cure? You'd think that when you're sick you should just get better if you can; you shouldn't need to wait for permission from a doctor, a shaman, or a psychotherapist to utilize your own resources.

It's this level of question that has set me looking for some possible evolutionary explanation. Why should humans and other animals hold healing resources in reserve? What can be the advantages of not getting better when you actually could? As I've looked further, I've found many examples of it.

People may die from cancer when they have immune resources still waiting in reserve which could have been deployed against the cancer. People die in head-on car collisions because they don't apply the brakes hard enough. When athletes are running a marathon, they may reach the end of what they can do and collapse from fatigue, when, in fact, their muscles still have significant reserves left in them.

What's going on?

You'll have guessed the way I want to go with this: my idea is that nature has designed us to play safe, and never to use up everything we've got — because we never know what might still lie around the corner. When we reach the end of a marathon there may still be a lion waiting at the finishing post that's going to suddenly give chase. When we're sick with an infection and respond with an immune reaction, we may still be hit by a further infection the next day. Remember the story of the wise and foolish virgins and their lamps: it's always wise to keep something in reserve.

I'm now thinking in terms of there being what I call a "natural health management system", which does a kind of economic analysis of what the opportunities and the costs of self-cure will be — what resources we've got, how dangerous the situation is right now, and what predictions we can make of what the future holds. It's like a good hospital manager who has to choose if and when to throw resources against this or that problem, to hold so much back, to decide if it's essential to build up this area or that area — basically to try to produce an optimal solution to the problem of maintaining health with enough left over to meet coming challenges.

If this is right, it makes the placebo effect fit into a much larger picture of homeostasis and health management. And it converges with ideas being developed by researchers coming from quite different disciplines. I've been particularly struck by the work of the South African physiologist, Timothy Noakes, who has come up with the idea of there being what he calls "a central governor" in the brain which regulates just how far the body should be allowed to go in meeting the demands of extreme exercise.

These ideas are big, because they are producing a new perspective on how we and other animals have evolved to manage our internal healing resources across the board. But it already goes much beyond mere theory.

There's a phenomenon, well known to sports physiologists and athletes called "interval training". If you want to improve your prowess as an athlete, one highly effective method of doing it is to build up in the following way. If you're a sprinter, for example, you sprint for two minutes and then relax and jog for five minutes. Then you repeat this pattern again, and again. The result is that you soon find you can run about 15% better than you could before.

Why does this work? According to Tim Noakes, what may be happening is this. In order to improve peak performance you need to persuade your central governor to let you go beyond your own self-imposed limits, when otherwise "cautionary tiredness" would kick in and say, "No more." And one way of doing this is by teaching your central governor that the risks are not actually so great after all. Through interval training you can teach your own brain that you are not going to get into trouble by pushing yourself a little further than you might otherwise have done.

Noakes' theory is a clever way of looking at how to stretch the limits of athletic performance. But what about applying the same idea in other areas? In particular, what about the possibility that we could have interval training for the immune system? If people are not deploying their immune resources to maximum extent, so that they don't get better when they could have, could we teach them by a similar schedule of exercise for the immune system that it's safe to do so?

Smolin, Pinker, Guth, Himphrey, Dennett (June, 1997)

Here's the experiment. Let's do it in mice before we try it in humans. We give a mouse a bacterial infection. The mouse gets sick, and throws its immune resources against the infection — but only so far as it dares. Twenty-four hours later we follow up with antibiotics, and the mouse gets better. So the mouse's health management system gets the message that it's safe to go at least this far. Now, a week later, we repeat this pattern of infection followed by relief. Then we do it again, and again. And what I'd hope we'd find is that the mouse's health management system will learn that it can afford to use more of its resources than it otherwise would have dared to, because every time it goes to its own self-imposed limits it discovers it's followed by safe recovery.

Now, suppose we take one mouse which has been put through this regime, and another mouse which hasn't, and we inject them both with a carcinogen. I predict that the mouse which has been through interval training for its immune system will survive the cancer in a way in which a mouse that hasn't done won't.

If this were to work with people, imagine how it might turn medicine around! It might prove to be one of the best ways ever of achieving one of the main goals of modern medicine, which is to get people to use their own healing resources to greater and better effect than they usually do.

I have to say I really like the idea. Maybe this interview will be remembered as its first airing (I hope!).

Daniel C. Dennett responds to Nicholas Humphrey

Daniel C. Dennett

If only more scientists were as willing as Nick is to show us the "early" parts of their thinking—the thinking you do before you present your findings, or design your experiments, or formulate your hypotheses, or even choose your field!—the wishful, impressionistic explorations in imagination that uncover the hunches that then actually motivate your life's work. If you want to know why scientists disagree so vehemently with each other, resist each other's arguments so pigheadedly, persist for so long in the effort to refute the competition, you often have to delve back into the way their imaginations have formed their unspoken setting of the issues. Nick tells us not just how he got there but why he wants the science of consciousness to turn out his way, and I daresay he is not alone in much or all of his motivation, so he manages to uncover a hidden agenda that probably drives a lot of others as well. Since I have been gamely resisting much of this drift for many years—with scant success!—I find it is always valuable to get a glimpse into what may be driving it.

"What can be the biological advantage to us of experiencing our own presence in the world in this magically rich way?" This question compresses several different questions into one "magical" lump: Who is "us"? Homo sapiens, or primates, or mammals, or vertebrates? (Do fish "experience their own presence"? Do birds?) Nick says "we humans gain new confidence and interest in our own survival" so perhaps he is reserving this explanation for human consciousness, but I don't see any reason to believe we are any more intent on our own survival than, say, a fox that gnaws off its own leg to escape from a trap. And why would the advantage have to be "to us" in the first place? Might consciousness (of the human sort) be an affliction that spreads because it can? Perhaps the benefit in fitness is to the parasitic habit we spread to our children when we raise them with language, an energy-wasting, distracting price we must pay to be communicators! (Remember: genetic fitness isn't about pleasure or delight; it's about how many offspring your offspring have.)

Other remarks of his suggest that he means to include primates, at least, in the ambit of his thesis, but then his remarks about the "first animal who . . . .said [sic] 'This is me'" raise a problem. And—most crucial of all—the motivation that Nick imagines qualia to underwrite has to be explained by a functional model that deconstructs qualia into something else, something that is not a content of consciousness. If qualia are presupposed to be wonderful (set aside "magical," which is just a rhetorical flourish) or delightful or delicious, or anything of the sort, then we're stuck with something like intrinsically delicious" properties, which couldn't explain anything (any more than "intrinsically awful" pains could explain pain). The deliciousness or awfulness, the importance, in short, that makes selves worth having, as Nick says, has to be constructed out of dispositions to behave, to seek or avoid (and the convoluted variations thereof), not the other way around. But it sure doesn't seem that way. Here Nick goes along with, actively endorses, what I consider a prime example of a pre-scientific perspective that must be challenged.

I don't know if Gottlob Frege ever observed that a first-person subject has to be the subject of something; he is sometimes cited as making the mirror-image point: that an experience has to be someone's, some subject's. I myself am dubious of the utility of both versions of the point, since unless they are deemed definitional, they leave problem cases in their wake. The "pains" that cause you to shift position while you sleep—is there a subject of those pains? Are they not experienced because there is no subject at the time? Could a robot be a subject, and if not, why not?

Robots, many think, would have to be "zombies," and Nick asks you to imagine you were turned into a "sensationless ‘zombie': someone who is in every respect exactly like a normal human being except for not having phenomenal consciousness (and all that follows from it)—someone for whom the subject present never lights up." We are asked to imagine being turned into a person who was like Nick's blind woman squared, cubed—sensationless in every modality. A pitiful state indeed, but this is not what a philosopher's zombie is. This is a being that would be hugely different behaviorally from a normal human being, an unmotivated, listless vegetable, while a philosopher's zombie, by definition, is as lively and (apparently) motivated as anybody could be. It is this (inadvertent) sleight-of-hand, this mis-imagining of the zombic hunch, that keeps the zombie concept alive (well, undead) when it should have lapsed into oblivion years ago.

Nick knows all this. But he persists, and he tells us why. He wants us not to forget "how much consciousness matters," and he proposes that we've evolved to regard consciousness as a wonderfully good thing "because consciousness is a wonderfully good thing in its own right!" Think about what this "in its own right" could mean. Are we to imagine the possibility of creatures that had consciousness (that wonderfully good thing in its own right) but were oblivious, somehow, to their good fortune? Would they be deeply wrong not to treasure it? Would they leave less descendants than cousins who somehow began to get an inkling of how wonderful consciousness actually was? What would be wonderful about it if they were ill-equipped to enjoy it? (Imagine the Planet of the Rolexes—inhabited only by tortoises that happened by cosmic coincidence to be born with exquisite Rolex watches embedded in their shells. But they don't tell time, have no need to tell time, and often scrape off their Rolexes in the course of mating. Dumb tortoises! If only they knew what they had! But in what sense would they be wrong?) If wonderfulness must co-evolve with the capacity and disposition to appreciate and exploit it, then it isn't wonderfulness "in its own right." Is it?

Nick and I have been going round and round on these topics for almost twenty years, and I've been amazed and provoked by his ingenious ways of putting his points—but never convinced. I'm pretty sure I still don't get it, but it's always a joy to play another round.


" ...inspiring glimpses into the minds of today’s scientific intelligentsia" Publishers' Weekly

Curious Minds:
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Original essays vy Nicholas Humphrey • David M. Buss • Robert M. Sapolsky • Mihaly Csikszentmihalyi • Murray Gell-Mann • Alison Gopnik • Paul C. W. Davies • Freeman Dyson • Lee Smolin • Steven Pinker • Mary Catherine Bateson • Lynn Margulis • Jaron Lanier • Richard Dawkins • Howard Gardner • Joseph LeDoux • Sherry Turkle • Marc D. Hauser • Ray Kurzweil • Janna Levin • Rodney Brooks • J. Doyne Farmer • Steven Strogatz • Tim White • V. S. Ramachandran • Daniel C. Dennett • Judith Rich Harris • edited, with an introduction by John Brockman

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When We Were Kids:
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Science at the Edge

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Next Fifty Years: Science in the First Half of the Twenty-First Century


Original essays by Peter Atkins, • Samuel Barondes • Paul Bloom • Rodney Brooks • Mihalyi Csikszentmihalyi • Paul C. W. Davies • Richard Dawkins • Nancy Etcoff • Paul W. Ewald • David Gelernter • Brian Goodwin • Alison Gopnik • Judith Rich Harris • Marc D. Hauser • John H. Holland • Stuart Kauffman • Jaron Lanier • Joseph LeDoux • Geoffrey Miller • Martin Rees • Robert Sapolsky • Roger C. Schank • Lee Smolin • Ian Stewar • , Steven Strogatz • edited, with an introduction by John Brockman

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Next Fifty Years: Science in the First Half of the Twenty-First Century


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