2005 : WHAT DO YOU BELIEVE IS TRUE EVEN THOUGH YOU CANNOT PROVE IT?

I believe that human consciousness is a conjuring trick, designed to fool us into thinking we are in the presence of an inexplicable mystery. Who is the conjuror and why is s/he doing it? The conjuror is natural selection, and the purpose has been to bolster human self-confidence and self-importance—so as to increase the value we each place on our own and others' lives.

If this is right, it provides a simple explanation for why we, as scientists or laymen, find the "hard problem" of consciousness just so hard. Nature has meant it to be hard. Indeed "mysterian" philosophers—from Colin McGinn to the Pope—who bow down before the apparent miracle and declare that it's impossible in principle to understand how consciousness could arise in a material brain, are responding exactly as Nature hoped they would, with shock and awe.

Can I prove it? It's difficult to prove any adaptationist account of why humans experience things the way they do. But here there is an added catch. The Catch-22 is that, just to the extent that Nature has succeeded in putting consciousness beyond the reach of rational explanation, she must have undermined the very possibility of showing that this is what she's done.

But nothing's perfect. There may be a loophole. While it may seem—and even be—impossible for us to explain how a brain process could have the quality of consciousness, it may not be at all impossible to explain how a brain process could (be designed to) give rise to the impression of having this quality. (Consider: we could never explain why 2 + 2 = 5, but we might relatively easily be able to explain why someone should be under the illusion that 2 + 2 = 5).

Do I want to prove it? That's a difficult one. If the belief that consciousness is a mystery is a source of human hope, there may be a real danger that exposing the trick could send us all to hell.

Interspecies coevolution of languages on the Northwest Coast.

During the years I spent kayaking along the coast of British Columbia and Southeast Alaska, I observed that the local raven populations spoke in distinct dialects, corresponding surprisingly closely to the geographic divisions between the indigenous human language groups. Ravens from Kwakiutl, Tsimshian, Haida, or Tlingit territory sounded different, especially in their characteristic "tok" and "tlik."

I believe this correspondence between human language and raven language is more than coincidence, though this would be difficult to prove.

The electron has been with us for over a century, laying the foundations to the electronic revolution and all of information technology. It is believed to be a point-like, elementary and indivisible particle. Is it?

The neutrino, more than a million times lighter than the electron, was predicted in the 1920's and discovered in the 1950's. It plays a crucial role in the creation of the stars, the sun and the heavy elements. It is elusive, invisible and weakly interacting. It is also considered fundamental and indivisible. Is it?

Quarks do not exist as free objects, except at extremely tiny distances, deep within the confines of the particles which are constructed from them. Since the 1960's we believe that they are the most fundamental indivisible building blocks of protons, neutrons and nuclei. Are they?

Nature has created two additional, totally unexplained, replicas of the electron, the neutrino and the most abundant quarks, u and d, forming three "generations" of fundamental particles. Each "generation" of particles is identical to the other two in all properties, except that the particle masses are radically different. Since each "generation" includes four fundamental particles, we end up with 12 different particles, which are allegedly indivisible, point-like and elementary. Are they?

The Atom, the nucleus and the proton, each in its own time, were considered elementary and indivisible, only to be replaced later by smaller objects as the fundamental building blocks. How can we be so arrogant as to exclude the possibility that this will happen again? Why would nature arbitrarily produce 12 different objects, with a very orderly pattern of electric charges and "color forces", with simple charge ratios between seemingly unrelated particles (such as the electron and the quark) and with a pattern of masses, which appears to be taken from the results of a lottery? Doesn't this "smell" again of further sub-particle structure?

There is absolutely no experimental evidence for a further substructure within all of these particles. There is no completely satisfactory theory which might explain how such light and tiny particles can contain objects moving with enormous energies, a requirement of quantum mechanics. This is, presumably, why the accepted "party line" of particle physicists is to assume that we already have reached the most fundamental level of the structure of matter.

For over twenty years, the hope has been that the rich spectrum of so-called fundamental particles will be explained as various modes of string vibrations and excitations. The astonishingly tiny string or membrane, rather than the point-like object, is allegedly at the bottom of the ladder describing the structure of matter. However, in spite of absolutely brilliant and ingenious mathematical work, not one experimental number has been explained in more than twenty years, on the basis of the string hypothesis.

Based on common sense and on an observation of the pattern of the known particles, without any experimental evidence and without any comprehensive theory, I have believed for many years, and I continue to believe, that the electron, the neutrino and the quarks are divisible. They are presumably made of different combinations of the same small number (two?) of more fundamental sub-particles. The latter may or may not have the string structure, and may or may not be themselves composites.

Will we live to see the components of the electron?

One of the biggest of the Big Questions of existence is, Are we alone in the universe? Science has provided no convincing evidence one way or the other. It is certainly possible that life began with a bizarre quirk of chemistry, an accident so improbable that it happened only once in the entire observable universe—and we are it. On the other hand, maybe life gets going wherever there are earthlike planets. We just don't know, because we have a sample of only one. However, no known scientific principle suggests an inbuilt drive from matter to life. No known law of physics or chemistry favors the emergence of the living state over other states. Physics and chemistry are, as far as we can tell, "life blind."

Yet I don't believe that life is a freak event. I think the universe is teeming with it. I can't prove it; indeed, it could be that mankind will never know the answer for sure. If we find life in our solar system, it most likely got there from Earth (or vice versa) in rocks kicked off planets by comet impacts. And to go beyond the solar system is the stuff of dreams. The best hope is that we develop instruments sensitive enough to detect life on extra-solar planets from Earth orbit. But, whilst not impossible, this is a formidable technical challenge.

So why do I think we are not alone, when we have no evidence for life beyond Earth? Not for the fallacious popular reason: "the universe is so big there must be life out there somewhere." Simple statistics shows this argument to be bogus. If life is in fact a freak chemical event, it would be so unlikely to occur that it wouldn't happen twice among a trillion trillion trillion planets. Rather, I believe we are not alone because life seems to be a fundamental, and not merely an incidental, property of nature. It is built into the great cosmic scheme at the deepest level, and therefore likely to be pervasive. I make this sweeping claim because life has produced mind, and through mind, beings who do not merely observe the universe, but have come to understand it through science, mathematics and reasoning. This is hardly an insignificant embellishment on the cosmic drama, but a stunning and unexpected bonus. Somehow life is able to link up with the basic workings of the cosmos, resonating with the hidden mathematical order that makes it tick. And that's a quirk too far for me.

The orthodoxy in biology states that every cell in your body shares exactly the same DNA. It's your identity, your indelible fingerprint, and since all the cells in your body have been duplicated from your initial unique stem cell these zillion of offspring cells all maintain your singular DNA sequence. It follows then that when you submit a tissue sample for genetic analysis it doesn't matter where it comes from. Normally technicians grab some from the easily accessible pars of your mouth, but they could just as well take some from your big toe, or your liver, or eyelash and get the same results.

I believe, but cannot prove, that the DNA in your body (and all bodies) varies from part to part. I make this prediction based on what we know about biology, which is that natures abhors uniformity. No where else in nature do we see identity maintained to such exactness. No where else is there such fixity.

I do not expect intra-soma variation to diverge very much. Indeed the genetic variation among individual humans is already relatively mild, among the least of all animals, so the diversity within a human body is unlikely to be greater than among human bodies—although that may be possible. More likely, intra-soma variation will be less than racial diversity but greater than zero.

Biologists already know (even if the public doesn't) that the full sequence of DNA in your cells changes over time as your chromosomes are shorten each time they divide in growth. Because of a bug in the system, DNA is unable to duplicate itself when it gets to the very very tip of its chain, so at each division it winds up a few hundred bases short. This slight reduction after each of the cell's scores of divisions is currently seen as the chief culprit in cell death and thus your own death. But the variation I believe is happening is more fundamental. My guess is that DNA mutates in a population of the cells in your body much as it does in a population of bodies.

The consequences are more than just curious. At the trivial end, if my belief were true, it would matter where you selected to sample your DNA from. And it might also affect when you get it, as this variation could change over time. If true, this variation might have some effect on locating the correct seminal cells for growing replacement organs and tissues.

While I have no evidence for my belief right now, it is a provable assertion. It will be shown to be true or false as soon as we have ubiquitous cheap full-genome sequences at discount mall prices. That is, pretty soon. I believe that once we have a constant reading of our individual full DNA (many times over our lives) we will have no end of surprises. I would not be surprised to discover that pet owners accumulate some tiny fragments of their pet's DNA,which has somehow been laterally transferred via viruses to their own cellular DNA. Or that diary farmers amass noticeable fragments of bovine DNA. Or that the DNA in our limbs somehow drift genetically in a "limby" way, distinct from the variation in the cells in our nervous systems.

But I consider all this minor compared to a possible major breakthrough in understanding. We have a pretty good idea of how the "selection" in natural selection works: less fit organisms die. But when it comes to understanding how variation arises in Darwinian evolution all we can say is "random mutation" which is another way of saying "we don't know exactly." If there were intra-somatic variation and if we could easily observe it via massive constant full-genome sequencing then we might be able to figure out exactly how a mutation occurs, and whether there are patterns to those mutations, and to what extant such variation is induced or influenced by the body or the environment—all ideas which currently challenge the Darwinian wisdom that the body does not directly influence the genetic makeup of a cell. Monitoring genetic drift within a body may be a window into the origins of mutation itself.

Even if these larger ideas don't pan out, the simple fact that DNA in each cell of your body is not 100% identical would be worth investigating. Such a fact would be a surprise, except to me.

Is string theory a futile exercise as physics, as I believe it to be? It is an interesting mathematical specialty and has produced and will produce mathematics useful in other contexts, but it seems no more vital as mathematics than other areas of very abstract or specialized math, and doesn't on that basis justify the incredible amount of effort expended on it.

My belief is based on the fact that string theory is the first science in hundreds of years to be pursued in pre-Baconian fashion, without any adequate experimental guidance. It proposes that Nature is the way we would like it to be rather than the way we see it to be; and it is improbable that Nature thinks the same way we do.

The sad thing is that, as several young would-be theorists have explained to me, it is so highly developed that it is a full-time job just to keep up with it. That means that other avenues are not being explored by the bright, imaginative young people, and that alternative career paths are blocked.

Mental processes: An out-of-body existence?

These days, it seems obvious that the mind arises from the b rain (not the heart, liver, or some other organ). In fact, I personally have gone so far as to claim that "the mind is what the brain does." But this notion does not preclude an unconventional idea: Your mind may arise not simply from your own brain, but in part from the brains of other people.

Let me explain. This idea rests on three key observations.

The first is that our brains are limited, and so we use crutches to supplement and extend our abilities. For example, try to multiply 756 by 312 in your head. Difficult, right? You would be happier with a pencil and piece of paper—or, better yet, an electronic calculator. These devices serve as prosthetic systems, making up for cognitive deficiencies (just as a wooden leg would make up for a physical deficiency).

The second observation is that the major prosthetic system we use is other people. We set up what I call "Social Prosthetic Systems" (SPSs), in which we rely on others to extend our reasoning abilities and to help us regulate and constructively employ our emotions. A good marriage may arise in part because two people can serve as effective SPSs for each other.

The third observation is that a key element of serving as a SPS is learning how best to help someone. Others who function as your SPSs adapt to your particular needs, desires and predilections. And the act of learning changes the brain. By becoming your SPS, a person literally lends you part of his or her brain!

In short, parts of other people's brains come to serve as extensions of your own brain. And if the mind is "what the brain does," then your mind in fact arises from the activity of not only your own brain, but those of your SPSs.

There are many implications of these ideas, ranging from reasons why we behave in certain ways toward others to foundations of ethics and even to religion. In fact, one could even argue that when your body dies, part of your mind may survive. But before getting into such dark and dusty corners, it would be nice to have firm footing—to collect evidence that these speculations are in fact worth taking seriously.

For me, this is an easy question. I believe that animals have feelings and other states of consciousness, but neither I, nor anyone else, has been able to prove it. We can't even prove that other people are conscious, much less other animals. In the case of other people, though, we at least can have a little confidence since all people have brains with the same basic configurations. But as soon as we turn to other species and start asking questions about feelings, and consciousness in general, we are in risky territory because the hardware is different.

When a rat is in danger, it does things that many other animals do. That is, it either freezes, runs away or fights back. People pretty much do the same things. Some scientists say that because a rat and a person act the same in similar situations, they have the same kinds of subjective experiences. I don't think we can really say this.

There are two aspects of brain hardware that make it difficult for us to generalize from our personal subjective experiences to the experiences of other animals. One is the fact that the circuits most often associated with human consciousness involve the lateral prefrontal cortex (via its role in working memory and executive control functions). This broad zone is much more highly developed in people than in other primates, and whether it exists at all in non-primates is questionable. So certainly for those aspects of consciousness that depend on the prefrontal cortex, including aspects that allow us to know who we are and to make plans and decisions, there is reason to believe that even other primates might be different than people. The other aspect of the brain that differs dramatically is that humans have natural language. Because so much of human experience is tied up with language, consciousness is often said to depend on language. If so, then most other animals are ruled out of the consciousness game. But even if consciousness doesn't depend on language, language certainly changes consciousness so that whatever consciousness another animal has it is likely to differ from most of our states of consciousness.

For these reasons, I think it is hard to know what consciousness might be like in another animal. If we can't measure it (because it is internal and subjective) and can't use our own experience to frame questions about it (because the hardware that makes it possible is different), it become difficult to study.

Most of what I have said applies mainly to the content of conscious experience. But there is another aspect of consciousness that is less problematic scientifically. It is possible to study the processes that make consciousness possible even if we can't study the content of consciousness in other animals. This is exactly what is done in studies of working memory in non-human primates. One approach by that has had some success in the area of conscious content in non-human primates has focused on a limited kind of consciousness, visual awareness. But this approach, by Koch and Crick, mainly gets at the neural correlates of consciousness rather than the causal mechanisms. The correlates and the mechanisms may be the same, but they may not. Interestingly, this approach also emphasizes the importance of prefrontal cortex in making visual awareness possible.

So what about feelings? My view is that a feeling is what happens when an emotion system, like the fear system, is active in a brain that can be aware of its own activities. That is, what we call "fear" is the mental state that we are in when the activity of the defense system of the brain (or the consequences of its activity, such as bodily responses) is what is occupying working memory. Viewed this way, feelings are strongly tied to those areas of the cortex that are fairly unique to primates and especially well developed in people. When you add natural language to the brain, in addition to getting fairly basic feelings you also get fine gradations due to the ability to use words and grammar to discriminate and categorize states and to attribute them not just to ourselves but to others.

There are other views about feelings. Damasio argues that feelings are due to more primitive activity in body sensing areas of the cortex and brainstem. Pankseep has a similar view, though he focuses more on the brainstem. Because this network has not changed much in the course of human evolution, it could therefore be involved in feelings that are shared across species. I don't object to this on theoretical grounds, but I don't think it can be proven because feelings can't be measured in other animals. Pankseep argues that if it looks like fear in rats and people, it probably feels like fear in both species. But how do you know that rats and people feel the same when they behave the same? A cockroach will escape from danger--does it, too, feel fear as it runs away? I don't think behavioral similarity is sufficient grounds for proving experiential similarity. Neural similarity helps—rats and people have similar brainstems, and a roach doesn't even have a brain. But is the brainstem responsible for feelings? Even if it were proven in people, how would you prove it in a rat?

So now we're back where we started. I think rats and other mammals, and maybe even roaches (who knows?), have feelings. But I don't know how to prove it. And because I have reason to think that their feelings might be different than ours, I prefer to study emotional behavior in rats rather than emotional feelings. I study rats because you can make progress at the neural level, provided that the thing you measure is the same in rats and people. I wouldn't study language and consciousness in rats, so I don't study feelings either, because I don't know that they exist. I may be accused of being short-sighted for this, but I'd rather make progress on something I can study in rats than beat my head against the consciousness wall in these creatures.

There's lots to learn about emotion through rats that can help people with emotional disorders. And there's lots we can learn about feelings from studying humans, especially now that we have powerful function imaging techniques. I'm not a radical behaviorist. I'm just a practical emotionalist.

What do you believe is true even though you cannot prove it?

Progress. 

The enterprise that employs me, seeking to understand and apply insight into how the world works, is ultimately based on the belief that this is a good thing to do. But it's something of a leap of faith to believe that that will leave the world a better place—the evidence to date is mixed for technical advances monotonically mapping onto human advances.

Naturally, this question has a technical spin for me. My current passion is the creation of tools for personal fabrication based on additive digital assembly, so that the uses of advanced technologies can be defined by their users. It's still no more than an assumption that that will lead to more good things than bad things being made, but, like the accumulated experience that democracy works better than monarchy, I have more faith in a future based on widespread access to the means for invention than one based on technocracy.

I believe our universe is not unique. As science has evolved, our place within the universe has continued to diminish in significance.

First it was felt that the Earth was the center of the universe, then that our Sun was the center, and so on. Ultimately we now realize that we are located at the edge of a random galaxy that is itself located nowhere special in a large, potentially infinite universe full of other galaxies. Moreover, we now know that even the stars and visible galaxies themselves are but an insignificant bit of visible pollution in a universe that is otherwise dominated by 'stuff' that doesn't shine.

Dark matter dominates the masses of galaxies and clusters by a factor of 10 compared to normal matter. And now we have discovered that even matter itself is almost insignificant. Instead empty space itself contains more than twice as much energy as that associated with all matter, including dark matter, in the universe. Further, as we ponder the origin of our universe, and the nature of the strange dark energy that dominates it, every plausible theory that I know of suggests that the Big Bang that created our visible universe was not unique. There are likely to be a large, and possibly infinite number of other universes out there, some of which may be experiencing Big Bangs at the current moment, and some of which may have already collapsed inward into Big Crunches. From a philosophical perspective this may be satisfying to some, who find a universe with a definite beginning but no definite end dissatisfying. In this case, in the 'metaverse', or 'multiverse' things may seem much more uniform in time.

At every instant there may be many universes being born, and others dying. But philosophy aside, the existence of many different causally disconnected universes—regions with which we will never ever be able to have direct communication, and thus which will forever be out of reach of direct empirical verification—may have significant impacts on our understanding of our own universe. Their existence may help explain why our own universe has certain otherwise unexpected features, because in a metaverse with a possibly infinite number of different universes, which may themselves vary in their fundamental features, it could be that life like our own would evolve in only universes with a special set of characteristics.

Whether or not this anthropic type of argument is necessary to understand our universe—and I personally hope it isn't—I nevertheless find it satisfying to think that it is likely that not only are we not located in a particularly special place in our universe, but that our universe itself may be relatively insignificant on a larger cosmic scale. It represents perhaps the ultimate Copernican Revolution.

I believe, but cannot prove, that babies and young children are actually more conscious, more vividly aware of their external world and internal life, than adults are. I believe this because there is strong evidence for a functional trade-off with development. Young children are much better than adults at learning new things and flexibly changing what they think about the world. On the other hand, they are much worse at using their knowledge to act in a swift, efficient and automatic way. They can learn three languages at once but they can't tie their shoelaces. 

This trade-off makes sense from an evolutionary perspective. Our species relies more on learning than any other, and has a longer childhood than any other. Human childhood is a protected period in which we are free to learn without being forced to act. There is even some neurological evidence for this. Young children actually have substantially more neural connections than adults—more potential to put different kinds of information together. With experience, some connections are strengthened and many others disappear entirely. As the neuroscientists say, we gain conductive efficiency but lose plasticity.

What does this have to do with consciousness? Consider the experiences we adults associate with these two kinds of functions. When we know how to do something really well and efficiently, we typically lose, or at least, reduce, our conscious awareness of that action. We literally don't see the familiar houses and streets on the well-worn route home, although, of course, in some functional sense we must be visually taking them in. In contrast, as adults when we are faced with the unfamiliar, when we fall in love with someone new, or when we travel to a new place, our consciousness of what is around us and inside us suddenly becomes far more vivid and intense. In fact, we are willing to expend lots of money, and lots of emotional energy, for those few intensely alive days in Paris or Beijing that we will remember long after months of everyday life have vanished.

Similarly, as adults when we need to learn something new, say when we learn to skydive, or work out a new scientific idea, or even deal with a new computer, we become vividly, even painfully, conscious of what we are doing—we need, as we say, to pay attention. As we become expert we need less and less attention, and we experience the actual movements and thoughts and keystrokes less and less. We sometimes say that adults are better at paying attention than children, but really we mean just the opposite. Adults are better at not paying attention. They're better at screening out everything else and restricting their consciousness to a single focus. Again there is a certain amount of brain evidence for this. Some brain areas, like the dorsolateral prefrontal cortex, consistently light up for adults when they are deeply engaged in learning something new. But for more everyday tasks, these areas light up much less. For children, though the pattern is different—these areas light up even for mundane tasks. 

I think that, for babies, every day is first love in Paris. Every wobbly step is skydiving, every game of hide and seek is Einstein in 1905.

The astute reader will note that this is just the opposite of what Dan Dennett believes but cannot prove. And this brings me to a second thing I believe but cannot prove. I believe that the problem of capital-C Consciousness will disappear in psychology just as the problem of Life disappeared in biology. Instead we'll develop much more complex, fine-grained and theoretically driven accounts of the connections between particular types of phenomenological experience and particular functional and neurological phenomena. The vividness and intensity of our attentive awareness, for example, may be completely divorced from our experience of a constant first-person I. Babies may be more conscious in one way and less in the other. The consciousness of pain may be entirely different from the consciousness of red which may be entirely different from the babbling stream of Joyce and Woolf.

The Big Bang, that giant explosion of more than 13 billion years ago, provides the accepted description of our Universe's beginning. We can trace with exquisite precision what happened during the expansion and cooling that followed that cataclysm, but the presence of neutrinos in that earliest phase continues to elude direct experimental confirmation.

Neutrinos, once in thermal equilibrium, were supposedly freed from their bonds to other particles about two seconds after the Big Bang. Since then they should have been roaming undisturbed through intergalactic space, some 200 of them in every cubic centimeter of our Universe, altogether a billion of them for every single atom. Their presence is noted indirectly in the Universe's expansion. However, though they are presumably by far the most numerous type of material particle in existence, not a single one of those primordial neutrinos has ever been detected. It is not for want of trying, but the necessary experiments are almost unimaginably difficult. And yet those neutrinos must be there. If they are not, our whole picture of the early Universe will have to be totally reconfigured.

Wolfgang Pauli's original 1930 proposal of the neutrino's existence was so daring he didn't publish it. Enrico Fermi's brilliant 1934 theory of how neutrinos are produced in nuclear events was rejected for publication byNature magazine as being too speculative. In the 1950s neutrinos were detected in nuclear reactors and soon afterwards in particle accelerators. Starting in the 1960s, an experimental tour de force revealed their existence in the solar core. Finally, in1987 a ten second burst of neutrinos was observed radiating outward from a supernova collapse that had occurred almost 200,000 years ago. When they reached the Earth and were observed, one prominent physicist quipped that extra-solar neutrino astronomy "had gone in ten seconds from science fiction to science fact". These are some of the milestones of 20th century neutrino physics.

In the 21st century we eagerly await another one, the observation of neutrinos produced in the first seconds after the Big Bang. We have been able to identify them, infer their presence, but will we be able to actually see these minute and elusive particles? They must be everywhere around us, even though we still cannot prove it.

I believe, but cannot yet prove, that acquiring a human language (an oral or sign language) is a necessary precondition for consciousness–in the strong sense of there being a subject, an I, a 'something it is like something to be.' It would follow that non-human animals and pre-linguistic children, although they can be sensitive, alert, responsive to pain and suffering, and cognitively competent in many remarkable ways–including ways that exceed normal adult human competence–are not really conscious (in this strong sense): there is no organized subject (yet) to be the enjoyer or sufferer, no owner of theexperiences as contrasted with a mere cerebral locus of effects.

This assertion is shocking to many people, who fear that it would demote animals and pre-linguistic children from moral protection, but this would not follow. Whose pain is the pain occurring in the newborn infant? There is not yet anybody whose pain it is, but that fact would not license us to inflict painful stimuli on babies or animals any more than we are licensed to abuse the living bodies of people in comas who are definitely not conscious. If selfhood develops gradually, then certain types of events only gradually become experiences, and there will be no sharp line between unconscious pains (if we may call them that) and conscious pains, and both will merit moral attention. (And, of course, the truth of the empirical hypothesis is in any case strictly independent of its ethical implications, whatever they are. Those who shun the hypothesis on purely moral grounds are letting wishful thinking overrule a properly inquisitive scientific attitude. I am happy to give animals and small children "the benefit of the doubt" for moral purposes, but not for scientific purposes. Those who are shocked by my hypothesis should pause, if they can bear it, to notice that it is as just as difficult to prove its denial as its assertion. But it can, I think, be proven eventually. Here's what it will take, one way or the other:

(1) a well-confirmed model of the functional architecture of adult human consciousness, showing how long-distance pathways of re-entrant or reverberant interactions have to be laid down andsustained by the sorts of self-stimulation cascades that entrain language use;

(2) an interpretation of the dynamics of the model that explains why, absent these well-traveled pathways of neural micro habit, there is no functional unity to the nervous system–no unity to distinguish an I from a we (or a multitude) as the candidate subject(s) subserved by that nervous system;

(3) a host of further experimental work demonstrating the importance of what Thomas Metzinger calls the phenomenal model of the intentionality relation (PMIR) in enabling the sorts of experiences we consider central to our own adult consciousness. This work will demonstrate that animal cleverness never requires the abilities thus identified in humans, and that animals are in fact incapable of appreciating many things we normally take for granted as aspects of our conscious experience.

This is an empirical hypothesis, and it could just as well be proven false. It could be proven false by showing that in fact the necessary pathways functionally uniting the relevant brain systems (in the ways I claim are required for consciousness) are already provided in normal infant or fetal development, and are in fact present in, say, all mammalian nervous systems of a certain maturity. I doubt that this is true because it seems clear to me that evolution has already demonstrated that remarkable varieties of adaptive coordination can be accomplished without such hyper-unifying meta-systems, by colonies of social insects, for instance. What is it like to be an ant colony? Nothing, I submit, and I think most would agree intuitively. What is it like to be a brace of oxen? Nothing (even if it is like something to be a single ox). But then we have to take seriously the extent to which animals–not just insect colonies and reptiles, but rabbits, whales, and, yes, bats and chimpanzees–can get by with somewhat disunified brains.

Evolution will not have provided for the further abilities where they were not necessary for members of these species to accomplish the tasks their lives actually pose them. If animals were like the imaginary creatures in the fictions of Beatrix Potter or Walt Disney, they would have to be conscious pretty much the way we are. But animals are more different from us than we usually imagine, enticed as we are by these charming anthropomorphic fictions. We need these abilities to become persons, communicating individuals capable of asking and answering, requesting and forbidding and promising (and lying). But we don't need to be born with these abilities, since normal rearing will entrain the requisite neural dispositions. Human subjectivity, I am proposing, is thus a remarkable byproduct of human language, and no version of it should be extrapolated to any other species by default, any more than we should assume that the rudimentary communication systems of other species have verbs and nouns, prepositions and tenses.

Finally, since there is often misunderstanding on this score, I am not saying that all human consciousness consists in talking to oneself silently, although a great deal of it does. I am saying that the ability to talk to yourself silently, as it develops, also brings along with it the abilities to review, to muse, to rehearse, recollect, and in general engage the contents of events in one's nervous system that would otherwise have their effects in a purely "ballistic" fashion, leaving no memories in their wake, and hence contributing to one's guidance in ways that are well described as unconscious. If a nervous system can come to sustain all these abilities without having language then I am wrong.

I believe there is an external reality and you are not all figments of my imagination. My friend asks me through the steam he blows off the surface of his coffee, how I can trust the laws of physics back to the origins of the universe. I ask him how he can trust the laws of physics down to his cup of coffee. He shows every confidence that the scalding liquid will not spontaneously defy gravity and fly up in his eyes. He lives with this confidence born of his empirical experience of the world. His experiments with gravity, heat, and light began in childhood when he palpated the world to test its materials. Now he has a refined and well-developed theory of physics, whether expressed in equations or not.

I simultaneously believe more and less than he does. It is rational to believe what all of my empirical and logical tests of the world confirm—that there is a reality that exists independent of me. That the coffee will not fly upwards. But it is a belief nonetheless. Once I've gone that far, why stop at the perimeter of mundane experience? Just as we can test the temperature of a hot beverage with a tongue, or a thermometer, we can test the temperature of the primordial light left over from the big bang. One is no less real than the other simply because it is remarkable.

But how do I really know? If I measure the temperature of boiling water, all I really know is that mercury climbs a glass tube. Not even that, all I really know is that I see mercury climb a glass tube. But maybe the image in my mind's eye isn't real. Maybe nothing is real, not the mercury, not the glass, not the coffee, not my friend. They are all products of a florid imagination. There is no external reality, just me. Einstein? My creation. Picasso? My mind's forgery. But this solopsism is ugly and arrogant. How can I know that mathematics and the laws of physics can be reasoned down to the moment of creation of time, space, the entire universe? In the very same way that my friend believes in the reality of the second double cappuccino he orders. In formulating our beliefs, we are honest and critical and able to admit when we are wrong—and these are the cornerstones of truth.

When I leave the café, I believe the room of couches and tables is still on the block at 122nd Street, that it is still full of people, and that they haven't evaporated when my attention drifts away. But if I am wrong and there is no external reality, then not only is this essay my invention, but so is the web,edge.org, all of its participants and their ingenious ideas. And if you are reading this, I have created you too. But if I am wrong and there is no external reality, then maybe it is me who is a figment of your imagination and the cosmos outside your door is your magnificent creation.

Twenty-two percent of Americans claim to be certain that Jesus will return to earth to judge the living and the dead sometime in the next fifty years. Another twenty-two percent believe that he is likely to do so. The problem that most interests me at this point, both scientifically and socially, is the problem of belief itself. What does it mean, at the level of the brain, to believe that a proposition is true? The difference between believing and disbelieving a statement—Your spouse is cheating on you; you've just won ten million dollars—is one of the most potent regulators of human behavior and emotion. The instant we accept a given representation of the world as true, it becomes the basis for further thought and action; rejected as false, it remains a string of words.

What I believe, though cannot yet prove, is that belief is a content-independent process. Which is to say that beliefs about God—to the degree that they are really believed—are the same as beliefs about numbers, penguins, tofu, or anything else. This is not to say that all of our representations of the world are acquired through language, or that all linguistic representations are on the same logical footing. And we know that different regions of the brain are involved in judging the truth-value of statements drawn from different content domains. What I do believe, however, is that the neural processes that govern the final acceptance of a statement as "true" rely on more fundamental, reward-related circuitry in our frontal lobes—probably the same regions that judge the pleasantness of tastes and odors. Truth may be beauty, and beauty truth, in more than a metaphorical sense. And false statements may, quite literally, disgust us.

Once the neurology of belief becomes clear, and it stands revealed as an all-purpose emotion arising in a wide variety of contexts (often without warrant), religious faith will be exposed for what it is: a humble species of terrestrial credulity. We will then have additional, scientific reasons to declare that mere feelings of conviction are not enough when it comes time to talk about the way the world is. The only thing that guarantees that (sufficiently complex) beliefs actually represent the world, are chains of evidence and argument linking them to the world. Only on matters of religious faith do sane men and women regularly dispute this fact. Apart from removing the principle reason we have found to kill one another, a revolution in our thinking about religious belief would clear the way for new approaches to ethics and spiritual experience. Both ethics and spirituality lie at the very heart of what is good about being human, but our thinking on both fronts has been shackled to the preposterous for millennia. Understanding belief at the level of the brain may hold the key to new insights into the nature of our minds, to new rules of discourse, and to new frontiers of human cooperation.

I feel that I know something that will turn out to be correct and eventually proved to be true beyond doubt 

What?

That our ability to perceive signals in the environment evolved directly from our bacterial ancestors. That is, we, like all other mammals including our apish brothers detect odors, distinguish tastes, hear bird song and drum beats and we too feel the vibrations of the drums. With our eyes closed we detect the light of the rising sun. These abilities to sense our surroundings are a heritage that preceded the evolution of all primates, all vertebrate animals, indeed all animals. Such sensitivities to wafting plant scents, tasty salted mixtures, police cruiser sirens, loving touches and star light register because of our "sensory cells".

These avant guard cells of the nasal passages, the taste buds, the inner ear, the touch receptors in the skin and the retinal rods and cones all have in common the presence at their tips of projections ("cell processes") called cilia. Cilia have a recognizable fine structure. With a very high power ("electron") microscope a precise array of protein tubules, nine, exactly nine pairs of tubules are arranged in a circular array and two singlet tubules are in the center of this array. All sensory cells have this common feature whether in the light-sensitive retina of the eye or the balance-sensitive semicircular canals of the inner ear. Cross-section slices of the tails of human, mouse and even insect (fruit-fly) sperm all share this same instantly recognizable structure too. Why this peculiar pattern? No one knows for sure but it provides the evolutionist with a strong argument for common ancestry. The size (diameter) of the circle (0.25 micrometers) and of the constituent tubules (0.024 micrometers) aligned in the circle is identical in the touch receptors of the human finger and the taste buds of the elephant.

What do I feel that I know, what Oscar Wilde said (that "even true things can be proved")?

Not only that the sensory cilia derive from these exact 9-fold symmetrical structures in protists such as the "waving feet" of the paramecium or the tail of the vaginal-itch protist called Trichomonas vaginalis. Indeed, all biologists agree with the claim that sperm tails and all these forms of sensory cilia share a common ancestry.

But I go much farther. I think the the common ancestor of the cilium, but not the rest of the cell, was a free-swimming entity, a skinny snake-like bacterium that, 1500 million years ago squiggled through muds in a frantic search for food. Attracted by some smells and repelled by others the bacteria, by themselves, already enjoyed a repertoire of sensory abilities that remain with their descendants to this day. In fact, this bacterial ancestor of the cilium never went extinct, rather some of its descendants are uncomfortably close to us today. This hypothetical bacterium, ancestor to all the cilia, was no ordinary rod-shaped little dot.

No, this bacterium who still has many live relatives, entered into symbiotic partnerships with other very different kinds of bacteria. Together this two component partnership swam and stuck together both persisted. What kind of bacterium became an attached symbiont that impelled its partner forward? None other than a squirming spirochete bacterium.

The spirochete group of bacteria includes many harmless mud-dwellers but it also contains a few scary freaks: the treponeme of syphilis and the borrelias of Lyme disease. We animals got our exquisite ability to sense our surroundings—to tell light from dark, noise from silence, motion from stillness and fresh water from brackish brine—from a kind of bacterium whose relatives we despise. Cilia were once free-agents but they became an integral part of all animal cells. Even though the concept that cilia evolved from spirochetes has not been proved I think it is true. Not only is it true but, given the powerful new techniques of molecular biology I think the hypothesis will be conclusively proved. In the not-too-distant future people will wonder why so many scientists were so against my idea for so long!

If computers are made up of hardware and software, transistors and resistors, what are neural machines we know as minds made up of?

Minds clearly are not made up of transistors and resistors, but I firmly believe that at least one of the most basic elements of computation is shared by man and machine: the ability to represent information in terms of an abstract, algebra-like code.

In a computer, this means that software is made up of hundreds, thousands, even millions of lines that say things like IF X IS GREATER THAN Y, DO Z, orCALCULATE THE VALUE OF Q BY ADDING A, B, AND C. The same kind of abstraction seems to underlie our knowledge of linguistics. For instance, the famous linguistic dictum that a Sentence consists of a Noun Phrase plus a Verb Phrase can apply to an infinite number of possible nouns and verbs, not just a few familiar words. In its open-endedness, it is an example of mental algebra par excellence.

In my lab, we discovered that even infants seem to be able to grasp something quite similar. For example, in the course of just two minutes, a seven-month-old baby can extract the ABA "grammar" inherent in set of made-up sentences like la ta la, ga na ga, je li je. Or the ABB "grammar" in sentences like la ta ta, ga na na, je li li.

Of course, this experiment doesn't prove that there is an "algebra" circuit in the brain—psychological techniques alone can't do that. For final proof, we'll need neuroscientific techniques far more sophisticated than contemporary brain imaging, such that we can image the brain at the level of interactions between individual neurons. But every bit of evidence that we can collect now—from babies, from toddlers, from adults, from psychology and from linguistics—seems to confirm the idea that algebra-like abstraction is a fundamental component of thought.

I believe neuroscientists will never have enough understanding of the neural code, the secret language of the brain, to read peoples' thoughts without their consent.

The neural code is the software, algorithm, or set of rules whereby the brain transforms raw sensory data into perceptions, memories, decisions, meanings. A complete solution to the neural code could, in principle, allow scientists to monitor and manipulate minds with exquisite precision; you might, for example, probe the mind of a suspected terrorist for memories of past attacks or plans for future ones. The problem is, although all brains operate according to certain general principles, each person's neural code is to a certain extent idiosyncratic, shaped by his or her unique life history.

The neural pattern that underpins my concept of "George Bush" or "Heathrow Airport" or "surface-to-air missile" differs from yours. The only way to know how my brain encodes this kind of specific information would be to monitor its activity—ideally with thousands or even millions of implanted electrodes, which can detect the chatter of individual neurons—while I tell you as precisely as possible what I am thinking. But data you glean from studying me will be of no use for interpreting the signals of any other person. For ill or good, our minds will always remain hidden to some extent from Big Brother.

I have proposed a law of conscious content which asserts that for any experience, thought, question, or solution, there is a corresponding analog in the biophysical state of the brain. As a corollary to this principle, I have argued that conventional attempts to understand consciousness by simply searching for the neural correlates of consciousness (NCC) in theoretical and empirical investigations are too weak to ground a good understanding of conscious content. Instead, I have proposed that we go beyond NCC and explore brain events that have at least some similarity to our phenomenal experiences, namely, neuronal analogs of conscious content (NAC). In support of this approach, I have presented a theoretical model that goes beyond addressing the sheer correlation between mental states and neuronal events in the brain. It explains how neuronal analogs of phenomenal experience (NAC) can be generated, and it details how other essential human cognitive tasks can be accomplished by the particular structure and dynamics of putative neuronal mechanisms and systems in the brain.

A large body of experimental findings, clinical findings, and phenomenal reports can be explained within a coherent framework by the neuronal structure and dynamics of my theoretical model. In addition, the model accurately predicts many classical illusions and perceptual anomalies. So I believe that the neuronal mechanisms and systems that I have proposed provide a true explanation for many important aspects of human cognition and phenomenal experience. But I can't prove it. Of course, competing theories about the brain, cognition, and consciousness can't be proved either. But I can't prove it. Providing the evidence is the best we can do—I think.

There is no God that has existence apart from people's thoughts of God. There is certainly no Being that can simply suspend the (nomological) laws of the universe in order to satisfy our personal or collective yearnings and whims—like a stage director called on to change and improve a play. But there is a mental (cognitive and emotional) process common to science and religion of suspending belief in what you see and take for obvious fact. Humans have a mental compulsion—perhaps a by-product of the evolution of a hyper-sensitive reasoning device to serve our passions—to situate and understand the present state of mundane affairs within an indefinitely extendable and overarching system of relations between hitherto unconnected elements. In any event, what drives humanity forward in history is this quest for non-apparent truth.

I believe, but cannot prove, that a First Breakthrough on Consciousness is actually around the corner. "Actually around the corner" means: less than 50 years away. My intuition is that, roughly, all we need for this first breakthrough are four convincing stories.

The first story will be about global integration, about the dynamical self-organization of long-range binding operations in the human brain. It will probably involve something like synchrony in multiple frequency bands, and will let us understand how a unified model of the world can emerge in our own heads.

The second story will be about "transparency": Why is it that we are unable to consciously experience most of the images our brain generates as images? The answer to this question will give us a real world. The transparency-tale has to do with not being able to see earlier processing stages and becoming a naive realist.

The third story will focus on the Now, the emergence of a psychological moment—on a deeper understanding of what William James' called the "specious present". Experts on short term memory and neural network modelers with tell this story for us. As it unfolds, it will explain the emergence of a subjective present and let us understand how conscious experience, in its simplest and most essential form, is the presence of a world.

Interestingly, today almost everybody in the consciousness community already agrees on some version of the fourth story: Consciousness is directly linked to attentional processing, more precisely, to a hidden mechanism constantly holding information available for attention. The subjective presence of a world is a clever strategy of making integrated informationavailable for attention.

I believe, but cannot prove, that this will allow us to find the global neural correlate for consciousness. However, being a philosopher, I want much more than that—I am also interested in precise concepts. What I will be waiting for is the young mathematician who then comes along and suddenly allows us to see how all of these four stories were actually only one: The genius who gives us a formal model describing the information flow in this neural correlate, and in just the right way. She will harvest the fruits of generations or researchers before her, and this will be the First Breakthrough on Consciousness.

Then three things will happen.

1. The Second Breakthrough on Consciousness will take much longer. Things will get messy and complicated. The philosophy and neuroscience of consciousness will get bogged down in diabolic details and ugly technical problems. Public attention will soon shift away from the problem of consciousness per se. Instead, new generations of young researchers will now focus on the nature of self and social cognition.

2. The overall development will have an unexpectedly strong cultural impact. People will not want to face their own mortality. There will be fundamentalist and anti-rational counter movements against the scientific image of man. At the same time crude new ideologies propagating vulgar forms of materialism and primitive forms of hedonism will spring up. Scientists will realize that one can not reductively explain the human mind and then simply look another way, leaving the consequences for someone else to deal with.

3. We will be able to influence consciousness in ways we have never dreamt of. There will be a new form of technology—Consciousness Technology—exclusively focusing on how to manipulate the neural correlate of consciousness in ever more fine-grained, efficient, and risk-free ways. People will realize that we need some sort of applied ethics for this new type of technology. And hopefully we will all together start to tell a newstory—a story about how to live with these brains and about what a good state of consciousness actually is.

I can sum my intuition up in five words: we're in for climatic mayhem.

I believe, but can't prove, that human language evolved from a combination of gesture and innate vocalizations, via the concomitant evolution of mirror neurons, and that birds will provide the best model for language evolution.  

Work on mirror neurons over the past decade has provided intriguing evidence, although no solid proof, for the gestural origins of speech. What can be called the mirror neuron hypothesis(MNH) suggests that only a small re-organization of the nonhuman primate brain was needed to create the wiring that underlies speech acquisition/learning. What is missing from the MNH is a model of the development of language from speech; it is here that I believe that a model based on avian vocalizations is most valuable.

First, some background. Passerine birds can be divided into two groups: the oscines, who learn their songs, and the sub-oscines, who have a limited number of what seem to be innately-specified songs; the former have a well-defined neural architectures and mechanisms for song acquisition; the latter lack brain structures for song acquisition, although they obviously have brain and vocal tract structures for producing song. The sub-oscines, in parallel with nonhuman primates, often use various activities or gestures (posture, numbers of repetitions of songs, feather erectness, types of flights, etc) to provide additional information about the meaning of their utterances. W. John Smith, for example, can predict a flycatchers actions by the combination of posture, flight, and singing pattern he observes. The songbirds, like human children learning language, will not learn their vocalizations if deafened, and need to hear, babble and practice songs before attaining adult competence; very recent work by Rose et al. demonstrate that even the syntax of their song is learned through early exposure to paired phrases, which are then combined to create the adult vocalizations. Such data, demonstrating how sparrows integrate information about temporally-related events and how they use that information to develop sequential vocal behavior, is a viable model for human syntax acquisition.

Now, no one knows if any birds have any mirror neurons, and how their mirror neurons would function if they did exist; some neural data on responses to self-song provide intriguing hints but go no further. I predict (a) the existence of such neurons in oscines and (b) that such neurons will have a robust role in oscine song development, but (c) that only more primitively-functioning mirror neurons (akin to the differences separating monkey and human MNs) will be found in sub-oscines.

Now, what about the so-called missing link between learned and unlearned vocal behavior? No one has found such a missing link in the primate line. But Donald Kroodsma has recently discovered a flycatcher (a supposedly sub-oscine bird) that apparently learns its song. The song is simple, but has variations among groups of birds that constitute dialects. No one yet knows if these birds have brain mechanisms for song learning, or what these mechanisms might be. But I predict that Kroodsma's flycatchers will have mirror neurons that function in intermediate manner, between those of the oscines and sub-oscines, and will provide a model for the missing link between nonhuman primate and human communication.

I believe that all life, all intelligence, all creativity and all 'design' anywhere in the universe, is the direct or indirect product of Darwinian natural selection. It follows that design comes late in the universe, after a period of Darwinian evolution. Design cannot precede evolution and therefore cannot underlie the universe

Tribal Mind.

What would it be like to be part of a distributed intelligence but still with an individual consciousness? Well for starters, you might expect to see the collective mind 'take over' from time to time, directly guiding the individual minds. In humans, the behavior of angry mobs and frightened crowds seem to qualify as examples of a 'collective mind' in action, with non-linguistic channels of communication usurping the individual capacity for rational behavior.

But as powerful as this sort of group compulsion can be, it is usually regarded as simply a failure of individual rationality, a primitive behavioral safety net for the tribe in times of great stress. Surely this tribal mind doesn't operate in normal day-to-day behavior—or does it? If we imagined that human behavior was in substantial part due to a collective tribal mind, you would expect that non-linguistic social signaling—the type that drives mob behavior—would be predictive of even the most rational and important human interactions. Analogous with the wiggle dance of the honeybee, there ought to be non-linguistic signals that accurately predict important behavioral outcomes.

And that is exactly what I find. Together with my research group I have built a computer system that objectively measures a set of non-linguistic social signals, such as engagement, mirroring, activity, and stress, by looking at 'tone of voice' over one minute time periods. Although people are largely unconscious of this type of behavior, other researchers (Jaffe, Chartrand and Bargh, France, Kagen) have shown that similar measurements are predictive of infant language development, judgments of empathy, depression, and even personality development in children. Working with colleagues, we have found that we can use these measurements of social signaling to automatically predict a wide range of important behavioral outcomes—objective, instrumental, and subjective—with high accuracy, accounting for between 30% and 80% of the total outcome variance.

Examples of objective and instrumental behaviors where we can accurately predict the outcome include salary negotiations, dating decisions, and role in the social network. Examples of subjective predictions include hiring preferences, empathy perceptions, and interest ratings. Even for lengthy interactions, accurate predictions can be made by observing only the initial few minutes of interaction, even though the linguistic content of these 'thin slices' of the behavior seem to have little predictive power.

I find all of this astounding. We are examining some of the most important interactions a human has: finding a mate, getting a job, negotiating a salary, finding your place in your social network. These are activities for which we prepare intellectually and strategically for decades. And yet the largely unconscious social signaling that occurs at the start of the interaction appears to be more predictive than either the contextual facts (is he attractive? is she experienced?) or the linguistic structure (e.g., strategy chosen, arguments employed, etc.).

So what is going on here? One might speculate that the social signaling we are measuring evolved as a method of establishing tribal hierarchy and cohesion, analogous to Dunbar's view that language evolved as grooming behavior. On this view the tribal mind would function as unconscious collective discussion about relationships and resources, risks and rewards, and would interact with the conscious individual minds by filtering ideas by their value relative to the tribe. Our measurements tap into the discussion, and predict outcome by use of social regularities. For instance, in a salary negotiation it is important for the lower-status individual to establish that they are 'team player' by being empathetic, while in a potential dating situation the key variable is the female's level of interest. In our data there seem to be patterns of signaling that reliably lead to these desired states.

One question to ask about this social signaling is whether or not it is an independent channel of communication, e.g., is it causal or do the signals arise from the linguistic structure? We don't have the full answer to that yet, but we do know that similar measurements predict infant language and personality development, that adults can change their signaling by adopting different roles or identities within a conversation, and in our studies the linguistic and factual content seems uncorrelated with the pattern or intensity of social signaling. So even if social signaling turns out to be only an adjunct to normal linguistic structure, it is a very interesting addition: it is a little like having speech annotated with speaker intent!

So here is what I suspect but can not prove: a very large proportion of our behavior is determined by largely unconscious social signaling, which sets the context, risk, and reward structure within which traditional cognitive processes proceed. This conjecture resonates with Pinker's view about brain complexity, and with Kosslyn's thoughts about social prosthetic systems. It is also provides a concrete mechanism for the well-known processes of group polarization ('the risky shift'), groupthink, and the sometimes irrational behaviors of larger groups. In short, it may be useful to starting thinking of humans as having a collective, tribal mind in addition to their personal mind.

My career has been guided by just the sort of unproven guess this year's question seeks.

My belief is that the potential for expanded communication between people far exceeds the potential both of language as we think of it (the stuff we say, read and write) and of all the other communication forms we already use.

Suppose for a moment that children in the future will grow up with an easy and intimate virtual reality technology and that their use of it will become focused on invention and design instead of the consumption of pre-created holo-video games, surround movies, or other content.

Maybe these future children will play virtual musical instrument-like things that cause simulated trees and spiders and seasons and odors and ecologies to spring up just as manipulating a pencil causes words to appear on a page. If people grew up with a virtuosic ability to improvise the contents of a shared virtual world, a new sort of communication might also appear.

It's barely possible to imagine what a "reality conversation" would be like. Each person would be changing the shared world at the speed of language, all at once, an image that suggests chaos, but often there would be a coherence, which would indicate meaning. A kid becomes a monster, eats his little brother, who becomes a vitriolic turd, and so on.

This is what I've called "Post-symbolic communication," though really it won't exist in isolation of or in opposition to symbolic communication techniques. It will be something different, however, and will expand what people can mean to each other.

Post-symbolic communication will be like a shared, waking state, intentional dream. Instead of the word "house", you will express a particular house and be able to walk into it, and instead of the category "house" you will peer into an apparently small bucket that is big enough inside to hold all the universe's houses so you can assess what they have in common directly. It will be a fluid form of experiential concreteness providing similar but divergent expressive power to that of abstraction.

Why care? The acquisition of post-symbolic communication will be a centuries-long adventure, an expansion of meaning, something beautiful, and a way to seek cool, advanced technology that focuses on connection instead of mere power. It will be a form of beauty which also enhances survivability; Since the drive for "cool tech" is unstoppable, the invention of provocative cool tech that is lovely enough to seduce the attention of young smart men away from arms races is a prerequisite to the survival of the species.

Some of the examples above (houses, spiders) are of people improvising the external environment, but post-symbolic communication might typically look a lot more like people morphing themselves into varied forms. Experiments have already been conducted with kids wearing special body suits and goggles "turning into" triangles to learn trigonometry, or molecules to learn chemistry.

It's not only the narcissism of the young (and not so young) human mind or the primality of the control of one's own body that makes self-transformation compelling. Evolution, as generous as she ended up being with us humans, was stingy with potential means of expression. Compare us with the mimic octopus which can morph into all sorts of creatures and objects, and can animate its skin. An advanced civilization of cephalopods might develop words as we know them, but probably only as an adjunct to a natural form of post-symbolic communication.

We humans can control precious little of the world with enough agility to keep up with our thoughts and feelings. The fingers and the tongue are the about it. Symbols as we know them in language are a trick, or what programmers call a "hack," that expands the power of little appendage wiggles to refer to all that we can't instantly become or create. Another belief: The tongue that can speak could also someday control fantastic forms beyond our current imaginings. (Some early experiments along these lines have been done, using ultrasound sensing through the cheek. and the results are at least not terrible.)

While we're confessing unprovable beliefs, here's another one: The study of the genetic components of pecking order behavior, group belief cues, and clan identification leading to inter-clan hostility will be the core of psychology and sociology for the next few generations, and it will turn out we can't turn off or control these elements of human character without losing other qualities we love, like creativity. If this dark guess is correct, then the means to survival is to create societies with a huge variety of paths to success and a multitude of overlapping, intertwined clans and pecking orders, so that everyone can be a winner from equally valid individual perspectives. When the American experiment has worked best, it has approximated this level of variety. The virtual worlds of post-symbolic communication can provide the highest level of variety to satisfy the dangerous psychic inheritance I'm guessing we suffer as a species.

Implicit in the futures I am imagining here is a solution to the software crisis. If children are breathing out fully realized creatures and skies just as they form sentences today, there must be software present which isn't crashing and is marvelously flexible and responsive, yet free of limiting pre-conceptions, which would revive symbolism. Can such software exist? Ah! Another belief! My guess is it can exist, but not anytime soon. The only two good examples of software we have at this time are evolution and the brain, and they both are quite good, so why not be encouraged?

The beliefs I chose for this response are not fundamentally untestable. They might be tested someday, perhaps in a few centuries. It's not impossible that medical progress could keep me alive long enough to participate in testing them, so strictly speaking I can't guarantee that I can't ever prove these beliefs to be true.

There are not too many potential beliefs that could really never be tested by anyone ever. 

Consciousness, meaning, truth, and free will and their endless permutations just about complete the list. The reason philosophy is so much harder to talk about than science is that there's so little to talk about. It quickly becomes almost impossible to distinguish repetition from resonance.

Proposals like post-symbolic communication, however, frame questions about meaning that are small enough to be fresh and useful. Am I right that there can be meaning outside of words, or are the word-as-center-of-meaning folks correct?

That our universe is infinite in size, finite in age, and just one among many. Not only can I not prove it but I believe that these statements will prove to be unprovable in principle and we will eventually hold that principle to be self-evident.

I am convinced that quantum mechanics is not a final theory. I believe this because I have never encountered an interpretation of the present formulation of quantum mechanics that makes sense to me. I have studied most of them in depth and thought hard about them, and in the end I still can't make real sense of quantum theory as it stands. Among other issues, the measurement problem seems impossible to resolve without changing the physical theory.

Quantum mechanics must then be an approximate description of a more fundamental physical theory. There must then be hidden variables, which are averaged over to derive the approximate, probabilistic description which is quantum theory. We know from the experimental falsifications of the Bell inequalities that any theory which agrees with quantum mechanics on a range of experiments where it has been checked must be non-local. Quantum mechanics is non-local, as are all proposals for replacing it with something that makes more sense. So any additional hidden variables must be non-local. But I believe we can say more. I believe that the hidden variables represent relationships between the particles we do see, which are hidden because they are non-local and connect widely separated particles.

This fits in with another core belief of mine, which derives from general relativity, which is that the fundamental properties of physical entities are a set of relationships, which evolve dynamically. There are no intrinsic, non-relational properties, and there is no fixed background, such as Newtonian space and time, which exists just to give things properties.

One consequence of this is that the geometry of space and time is also only an approximate, emergent description, applicable only on scales too large to see the fundamental degrees of freedom. The fundamental relations are non-local with respect to the approximate notion of locality that emerges at the scale where it becomes sensible to talk about things located in a geometry.

Putting these together, we see that quantum uncertainty must be a residue of the resulting non-locality, which restricts our ability to predict the future of any small region of the universe. Hbar, the fundamental constant of quantum mechanics that measures the quantum uncertainty, is related to N, the number of degrees of freedom in the universe. A reasonable conjecture is that hbar is proportional to the inverse of the square root of N.

But how are we to describe physics, if it is not in terms of things moving in a fixed spacetime? Einstein struggled with this, and my only answer is the one he came to near the end of his life: fundamental physics must be discrete, and its description must be in terms of algebra and combinatorics.

Finally, what of time? I have been also unable to make sense of any of the proposals to do away with time as a fundamental aspect of our description of nature. So I believe in time, in the sense of causality. I also doubt that the "big bang" is the beginning of time, I strongly suspect that our history extends backwards before the big bang.

Finally, I believe that in the near future, we will be able to make predictions based on these ideas that will be tested in real experiments. 

True love.

I've spent two decades of my professional life studying human mating. In that time, I've documented phenomena ranging from what men and women desire in a mate to the most diabolical forms of sexual treachery. I've discovered the astonishingly creative ways in which men and women deceive and manipulate each other. I've studied mate poachers, obsessed stalkers, sexual predators, and spouse murderers. But throughout this exploration of the dark dimensions of human mating, I've remained unwavering in my belief in true love.

While love is common, true love is rare, and I believe that few people are fortunate enough to experience it. The roads of regular love are well traveled and their markers are well understood by many—the mesmerizing attraction, the ideational obsession, the sexual afterglow, profound self-sacrifice, and the desire to combine DNA. But true love takes its own course through uncharted territory. It knows no fences, has no barriers or boundaries. It's difficult to define, eludes modern measurement, and seems scientifically wooly. But I know true love exists. I just can't prove it.

Human Behavior is Unconsciously Controlled.

Until proven otherwise, why not assume that consciousness does not play a role in human behavior? Although it may seem radical on first hearing, this is actually the conservative position that makes the fewest assumptions. The null position is an antidote to philosopher's disease, the inappropriate attribution of rational, conscious control over processes that may be irrational and unconscious. The argument here is not that we lack consciousness, but that we over-estimate the conscious control of behavior. I believe this statement to be true. But proving it is a challenge because it's difficult to think about consciousness. We are misled by an inner voice that generates a reasonable but often fallacious narrative and explanation of our actions. That the beam of conscious awareness that illuminates our actions is on only part of the time further complicates the task. Since we are not conscious of our state of unconsciousness, we vastly overestimate the amount of time that we are aware of our own actions, whatever their cause.

My thinking about unconscious control was shaped by my field studies of the primitive play vocalization of laughter. When I asked people to explain why they laughed in a particular situation, they would concoct some reasonable fiction about the cause of their behavior—"someone did something funny," "it was something she said," "I wanted to put her at ease." Observations of social context showed that such explanations were usually wrong. In clinical settings, such post hoc misattributions would be termed "confabulations," honest but flawed attempts to explain one's actions.

Subjects also incorrectly presumed that laughing is a choice and under conscious control, a reason for their confident, if bogus, explanations of their behavior. But laughing is not a matter speaking "ha-ha," as we would choose a word in speech. When challenged to laugh on command, most subjects could not do so. In certain, usually playful, social contexts, laughter simply happens. However, this lack of voluntary control does not preclude a lawful pattern of behavior. Laughter appears at those places where punctuation would appear in a transcription of a conversation—laughter seldom interrupts the phrase structure of speech. We may say, "I have to go now—ha-ha," but rarely, "I have to—ha-ha—go now." This punctuation effect is highly reliable and requires the coordination of laughing with the linguistic structure of speech, yet it is performed without conscious awareness of the speaker. Other airway maneuvers such as breathing and coughing punctuate speech and are performed without speaker awareness.

The discovery of lawful but unconsciously controlled laughter produced by people who could not accurately explain their actions led me to consider the generality of this situation to other kinds of behavior. Do we go through life listening to an inner voice that provides similar confabulations about the causes of our action? Are essential details of the neurological process governing human behavior inaccessible to introspection? Can the question of animal consciousness be stood on its head and treated in a more parsimonious manner? Instead of considering whether other animals are conscious, or have a different, or lesser consciousness than our own, should we question if our behavior is under no more conscious control than theirs? The complex social order of bees, ants, and termites documents what can be achieved with little, if any, conscious control as we think of it. Is machine consciousness possible or even desirable? Is intelligent behavior a sign of conscious control? What kinds of tasks require consciousness? Answering these questions requires an often counterintuitive approach to the role, evolution and development of consciousness.

John MacNamara once proposed that children come to learn about right and wrong, good and evil, in much the same way that they learn about geometry and mathematics. Moral development is not merely cultural learning, and it does not arise from innate principles that have evolved through natural selection. It is not like the development of language or sexual preference or taste in food. 

Instead, moral development involves the construction of a intricate formal system that makes contact with the external world in a significant way. This cannot be entirely right. We know that gut-feelings, such as reactions of empathy or disgust, have a major influence on how children and adults reason about morality. And no serious theory of moral development can ignore the role of natural selection in shaping our moral intuitions. But what I like about Macnamara's proposal is that it allows for moral realism. It allows for the existence of moral truths that people come to discover, just as we come to discover truths of mathematics. We can reject the nihilistic position (help by many researchers) that our moral intuitions are nothing more than accidents of biology or culture. 

And so I believe (though I cannot prove it) that the development of moral reasoning is the same sort of process as the development of mathematical reasoning.

I believe that the prison guards at the Abu Ghraib Prison in Iraq, who worked the night shift in Tier 1A, where prisoners were physically and psychologically abused, had surrendered their free will and personal responsibility during these episodes of mayhem. 

But I could not prove it in a court of law. These eight army reservists were trapped in a unique situation in which the behavioral context came to dominate individual dispositions, values, and morality to such an extent that they were transformed into mindless actors alienated from their normal sense of personal accountability for their actions—at that time and place.

The "group mind" that developed among these soldiers was created by a set of known social psychological conditions, some of which are nicely featured in Golding's Lord of the Flies. The same processes that I witnessed in my Stanford Prison Experiment were clearly operating in that remote place: Deindividuation, dehumanization, boredom, groupthink, role-playing, rule control, and more. Beyond the relatively benign conditions in my study, in that Iraqi prison, the guards experienced extreme fatigue and exhaustion from working 12-hour shifts, 7 days a week, for over a month at a time with no breaks.

There was fear of being killed from mortar and grenade attacks and from prisoners rioting. There was revenge for buddies killed, and prejudice against these foreigners for their strange religion and cultural traditions. There was encouragement by staff "to soften up" the detainees for interrogation because Tier 1A was the Interrogation-Soft Torture center of that prison. Already in place when these young men and women arrived there for their tour of duty were abusive practices that had been "authorized" from the top of the chain of command: Use of nakedness as a humiliation tactic, sensory and sleep deprivation, stress positions, dog attacks, and more.

In addition to the situational variables and processes operating in that behavioral setting were a serious of systemic processes that created the barrel into which these good soldiers were forced to live and work. Most of the reports of independent investigation committees cite a failure of leadership, lack of leadership, or irresponsible leadership as factors that contributed to these abuses. Then there was lack of mission-specific training of the guards, no oversight, no accountability to senior officers, poor resources, overcrowded facilities, confusing commands from civilian interrogators at odds with the CIA, military intelligence and other agencies and agents all working in Tier 1A without clear communication channels and much confusion.

I was recently an expert witness for the defense of Sgt. Ivan "Chip" Frederick in his Baghdad trial. Before the trial, I spent a day with him, giving him an in-depth interview, checking all background information, and arranging for him to be psychologically assessed by the military. He is one of the alleged "bad apples" who these investigations have labeled as "morally corrupt." What did he bring into that situation and what did that situation bring into him?

He seemed very much to be a normal young American. His psych assessments revealed no sign of any pathology, no sadistic tendencies, and all his psych assessment scores are in the normal range, as is his intelligence. He had been a prison guard at a small minimal security prison where he performed for many years without incident. So there is nothing in his background, temperament, or disposition that could have been a facilitating factor for the abuses he committed at the Abu Ghraib Prison.

After a four-day long trial, part of which included my testimony elaborating on the points noted here, the Judge took barely one hour to find him guilty of all eight counts and to sentence Sgt. Frederick to 8 years in prison, starting in solitary confinement in Kuwait, dishonorable discharge, broken in rank from Sgt. to Pvt., loss of his 20 years retirement income and his salary. This military judge held Frederick personally responsible for the abuses, because he had acted out of free will to intentionally harm these detainees since he was not forced into these acts, was not mentally incompetent, or acting in self-defense. All of the situational and systemic determinants of his behavior and that of his buddies were disregarded and given a zero weighting coefficient in assessing causal factors.

The real reason for the heavy sentence was the photographic documentation of the undeniable abuses along with the smiling abusers in their "trophy photos." It was the first time in history that such images were publicly available of what goes on in many prisons around the world, and especially in military prisons. They humiliated the military, and the entire chain of command all the way up the ladder to the White House. Following this exposure, investigations of all American military prisons in that area of the world uncovered similar abuses and worse, many murders of prisoners. Recent evidence has revealed that similar abuses started taking place again in Abu Ghraib prison barely one month after these disclosures became public—when the "Evil Eight Culprits" were in other prisons—as prisoners.

Based on more than 30 years of research on "The Lucifer Effect"—the transformation of good people into perpetrators of evil—I believe that there are powerful situational and systemic forces operating on individuals in certain situations that can undercut a lifetime of morality and rationality. The Dionysian aspect of human nature can triumph over the Apollonian, not only during Mardi Gras, but in dynamic group settings like gang rapes, fraternity hazing, mob riots, and in that Abu Ghraib prison. I believe in that truth in general and especially in the case of Sgt. Frederick, but I was not able to prove it in a military court of law.

Strangely, I believe that cockroaches are conscious. That is probably an unappealing thought to anyone who switches on a kitchen light in the middle of the night and finds a family of roaches running for cover. But it's really shorthand for saying that I believe that many quite simple animals are conscious, including more attractive beasts like bees and butterflies.

I can't prove that they are, but I think in principle it will be provable one day and there's a lot to be gained about thinking about the worlds of these relatively simple creatures, both intellectually—and even poetically. I don't mean that they are conscious in even remotely the same way as humans are; if that we were true the world would be a boring place. Rather the world is full of many overlapping alien consciousnesses.

Why do I think they might be multiple forms of conscious out there? Before becoming a journalist I spent 10 years and a couple of post-doctoral fellowships getting inside the sensory worlds of a variety of insects, including bees and cockroaches. I was inspired by A Picture Book of Invisible Worlds, a slim out-of-print volume by Jakob von Uexkull (1864-1944). 

The same book had also inspired Niko Tinbergen and Konrad Lorenz, the Nobel Prize winners who founded the field of ethology (animal behaviour). Von Uexkull studied the phenomenal world of animals, what he called their "umwelt", the worlds around animals as they themselves perceive them. Everything that an animals senses means something to it, for it has evolved to fit and create its world. Study of animals and their sensory worlds have now morphed into the field of sensory ecology, or on a wilder path, the newer science of biosemiotics.

I studied time studying how honey bees could find their way around my laboratory room (they had learnt to fly in through a small opening in the window) and find a hidden source of sugar. Bees could learn all about the pattern of key features in the room and would show they were confused if objects were moved around when they were out of the room. They were also easily distracted by certain kinds of patterns, particularly ones with lots of points and lines that had very abstract similarities to the patterns on flowers, as well as by floral scents, and by sudden movements that signalled danger. In contrast, when they were busy gorging on the sugar almost nothing could distract them, making it possible for myself to paint a little number on their backs so I distinguish individual bees.

To make sense of this ever changing behaviour, with its shifting focus of attention, I always found it simplest to figure out what was happening by imagining the sensory world of the bee, with its eye extraordinarily sensitive to flicker and colours we can't see, as a "visual screen" in the same way I can sit back and "see" my own visual screen of everything happening around me, with sights and sounds coming in and out of prominence. The objects in the bees world have significances or "meaning" quite different from our own, which is why its attention is drawn to things we would barely perceive.

That's what I mean by consciousness—the feeling of "seeing" the world and its associations. For the bee, it is the feeling of being a bee. I don't mean that a bee is self-conscious or spends time thinking about itself. But of course the problem of why the bee has its own "feeling" is the same incomprehensible "hard problem" of why the activity of our nervous system gives rise to our own "feelings".

But at least the bee's world is very visual and capable of being imagined. Some creatures live in sensory worlds that are much harder to access. Spiders that hunt at night live in a world dominated by the detection of faint vibration and of the tiniest flows of air that allow them to see fly passing by in pitch darkness. Sensory hairs that cover their body give them a sensitivity to touch far more finely grained than we can possibly feel through our own skin.

To think this way about simple creatures is not to fall into the anthropomorphic fallacy. Bees and spiders live in their own world in which I don't see human-like motives. Rather it is a kind of panpsychism, which I am quite happy to sign up to, at least until we know a lot more about the origin of consciousness. That may take me out of the company of quite a few scientists who would prefer to believe that a bee with a brain of only a million neurones must surely be a collection of instinctive reactions with some simple switching mechanism between then, rather have some central representation of what is going on that might be called consciousness. But it leaves me in the company of poets who wonder at the world of even lowly creatures.

"In this falling rain, 
where are you off to
snail?"

wrote the haiku poet Issa.

And as for the cockroaches, they are a little more human than the spiders. Like the owners of the New York apartments who detest them, they suffer from stress and can die from it, even without injury. They are also hierarchical and know their little territories well. When they are running for it, think twice before crushing out another world.

We all believe in something and science itself is premised on a whole set of beliefs. Above all, science is founded on the belief that things are comprehensible and that by the ingenuity of our minds and the probing of ever more subtle instruments we will ultimately come to know It All. But is the All inherently knowable? I believe, though I cannot prove it, that there will always be things we do not know—large things, small things, interesting things and important things.

If theoretical physics is any guide we might suppose that science is a march towards a finite goal. For the past few decades theoretical physicists have been searching for a so-called "Theory of Everything," what Nobel laureate Stephen Weinberg has also called a "Final Theory." This "ultimate" set of equations that would tie together all the fundamental forces which physicists recognize today—the four essential powers of gravity, electromagnetism, and the nuclear forces inside the cores of atoms. But such theory—if we are lucky enough to extract it from the current mass of competing contenders—would not tell us anything about how proteins form or how DNA came into being. Less still would it illuminate the machinations of a living cell, or the workings of the human mind. Frankly, a "theory of everything" would not even help us to understand how snowflakes form. 

In an age when we have discovered the origin of the universe and observed the warping of space and time it is shocking to hear that scientists do not understand something as "paltry" as the formation of ice crystals. But that is indeed the case.

Kenneth Libbrecht, chairman of the Cal tech physics department is a world expert on ice crystal formation, a hobby project he took on more than twenty years ago precisely because as he puts it "there are six billion people on this planet, and I thought that at least one of us should understand how snow crystals form." After two decades of meticulous experimentation inside specially constructed pressurized chambers Libbrecht believes he has made some headway in understanding how ice crystallizes at the edge of the quasi-liquid layer which surrounds all ice structures. He calls his theory "structure dependent attachment kinetics," but he is quick to point out that this is far from the ultimate answer. The transition from water to ice is a mysteriously complex process that has engaged minds as brilliant as Johannes Kepler and Michael Faraday. Libbrecht hopes he can add the small next step in our knowledge of this wondrous substance that is so central to life itself. 

Studying ice crystals is Libbrecht's hobby—in his "day job" he is one of the hundreds of physicists who are working on the LIGO detector which is designed to detect gravitational waves that are believed to emanate from black holes and other massive cosmological entities. Gravity waves have been predicted by the general theory of relativity, and hence physicists believe they must exist. Here the matter of belief has literally bought into being a an extremely expensive machine. Any successful theory of everything will have to account for gravity, the most mysterious of all the forces and the one physicists least understand. Like the other three forces, physicists believe gravity must ultimately manifest itself in both wave and particle forms. LIGO is designed to detect such waves, if indeed they do exist.

Some years ago the science writer John Horgan wrote a marvelously provocative book in which he suggested that science was coming to an end, all the major theoretical edifices now supposedly being in place. Horgan was right in one sense, for high-energy physics may be on the verge of achieving its final unification. But in so many other areas, science is just beginning. Only now are we acquiring the scientific tools and techniques to begin to investigate how our atmosphere works, how ecological systems function, how genes create proteins, how cells evolve, and how brains work. The very success of "fundamental science" has opened doors undreamed of by earlier generations and in many ways it seems there is more than ever that we do not know. At a time when journals tout theories about how to create entire universes it is easy to imagine that science has grasped the whole of reality. In truth our ignorance is vast—and personally I believe it will always be so. 

Rather than pretend we will soon know it all, I suggest we might adopt instead the attitude of the great fifteenth century champion of science, Cardinal Nicholas of Cusa. Cusa titled his major work On Learned Ignorance. A complex and poetic fusion of mathematics, scientific speculation and Catholic theology, Cusa puts forward in this book the view that we can never —even in principle—know everything. Only God can do that. We mortals, confined within the world itself can never see it whole, from the outside as it were. But while we cannot know it All, Cusa insists we can know a great deal and that science and mathematics will take our knowledge forward. Our ignorance then can be ever more learned. Not omniscience then, but an ever more subtle and insightful unknowing is the goal that Cusa advocated. In the humble snowflakes Ken Libbrecht studies we have the perfect metaphor for such a view—though they melt on your tongue, each tiny crystal of ice encapsulates a universe whose basic rules we have barely begun to unravel.

I believe that scientific theories are a means of going—somewhat mysteriously—beyond what we are able to observe of the physical world, penetrating into the structure of nature. The "theoretical" parts of scientific theories—the parts that speak in seemingly non-observational terms—aren't, I believe, ultimately translatable into observations or aren't just algorithmic black boxes into which we feed our observations and churn out our predictions. I believe the theoretical parts have descriptive content and are true (or false) in the same prosaic way that the observational parts of theories are true (or false). They're true if and only if they correspond to reality.

I also believe that my belief about scientific theories isn't itself scientific. Science itself doesn't decide how it is to be interpreted, whether realistically or not.

That the penetration into unobservable nature is accomplished by way of abstract mathematics is a large part of what makes it mystifying—mystifying enough to be coherently if unpersuasively (at least to me) denied by scientific anti-realists. It's difficult to explain exactly how science manages to do what it is that I believe it does—notoriously difficult when trying to explain how quantum mechanics, in particular, describes unobserved reality. The unobservable aspects of nature that yield themselves to our knowledge must be both mathematically expressible and connected to our observations in requisite ways. The seventeenth-century titans, men like Galileo and Newton, figured out how to do this, how to wed mathematics to empiricism. It wasn't a priori obvious that it was going to work. It wasn't a priori obvious that it was going to get us so much farther into nature's secrets than the Aristotelian teleological methodology it was supplanting. A lot of assumptions about the mathematical nature of the world and its fundamental correspondence to our cognitive modes (a correspondence they saw as reflective of God's friendly intentions toward us) were made by them in order to justify their methodology.

I also believe that since not all of the properties of nature are mathematically expressible—why should they be? it takes a very special sort of property to be so expressible—that there are aspects of nature that we will never get to by way of our science. I believe that our scientific theories—just like our formalized mathematical systems (as proved by Gödel)—must be forever incomplete. The very fact of consciousness itself (an aspect of the material world we happen to know about, but not because it was revealed to us by way of science) demonstrates, I believe, the necessary incompleteness of scientific theories.

My friend, the theoretical physicist, believed so strongly in String Theory, "It must be true!" He was called to testify in a lawsuit, which contested the claims of String Theory against Quantum Loop Gravity. The lawyer was skeptical. "What makes you such an authority?" he asked. "Oh, I am without question the world's most outstanding theoretical physicist", was the startling reply. It was enough to convince the lawyer to change the subject. However, when the witness came off the stand, he was surrounded by protesting colleagues.

"How could you make such an outrageous claim?" they asked. The theoretical physicist defended, "Fellows, you just don't understand; I was under oath."

To believe without knowing it cannot be proved (yet) is the essence of physics. Guys like Einstein, Dirac, Poincaré, etc. extolled the beauty of concepts, in a bizarre sense, placing truth at a lower level of importance. There are enough examples that I resonated with the arrogance of my theoretical masters who were in effect saying that God, a.k.a. the Master, Der Alte, may have, in her fashioning of the universe, made some errors in favoring of a convenient truth over a breathtakingly wondrous mathematics. This inelegant lack of confidence has heretofore always proved hasty. Thus, when the long respected law of mirror symmetry was violated by weakly interacting but exotic particles, our pain at the loss of simplicity and harmony was greatly alleviated by the discovery of the failure of particle-antiparticle symmetry. The connection was exciting because the simultaneous reflection in a mirror and change of particles to antiparticles seemed to restore a new and more powerful symmetry—"CP" symmetry now gave us a connection of space (mirror reflection) and electric charge. How silly of us to have lost confidence in the essential beauty of nature!

The renewed confidence remained even when it turned out that "CP" was also imperfectly respected. "Surely," we now believe, "there is in store some spectacular, new, unforeseen splendor in all of us." She will not let us down. This we believe, even though we can't prove it.

I believe that consciousness and its contents are all that exists. Spacetime, matter and fields never were the fundamental denizens of the universe but have always been, from their beginning, among the humbler contents of consciousness, dependent on it for their very being.

The world of our daily experience—the world of tables, chairs, stars and people, with their attendant shapes, smells, feels and sounds—is a species-specific user interface to a realm far more complex, a realm whose essential character is conscious. It is unlikely that the contents of our interface in any way resemble that realm. Indeed the usefulness of an interface requires, in general, that they do not. For the point of an interface, such as the windows interface on a computer, is simplification and ease of use. We click icons because this is quicker and less prone to error than editing megabytes of software or toggling voltages in circuits. Evolutionary pressures dictate that our species-specific interface, this world of our daily experience, should itself be a radical simplification, selected not for the exhaustive depiction of truth but for the mutable pragmatics of survival.

If this is right, if consciousness is fundamental, then we should not be surprised that, despite centuries of effort by the most brilliant of minds, there is as yet no physicalist theory of consciousness, no theory that explains how mindless matter or energy or fields could be, or cause, conscious experience. There are, of course, many proposals for where to find such a theory—perhaps in information, complexity, neurobiology, neural darwinism, discriminative mechanisms, quantum effects, or functional organization. But no proposal remotely approaches the minimal standards for a scientific theory: quantitative precision and novel prediction. If matter is but one of the humbler products of consciousness, then we should expect that consciousness itself cannot be theoretically derived from matter. The mind-body problem will be to physicalist ontology what black-body radiation was to classical mechanics: first a goad to its heroic defense, later the provenance of its final supersession.

The heroic defense will, I suspect, not soon be abandoned. For the defenders doubt that a replacement grounded in consciousness could attain the mathematical precision or impressive scope of physicalist science. It remains to be seen, of course, to what extent and how effectively mathematics can model consciousness. But there are fascinating hints: According to some of its interpretations, the mathematics of quantum theory is itself, already, a major advance in this project. And perhaps much of the mathematical progress in the perceptual and cognitive sciences can also be so interpreted. We shall see.

The mind-body problem may not fall within the scope of physicalist science, since this problem has, as yet, no bona fide physicalist theory. Its defenders can surely argue that this penury shows only that we have not been clever enough or that, until the right mutation chances by, we cannot be clever enough, to devise a physicalist theory. They may be right. But if we assume that consciousness is fundamental then the mind-body problem transforms from an attempt to bootstrap consciousness from matter into an attempt to bootstrap matter from consciousness. The latter bootstrap is, in principle, elementary: Matter, spacetime and physical objects are among the contents of consciousness.

The rules by which, for instance, human vision constructs colors, shapes, depths, motions, textures and objects, rules now emerging from psychophysical and computational studies in the cognitive sciences, can be read as a description, partial but mathematically precise, of this bootstrap. What we lose in this process are physical objects that exist independent of any observer. There is no sun or moon unless a conscious mind perceives them, for both are constructs of consciousness, icons in a species-specific user interface. To some this seems a patent absurdity, a reductio of the position, readily contradicted by experience and our best science. But our best science, our theory of the quantum, gives no such assurance. And experience once led us to believe the earth flat and the stars near. Perhaps, in due time, mind-independent objects will go the way of flat earth.

This view obviates no method or result of science, but integrates and reinterprets them in its framework. Consider, for instance, the quest for neural correlates of consciousness (NCC). This holy grail of physicalism can, and should, proceed unabated if consciousness is fundamental, for it constitutes a central investigation of our user interface. To the physicalist, an NCC is, potentially, a causal source of consciousness. If, however, consciousness is fundamental, then an NCC is a feature of our interface correlated with, but never causally responsible for, alterations of consciousness. Damage the brain, destroy the NCC, and consciousness is, no doubt, impaired. Yet neither the brain nor the NCC causes consciousness. Instead consciousness constructs the brain and the NCC. This is no mystery. Drag a file's icon to the trash and the file is, no doubt, destroyed. Yet neither the icon nor the trash, each a mere pattern of pixels on a screen, causes its destruction. The icon is a simplification, a graphical correlate of the file's contents (GCC), intended to hide, not to instantiate, the complex web of causal relations.

I believe I can explain the Cambrian explosion.

The Cambrian explosion refers to the first appearance in a relatively short space of geological time of a very wide assortment of animals more than 500 million years ago. I believe it came about through hybridization. 

Many well preserved Cambrian fossils occur in the Burgess shale, in the Canadian Rockies. These fossils include small and soft-bodied animals, several of which were planktonic but none were larvae. Compared with modern animals, some of them seem to have the front end of one animal and rear end of another. Modern larvae present a comparable set-up: larvae seem to be derived from animals in different groups from their corresponding adults. I have amassed a bookful of evidence that the basic forms of larvae did indeed originate as animals in other groups and that such forms were transferred by hybridization. Animals with larvae are "sequential chimeras", in which one body-form—the larva—is followed by another, distantly related form—the adult. I believe there were no Cambrian larvae, and Cambrian hybridizations produced "concurrent chimeras", in which two distantly related body-forms appeared together.

About 600 million years ago, shortly before the Cambrian, animals with tissues (metazoans) made their first appearance. I agree with Darwin that there were several different forms (Darwin suggested four or five), and I believe they resulted from hybridizations between different colonial protists. Protists are mostly single-celled, but colonial forms consist of many similar cells. All Cambrian animals were marine, and, like most modern marine animals, they shed their eggs and sperm into the water, where fertilization took place. Eggs of one species frequently encountered sperm of another, and there were only poorly developed mechanisms to prevent hybridization. Early animals had small genomes, leaving plenty of spare gene capacity. These factors led to many fruitful hybridizations, which resulted in concurrent chimeras. Not only did the original metazoans hybridize but the new animals resulting from these hybidizations also hybridized, and this produced the explosion in animal form.

The acquisition of larvae by hybridization came much later, when there was little spare genome capacity in recipes for single animals, and it is still going on. In the echinoderms (the group that includes sea-urchins and starfish) there is evidence that there were no larvae in either the Cambrian or the Ordovician (the following period), and this might well apply to other major groups. Acquiring parts, rather than larvae, by hybridization continued, I believe, throughout the Cambrian and Ordovician and probably later, but, as genomes became larger and filled most of the available space, later hybridizations led to smaller changes in adult form or to acquisitions of larvae. The gradual evolution of better mechanisms to prevent eggs being fertilized by foreign sperm resulted in fewer fruitful hybridizations, but occasional hybridizations still take place. 

Hybridogenesis, the generation of new organisms by hybridization, and symbiogenesis, the generation of new organisms by symbiosis, both involve fusion of lineages, whereas Darwinian "descent with modification" is entirely within separate lineages. These forms of evolution function in parallel, and "natural selection" works on the results.

I cannot prove that Cambrian animals had poorly developed specificity and spare gene capacity, but it makes sense.

The great breakthrough will involve a new understanding of time...that moving through time is not free, and that consciousness itself will be seen to only be a time sensor, adding to the other sensors of light and space.

As a Christian monotheist, I start with two unproven axioms:

1. There is a God.

2. It's not me (and it's also not you).

Together, these axioms imply my surest conviction: that some of my beliefs (and yours) contain error. We are, from dust to dust, finite and fallible. We have dignity but not deity.

And that is why I further believe that we should

a) hold all our unproven beliefs with a certain tentativeness (except for this one!),

b) assess others' ideas with open-minded skepticism, and

c) freely pursue truth aided by observation and experiment.

This mix of faith-based humility and skepticism helped fuel the beginnings of modern science, and it has informed my own research and science writing. The whole truth cannot be found merely by searching our own minds, for there is not enough there. So we also put our ideas to the test. If they survive, so much the better for them; if not, so much the worse.

Within psychology, this "ever-reforming" process has many times changed my mind, leading me now to believe, for example, that newborns are not so dumb, that electro convulsive therapy often alleviates intractable depression, that America's economic growth has not improved our morale, that the automatic unconscious mind dwarfs the conscious mind, that traumatic experiences rarely get repressed, that most folks don't suffer low self-esteem, and that sexual orientation is not a choice.

I believe the following aspects of evolution to be true without knowing how to turn them into (respectable) research topics.

Important steps in evolution are robust. Multi-cellularity evolved at least ten times. There are several independent origins of eusociality. There were a number of lineages leading from primates to humans. If our ancestors would not have evolved language, somebody else would have.

Cooperation and language define humanity. Every special trait of humans is derivative of language.

Mathematics is a language and therefore a product of evolution.

Most of what I believe I cannot prove, simply for lack of time and energy; truths that I'd claim to know because they have been proved by others. That is how inextricably our beliefs are tied up with labors accomplished by fellow beings. And then there are mathematical truths that we now know are not provable. These phenomena have become favorites with the media but can only be made sense of by a serious scrutiny of the idea of mathematical truth and a specific articulation of a proof-concept,

But running across Esther's contribution I came up with a catchy response:

I believe in the creative power of boredom.

Or, to put it into the form suggested by the Edge question:

I believe that, no matter how relentlessly we overfeed our young with prepackaged interactive entertainments, before long they will break out and invent their own amusements. I know from experience; boredom drove me into mathematics during my preteens. But I cannot prove it, till it actually happens. Probably in less than a generation kids will be amusing themselves and each other in ways that we never dreamt of.

Such is my belief in human nature, in the resilience of its good sense.

Here is an observation from mathematical practice. By now the concept of an algorithm, well- defined, is widely hailed as the way to solve problems, more precisely sequences of problems labeled by a numerical parameter. The implementation of a specific algorithm may be boring, a task best left to a machine, while the construction of the algorithm together with a rigorous proof that it works is a creative and often laborious enterprise.

For illustration consider group theory. A group is defined as a structure consisting of a non-empty set and a binary operation obeying certain laws. The theory of groups consists of all sentences true of all groups; its restriction to the formal "first order" language L determined by the group structure is called the elementary theory TG of groups. Here we have a formal proof procedure, proven complete by Gödel in his PHD thesis the year before his incompleteness proof was published. The elementary theory of groups is axiomatizable: it consists of exactly those sentences that are derivable from the axioms by means of the rules of first order logic. Thus TG is an effectively (recursively) enumerable subset of L; a machine, unlimited in power and time, could eventually come up with a proof of every elementary theorem of group theory. However, a human group theorist would still be needed to select the interesting theorems out of the bulk of the merely true. The development of TG is no mean task, although its language is severely restricted.

The axiomatizability of a theory always raises the question how to recognize the non-theorems. The set FF of those L-sentences that fail in some finite group is recursively enumerable by an enumeration of all finite groups, a simple matter, in principle. But, as all the excitement over the construction of finite simple monsters has amply demonstrated, that again is in reality no simple task.

Neither the theory of finite groups nor the theory of all groups is decidable. The most satisfying proof of this fact shows how to construct to every pair (A, B) of disjoint recursively enumerable sets of L-sentences, where A contains all of TG and B contains FF, a sentence S that belongs neither to A nor to B. This is the deep and sophisticated theorem of effective non-separability proved in the early sixties independently by Mal'cev in the SSSR and Tarski's pupil Cobham.

It follows that constructing infinite counter-examples in group theory is a truly creative enterprise, while the theory of finite groups is not axiomatizable and so, to recognize a truth about finite groups requires deep insight and a creative jump. The concept of finiteness in group theory is not elementary and yet we have a clear idea of what is meant by talking about all finite groups, a marvelously intriguing situation.

To wind up with a specific answer to the 2005 Question:

I do believe that every sentence expressible in the formal language of elementary group theory is either true of all finite groups or else fails for at least one of them.

This statement may at first sight look like a logical triviality. But when you try to prove it honestly you find that you would need a decision procedure, which would, given any sentence of L, yield either a proof that S holds in all finite groups or else a finite group in which S fails. By the inseparability theorem mentioned above, there is no such procedure.

If asked whether I hold the equivalent belief for the theory of all groups I would hesitate because the concept of an infinite counterexample is not as concrete to my mind as that of the totality of all finite groups. These are the areas where personal intuition starts to come into play.

I believe that we humans, who know so much about cosmology and immunology, lack a framework for thinking about why and how humans cooperate. I believe that part of the reason for this is an old story we tell ourselves about the world:  Businesses and nations succeed by competing well. Biology is a war, where only the fit survive. Politics is about winning. Markets grow solely from self-interest. Rooted in the zeitgeist of Adam Smith's and Charles Darwin's eras, the scientific, social, economic, political stories of the 19th and 20th centuries overwhelmingly emphasized the role of competition as a driver of evolution, progress, commerce, society.

I believe that the outlines of a new narrative are becoming visible—a story in which cooperative arrangements, interdependencies, and collective action play a more prominent role and the essential (but not all-powerful) story of competition and survival of the fittest shrinks just a bit.

Although new knowledge in biology about the evolution of altruistic behavior and the role of symbiotic relationships, new understandings of economic behavior derived from experiments in game theory, neuroeconomic research, sociological investigations of institutions for collective action, computation-enabled technologies such as grid computing, mesh networks, and online markets all provide important clues, I don't believe anyone is likely to formulate an algorithm or recipe for human cooperation. I suspect that the complex interdependencies of human thought, behavior and culture entails an equivalent to the limits Heisenberg found to physics and Gödel established for mathematics.

I believe that more knowledge than what we have now, together with a conceptual framework that is neither reductionistic nor theological, could lead to better-designed economic and political policies and institutions. Institutional and conceptual barriers to mounting such an effort are as formidable as the methodological barriers. I am reminded of Doug Engelbart's problem in the 1950s. He couldn't convince computer engineers, librarians, public policy analysts that computing machinery could be used to augment human thinking, as well as performing scientific calculation and business data processing. Nobody and no institution had ever thought about computing machinery that way, and older ways of thinking about what machines could be designed to do were inadequate. Engelbart had to create "A Framework for Augmenting Human Intellect" before the various hardware, software, and human interface designers could create the first personal computers and networks.

By necessity, useful new understandings of how humans cooperate and fail to cooperate is an interdisciplinary task. I don't believe that the obvious importance of such an effort guarantees that it will be successfully accomplished. All our institutions for gathering and validating knowledge—universities, corporate research laboratories, and foundations—reward and support specialization.

Nature Is Culture.

I believe that nature and culture can now be understood as one unified process, not two distinct domains separated by some property of humans such as written or spoken language, consciousness, or ethics. Although there is no proof of this, and no consensus in the scientific community or in the humanities, the revelations of the past few years provide a foundation for both empirical and conceptual work that I believe will lead to a coherent, unified perspective on the process in which we and nature are engaged. This is not a take-over of the humanities by science, but a genuine fusion of the two based on clear articulations of basic concepts such as meaning and wholeness in natural and cultural processes, with implications for scientific studies, their applications in technology and their expression in the arts.

For me this vision has arisen primarily through developments in biology, which occupies the middle ground between culture and the physical world. The key conceptual changes have arisen from complexity theory through detailed studies of the networks of interactions between components within organisms, and between them in ecosystems. When the genome projects made it clear that we are unable to make sense of the information in DNA, attention necessarily shifted to understanding how organisms use this in making themselves with forms that allow them to survive and reproduce in particular habitats. The focus shifted from the hereditary material to its organised context, the living cell, so that organisms as agencies with a distinctive kind of organisation returned to the biological foreground.

Examination of the self-referential networks that regulate gene activities in organisms, that carry out the diverse functions and constructions within cells through protein-protein interactions (the proteome), and the sequences of metabolic transformations that make up the metabolome, have revealed that they all have distinctive properties of self-similar, fractal structure governed by power-law relationships. These properties are similar to the structure of languages, which are also self-referential networks described by power-laws, as discovered years ago by G.K. Zipf. A conclusion is that organisms use proto-languages to make sense of both their inherited history (written in DNA and its molecular modifications) and their external contexts (the environment) in the process of making themselves as functional agencies. Organisms thus become participants in cultures with histories that have meaning, expressed in the forms (morphologies and behaviours) distinctive to their species. This is of course embodied or tacit meaning, which cognitive scientists now recognise as primary in human culture also.

Understanding species as cultures that have experienced 3.7 billion years of adaptive evolution on earth makes it clear that they are repositories of meaningful knowledge and experience about effective living that we urgently need to learn about in human culture. Here is a source of deep wisdom about living in participation with others that is energy and resource efficient, that recycles everything, produces forms that are simultaneously functional and beautiful, and is continuously innovative and creative. We can now proceed with a holistic science that is unified with the arts and humanities and has at its foundation the principles that arise from a naturalistic ethic based on an extended science that includes qualities as well as quantities within the domain of knowledge.

There is plenty of work to do in articulating this unified perspective, from detailed empirical studies of the ways in which organisms achieve their states of coherence and adaptability to the application of these principles in the organic design of all human artefacts, from energy-generating devices and communication systems to cars and factories. The goal is to make human culture as integrated with natural process as the rest of the living realm so that we enhance the quality of the planet instead of degrading it. This will require a rethinking of evolution in terms of the intrinsic agency with meaning that is embodied in the life cycles of different species, understood as natural cultures. Integrating biology and culture with physical principles will be something of a challenge, but there are already many indications of how this can be achieved, without losing the thread of language and meaning that runs through living nature. The emphasis on wholeness that lies at the heart of quantum mechanics and its extensions in quantum gravity, together with the subtle order revealed as quantum coherence, is already stimulating a rethinking of the nature of wholeness, coherence and robust adaptability in organisms as well as quality of life in cultures. Furthermore, the self-similar, fractal patterns that arise in physical systems during phase transitions, when new order is coming into being, have the same characteristics as the patterns observed in organismic and cultural networks involved in generating order and meaning. The unified vision of a creative and meaningful cosmic process seems to be on the agenda as a replacement for the meaningless mechanical cosmos that has dominated Western scientific thought and cultural life for a few hundred years.

Reality Is A Novel.

I'd like to propose a modified Many Universes theory. Rather than saying every possible universe exists, I'd say, rather, that there is a sequence of possible universes, akin to the drafts of a novel.

We're living in a draft version of the universe—and there is no final version. The revisions never stop.

From time to time it's possible to be aware of this. In particular, when you relax and stop naming things and forming opinions, your consciousness spreads out across several drafts of the universe. Things don't need to be particularly one way or the other until you pin them down.

Each draft, each spacetime, each sheet of reality is itself rigorously deterministic; there really is no underlying randomness in the world. Instead we have a great web of synchronistic entanglements, with causes and effects flowing forward and backwards through time. The start of a novel matches its ending; the past matches the future. Changing one thing changes everything. If we fully know everything about the Now moment, we know the entire past and future.

With this in mind, explaining an given draft of the universe becomes a matter of explaining the contents of a single Now moment of that draft. This in turn means that we can view the evolution of the successive drafts as an evolution of different versions of a particular Now moment. As Scarlett's climactic scene with Rhett is repeatedly rewritten, all the rest of Gone With The Wind changes to match.

And this evolution, too, can be deterministic. We can figure we think of there as being two distinct deterministic rules, a Physics Rule and a Metaphysics Rule. The Physics Rule consists of time-reversible laws that grow the Now moment upwards and downwards to fill out the entire past and future of spacetime. And we invoke the Metaphysics Rule to account for the contents of the Now moment. The Metaphysics Rule is deterministic but not reversible; it grows sideways across a dimension that we might call paratime, turning some simple seed into the space-filling pattern found in the Now.

The Metaphysics rule is...what? One possibility is that it's something quite simple, perhaps as simple as an eight-bit cellular automaton rule generating complex-looking patterns out of pure computation. Or perhaps the Metaphysics rule is like the mind of an author creating a novel, searching out the best word to write next, somehow peering into alternate realities. Or, yet again, the big Metaphysics rule in the sky could be the One cosmic mind, the Big Aha, the eternal secret, living in the spaces between your thoughts.

How do we remember the past? There are many answers to this question, depending on whether you are an historian, artist or scientist. As a scientist I have wanted to know where in the brain memories are stored and how they are stored¦the genetic and neural mechanisms. Although neuroscientists have made tremendous progress in uncovering neural mechanisms for learning, I believe, but cannot prove, that we are all looking in the wrong place for long-term memory.

I have been puzzled by my ability to remember my childhood, despite the fact that most of the molecules in my body today are not the same ones I had as a child¦in particular, the molecules that make up my brain are constantly turning over, being replaced with newly minted molecules. Perhaps memories only seem to be stable. Rehearsal strengthens memories, and can even alter them. However, I have detailed memories of specific places where I lived 50 years ago that I doubt I ever rehearsed but can be easily verified, so the stability of long-term memories is a real problem.

Textbooks in neuroscience, including one that I coauthored, say that memories are stored at synapses between neurons in the brain, of which there are many. In neural network models of memory, information can be stored by selectively altering the strengths of the synapses, and "spike-time dependent plasticity" at synapses in the cerebral cortex has been found with these properties. This is a hot area of research, but all we need to know here is that patterns of neural activity can indeed modify a lot of molecular machinery inside a neuron.

If memories are stored as changes to molecules inside cells, which are constantly being replaced, how can a memory remain stable over 50 years? My hunch is that everyone is looking in the wrong place: that the substrate of really old memories is located not inside cells, but outside cells, in the extracellular space. The space between cells is not empty, but filled with a matrix of tough material that is difficult to dissolve and turns over very slowly if at all. The extracellular matrix connects cells and maintains the shape of the cell mass. This is why scars on your body haven't changed much after decades of sloughing off skin cells.

My intuition is based on a set of classic experiments on the neuromuscular junction between a motor neuron and a muscle cell, a giant synapse that activates the muscle. The specialized extracellular matrix at the neuromuscular junction, called the basal lamina, consists of proteoglycans, glycoproteins, including collagen, and adhesion molecules such as laminin and fibronectin. If the nerve that activates a muscle is crushed, the nerve fiber grows back to the junction and forms a specialized nerve terminal ending. This occurs even if the muscle cell is also killed. The memory of the contact is preserved by the basal lamina at the junction. Similar material exists at synapses in the brain, which could permanently maintain overall connectivity despite the coming and going of molecules inside neurons.

How could we prove that the extracellular matrix really is responsible for long-term memories? One way to disprove it would be to disrupt the extracellular matrix and see if the memories remain. This can be done with enzymes or by knocking out one or more key molecules with techniques from molecular genetics. If I am right, then all of your memories¦what makes you a unique individual¦are contained in the endoskeleton that connects cells to each other. The intracellular machinery holds memories temporarily and decides what to permanently store in the matrix, perhaps while you are sleeping. It might be possible someday to stain this memory endoskeleton and see what memories look like.

Think true, cannot prove. 

I believe that deceit and self deception play a disproportinate role in human-generated disasters, including misguided wars, international affairs more gnerally, the collapse of civilizations, and state affairs, including disastrous social, political and economic policies and miscarriages of justice.

I believe deceit and self deception play an important role in the relative
underdevelopment of the social sciences.

I believe that processes of self deception are important in limiting the
achievement of individuals.

There are good reasons to believe that the universe is infinite. 

If so, it contains an infinite number of regions of the same size as our observable region (which is 80 billion light years across). It follows from quantum mechanics that the number of distinct histories that could occur in any of these finite regions in a finite time (since the big bang) is finite. By history I mean not just the history of the civilization, but everything that happens, down to the atomic level. The number of possible histories is fantastically large (it has been estimated as 10 to the power 10 to the power 150), but the important point is that it is finite.

Thus, we have an infinite number of regions like ours and only a finite number of histories that can play out in them. It follows that every possible history will occur in an infinite number of regions. In particular, there should be an infinite number of regions with histories identical to ours. So, if you are not satisfied with the result of the presidential elections, don't despair: you candidate has won on an infinite number of earths.

This picture of the universe robs our civilization of any claim for uniqueness: countless identical civilizations are scattered in the infinite expanse of the cosmos. I find this rather depressing, but it is probably true.

Another thing that I believe to be true, but cannot prove, is that our part of the universe will eventually stop expanding and will recollapse to a big crunch. But this will happen no sooner than 20 billion years from now, and probably much later.

I believe that it is possible to change adult cells from one phenotype to another.

The birth of Dolly provided the insight behind this belief. She was the first adult cloned from another adult, of any species. Previously biologists had believed that the mechanisms that direct the formation of all of the different tissues that make up an adult were so complex and so rigidly fixed that they could not be reversed. Her birth demonstrated that the mechanisms that were active in the nucleus transferred from the mammary epithelial cell could be reversed by unknown factors in the recipient unfertilised egg.

We take for-granted the process by which the single cell embryo at fertilisation gives rise to all of the many tissues of an adult. As almost all of those cells have the same genetic information, the changes must be brought about by sequential differences in function of the genes. An impression is beginning to emerge of the factors that bring about these sequential changes, although much more remains to be learned. In particular, very little is known of the hierarchy of influence of the several regulatory factors.

I believe that a greater understanding of these mechanisms will allow us to cause cells from one tissue to form another different tissue. We have long been accustomed to the idea that cells are influenced by their external environment and use specific methods of tissue culture to control their function in the laboratory. The new research introduces an additional dimension. We will learn how to increase the activity of the intracellular factors to achieve our aims. This may be by direct introduction of the proteins, use of small molecule drugs to modulate expression of regulatory genes or transient expression of those key genes. We have much to learn about the optimal approach to „transdifferentiation¾. Is it necessary to reverse the process of differentiation to an early stage in the same pathway? Or is it possible to achieve change directly from one path to another? The answer may vary from one tissue to another.

The medical implications will be profound. Cells of specific tissues will be available from patients either for research to understand genetic differences or for their therapy, This is not to suggest that we cease research on embryo stem cells because knowledge from their use will be essential to develop the new approaches that I envisage. Conversely, understanding of the mechanisms of reprogramming cells will create important new opportunities in the use of embryo stem cells. As many options as possible should be available to the researcher and clinician.

It is my belief that, ultimately, this approach to tissue formation will be the greatest inheritance of the Dolly experiment. The ramifications are far wider than those that involve the production of cloned offspring.

I've always found belief a bit difficult; people tend to assume that I have rather strong beliefs, but I don't experience them in that way. As far as knowledge goes I'm a consumer, and sometimes a distributor, not a producer; most of what I believe to be true lies far beyond my capacity for proof, and I try to moderate the timbre of my belief accordingly. I know that almost all my beliefs are based on faith in people, and processes, and institutions, and their various capacities for correcting themselves when in error.

I think the same is true for most of us; those who can prove their beliefs in their field of expertise are still reliant on faith in others when it comes to other fields. To acknowledge this at all times is not possible—it would make every utterance tentative, encrust every concept with ceteris paribus clauses. But when faced with a question like this, the role of our faith in people and in social institutions has to be acknowledged. And it does no harm to acknowledge it now and then even when not faced with such a question, in order to reinforce the need to keep people, institutions and the processes of knowledge production held in helpful scrutiny.

Which I suppose means that, for me, the real question is what do I believe that I don't think anyone can prove. In answer I'd put forward the belief that there is a future much better, in terms of reduced human suffering and increased human potential, than the present, and that one part of what makes it better is a greater, subtler knowledge of the world at large.

If I can't prove this, why do I believe it? Because it's better than believing the alternative. Because it provides a context for social and political action that would otherwise be futile; in this, it is an exhortatory belief. It is also, in part, a self-serving one, in that it suggests that by trying to clarify and disseminate knowledge (a description that makes me sound like the chef at a soup kitchen) I'm doing something that helps the better future, if only a bit.

Besides the question of why, though, there's the question of how. And there the answer is "with difficulty". It is not an easy thing for me to make myself believe. But it is what I want to believe, and on my best days I do.

What I believe but cannot prove is that quantum physics teaches us to abandon the distinction between information and reality.

The fundamental reason why I believe in this is that it is impossible to make an operational distinction between reality and information. In other words, whenever we make any statement about the world, about any object, about any feature of any object, we always make statements about the information we have. And, whenever we make scientific predictions we make statements about information we possibly attain in the future. So one might be tempted to believe that everything is just information. The danger there is solipsism and subjectivism. But we know, even as we cannot prove it, that there is reality out there. For me the strongest argument for a reality independent of us is the randomness of the individual quantum event, like the decay of a radioactive atom. There is no hidden reason why a given atom decays at the very instant it does so.

So if reality exists and if we will never be able to make an operational distinction between reality and information, the hypothesis suggests itself that reality and information are the same. We need a new concept which encompasses both. In a sense, reality and information are the two sides of the same coin.

I feel that this is the message of the quantum. It is the natural extension of the Copenhagen interpretation. Once you adopt the notion that reality and information are the same all quantum paradoxes and puzzles disappear, like the measurement problem or Schrödinger's cat. Yet the price to pay is high. If my hypothesis is true, many questions become meaningless. There is no sense then to ask, what is "really" going on out there. Schrödinger's cat is neither dead nor alive unless we obtain information about her state.

By the way, I also believe that some day all computers will be quantum computers. The reason I believe this is the ongoing miniaturization of electronic components. And, certainly, we will learn to overcome decoherence. We will learn how to observe quantum phenomena outside the shielded environment of laboratories. I hope I will still be alive when this happens.

I believe that our universe is not accidental, but I cannot prove it. 

Historically, most physicists have shared this point-of-view. For centuries, most of us have believed that the universe is governed by a simple set of physical laws that are the same everywhere and that these laws derive from a simple unified theory. 

However, in the last few years, an increasing number of my most respected colleagues have become enamored with the anthropic principle—the idea that there is an enormous multiplicity of universes with widely different physical properties and the properties of our particular observable universe arise from pure accident. The only special feature of our universe is that its properties are compatible with the evolution of intelligent life. The change in attitude is motivated, in part, by the failure to date to find a unified theory that predicts our universe as the unique possibility. According to some recent calculations, the current best hope for a unified theory—superstring theory—allows an exponentially large number of different universes, most of which look nothing like our own. String theorists have turned to the anthropic principle for salvation. 

Frankly, I view this as an act of desperation. I don't have much patience for the anthropic principle. I think the concept is, at heart, non-scientific. A proper scientific theory is based on testable assumptions and is judged by its predictive power. The anthropic principle makes an enormous number of assumptions—regarding the existence of multiple universes, a random creation process, probability distributions that determine the likelihood of different features, etc.—none of which are testable because they entail hypothetical regions of spacetime that are forever beyond the reach of observation. As for predictions, there are very few, if any. In the case of string theory, the principle is invoked only to explain known observations, not to predict new ones. (In other versions of the anthropic principle where predictions are made, the predictions have proven to be wrong. Some physicists cite the recent evidence for a cosmological constant as having anticipated by anthropic argument; however, the observed value does not agree with the anthropically predicted value.)

I find the desperation especially unwarranted since I see no evidence that our universe arose by a random process. Quite the contrary, recent observations and experiments suggest that our universe is extremely simple. The distribution of matter and energy is remarkably uniform. The hierarchy of complex structures ranging from galaxy clusters to subnuclear particles can all be described in terms of a few dozen elementary constituents and less than a handful of forces, all related by simple symmetries. A simple universe demands a simple explanation. Why do we need to postulate an infinite number of universes with all sorts of different properties just to explain our one? 

Of course, my colleagues and I are anxious for further reductionism. But I view the current failure of string theory to find a unique universe simply as a sign that our understanding of string theory is still immature (or perhaps that string theory is wrong). Decades from now, I hope that physicists will be pursuing once again their dreams of a truly scientific "final theory" and will look back at the current anthropic craze as millennial madness.

When did humans complete their expansion around the world? I'm convinced, but can't yet prove, that humans first reached the continents of North America, South America, and Australia only very recently, at or near the end of the last Ice Age. Specifically, I'm convinced that they reached North America around 14,000 years ago, South America around 13,500 years ago, and Australia and New Guinea around 46, 000 years ago; and that humans were then responsible for the extinctions of most of the big animals of those continents within a few centuries of those dates; and that scientists will accept this conclusion sooner and less reluctantly for Australia and New Guinea than for North and South America.

Background to my conjecture is that there are now hundreds of thousands of sites with undisputed evidence of human presence dating back to millions of years ago in Africa, Europe, and Asia, but none with even disputed evidence of human presence over 100,000 years ago in the Americas and Australia. In the Americas, undisputed evidence suddenly appears in all the lower 48 U.S. states around 14,000 years ago, at numerous South American sites soon thereafter, and at hundreds of Australian sites between 46,000 and 14,000 years ago. Evidence of most of the former big mammals of those continents—e.g., elephants and lions and giant ground sloths in the Americas, giant kangaroos and one-ton Komodo dragons in Australia—disappears within a few centuries of those dates. The transparent conclusion: people arrived then, quickly filled up those continents, and easily killed off their big animals that had never seen humans and that let humans walk up to them, as Galapagos and Antarctica animals still do today.

But some Australian archaeologists, and many American archaeologists, resist this obvious conclusion, for several reasons. Archaeologists try hard to find convincing earlier sites, because it would be a dramatic discovery. Every year, discoveries of many purportedly older sites are announced, then to be forgotten. As the supporting evidence dissolves or remains disputed, we're now in a steady state of new claims and vanishing old claims, like a hydra constantly sprouting new heads. There are still a few sites known for the Americas with evidence of human butchering of the extinct big animals, and none known for Australia and New Guinea—but one expects to find very few sites anyway, among all the sites of natural deaths for hundreds of thousands of years, if the hunting was all finished locally (because the prey became extinct) within a few decades. American archaeologists are especially persistent in their quest for pre-14,000 sites—perhaps because secured dating requires use of multiple dating techniques (not just radiocarbon), but American archaeologists distrust alternatives to radiocarbon (discovered by U.S. scientists) because the alternative dating techniques were discovered by Australian scientists.

Every year, beginning graduate students in archaeology and paleontology, working in Africa or Europe or Asia, go out and discover undisputed new sites with ancient human presence. Every year, new such discoveries are announced to the other three continents, but none has ever met the requirements of evidence accepted for Africa, Europe, or Asia. The big animals of the latter three continents survive, because they had millions of years to learn fear of human hunters with very slowly evolving skills; most big animals of the former three continents didn't survive, because they had the misfortune that their first encounter with humans was a sudden one, with fully modern skilled hunters.

To me, the case is already proved. How many more decades of unconvincing claims will it take to convince the holdouts among my colleagues? I don't know. It makes better newspaper headlines to report "Wow!! New discovery overturns the established paradigm of American archaeology!!" than to report, "Ho hum, yet another reportedly paradigm-overturning discovery fails to hold up."

I believe that intelligent life may presently be unique to our Earth, but that, even so, it has the potential to spread through the galaxy and beyond—indeed, the emergence of complexity could still be near its beginning. If SETI searches fail, that would not render life a cosmic sideshow Indeed, it would be a boost to our cosmic self-esteem: terrestrial life, and its fate, would become a matter of cosmic significance. Even if intelligence is now unique to Earth, there's enough time lying ahead for it to spread through the entire Galaxy, evolving into a teeming complexity far beyond what we can even conceive.

There's an unthinking tendency to imagine that humans will be around in 6 billion years, watching the Sun flare up and die. But the forms of life and intelligence that have by then emerged would surely be as different from us as we are from a bacterium. That conclusion would follow even if future evolution proceeded at the rate at which new species have emerged over the 3 or 4 billion years of the geological past. But post-human evolution (whether of organic species or of artefacts) will proceed far faster than the changes that led to emergence, because it will be intelligently directed rather than being—like pre-human evolution—the gradual outcome of Darwinian natural selection. Changes will drastically accelerate in the present century—through intentional genetic modifications, targeted drugs, perhaps even silicon implants in to the brain. Humanity may not persist as a single species for more than a few centuries—especially if communities have by then become established away from the earth.

But a few centuries is still just a millionth of the Sun's future lifetime—and the entire universe probably has a longer future still. The remote future is squarely in the realm of science fiction. Advanced intelligences billions of years hence might even create new universes. Perhaps they'll be able to choose what physical laws prevail in their creations. Perhaps these beings could achieve the computational capability to simulate a universe as complex as the one we perceive ourselves to be in.

My belief may remain unprovable for billions of years. It could be falsified sooner—for instance, we (or our immediate post-human descendents) may develop theories that reveal inherent limits to complexity. But it's a substitute for religious belief, and I hope it's true.

Wandering through the frontiers of the sciences, and the arts, I have always trusted the eye while leaving aside the issues that elude it. It can mislead—of course—therefore I check endlessly and never rush to print. 

Meanwhile, for over fifty years, I have watched as some disciplines exhaust the "top down" problems they know how to tackle. So they wander around seeking totally new patterns in a dark and deep mess, where an unlit lamp is of little help.

But the eye can continually be trained and, long ago, I have vowed to follow it, therefore work "from the bottom up." Like the Antaeus of Greek myth, I gather strength and persist by often touching the earth.

A few of the truths the eye told me have been disproven. Let it be. Others have been confirmed by enormous and fruitful effort, and then blossomed, one being the four thirds conjecture in Brownian motion. Many others remain, one being the MLC conjecture about the Mandelbrot set, in which I believe for no other reason than trust in the eye.

The Search Problem is solvable.

Advances in computational linguistics and user interface design will eventually enable people to find answers to any question they have, so long as the answer is encoded in textual form and stored in a publicly accessible location. Advances in reasoning systems will to a limited degree be able to draw inferences in order to find answers that are not explicitly present in the existing documents.

There have been several recent developments that prompt me to make this claim. First, computational linguistics (also known as natural language processing or language engineering) has made great leaps forward in the last decade, due primarily to advances stemming from the availability of huge text collections, from which statistics can be derived. Today's automatic language translation systems, for example, are now derived almost entirely from statistical patterns extracted from text collections. They now work as well as hand-engineered systems, and promise to continue to improve. As another example, recent government-sponsored research in the area of (simple) question answering has produced a radical leap forward in the quality of results in this arena.

Of course, another important development is the rise of the Web and its most voracious consumer, the internet search engine. It is common knowledge that search engines make use of information associated with link structure to improve results rankings. But search engine companies also have enormous, albeit somewhat impoverished, repositories of information about how people ask for information. This behavioral information can be used to build better search tools. For example, some spelling correction algorithms make use of how people have corrected erroneous spellings in the past, by observing pairs of queries that occur one after the next. The second query is assumed to be the correction, if it is sufficiently similar to the first. Patterns are then derived that convert from different types of misspellings to their corrections.

Another development in the field of computational linguistics is the manual creation of enormous lexical ontologies, which are then used to build axioms and rules about language use. These modern ontologies, unlike their predecessors, are of a large enough scale and simple enough design to be useful, although this work is in the early stages. There are also many attempts to build such ontologies automatically from large text collections; the most promising approach seems to be to combine the automated and the manual approaches.

As a side note, I am skeptical about the hype surrounding the Semantic Web—it is very difficult to characterize concepts in a systematic way, and even more so to force all the world's creators of information to conform to one schema. Automated analysis tools adapt to what people really do, rather than try to force people's expressions of information to conform to a standard.

Finally, advances in user interface design are key to producing better search results. The search field has learned an enormous amount in the ten years since the Web became a major presence in society, but as is often noted in the field, the interface itself hasn't changed much: after all this time, we still type words into a blank box and then select from a list of results. Experience shows that a search interface has to be a qualitative leap better than the standard in order to entice people to switch. I believe headway will be made in this area, most likely occurring in tandem with advances in natural language analysis.

It may well be the case that advances in audio, image, and video processing will keep pace with those of language analysis, thus making possible the answering of questions that can be answered by information stored in graphical and audio form. However, my expertise does not extend to these fields, so I will not make a claim about this.

I believe that we are writing software the wrong way. There are sound evolutionary reasons for why we are doing what we are doing—that we can call the "programming the problem in a computer language" paradigm, but the incredible success of Moore's law blinded us to being stuck in what is probably an evolutionary backwater.

There are many warning signs. Computers are demonstrably ten thousand times better than not so long ago. Yet we are not seeing their services improving at the same rate (with some exceptions—for example games and internet searches.) On an absolute scale, a business or administration problem that would take maybe one hundred pages to describe precisely, will take millions of dollars to program for a computer and often the program will not work. Recently a smaller airline came to a standstill due to a problem in crew scheduling software—raising the ire of Congress, not to mention their customers.

My laptop could store 200 pages of text (1/2 megabytes) for each and every crew member at this airline just in its fast memory and hundred times more (a veritable encyclopedia of 20,000 pages) for each person on its hard disk. Of course for a schedule we would need maybe one or two—or at most ten pages per person. Even with all the rules—the laws, the union contracts, the local, state, federal taxes, the duty time limitations, the FAA regulations on crew certification; is there anyone who believes that the problem is not simple in terms of computing? We need to store and process at the maximum 10 pages per person where we have capacity for two thousand times more in one cheap laptop! Of course the problem is complex in terms of the problem domain—but not shockingly so. I would estimate that all the rules possibly relevant to aircraft crew scheduling are expressible in less than a thousand pages—or 1/2 of one percent of the fast memory.

Software is surely the bottleneck on the high-tech horn of plenty. The scheduling program for the airline takes many thousand times more memory than what I believe it should be. Hence the software represents complexity that is many thousand times greater than what I believe the problem is—no wonder that some planes are assigned three pilots by the software while the others can't fly because the copilot is not scheduled. Note that the cost of the memory is not the issue—we could afford that waste. But the use of so much memory for software is an indication of some complexity inflation that occurs during programming that is the real bottleneck.

What is going on? I like to use cryptography as the metaphor. As we know, in cryptography we take a message and we combine it with a key using a difficult-to-invert function to get the code. Programmers using today's paradigm start from a problem statement, for example that a Boeing 767 requires a pilot, a copilot, and seven cabin crew with various certification requirements for each—and combine this with their knowledge of computer science and software engineering—that is how this rule can be encoded in computer language and turned into an algorithm. This act of combining is the programming process, the result of which is called the source code. Now, programming is well known to be a difficult-to-invert function, perhaps not to cryptography's standards, but one can joke about the possibility of the airline being able to keep their proprietary scheduling rules secret by publishing the source code for the implementation since no one could figure out what the rules were—or really whether the code had to do with scheduling or spare parts inventory—by studying the source code, it can be that obscure.

The amazing thing is that today it is the source code—that is the encrypted problem—which is the artifact all of software engineering is focusing on. To add insult to the injury, the "encryption", that is programming, is done manually which means high costs, low throughput and high error rates. In contrast with software maintenance, when the General realizes that he is about to send a wrong encrypted message, no one would think of editing the code after the encryption or "fixing the code"; instead the clear text would be first edited and then this improved message would be re-encrypted at computer speeds and computer accuracy. In other words the message may be wrong, but it won't be wrong because of the encryption and it is easily fixed.

We see that the complexity inflation comes from encoding. The problem statement above is obviously oversimplified, but remember that we used just two lines from our realistic budget of a thousand pages and we haven't even used the aviation jargon which can make these statements even more compact and more precise. But once these statements are viewed through the funhouse mirror of software coding, it becomes all but unrecognizable: thousand times fatter, disjointed, foreign. And as any manual product, it will have many flaws—beyond the errors in the rules themselves.

What can be done? Follow the metaphor. First, refocus on recording the problem statement—the "cleartext" in our metaphor. This is not a program in any sense of the word—it is just a straightforward recording of the subject matter experts' contributions using their own terms-of-art, their jargon, their own notations. Next, empower the programmers to program not the problem itself, but to express their software engineering expertise and decisions as a computer code for the encoder that takes the recorded problem statement and generates the code from it. This is called generative programming and I believe it is the future of software.

I believe in belief—or rather: I have faith in having faith. Yet, I am an atheist (or a "bright" as some would have it). How can that be?

It is important to have faith, but not necessarily in God. Faith is important far outside the realm of religion: having faith in other people, in oneself, in the world, in the existence of truth, justice and beauty. There is a continuum of faith, from the basic everyday trust in others to the grand devotion to divine entities.

Recent discoveries in behavioural sciences, such as experimental economics and game theory, shows that it is a common human attitude towards the world to have faith. It is vital in human interactions; and it is no coincidence that the importance of anchoring behaviour in riskful trust is stressed in worlds as far apart as Søren Kierkegaard's existentialist christianity and modern theories of bargaining behaviour in economic interactions. Both stress the importance of the inner, subjective conviction as the basis for actions, the feeling of an inner glow.

One could say that modern behavioral science is re-discovering the importance of faith that has been known to religions for a long time. And I would argue that this re-discovery shows us that the activity of having faith can be decoupled from the belief in divine entities.

So here is what I have faith in: We have a hand backing us, not as a divine foresight or control, but in the very simple and concrete sense that we are all survivors. We are all the result of a very long line of survivors who survived long enough to have offspring. Amoeba, rodents and mammals. We can therefore have confidence that we are experts in survival. We have a wisdom inside, inherited from millions of generations of animals and humans, a knowledge of how to go about life. That does not in any way imply foresight or planning ahead on our behalf. It only implies that we have a reason to trust out ability to deal with whatever challenges we meet. We have inherited such an ability.

Therefore, we can trust each other, ourselves and life itself. We have no guarantee or promises for eternal life, not at all. The enigma of death is still there, ineradicable. 

But we a reason to have confidence in ourselves. The basic fact that we are still here—despite snakes, stupidity and nuclear weapons—gives us reason to have confidence in ourselves and each other, to trust others and to trust life. To have faith.

Because we are here, we have reason for having faith in having faith.

I can't prove it, but I am pretty sure that people gain a selective advantage from believing in things they can't prove. I am dead serious about this. People who are sometimes consumed by false beliefs do better than those who insist on evidence before they believe and act. People who are sometimes swept away by emotions do better in life than those who calculate every move. These advantages have, I believe, shaped mental capacities for intense emotion and passionate beliefs because they give a selective advantage in certain situations.

I am not advocating for irrationality or extreme emotionality. Many, perhaps even most problems of individuals and groups arise from actions based on passion. The Greek initiators and Enlightenment implementers recognized correctly that the world would be better off if reason displaced superstition and crude emotion. I have no interest in going back on that road and fundamentalism remains a severe threat to enlightened civilization. I am arguing, however, that if we want to understand these tendencies we need to quit dismissing them as defects and start considering how they came to exist. 

I came to this belief from seeing psychiatric patients while studying game theory and evolutionary biology. Many patients are consumed by fears, sadness, and other emotions they find painful and senseless. Others are crippled by grandiose fantasies or bizarre beliefs. On the other side are those with obsessive compulsive personality. They do not have obsessive compulsive disorder; they do not wash and count all day. They have obsessive compulsive personality characterized by hyper-rationality. They are mystified by other people's emotional outbursts. They do their duty and expect others will too. They are often disappointed in this, giving rise to frequent resentment if not anger. They trade favors according to the rules, and they can't fathom genuine generosity or spiteful hatred.

People who lack passions suffer several disadvantages. When social life results in situations that can be mapped onto game theory, regular predictable behavior is a strategy inferior to allocating actions randomly among the options. The angry person who might seek spiteful revenge is a force to be reckoned with, while a sensible opponent can be easily dealt with. The passionate lover sweeps away a superior but all too practical offer of marriage.

It is harder to explain the disadvantages suffered by people who lack a capacity for faith, but consider the outcomes for those who wait for proof before acting, compared to the those who act on confident conviction. The great things in life are done by people who go ahead when it seems senseless to others. Usually they fail, but sometimes they succeed.

Like nearly every other trait, tendencies for passionate emotions and irrational convictions are most advantageous in some middle range. The optimum for modern life seems to me to be quite a ways towards the rational side of the median, but there are advantages and disadvantages at every point along the spectrum. Making human life better requires that we understand these capacities, and to do that we must seek their origins and functions. I cannot prove this is true, but I believe it is. This belief spurs my search for evidence which will either strengthen my conviction or, if I can discipline my mind sufficiently, convince me that it is false.