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

What makes humans uniquely smart?

Here's my best guess: we alone evolved a simple computational trick with far reaching implications for every aspect of our life, from language and mathematics to art, music and morality. The trick: the capacity to take as input any set of discrete entities and recombine them into an infinite variety of meaningful expressions.

Thus, we take meaningless phonemes and combine them into words, words into phrases, and phrases into Shakespeare. We take meaningless strokes of paint and combine them into shapes, shapes into flowers, and flowers into Matisse's water lilies. And we take meaningless actions and combine them into action sequences, sequences into events, and events into homicide and heroic rescues.

I'll go one step further: I bet that when we discover life on other planets, that although the materials may be different for running the computation, that they will create open ended systems of expression by means of the same trick, thereby giving birth to the process of universal computation.

The Brain Basis of Talent

I believe that human talents are based on distinct patterns of brain connectivity. These patterns can be observed as the individual encounters and ultimately masters an organized activity or domain in his/her culture.

Consider three competing accounts:

#1 Talent is a question of practice. We could all become Mozarts or Einsteins if we persevered.

#2 Talents are fungible. A person who is good in one thing could be good in everything. 

#3 The basis of talents is genetic. While true, this account misleadingly implies that a person with a "musical gene" will necessarily evince her musicianship, just as she evinces her eye color or, less happily, Huntington's disease.

My Account: The most apt analogy is language learning. Nearly all of us can easily master natural languages in the first years of life. We might say that nearly all of us are talented speakers. An analogous process occurs with respect to various talents, with two differences:

1. There is greater genetic variance in the potential to evince talent in areas like music, chess, golf, mathematics, leadership, written (as opposed to oral) language, etc. 

2. Compared to language, the set of relevant activities is more variable within and across cultures. Consider the set of games. A person who masters chess easily in culture l, would not necessarily master poker or 'go' in culture 2.

As we attempt to master an activity, neural connections of varying degrees of utility or disutility form. Certain of us have nervous systems that are predisposed to develop quickly along the lines needed to master specific activities (chess) or classes of activities (mathematics) that happen to be available in one or more cultures. Accordingly, assuming such exposure, we will appear talented and become experts quickly. The rest of us can still achieve some expertise, but it will take longer, require more effective teaching, and draw on intellectual faculties and brain networks that the talented person does not have to use.

This hypothesis is currently being tested by Ellen Winner and Gottfried Schlaug. These investigators are imaging the brains of young students before they begin music lessons and for several years thereafter. They also are imaging control groups and administering control (non-music) tasks. After several years of music lessons, judges will determine which students have musical "talent." The researchers will document the brains of musically talented children before training, and how these brains develop.

If Account #1 is true, hours of practice will explain all. If #2 is true, those best at music should excel at all activities. If #3 is true, individual brain differences should be observable from the start. If my account is true, the most talented students will be distinguished not by differences observable prior to training but rather by the ways in which their neural connections alter during the first years of training.

Irrational choices.

I do not believe that people are capable of rational thought when it comes to making decisions in their own lives. People believe that are behaving rationally and have thought things out, of course, but when major decisions are made—who to marry, where to live, what career to pursue, what college to attend, people's minds simply cannot cope with the complexity. When they try to rationally analyze potential options, their unconscious, emotional thoughts take over and make the choice for them.

As an example of what I mean consider a friend of mine who was told to select a boat as a wedding present by his father in law. He chose a very peculiar boat which caused a real rift between him and his bride. She had expected a luxury cruiser, which is what his father in law had intended. Instead he selected a very rough boat that he could fashion as he chose. As he was an engineer his primary concern was how it would handle open ocean and he made sure the engines were special ones that could be easily gotten at and that the boat rode very low in the water. When he was finished he created a very functional but very ugly and uncomfortable boat.

Now I have ridden with him on his boat many times. Always he tells me about its wonderful features that make it a rugged and very useful boat. But, the other day, as we were about to start a trip, he started talking about how pretty he thought his boat was, how he liked the wood, the general placement of things, and the way the rooms fit together. I asked him if he was describing a boat that he had been familiar with as a child and suggested that maybe this boat was really a copy of some boat he knew as a kid. He said, after some thought, that that was exactly the case, there had been a boat like in his childhood and he had liked it a great deal.

While he was arguing with his father in law, his wife, and nearly everyone he knew about his boat, defending his decision with all the logic he could muster, destroying the very conceptions of boats they had in mind, the simple truth was his unconscious mind was ruling the decision making process. It wanted what it knew and loved, too bad for the conscious which had to figure how to explain this to everybody else.

Of course, psychoanalysts have made a living on trying to figure out why people make the decisions they do. The problem with psychoanalysis is that it purports to be able to cure people. This possibility I doubt very much. Freud was a doctor so I guess he got paid to fix things and got carried away. But his view of the unconscious basis of decision making was essentially correct. We do not know how we decide things, and in a sense we don't really care. Decisions are made for us by our unconscious, the conscious is in charge of making up reasons for those decisions which sound rational. We can, on the other hand, think rationally about the choices that other people make. We can do this because we do not know and are not trying to satisfy unconscious needs and childhood fantasies. As for making good decisions in our lives, when we do it is mostly random. We are always operating with too little information consciously and way too much unconsciously.

Dan Dennett has it right in his comments below when he puts the emphasis on acquiring language, not having language, as a precondition for our kind of consciousness. For what it's worth, I have some (likely unproveable) beliefs about why the preschooler's acquisition of a structured language is so important for all the rest of her higher intellectual function. Besides syntax, intellect includes structured stuff such as multistage contingent planning, chains of logic, games with arbitrary rules, and our passion for discovering "how things hang together."

Many animals have some version of a critical period for tuning up sensory perception. Humans also seem to have one for structured language, judging from the experience with the deaf children of hearing parents who are not exposed to a rich sign language during the preschool years. Oliver Sacks in "Seeing Voices" described an 11-year-old boy who had been thought to be retarded but proved to be merely deaf. After a year of ASL instruction, Sacks interviewed him:

"Joseph saw, distinguished, categorized, used; he had no problems with perceptual categorization or generalization, but he could not, it seemed, go much beyond this, hold abstract ideas in mind, reflect, play, plan. He seemed completely literal—unable to juggle images or hypotheses or possibilities, unable to enter an imaginative or figurative realm.... He seemed, like an animal, or an infant, to be stuck in the present, to be confined to literal and immediate perception..."

In the first year, an infant is busy creating categories for the speech sounds she hears. By the second year, the toddler is busy picking up new words, each composed of a series of those phoneme building blocks. In the third year, she starts picking up on those typical combinations of words that we call grammar or syntax. She soon graduates to speaking long structured sentences. In the fourth year, she infers a patterning to the sentences and starts demanding proper endings for her bedtime stories. It is pyramiding, using the building blocks at the immediately subjacent level. Four levels in four years!

These years see a lot of softwiring via the pruning and enhancement of the prenatal connections between cortical neurons, partly on the basis of how useful a connection has been so far in life. Some such connections help you assemble a novel combination of words, check them for nonsense via some sort of quality control, and then—mirabile dictu—speak a sentence you've never uttered before. Some must be in workspaces that could plan not only sentences but an agenda for the weekend or a chain of logic or check out a chess move before you make it—even be tickled by structured music with its multiple interwoven melodies.

Then tuning up the workspace for structured language in the preschool years would likely carry over to those other structured aspects of intellect. That's why I like the emphasis on acquiring language as a precondition for consciousness: tuning up to sentence structure might make the child better able to perform at nonlanguage tasks which also need some structuring. Improve one, improve them all?

Is that what boosts our cleverness and intelligence? Is "our kind of consciousness" nothing but structured intellect with good quality control? Can't prove it, but it sure looks like a good candidate.

In 1974, Marvin Minsky wrote that "there is room in the anatomy and genetics of the brain for much more mechanism than anyone today is prepared to propose." Today, many advocates of evolutionary and domain-specific psychology are in fact willing to propose the richness of mechanism that Minsky called for thirty years ago. For example, I believe that the mind is organized into cognitive systems specialized for reasoning about object, space, numbers, living things, and other minds; that we are equipped with emotions triggered by other people (sympathy, guilt, anger, gratitude) and by the physical world (fear, disgust, awe); that we have different ways for thinking and feeling about people in different kinds of relationships to us (parents, siblings, other kin, friends, spouses, lovers, allies, rivals, enemies); and several peripheral drivers for communicating with others (language, gesture, facial expression).

When I say I believe this but cannot prove it, I don't mean that it's a matter of raw faith or even an idiosyncratic hunch. In each case I can provide reasons for my belief, both empirical and theoretical. But I certainly can't prove it, or even demonstrate it in the way that molecular biologists demonstrate their claims, namely in a form so persuasive that skeptics can't reasonably attack it, and a consensus is rapidly achieved. The idea of a richly endowed human nature is still unpersuasive to many reasonable people, who often point to certain aspects of neuroanatomy, genetics, and evolution that appear to speak against it. I believe, but cannot prove, that these objections will be met as the sciences progress.

At the level of neuroanatomy and neurophysiology, critics have pointed to the apparent homogeneity of the cerebral cortex and of the seeming interchangeability of cortical tissue in experiments in which patches of cortex are rewired or transplanted in animals. I believe that the homogeneity is an illusion, owing to the fact that the brain is a system for information processing. Just as all books look the same to someone who does not understand the language in which they are written (since they are all composed of different arrangements of the same alphanumeric characters), and the DVD's of all movies look the same under a microscope, the cortex may look homogeneous to the eye but nonetheless contain different patterns of connectivity and synaptic biases that allow it to compute very different functions. I believe this these differences will be revealed in different patterns of gene expression in the developing cortex. I also believe that the apparent interchangeability of cortex occurs only in early stages of sensory systems that happen to have similar computational demands, such as isolating sharp signal transitions in time and space.

At the level of genetics, critics have pointed to the small number of genes in the human genome (now thought to be less than 25,000) and to their similarity to those of other animals. I believe that geneticists will find that there is a large store of information in the noncoding regions of the genome (the so-called junk DNA), whose size, spacing, and composition could have large effects on how genes are expressed. That is, the genes themselves may code largely for the meat and juices of the organism, which are pretty much the same across species, whereas how they are sculpted into brain circuits may depend on a much larger body of genetic information. I also believe that many examples of what we call "the same genes" in different species may differ in tiny ways at the sequence level that have large consequences for how the organism is put together.

And at the level of evolution, critics have pointed to how difficult it is to establish the adaptive function of a psychological trait. I believe this will change as we come to understand the genetic basis of psychological traits in more detail. New techniques in genomic analysis, which look for statistical fingerprints of selection in the genome, will show that many genes involved in cognition and emotion were specifically selected for in the primate, and in many cases the human, lineage.

Science, like most human activities, is based on a belief, namely the assumption that nature is understandable.

If we are faced with a puzzling experimental result, we first try harder to understand it with currently available theory, using more clever ways to apply that theory. If that really doesn't work, we try to improve or perhaps even replace the theory. We never conclude that a not-yet understood result is in principle un-understandable.

While some philosophers might draw a different conclusion—see the contribution by Nicholas Humphrey—as a scientist I strongly believe that Nature is understandable. And such a belief can neither be proved nor disproved.

Note: undoubtedly, the notion of what counts as "understandable" will continue to change. What physicists consider to be understandable now is very different from what had been regarded as such one hundred years ago. For example, quantum mechanics tells us that repeating the same experiment will give different results. The discovery of quantum mechanics led us to relax the rigid requirement of a deterministic objective reality to a statistical agreement with a not fully determinable reality. Although at first sight such a restriction might seem to limit our understanding, we in fact have gained a far deeper understanding of matter through the use of quantum mechanics than we could possibly have obtained using only classical mechanics.

If we believe that consciousness is the result of patterns of neurons in the brain, our thoughts, emotions, and memories could be replicated in moving assemblies of Tinkertoys. The Tinkertoy minds would have to be very big to represent the complexity of our minds, but it nevertheless could be done, in the same way people have made computers out of 10,000 Tinkertoys. In principle, our minds could be hypostatized in patterns of twigs, in the movements of leaves, or in the flocking of birds. The philosopher and mathematician Gottfried Leibniz liked to imagine a machine capable of conscious experiences and perceptions. He said that even if this machine were as big as a mill and we could explore inside, we would find "nothing but pieces which push one against the other and never anything to account for a perception."

If our thoughts and consciousness do not depend on the actual substances in our brains but rather on the structures, patterns, and relationships between parts, then Tinkertoy minds could think. If you could make a copy of your brain with the same structure but using different materials, the copy would think it was you. This seemingly materialistic approach to mind does not diminish the hope of an afterlife, of transcendence, of communion with entities from parallel universes, or even of God. Even Tinkertoy minds can dream, seek salvation and bliss—and pray.

It is possible to live happily and morally without believing in free will. As Samuel Johnson said "All theory is against the freedom of the will; all experience is for it." With recent developments in neuroscience and theories of consciousness, theory is even more against it than it was in his time, more than 200 years ago. So I long ago set about systematically changing the experience. I now have no feeling of acting with free will, although the feeling took many years to ebb away.

But what happens? People say I'm lying! They say it's impossible and so I must be deluding myself to preserve my theory. And what can I do or say to challenge them? I have no idea—other than to suggest that other people try the exercise, demanding as it is.

When the feeling is gone, decisions just happen with no sense of anyone making them, but then a new question arises—will the decisions be morally acceptable? Here I have made a great leap of faith (or the memes and genes and world have done so). It seems that when people throw out the illusion of an inner self who acts, as many mystics and Buddhist practitioners have done, they generally do behave in ways that we think of as moral or good. So perhaps giving up free will is not as dangerous as it sounds—but this too I cannot prove.

As for giving up the sense of an inner conscious self altogether—this is very much harder. I just keep on seeming to exist. But though I cannot prove it—I think it is true that I don't.

Before we can answer this question we need to agree what we mean by proof. (This is one of the reasons why its good to have mathematicians around. We like to begin by giving precise definitions of what we are going to talk about, a pedantic tendency that sometimes drives our physicist and engineering colleagues crazy.) For instance, following Descartes, I can prove to myself that I exist, but I can't prove it to anyone else. Even to those who know me well there is always the possibility, however remote, that I am merely a figment of their imagination. If it's rock solid certainty you want from a proof, there's almost nothing beyond our own existence (whatever that means and whatever we exist as) that we can prove to ourselves, and nothing at all we can prove to anyone else. 

Mathematical proof is generally regarded as the most certain form of proof there is, and in the days when Euclid was writing his great geometry textElements that was surely true in an ideal sense. But many of the proofs of geometric theorems Euclid gave were subsequently found out to be incorrect—David Hilbert corrected many of them in the late nineteenth century, after centuries of mathematicians had believed them and passed them on to their students—so even in the case of a ten line proof in geometry it can be hard to tell right from wrong.

When you look at some of the proofs that have been developed in the last fifty years or so, using incredibly complicated reasoning that can stretch into hundreds of pages or more, certainty is even harder to maintain. Most mathematicians (including me) believe that Andrew Wiles proved Fermat's Last Theorem in 1994, but did he really? (I believe it because the experts in that branch of mathematics tell me they do.)

In late 2002, the Russian mathematician Grigori Perelman posted on the Internet what he claimed was an outline for a proof of the Poincare Conjecture, a famous, century old problem of the branch of mathematics known as topology. After examining the argument for two years now, mathematicians are still unsure whether it is right or not. (They think it "probably is.")

Or consider Thomas Hales, who has been waiting for six years to hear if the mathematical community accepts his 1998 proof of astronomer Johannes Keplers 360-year-old conjecture that the most efficient way to pack equal sized spheres (such as cannonballs on a ship, which is how the question arose) is to stack them in the familiar pyramid-like fashion that greengrocers use to stack oranges on a counter. After examining Hales' argument (part of which was carried out by computer) for five years, in spring of 2003 a panel of world experts declared that, whereas they had not found any irreparable error in the proof, they were still not sure it was correct.

With the idea of proof so shaky—in practice—even in mathematics,answering this year's Edge question becomes a tricky business. The best we can do is come up with something that we believe but cannot prove to our own satisfaction. Others will accept or reject what we say depending on how much credence they give us as a scientist, philosopher, or whatever, generally basing that decision on our scientific reputation and record of previous work. At times it can be hard to avoid the whole thing degenerating into a slanging match. For instance, I happen to believe, firmly, that staples of popular-science-books and breathless TV-specials such as ESP and morphic resonance are complete nonsense, but I can't prove they are false. (Nor, despite their repeated claims to the contrary, have the proponents of those crackpot theories proved they are true, or even worth serious study, and if they want the scientific community to take them seriously then the onus if very much on them to make a strong case, which they have so far failed to do.)

Once you recognize that proof is, in practical terms, an unachievable ideal, even the old mathematicians standby of GÏdel's Incompleteness Theorem (which on first blush would allow me to answer the Edge question with a statement of my belief that arithmetic is free of internal contradictions) is no longer available. GÏdel's theorem showed that you cannot prove an axiomatically based theory like arithmetic is free of contradiction within that theory itself. But that doesn't mean you can't prove it in some larger, richer theory. In fact, in the standard axiomatic set theory, you can prove arithmetic is free of contradictions. And personally, I buy that proof. For me, as a living, human mathematician, the consistency of arithmetic has beenproved—to my complete satisfaction.

So to answer the Edge question, you have to take a common sense approach to proof—in this case proof being, I suppose, an argument that would convince the intelligent, professionally skeptical, trained expert in the appropriate field. In that spirit, I could give any number of specific mathematical problems that I believe are true but cannot prove, starting with the famous Riemann Hypothesis. But I think I can be of more use by using my mathematician's perspective to point out the uncertainties in the idea of proof. Which I believe (but cannot prove) I have.

Conversation With a Slow Student

Student: Hi Prof. I've got a problem. I decided to do a little probability experiment—you know, coin flipping—and check some of the stuff you taught us. But it didn't work.

Professor: Well I'm glad to hear that you're interested. What did you do?

Student: I flipped this coin 1,000 times. You remember, you taught us that the probability to flip heads is one half. I figured that meant that if I flip 1,000 times I ought to get 500 heads. But it didn't work. I got 513. What's wrong?

Professor: Yeah, but you forgot about the margin of error. If you flip a certain number of times then the margin of error is about the square root of the number of flips. For 1,000 flips the margin of error is about 30. So you were within the margin of error.

Student: Ah, now I get if. Every time I flip 1,000 times I will always get something between 970 and 1,030 heads. Every single time! Wow, now that's a fact I can count on.

Professor: No, no! What it means is that you will probably get between 970 and 1,030.

Student: You mean I could get 200 heads? Or 850 heads? Or even all heads?

Professor: Probably not.

Student: Maybe the problem is that I didn't make enough flips. Should I go home and try it 1,000,000 times? Will it work better?

Professor: Probably.

Student: Aw come on Prof. Tell me something I can trust. You keep telling me what probably means by giving me more probablies. Tell me what probability means without using the word probably.

Professor: Hmmm. Well how about this: It means I would be surprised if the answer were outside the margin of error.

Student: My god! You mean all that stuff you taught us about statistical mechanics and quantum mechanics and mathematical probability: all it means is that you'd personally be surprised if it didn't work?

Professor: Well, uh...

If I were to flip a coin a million times I'd be damn sure I wasn't going to get all heads. I'm not a betting man but I'd be so sure that I'd bet my life or my soul. I'd even go the whole way and bet a year's salary. I'm absolutely certain the laws of large numbers—probability theory—will work and protect me. All of science is based on it. But, I can't prove it and I don't really know why it works. That may be the reason why Einstein said, "God doesn't play dice." It probably is.

Well, of course, it is tempting to go for something like, "That the wheel, agriculture, and the Macarena were all actually invented by yetis." Or to do the sophomoric pseudo-ironic logic twist of, "That every truth can eventually be proven." Or to get up my hackles, draw up to my full height and intone, "Sir, we scientists believe in nothing that cannot be proven by the whetstone of science, verily our faith is our lack of faith," and then go off in a lab coat and a huff.

The first two aren't worth the words, and the third just isn't so. No matter how many times we read Arrowsmith, scientists are subjective humans operating in an ostensibly objective business, so there 's probably lots of things we take on faith.

So mine would be a fairly simple, straightforward case of an unjustifiable belief, namely that there is no god(s) or such a thing as a soul (whatever the religiously inclined of the right persuasion mean by that word). I'm very impressed, moved, by one approach of people on the other side of the fence. These are the believers who argue that it would be a disaster, would be the very work of Beelzebub, for it to be proven that god exists. What good would religiosity be if it came with a transparently clear contract, instead of requiring the leap of faith into an unknowable void?

So I'm taken with religious folks who argue that you not only can, but should believe without requiring proof. Mine is to not believe without requiring proof. Mind you, it would be perfectly fine with me if there were a proof that there is no god. Some might view this as a potential public health problem, given the number of people who would then run damagingly amok. But it's obvious that there's no shortage of folks running amok thanks to their belief. So that wouldn 't be a problem and, all things considered, such a proof would be a relief—many physicists, especially astrophysicists, seem weirdly willing to go on about their communing with god about the Big Bang, but in my world of biologists, the god concept gets mighty infuriating when you spend your time thinking about, say, untreatably aggressive childhood leukemia.

Finally, just to undo any semblance of logic here, I might even continue to believe there is no god, even if it was proven that there is one. A religious friend of mine once said to me that the concept of god is very useful, so that you can berate god during the bad times. But it is clear to me that I don't need to believe that there is a god in order to berate him.

Since I am a mathematician, I give a precise answer to this question. Thanks to Kurt Gödel, we know that there are true mathematical statements that cannot be proved. But I want a little more than this. I want a statement that is true, unprovable, and simple enough to be understood by people who are not mathematicians. Here it is.

Numbers that are exact powers of two are 2, 4, 8, 16, 32, 64, 128 and so on. Numbers that are exact powers of five are 5, 25, 125, 625 and so on. Given any number such as 131072 (which happens to be a power of two), the reverse of it is 270131, with the same digits taken in the opposite order. Now my statement is: it never happens that the reverse of a power of two is a power of five.

The digits in a big power of two seem to occur in a random way without any regular pattern. If it ever happened that the reverse of a power of two was a power of five, this would be an unlikely accident, and the chance of it happening grows rapidly smaller as the numbers grow bigger. If we assume that the digits occur at random, then the chance of the accident happening for any power of two greater than a billion is less than one in a billion. It is easy to check that it does not happen for powers of two smaller than a billion. So the chance that it ever happens at all is less than one in a billion. That is why I believe the statement is true.

But the assumption that digits in a big power of two occur at random also implies that the statement is unprovable. Any proof of the statement would have to be based on some non-random property of the digits. The assumption of randomness means that the statement is true just because the odds are in its favor. It cannot be proved because there is no deep mathematical reason why it has to be true. (Note for experts: this argument does not work if we use powers of three instead of powers of five. In that case the statement is easy to prove because the reverse of a number divisible by three is also divisible by three. Divisibility by three happens to be a non-random property of the digits).

It is easy to find other examples of statements that are likely to be true but unprovable. The essential trick is to find an infinite sequence of events, each of which might happen by accident, but with a small total probability for even one of them happening. Then the statement that none of the events ever happens is probably true but cannot be proved.

This year, researching the languages of Indonesia for an upcoming book, I happened to find out about a few very obscure languages spoken on one island that are much simpler than one would expect.

Most languages are much, much more complicated than they need to be. They take on needless baggage over the millennia simply because they can. So, for instance, most languages of Indonesia have a good number of prefixes and/or suffixes. Their grammars often force the speaker to attend to nuances of difference between active and passive much more than a European languages does, etc.

But here were a few languages that had no prefixes or suffixes at all. Nor do they have any tones, like many languages in the world. For one thing, languages that have been around forever that have no prefixes, suffixes, or tones are very rare worldwide. But then, where we do find them, they are whole little subfamilies, related variations on one another. Here, though, is a handful of small languages that contrast bizarrely with hundreds of surrounding relatives.

One school of thought in how language changes says that this kind of thing just happens by chance. But my work has been showing me that contrasts like this are due to sociohistory. Saying that naked languages like this are spoken alongside ones as bedecked as Italian is rather like saying that kiwis are flightless just "because," rather than because their environment divested them of the need to fly.

But for months I scratched my head over these languages. Why just them? Why there?

So isn't it interesting that the island these languages is spoken on is none other than Flores, which has had its fifteen minutes of fame this year as the site where skeletons of the "little people" were found. Anthropologists have hypothesized that this was a different species of Homo. While the skeletons date back 13,000 years ago or more, local legend recalls "little people" living alongside modern humans, ones who had some kind of language of their own and could "repeat back" in modern humans' language.

The legends suggest that the little people only had primitive language abilities, but we can't be sure here: to the untutored layman who hasn't taken any twentieth-century anthropology or linguistics classes, it is easy to suppose that an incomprehensible language is merely babbling.

Now, I can only venture this highly tentatively now. But what I "know" but cannot prove this year is: the reason languages like Keo and Ngada are so strangely streamlined on Flores is that an earlier ancestor of these languages, just as complex as its family members tend to be, was used as second language by these other people and simplified. Just as our classroom French and Spanish avoids or streamlines a lot of the "hard stuff," people who learn a language as adults usually do not master it entirely.

Specifically, I would hypothesize that the little people were gradually incorporated into modern human society over time—perhaps subordinated in some way—such that modern human children were hearing the little people's rendition of the language as much as a native one.

This kind of process is why, for example, Afrikaans is a slightly simplified version of Dutch. Dutch colonists took on Bushmen as herders and nurses, and their children often heard second-language Dutch as much as their parents. Pretty soon, this new kind of Dutch was everyone's everyday language, and Afrikaans was born.

Much has been made over the parallels between the evolution of languages and the evolution of animals and plants. However, I believe that one important difference is that while animals and plants can evolve towards simplicity as well as complexity depending on conditions, languages do not evolve towards simplicity in any significant, overall sense—unless there is some sociohistorical factor that puts a spoke in the wheel.

So normally, languages are always drifting into being like Russian or Chinese or Navajo. They only become like Keo and Ngada—or Afrikaans, or creole languages like Papiamentu and Haitian, or even, I believe, English—because of the intervention of factors like forced labor and population relocation. Just maybe, we can now add interspecies contact to the list!

The "rotten-to-the-core" assumption about human nature espoused so widely in the social sciences and the humanities is wrong. This premise has its origins in the religious dogma of original sin and was dragged into the secular twentieth century by Freud, reinforced by two world wars, the Great Depression, the cold war, and genocides too numerous to list. The premise holds that virtue, nobility, meaning, and positive human motivation generally are reducible to, parasitic upon, and compensations for what is really authentic about human nature: selfishness, greed, indifference, corruption and savagery. The only reason that I am sitting in front of this computer typing away rather than running out to rape and kill is that I am "compensated," zipped up, and successfully defending myself against these fundamental underlying impulses.

In spite of its widespread acceptance in the religious and academic world, there is not a shred of evidence, not an iota of data, which compels us to believe that nobility and virtue are somehow derived from negative motivation. On the contrary, I believe that evolution has favored both positive and negative traits, and many niches have selected for morality, co-operation, altruism, and goodness, just as many have also selected for murder, theft, self-seeking, and terrorism.

More plausible than the rotten-to-the-core theory of human nature is the dual aspect theory that the strengths and the virtues are just as basic to human nature as the negative traits: that negative motivation and emotion have been selected for by zero-sum-game survival struggles, while virtue and positive emotion have been selected for by positive sum game sexual selection. These two overarching systems sit side by side in our central nervous system ready to be activated by privation and thwarting, on the one hand, or by abundance and the prospect of success, on the other.

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.

We will find ways to circumvent the speed of light as a limit on the communication of information.

We are expanding our computers and communication systems both inwardly and outwardly. Our chips use every smaller feature sizes, while at the same time we deploy greater amounts of matter and energy for computation and communication (for example, we're making a larger number of chips each year). In one to two decades, we will progress from two-dimensional chips to three-dimensional self-organizing circuits built out of molecules. Ultimately, we will approach the limits of matter and energy to support computation and communication. 

As we approach an asymptote in our ability to expand inwardly (that is, using finer features), computation will continue to expand outwardly, using readily available materials on Earth such as carbon. But we will eventually reach the limits of the resources available on our planet, and will expand outwardly to the rest of the solar system and beyond. 

So how quickly will we be able to do this? We could send tiny self-replicating robots at close to the speed of light along with electromagnetic transmissions containing the needed software. These nanobots could then colonize far-away planets. 

At this point, we run up against a seemingly intractable limit: the speed of light. Although a billion feet per second may seem fast, the Universe is spread out over such vast distances that this appears to represent a fundamental limit on how quickly an advanced civilization (such as we hope to become) can spread its influence. 

There are suggestions, however, that this limit is not as immutable as it may appear. Physicists Steve Lamoreaux and Justin Torgerson of the Los Alamos National Laboratory have analyzed data from an old natural nuclear reactor that two billion years ago produced a fission reaction lasting several hundred thousand years in what is now West Africa. Analyzing radioactive isotopes left over from the reactor and comparing them to isotopes from similar nuclear reactions today, they determined that the physics constant "alpha" (also called the fine structure constant), which determines the strength of the electromagnetic force apparently has changed since two billion years ago. The speed of light is inversely proportional to alpha, and both have been considered unchangeable constants. Alpha appears to have decreased by 4.5 parts out of 108. If confirmed, this would imply that the speed of light has increased. There are other studies with similar suggestions, and there is a table top experiment now under way at Cambridge University to test the ability to engineer a small change in the speed of light. 

Of course, these results will need to be carefully verified. If true, it may hold great importance for the future of our civilization. If the speed of light has increased, it has presumably done so not just because of the passage of time, but because certain conditions have changed. This is the type of scientific insight that technologists can exploit. It is the nature of engineering to take a natural, often subtle, scientific effect, and control it with a view towards greatly leveraging and magnifying it. If the speed of light has changed due to changing circumstances, that cracks open the door just enough for the capabilities of our future intelligence and technology to swing the door widely open. That is the nature of engineering. As one of many examples, consider how we have focused and amplified the subtle properties of Bernoulli's principle (that air rushing over a curved surface has a slightly lower air pressure than over a flat surface) to create the whole world of aviation. 

If it turns out that we are unable to actually change the speed of light, we may nonetheless circumvent it by using wormholes (which can be thought of as folds of the universe in dimensions beyond the three visible ones) as short cuts to far away places. 

In 1935, Einstein and physicist Nathan Rosen described "Einstein-Rosen" bridges as a way of describing electrons and other particles in terms of tiny space-time tunnels. In 1955, physicist John Wheeler described these tunnels as "wormholes," introducing the term for the first time. His analysis of wormholes showed them to be fully consistent with the theory of general relativity, which describes space as essentially curved in another dimension. 

In 1988, California Institute of Technology physicists Michael Morris, Kip Thorne, and Uri Yertsever described in some detail how such wormholes could be engineered. Based on quantum fluctuation, so-called "empty" space is continually generating tiny wormholes the size of subatomic particles. By adding energy and following other requirements of both quantum physics and general relativity (two fields that have been notoriously difficult to integrate), these wormholes could in theory be expanded in size to allow objects larger than subatomic particles to travel through them. Sending humans would not be impossible, but extremely difficult. However, as I pointed out above, we really only need to send nanobots plus information, which could go through wormholes measured in microns rather than meters. Anders Sandberg estimates that a one-nanometer wormhole could transmit a formidable 10^69 bits per second. 

Thorne and his Ph.D. students, Morris and Yertsever, also describe a method consistent with general relativity and quantum mechanics that could establish wormholes between Earth and far-away locations quickly even if the destination were many light-years away. 

Physicist David Hochberg and Vanderbilt University's Thomas Kephart point out that shortly after the Big Bang, gravity was strong enough to have provided the energy required to spontaneously create massive numbers of self-stabilizing wormholes. A significant portion of these wormholes are likely to still be around, and may be pervasive, providing a vast network of corridors that reach far and wide throughout the Universe. It might be easier to discover and use these natural wormholes than to create new ones. 

Would anyone be shocked if some subtle ways of getting around the speed of light were discovered? The point is that if there are even subtle ways around this limit, the technological powers that our future human-machine civilization will achieve will discover these means and leverage them to great effect. 

Is there a fourth law of thermodynamics, or some cousin of it, concerning self constructing non equilibrium systems such as biospheres anywhere in the cosmos?

I like to think there may be such a law.

Consider this, the number of possible proteins 200 amino acids long is 20 raised to the 200th power or about 10 raised to the 260th power. Now, the number of particles in the known universe is about 10 to the 80th power. Suppose, on a microsecond time scale the universe were doing nothing other than producing proteins length 200. It turns out that it would take vastly many repeats of the history of the universe to create all possible proteins length 200. This means that, for entities of complexity above atoms, such as modestly complex organic molecules, proteins, let alone species, automobiles and operas, the universe is on a unique trajectory (ignoring quantum mechanics for the moment). That is, the universe at modest levels of complexity and above is vastly non-ergodic.

Now conceive of the "adjacent possible", the set of entities that are one "step" away from what exists now. For chemical reaction systems, the adjacent possible from a set of compounds already existing (called the "actual" ) is just the set of novel compounds that can be produced by single chemical reactions among the initial "actual" set. Now, the biosphere has expanded into its molecular adjacent possible since 4.8 billion years ago.

Before life, there were perhaps a few hundred organic molecule species on the earth. Now there are perhaps a trillion or more. We have no law governing this expansion into the adjacent possible in this non-ergodic process. My hoped for law is that biospheres everywhere in the universe expand in such a way that they do so as fast as is possible while maintaining the rough diversity of what already exists. Otherwise stated, the diversity of things that can happen next increases on average as fast as it can.

I believe (I know—but can't prove!) that scientists will soon understand the physiological basis of the "cognitive spectrum," from the bright violet of tightly-focused analytic thought all the way down to the long, slow red of low-focus sleep thought—also known as "dreaming." Once they understand the spectrum, they'll know how to treat insomnia, will understand analogy-discovery (and therefore creativity), and the role of emotion in thought—and will understand that thought takes place not only when you solve a math problem but when you look out the window and let your mind wander. Computer scientists will finally understand the missing mystery ingredient that made all their efforts to simulate human thought such naive, static failures, and turned this once-thriving research field into a ghost town. (Their failures were "static" insofar as people think in different ways at different times—your energetic, wide-awake mind works very differently from your tired, soon-to-be-sleeping mind; but artificial intelligence programs always "thought" in the same way all the time.)

And scientists will understand why we can't force ourselves to fall asleep orto "be creative"—and how those two facts are related. They'll understand why so many people report being most creative while driving, shaving or doing some other activity that keeps the mind's foreground occupied and lets it approach open problems in a "low focus" way. In short, they'll understand the mind as an integrated dynamic process that changes over a day and a lifetime, but is characterized always by one continuous spectrum.

Here's what we know about the cognitive spectrum: every human being traces out some version of the spectrum every day. You're most capable of analysis when you are most awake. As you grow less wide-awake, your thinking grows more concrete. As you start to fall asleep, you begin to free associate. (Cognitive psychologists have known for years that you begin to dream before you fall asleep.) We know also that to grow up intellectually means to trace out the cognitive spectrum in reverse: infants and children think concretely; as they grow up, they're increasingly capable of analysis. (Not incidentally, newborns spend nearly all their time asleep.)

Here's what we suspect about the cognitive spectrum: as you move down-spectrum, as your thinking grows less analytic and more concrete and finally bottoms on the wholly non-logical, highly concrete type of thought we call dreaming, emotions function increasingly as the "glue" of thought. I can't prove (but I believe) that "emotion coding" explains the problem of analogy. Scientists and philosophers have knocked their head against this particular brick wall for years: how can people say "a brick wall and a hard problem seem wholly different yet I can draw an analogy between them?" If we knew that, we'd understand the essence of creativity. The answer is: we are able to draw an analogy between two seemingly unlike things because the twoare associated in our minds with the same emotion. And that emotion acts as a connecting bridge between them. Each memory comes with a characteristic emotion; similar emotions allow us to connect two otherwise-unlike memories. An emotion (NB!) isn't the crude, simple thing we make it out to be in speaking or writing—"happy," "sad," etc.; an emotion can be the delicate, complex, nuanced, inexpressible feeling you get on the first warm day in spring.

And here's what we don't know: what's the physiological mechanism of the cognitive spectrum? What's the genetic basis? Within a generation, we'll have the answers.

Why is there scientific law at all?

We physicists explain the origin and structure of matter and energy, but not the laws that do this. Does the idea of causation apply to where the laws themselves came from? Even Alan Guth's "free lunch" gives us the universe after the laws start acting. We have narrowed down the range of field theories that can yield the big bang universe we live in, but why do the laws that govern it seem to be constant in time, and always at work?

One can imagine a universe in which laws are not truly lawful. Talk of miracles does just this, when God is supposed to make things work. Physics aims to find The Laws and hopes that these will be uniquely constrained, as when Einstein wondered if God had any choice when He made the universe. One fashionable escape hatch from this asserts that there are infinitely many universes, each sealed off from the others, which can obey any sort of law one can imagine, with parameters or assumptions changed. This "multiverse" view represents the failure of our grand agenda, of course, and seems to me contrary to Occam's Razor—solving our lack of understanding by multiplying unseen entities into infinity.

Perhaps it is a similar philosophical failure of imagination to think, as I do, that when we see order, there is usually an ordering principle. But what can constrain the nature of physical law? Evolution gave us our ornately structured biosphere, and perhaps a similar principle operates in selecting universes. Perhaps our universe arises, then, from selection for intelligences that can make fresh universes, perhaps in high energy physics experiments. Or near black holes (as Lee Smiolin supposed), where space-time gets contorted into plastic forms that can make new space-times. Then an Ur-universe that had intelligence could make others, and this reproduction with perhaps slight variation ion "genetics" drives the evolution of physical law.

Selection arises because only firm laws can yield constant, benign conditions to form new life. Ed Harrison had similar ideas. Once life forms realize this, they could intentionally make more smart universes with the right, fixed laws, to produce ever more grand structures. There might be observable consequences of this prior evolution, If so, then we are an inevitable consequence of the universe, mirroring intelligences that have come before, in some earlier universe that deliberately chose to create more sustainable order. The fitness of our cosmic environment is then no accident. If we find evidence of fine-tuning in the Dyson and Rees sense, then, is this evidence for such views?

I believe it is true that if there is intelligent life elsewhere in the universe, of whatever form, it will be familiar with the same concept of counting numbers.

Some philosophers believe that pure mathematics is human-specific and that it is possible for an entirely different type of mathematics to emerge from a different type of intelligence, a type of mathematics that has nothing in common with ours and may even contradict it. But it is difficult to think of what sort of life-form would not need the counting numbers. The stars in the sky are discrete points and cry out to be counted by beings throughout the universe, but alien life-forms may not have vision. 

Intelligent objects with boundaries between being and non-being surely want to be measured— "I'm bigger that you", "I need a size 312 overcoat"—but perhaps there are life-forms which don't have boundaries but are continuously varying density changes in some Jovian sea. Intelligent life might be disembodied or at least lack a discrete body and merely be transmitted between various points in a solid material matrix, so that it was impossible to distinguish one intelligent being from another.

But sooner or later, whether it is to measure the passing of time, the magnitude of distance, the density of one Jovian being compared with another, numbers will have to be used. And if numbers are used, 2 + 2 must always equal 4, the number of stars in the Pleiades brighter than magnitude 5.7 will always be 11 which will always be a prime number, and two measurements of the speed of light in any units in identical conditions will always be identical. Of course, the fact that I find it difficult to think of beings which won't need our sort of mathematics doesn't mean they don't exist, but that's what I believe without proof.

Here's what I believe but cannot prove: human beings, like all animals, have evolved a range of capacities for fighting disease and recovering from injury, including a variety of 'sickness behaviors'; humans beings alone however have discovered the advantages of off-loading much of the responsibility for managing their sickness behaviors to other people; the result is that for human beings the very nature of illness has changed—human illness is now largely a social phenomenon.

This is possible because "illness" is a response. A rise in body temperature, for example, kills many bacteria and changes the membrane properties of cells so viruses cannot replicate. The pain of a broken bone or weak heart makes sure we let it heal or rest. Nature supplied our bodies in this way with a first-aid kit but unfortunately like many medicines their "treatments" are unpleasant. That unpleasantness, not the dysfunction which they seek to remedy is what we call "illness".

These remedies, however, have costs as well as benefits making it often difficult for the body to know whether to deploy them. A fever might fight an infection but if the body lacks sufficient energy stores, the fever might kill. The body therefore must make a decision whether the gain of clearing the infection merits the risk. Complicating that decision is that the body is blind, for example, to whether it faces a mild or a life-threatening virus. The body thus deploys its treatments in a precautionary manner. If only one in ten fevers actually clears an infection that would kill, it makes sense to tolerate the cost of the other nine. Most of the body's capacities for fighting disease and repairing injury are deployed in this precautionary way. We feel pain in a broken limb so we treat it over protectively—in nine occasions out of ten we could get by with less protective pain but on the tenth it stops us causing it further injury. But precautionary deployment is costly. Evolution therefore has put the evaluation of such deployment under the control of the brain in attempt to keep their use to a minimum.

But the brain on its own often lacks the experience to know our own condition. Fortunately, other people can, particularly those that have studied health and illness.

Human evolution therefore changed illness by offloading decisions about deployment whenever possible on to professionals. People that make themselves experienced in disease and injury, after all, have the background knowledge to know our bodies much better than ourselves. Healing professionals—healers, shamans, witch doctors and medics—exist in all human cultures. Of course, such professionals were seen by their patients as offering real treatments—and a few did help such as advising rest, eating well and some medicinal herbs. But most of what they did was ineffective. Doctors indeed had to wait until 1908 and Paul Ehrlich's discovery of Salvarsan for treating syphilis before they had a really effective treatment for a major disease. Nonetheless earlier doctors and healers were considered by themselves and their patients to be in the possession of very powerful cures.

Why? The answer I believe was that their ineffective rituals and potions actually worked. Evolution prepared us to offload control of our abilities to fight disease and heal injuries to those that knew more than us. The rituals and quackery of healers might have not worked but they certainly made a patient feel they were in the hands of an expert. That gave a healer great power over their patient. As noted, many of the body's own "treatments" are used on a precautionary basis so they can be stopped without harm. A healer could do this by applying an impressive "cure" that persuaded the body that its own "treatments" were no longer needed. The body would trust its healer and halt its own efforts and so the "illness". The patient as a result would feel much better, if not cured. Human evolution therefore made doctoring more than just a science and a question of prescribing the right treatment. It made it also an art by which a doctor persuades the patient's body to offload its decision making onto them.

I believe, though I cannot prove it, that three—not two—selection processes were involved in human evolution.

The first two are familiar: natural selection, which selects for fitness, and sexual selection, which selects for sexiness.

The third process selects for beauty, but not sexual beauty—not adult beauty. The ones doing the selecting weren't potential mates: they were parents. Parental selection, I call it.

What gave me the idea was a passage from a book titled Nisa: The Life and Words of a !Kung Woman, by the anthropologist Marjorie Shostak. Nisa was about fifty years old when she recounted to Shostak, in remarkable detail, the story of her life as a member of a hunter-gatherer group.

One of the incidents described by Nisa occurred when she was a child. She had a brother named Kumsa, about four years younger than herself. When Kumsa was around three, and still nursing, their mother realized she was pregnant again. She explained to Nisa that she was planning to "kill"—that is, abandon at birth—the new baby, so that Kumsa could continue to nurse. But when the baby was born, Nisa's mother had a change of heart. "I don't want to kill her," she told Nisa. "This little girl is too beautiful. See how lovely and fair her skin is?"

Standards of beauty differ in some respects among human societies; the !Kung are lighter-skinned than most Africans and perhaps they pride themselves on this feature. But Nisa's story provides a insight into two practices that used to be widespread and that I believe played an important role in human evolution: the abandonment of newborns that arrived at inopportune times (this practice has been documented in many human societies by anthropologists), and the use of aesthetic criteria to tip the scales in doubtful cases.

Coupled with sexual selection, parental selection could have produced certain kinds of evolutionary changes very quickly, even if the heartbreaking decision of whether to rear or abandon a newborn was made in only a small percentage of births. The characteristics that could be affected by parental selection would have to be apparent even in a newborn baby. Two such characteristics are skin color and hairiness.

Parental selection can help to explain how the Europeans, who are descended from Africans, developed white skin over such a short period of time. In Africa, a cultural preference for light skin (such as Nisa's mother expressed) would have been counteracted by other factors that made light skin impractical. But in less sunny Europe, light skin may actually have increased fitness, which means that all three selection processes might have worked together to produce the rapid change in skin color.

Parental selection coupled with sexual selection can also account for our hairlessness. In this case, I very much doubt that fitness played a role; other mammals of similar size—leopards, lions, zebras, gazelle, baboons, chimpanzees, and gorillas—get along fine with fur in Africa, where the change to hairlessness presumably took place. I believe (though I cannot prove it) that the transition to hairlessness took place quickly, over a short evolutionary time period, and involved only Homo sapiens or its immediate precursor.

It was a cultural thing. Our ancestors thought of themselves as "people" and thought of fur-bearing creatures as "animals," just as we do. A baby born too hairy would have been distinctly less appealing to its parents.

If I am right that the transition to hairlessness occurred very late in the sequence of evolutionary changes that led to us, then this can explain two of the mysteries of paleoanthropology: the survival of the Neanderthals in Ice Age Europe, and their disappearance about 30,000 years ago.

I believe, though I cannot prove it, that Neanderthals were covered with a heavy coat of fur, and that Homo erectus, their ancestor, was as hairy as the modern chimpanzee. A naked Neanderthal could never have made it through the Ice Age. Sure, he had fire, but a blazing hearth couldn't keep him from freezing when he was out on a hunt. Nor could a deerskin slung over his shoulders, and there is no evidence that Neanderthals could sew. They lived mostly on game, so they had to go out to hunt often, no matter how rotten the weather. And the game didn't hang around conveniently close to the entrance to their cozy cave.

The Neanderthals disappeared when Homo sapiens, who by then had learned the art of sewing, took over Europe and Asia. This new species, descended from a southern branch of Homo erectus, was unique among primates in being hairless. In their view, anything with fur on it could be classified as "animal"—or, to put it more bluntly, game. Neanderthal disappeared in Europe for the same reason the woolly mammoth disappeared there: the ancestors of the modern Europeans ate them. In Africa today, hungry humans eat the meat of chimpanzees and gorillas.

At present, I admit, there is insufficient evidence either to confirm or disconfirm these suppositions. However, evidence to support my belief in the furriness of Neanderthals may someday be found. Everything we currently know about this species comes from hard stuff like rocks and bones. But softer things, such as fur, can be preserved in glaciers, and the glaciers are melting. Someday a hiker may come across the well-preserved corpse of a furry Neanderthal.

In 1936, shortly after the outbreak of the Spanish Civil War, the moribund philosopher Miguel de Unamuno, author of the classic existential text Tragic Sense of Life, died alone in his office of heart failure at the age of 72.

Unamuno was no religious sentimentalist. As a rector and Professor of Greek at the University of Salamanca, he was an advocate of rationalist ideals and even died a folk hero for openly denouncing Francisco Franco's fascist regime. He was, however, ridden with a 'spiritual' burden that troubled him nearly all his life. It was the problem of death. Specifically, the problem was his own death, and what, subjectively, it would be "like" for him after his own death: "The effort to comprehend it causes the most tormenting dizziness." I've taken to calling this dilemma "Unamuno's paradox" because I believe that it is a universal problem. It is, quite simply, the materialist understanding that consciousness is snuffed out by death coming into conflict with the human inability to simulate the psychological state of death.

Of course, adopting a parsimonious stance allows one to easily deduce that we as corpses cannot experience mental states, but this theoretical proposition can only be justified by a working scientific knowledge (i.e., that the non-functioning brain is directly equivalent to the cessation of the mind). By stating that psychological states survive death, or even alluding to this possibility, one is committing oneself to a radical form of mind-body dualism. Consider how bizarre it truly is: Death is seen as a transitional event that unbuckles the body from its ephemeral soul, the soul being the conscious personality of the decedent and the once animating force of the now inert physical form. This dualistic view sees the self as being initially contained in bodily mass, as motivating overt action during this occupancy, and as exiting or taking leave of the body at some point after its biological expiration. So what, exactly, does the brain do if mental activities can exist independently of the brain? After all, as John Dewey put it, mind is a verb, not a noun.

And yet this radicalism is especially common. In the United States alone, as much as 95% of the population reportedly believes in life after death. How can so many people be wrong? Quite easily, if you consider that we're all operating with the same standard, blemished psychological hardware. It's tempting to argue, as Freud did, that it's just people's desire for an afterlife that's behind it all. But it would be a mistake to leave it at that. Although there is convincing evidence showing that emotive factors can be powerful contributors to people's belief in life after death, whatever one's motivations for rejecting or endorsing the idea of an immaterial soul that can defy physical death, the ability to form any opinion on the matter would be absent if not for our species' expertise at differentiating unobservable minds from observable bodies.

But here's the rub. The materialist version of death is the ultimate killjoy null hypothesis. The epistemological problem of knowing what it is "like" to be dead can never be resolved. Nevertheless, I think that Unamuno would be proud of recent scientific attempts to address the mechanics of his paradox. In a recent study, for example, I reported that when adult participants were asked to reason about the psychological abilities of a protagonist who had just died in an automobile accident, even participants who later classified themselves as "extinctivists" (i.e., those who endorsed the statement "what we think of as the 'soul,' or conscious personality of a person, ceases permanently when the body dies") nevertheless stated that the dead person knew that he was dead. For example, when asked whether the dead protagonist knew that he was dead (a feat demanding, of course, ongoing cognitive abilities), one young extinctivist's answer was almost comical. "Yeah, he'd know, because I don't believe in the afterlife. It is non-existent; he sees that now." Try hard as he might to be a good materialist, this subject couldn't help but be a dualist.

How do I explain these findings? Like reasoning about one's past mental states during dreamless sleep or while in other somnambulistic states, consciously representing a final state of non-consciousness poses formidable, if not impassable, cognitive constraints. By relying on simulation strategies to derive information about the minds of dead agents, you would in principle be compelled to "put yourself into the shoes" of such organisms, which is of course an impossible task. These constraints may lead to a number of telltale errors, namely Type I errors (inferring mental states when in fact there are none), regarding the psychological status of dead agents. Several decades ago, the developmental psychologist Gerald Koocher described, for instance, how a group of children tested on death comprehension reflected on what it might be like to be dead "with references to sleeping, feeling 'peaceful,' or simply 'being very dizzy.'" More recently, my colleague David Bjorklund and I found evidence that younger children are more likely to attribute mental states to a dead agent than are older children, which is precisely the opposite pattern that one would expect to find if the origins of such beliefs could be traced exclusively to cultural learning.

It seems that the default cognitive stance is reasoning that human minds are immortal; the steady accretion of scientific facts may throw off this stance a bit, but, as Unamuno found out, even science cannot answer the "big" question. Don't get me wrong. Like Unamuno, I don't believe in the afterlife. Recent findings have led me to believe that it's all a cognitive illusion churned up by a psychological system specially designed to think about unobservable minds. The soul is distinctly human all right. Without our evolved capacity to reason about minds, the soul would never have been. But in this case, the proof isn't in the empirical pudding. It can't be. It's death we're talking about, after all.

When considering this question one has to remember the basis of the scientific method: formulating hypotheses that can be disproved. Those hypotheses that are not disproved are thought to be true until disproved. Since it is more glamorous for a scientist to formulate hypotheses that it is to spend years disproving existing ones from other scientists and that it is unlikely that someone will spend enough time and energy trying to disprove his/her own statements, our body of scientific knowledge is surely full of statements we believe to be true but will eventually be proved to be false.

So I turn the question around: What scientific ideas that have not been disproved, do you believe are false.

In my field (theoretical economics), I believe that most ideas taught in economics 101 will be proved false eventually. Most of them would already have been officially defined as false in any other more hard-science, but, because of lack of better hypotheses they are still widely accepted and used in economics and general commentary. Eventually, someone will come up with another type of hypotheses explaining (and predicting) the economic reality in a way that will render most existing economics beliefs false.

Einstein said "You must learn to distinguish between what is true and what is real". An apt longer quote of his is: "As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality". I.e. it is "true" that the three angles of a triangle add up to 180 in Euclidean geometry of the plane, but it is not known how to show that this could hold in our physical universe (if there is any mass or energy in our universe then it doesn't seem to hold, and it is not actually known what our universe would be like without any mass or energy).

So, science is a relationship between what we can represent and are able to think about, and "what's out there": it's an extension of good map making, most often using various forms of mathematics as the mapping languages. When we guess in science we are guessing about approximations and mappings to languages, we are not guessing about "the truth" (and we are not in a good state of mind for doing science if we think we are guessing "the truth" or "finding the truth"). This is not at all well understood outside of science, and there are unfortunately a few people with degrees in science who don't seem to understand it either.

Sometimes in math one can guess a theorem that can be proved true. This is a useful process even if one's batting average is less than .500. Guessing in science is done all the time, and the difference between what is real and what is true is not a big factor in the guessing stage, but makes all the difference epistemologically later in the process.

One corner of computing is a kind of mathematics (other corners include design, engineering, etc.). But there are very few interesting actual proofs in computing. A good Don Knuth quote is: "Beware of bugs in the above code; I have only proved it correct, not tried it."

An analogy for why this is so is to the n-body problems (and other chaotic systems behaviors) in physics. An explosion of degrees of freedom (3 bodies and gravity is enough) make a perfectly deterministic model impossible to solve analytically for a future state. However, we can compute any future state by brute force simulation and see what happens. By analogy, we'd like to prove useful programs correct, but we either have intractable degrees of freedom, or as in the Knuth quote, it is very difficult to know if we've actually gathered all the cases when we do a "proof".

So a guess in computing is often architectural or a collection of "covering heuristics". An example of the latter is TCP/IP which has allowed "the world's largest and most scalable artifact—The Internet—to be successfully built. An example of the former is the guess I made in 1966 about objects—not that one could build everything from objects—that could be proved mathematically—but that using objects would be a much better way to represent most things. This is not very provable, but like the Internet, now has quite a body of evidence that suggests this was a good guess.

Another guess I made long ago—that does not yet have a body of evidence to support it—is that what is special about the computer is analogous to and an advance on what was special about writing and then printing. It's not about automating past forms that has the big impact, but as McLuhan pointed out, when you are able to change the nature of representation and argumentation, those who learn these new ways will wind up to be qualtitatively different and better thinkers, and this will (usually) help advance our limited conceptions of civilization.

This still seems like a good guess to me—but "truth" has nothing to do with 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.

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.

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.

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.

What I believe but cannot prove is that no part of my consciousness will survive my death. I exclude the fact that I will linger, fadingly, in the thoughts of others, or that aspects of my consciousness will survive in writing, or in the positioning of a planted tree or a dent in my old car. I suspect that many contributors to Edge will take this premise as a given—true but not significant. However, it divides the world crucially, and much damage has been done to thought as well as to persons, by those who are certain that there is a life, a better, more important life, elsewhere. That this span is brief, that consciousness is an accidental gift of blind processes, makes our existence all the more precious and our responsibilities for it all the more profound.

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.