2002 : WHAT IS YOUR QUESTION? ... WHY?

Why do we ask Edge questions?

Why do we ask Edge questions that challenge the "anesthesiology" of accepted wisdom and so the traditional answers we are given as to who and what we are? In most societies, accepted wisdom is to be respected not questioned, and who and what we are have long been decided by custom, elders, social betters and the sacred word of God. Moreover, why is it that the asking of Edge questions has only thrived and been encouraged in Western societies (with the help of such individuals as Socrates and the contributors to this Edge project)?

Children it should be noted readily ask Edge-type questions. The problem is that they stop when they become adults except in the civilization (with a few ups and downs) that started in Classical Greece — Western civilization.

"Are all our beliefs in gods, a myth, a lie foolishly cherished, while blind hazard rules the world?" That perhaps is the first Edge question (Euripides, Hecabe, lines 490-491) — and importantly a question not raised safely in private but before a large audience. Indeed, Euripides raised it to gain public reward. Greek playwrights wrote plays for competitions that were judged by ten randomly selected members of the audience — and given Euripides wanted to win — he must have believed that the average Greek would be hearing this Edge question raised about the Gods.

The public exploring of Edge questions is rare outside Western societies. Instead, "what was finally persuasive was appeal to established authority", and that, "the authority of tradition came to have more convincing effect than even direct observation and personal experience" (Robert Oliver, Communication And Culture In Ancient India And China, 1971). And as the Japanese scholar Hajime Nakamura noted, the Chinese "insisted that the traditional sacred books are more authoritative than knowledge based upon sense and inference" (Ways Of Thinking Of Eastern Peoples, 1964). Job might seem to be asking the Edge question "Why do the just suffer and the wicked flourish?" But the story of Job is not about rewarding Edge questioning but faith in the wisdom of God: "Who is this that darkens my counsel with words without knowledge".

This Edge question might be criticized as Eurocentric. But it was Western intellectuals that first asked the Edge question about whether ones own culture might be privileged falsely over others and so invented the idea of ethnocentricity.

So my Edge question is this: why is it only amongst adults in the Western world that has tradition been so insistently and constantly challenged by the raising of Edge questions?

The fact is that is "To be or not to be" is both a simple, perhaps the simplest, and a complex question, the hardest to sustain, let alone to ask. I ask it myself often — maybe as many times as five or six a week — and it is the asking, not any hope for an answer, that yields the most searing and immediate insight. I don't get it right every time, but when I do, I am thrown for a split second at the other side of being, the place where it begins.

But I can never retain that amazing feeling for long. What is required is a kind of radical pull-back of oneself from the most banal evidence of life and reality. Jean-Paul Sartre, after Shakespeare, was probably the thinker who framed the question best in his novels and philosophical treatises. The issue, however, is that this question is profoundly existential, not merely philosophical. It can be asked and should be by any living, thinking, sentient being, but cannot be answered.

There is huge energy and cognitive release to expect from it when it is properly framed. You have to somehow imagine that everything, absolutely everything has disappeared, or never was, that you have just happened upon your own circumstances by accident, the first accident of being. Another approach is to imagine sharply that anything that is, is a result of a warp, a blip in nothingness. It is not even a matter of finding out why or how, those demands are already far too elaborate. It is a crude, raw, brutal question followed by absolute, lightening speed amazement. And then the ordinary familiarity of all things known and named takes over, slipping your whole being into the stream of life, of being, with its attending problems and felicities. I feel strongly that there is a fundamental need for Shakespeare's question in every day life, but that is not what you and I were taught in school.

In or ordinary life, we ascribe action and doing to other humans, and lower organisms, even bacteria swimming up a glucose gradient to get food. Yet physics has no "doings" only happenings, and the bacterium is just a physical system. I have struggled with the question "What must a physical system be to be able to act on its own behalf?" Call such a system an autonomous agent. I may have found an answer, such systems must be able to replicate and do a thermodynamic work cycle. But of course I'm not sure of my answer. I am sure the question is of fundamental importance, for all free living organisms are autonomous agents, and with them, doing, not just happenings, enters the universe. We do manipulate the universe on our own behalf. Is there a better definition of autonomous agents? And what does their existence mean for science, particularly physics?

I've noticed that the more scientifically educated a person is, the more likely they will harbor a quiet heresy. This is a strongly held belief that goes against the grain of their peers, something not in the accepted cannon of their friends and colleagues. Often the person finds it difficult to fully justify their own belief. It may or may not be believed by others outside their circle, that doesn't matter. What is important is that this view is not held by people they respect and admire. It's become almost a game for me to uncover a person's heresy because I've found that this unconventional view — held with much effort against the tide of their peer's views — tells me more about them than does the bulk of their well-thought out, well-reasoned, and well argued conventional views. The more unexpected the belief is, the more I like them.

This question needs to be asked because of the widely held conviction that we already know the answer to it. We don't. Okay, we know half of the answer: one of the reasons why people differ from each other is that they have different genes. That's the easy half.

The hard half is the part that isn't genetic. Even people who have identical genes, like Freeman Dyson's twin grandsons (see his question), differ in personality. I am not asking about the feeling each twin has of being "me": George and Donald could be identical in personality, and yet each could have a sense of me-ness.

But if George and Donald are like most identical twins, they aren't identical in personality. Identical twins are more alike than fraternal twins or ordinary siblings, but less alike than you would expect. One might be more meticulous than the other, or more outgoing, or more emotional. The weird thing is that the degree of similarity is the same, whether twins are reared together or apart. George and Donald, according to their grandfather, "not only have the same genes but also have the same environment and upbringing." And yet they are no more alike in personality than twins reared by two different sets of parents in two different homes.

We know that something other than genes is responsible for some of the variation in human personality, but we are amazingly ignorant about what it is and how it works. Well-designed research has repeatedly failed to confirm commonly held beliefs about which aspects of a child's environment are important. The evidence indicates that neither those aspects of the environment that siblings have in common (such as the presence or absence of a caring father) nor those that supposedly widen the differences between siblings (such as parental favoritism or competition between siblings) can be responsible for the non-genetic variation in personality. Nor can the vague idea of an "interaction" between genes and environment save the day. George and Donald have the same genes, so how can an interaction between genes and environment explain their differences?

Only two hypotheses are compatible with the existing data. One, which I proposed in my book The Nurture Assumption, is that the crucial experiences that shape personality are those that children have outside their home. Unfortunately, there is as yet insufficient evidence to support (or disconfirm) this hypothesis.

The remaining possibility is that the unexplained variation in personality is random. Even for reared-together twins, there are minor, random differences in their experiences. I find it
implausible, however, that minor, random differences in experiences could be so potent, given the ineffectiveness of substantial, systematic differences. If randomness affects personality, the way it probably works is through biological means — not genetic but biological. The human genome is smallish and the human brain is vast; the genome couldn't possibly contain precise specifications for every neuron and synapse. Identical twins don't have identical brains for the same reason that they don't have identical freckles or fingerprints.

If these random physical differences in the brain are responsible for some or all of the personality differences between identical twins, they must also be responsible for some or all of the non-genetic variation in personality among the rest of us. "All" is highly unlikely; "some" is almost certainly true. What remains in doubt is not whether, but how much.

The bottom line is that scientists will probably never be able to predict human behavior with anything close to certainty. Next question: Is this discouraging news or cause for celebration?

The God machine is the name that journalists have given to a device invented by the Canadian psychologist Michael Persinger. It consists of a bunch of solenoids that, when strapped around the head, deliver pulses of electromagnetic radiation to specific regions of the brain. Persinger claims he can induce mystical visions by stimulating the temporal lobes, which have also been linked to religious experiences by other scientists, notably V.S. Ramachandran of the University of California at San Diego.

Persinger's machine is actually quite crude. It induces peculiar perceptual distortions but no classic mystical experiences. But what if, through further advances in neuroscience and other fields, scientists invent a God machine that actually works, that delivers satori, nirvana, to anyone on command, without any negative side effects? It doesn't have to be an electromagnetic brain-stimulating device. It could be a drug, a type of brain surgery, a genetic modification, or some combination thereof.

One psychedelic researcher recently suggested to me that enlightenment could be spread around the world by an infectious virus that boosts the brain's production of dimethyltryptamine, a endogenous psychedelic that the Nobel laureate Julius Axelrod of the National Institutes of Health detected in trace amounts in human brain tissue in 1972. But whatever form the God machine takes, it would be powerful enough to transform the world into what Robert Thurman, an authority on Tibetan Buddhism (and father of Uma), calls the "Buddhaverse," a mystical utopia in which everyone is enlightened.

The obvious followup question: Would the invention of a genuine God machine spell our salvation or doom?

Here I paraphrase Einstein's famous question: "Did God have any choice in the creation of the Universe". I get rid of the God part, which Einstein only added to make it seem more whimsical, I am sure, because that just confuses the issue. The important question, perhaps the most important question facing physics today is the question of whether there is only one consistent set of physical laws that allow a working universe, or rather whether the constants of nature are arbitrary, and could take any set of values. Namely, if we continue to probe into the structure of matter and the nature of elementary forces will we find that mathematical consistency is possible only for one unique theory of the Universe, or not? In the former case, of course, there is hope for an exactly predictive "theory of everything". In the latter case, we might expect that it is natural that our Universe is merely one of an infinite set of Universes within some grand multiverse, in each of which the laws of physics differ, and in which anthropic arguments may govern why we live in the Universe we do.

The goal of physics throughout the ages has been to explain exactly why the universe is the way it is, but as we push closer and closer to the ultimate frontier, we may find out that in fact the ultimate laws of nature may generically produce a universe that is quite different from the one we live in. This would force a dramatic shift in our concept of natural law.

Some may suggest that this question is mere philosophical nonsense, and is akin to asking how many angels may sit on the head of a pin. However, I think that if we are lucky it may be empirically possible to address it. If, for example, we do come up with some fundamental theory that predicts the values of many fundamental quantities correctly, but that predicts that other mysterious quantities, like the energy of empty space, is generically different than the value we measure, or perhaps is determined probabilistically, this will add strong ammunition to the notion that our universe is not unique, but arose from an ensemble of causally disconnected parts, each with randomly varying values of the vacuum energy.

In any case, answerable or not, I think this is the ultimate question in science.

Bill Joy, the prominent computer scientist, argued in a Wired article last year that "the future doesn't need us" because other creatures, artificial or just post-human, are going to take over the world in the 21st century. He is worried that various technologies — particularly robotics, genetic engineering and nanotechnology — are soon going to be capable of generating either a self-conscious machine (something like the Internet "waking up") or one capable of self-replication (nanotechnologists inspired by the vision of Eric Drexler are currently attempting to create a nano-scaled "universal assembler"). If either of these events came to pass, it would surely introduce major changes in the planetary ecology, and humans would have to find a new role to play in such a world. But is Joy right? Do we have to worry about mad scientists producing some invention that inadvertently renders us second-class citizens to machines in the next couple of decades? (Joy is so distraught by this prospect he would have everyone stop working in these areas.)

This is a difficult question to answer, mostly because we don't currently have a very good idea about how technology evolves, so it's hard to predict future developments. But I believe that we can get some way toward an answer by adopting an approach currently being developed by some of our best evolutionary thinkers, such as John Maynard Smith, Eors Szathmary, and others. This "major transition" theory is concerned with determining the conditions under which new kinds of agents emerge in some evolutionary lineage. Examples of such transitions occurred when prokaryotes became eukaryotes, or single-celled organisms became multi cellular. In each case, previously independent biological agents evolved new methods of cooperation, with the result that a new level of organization and agency appeared in the world. This theory hasn't yet been applied to the evolution of technology, but could help to pinpoint important issues. In effect, what I want to investigate is whether the futures that disturb Bill Joy can be appropriately analyzed as major transitions in the evolution of technology. Given current trends in science and technology, can we say that a global brain is around the corner, or that nano-robots are going to conquer the Earth? That, at least, is my current project.

Given the political sensitivities of the topic, it is hard to imagine that a suitably rigorous attempt to answer this question could be organized or its results published and discussed soberly, but it is striking that there is no serious basis on which to conduct such a conversation. Religion brings peace and solace to many; religion kills people, divides societies, diverts energy and resources. How to assess the net impact in some meaningfully quantitative way? Even to imagine the possibility of such an inquiry and to think through some of the categories you would use could be very enlightening.

While education is on every politician's agenda as an item of serious importance, it is astonishing that the notion of what it means to be educated never seems to come up. Our society, which is undergoing massive transformations almost on a daily basis never seems to transform its notion of what it means to be educated. We all seem to agree that an educated mind certainly entails knowing literature and poetry, appreciating history and social issues, being able to deal with matters of economics, being versatile in more than one language, understanding scientific principles and the basics of mathematics.

What I was doing in my last sentence was detailing the high school curriculum set down in 1892 by a committee chaired by the President of Harvard that was mandated for anyone who might want to enter a university. The curriculum they decided upon has not changed at all since then. Our implicit notions of an educated mind are the same as they were in the nineteenth century. No need to teach anything new, no need to reconsider how a world where a university education was offered solely to the elite might be different from a world in which a university degree is commonplace.

For a few years, in the early 90's, I was on the Board of Editors of the Encyclopedia Britannica. Most everyone else on the board were octogenarians — the foremost of these, since he seemed to have everyone's great respect, was Clifton Fadiman, a literary icon of the 40's. When I tried to explain to this board the technological changes that were about to come that would threaten the very existence of the Encyclopedia, there was a general belief that technology would not really matter much. There would always be a need for the encyclopedia and the job of the board would always be to determine what knowledge was the most important to have. Only Clifton Fadiman seemed to realize that my predictions about the internet might have some effect on the institution they guarded. He concluded sadly, saying: "I guess we will just have to accept the fact that minds less well educated than our own will soon be in charge."

Note that he didn't say "differently educated," but "less well educated." For some years the literati have held sway over the commonly accepted definition of education. No matter how important science and technology seem to industry or government or indeed to the daily life of the people, as a society we believe that those educated in literature and history and other humanities are in some way better informed, more knowing, and somehow more worthy of the descriptor "well educated."

Now if this were an issue confined to those who run the elite universities and prep schools or those whose bible is the New York Review of Books, this really wouldn't matter all that much to anybody. But this nineteenth century conception of the educated mind weighs heavily on our notions of how we educate our young. We are not educating our young to work or to live in the nineteenth century, or at least we ought not be doing so. Yet, when universities graduate thousands of English and history majors because it can only be because we imagine that such fields form the basis of the educated mind. When we choose to teach our high schoolers trigonometry instead of say basic medicine or business skills, it can only be because we think that trigonometry is somehow more important to an educated mind or that education is really not about preparation for the real world. When we focus on intellectual and scholarly issues in high school as opposed to more human issues like communications, or basic psychology, or child raising, we are continuing to rely upon out dated notions of the educated mind that come from elitist notions of who is to be educated.

While we argue that an educated mind can reason, but curiously there are no courses in our schools that teach reasoning. When we say that an educated mind can see more than one side of an argument we go against the school system which holds that there are right answers to be learned and that tests can reveal who knows them and who doesn't.

Now obviously telecommunications is more important than basic chemistry and HTML is more significant than French in today's world. These are choices that have to be made, but they never will be made until our fundamental conception of erudition changes or until we realize that the schools of today must try to educate the students who actually attend them as opposed to the students who attended them in 1892.

The 21st century conception of an educated mind is based upon old notions of erudition and scholarship not germane to this century. The curriculum of the school system bears no relation to the finished products we seek. We need to rethink what it means to be educated and begin to focus on a new conception of the very idea of education.

In several recent meetings that I have attended, I have been overwhelmed by the rift between what the sciences of mind, brain and behavior have uncovered over the past decade, and both how and what science educators teach.

In many arenas, educators hold on to a now dated view of the child's cognitive development, failing to appreciate the innate biases that our species has been equipped with. These biases constrain not only what the child can learn, but when it might most profitably learn such things. Take, for instance, the acquisition of mathematical knowledge. Educators aim for the acquisition of precise computations. There is now, however, evidence for an innately available approximate number system, one that operates spontaneously without education.

One might imagine that if educators attempted to push this system first — teaching children that 40 is a better answer to 25 + 12 than is 60 — that it might well facilitate the acquisition of the more precise system later in development. Similar issues arise in attempting to teach children about physics and biology. At some level, then, there must be a way for those in the trenches to work together with those in the ivory tower to advance the process of learning, building on what we have discovered from the sciences of the mind.

Humans spread out from a common origin into many different global environments. It was a triumph of our unique adaptability, for we display the broadest range of behaviours — nutritional, social, sexual and reproductive – of any animal. We also have classes of behaviour — religious, scientific, artistic, gendered, and philosophical, each underpinned by special languages — that animals lack. Paradoxically, success also came through conformity. Prehistorians track archaeological cultures by recognizing the physical symbolic codes (art styles, burial rites, settlement layouts) that channelled local routines. Each culture constrained diversity and could punish it with ostracism and death. Isolation bred idiosyncracy, and there was a shock when we began regional reintegration. Early empires created state religions which, although sometimes refracting species-wide instincts for a common-good, tended to elevate chosen peoples and their traditional ways.

Now we can monitor all of our cultures there is a need to adjudicate on conduct at a global level. But my question is not understood in the same way by everyone. To fundamentalists, it is heretical, because morality is God-given. Social theorists, on the other hand, often interpret absolute morality as imperialist —no more than local ethics metastasized by (for example) the United Nations. But appeals to protect cultural diversity are typically advanced without regard to the reality of individual suffering in particular communities. A third position, shared by many atheistic scientists and traditional Marxists, is based on ideas of utility, happiness and material truth: what is right is understood as being what is good for the species. But no one agrees on what this is, or how competing claims for access to it should be settled.

The 'ethics of care', first developed within feminist philosophy, moves beyond these positions. Instead of connecting morals either to religious rules and principles or reductive natural laws, it values shared human capacities, such as intimacy, sympathy, trust, fidelity, and compassion. Such an ethics might elide the distinction between relative and absolute by promoting species-wide common sense. Before we judge the prospect of my question vanishing as either optimistic or naïve, we must scrutinize the alternatives carefully.

When something is missing, it bothers us that things don't hang together. Consider: "Give him." In any language, that is a bothersome sentence. Something essential is missing, and it rings an alarm bell in our brains. We go in search of an implied "what" and try to guess what will make the words all hang together into a complete thought.

We ask questions in search of satisfying incompletes, again hoping to create some coherence. No other animal does such things. It even forms the basis of many of our recreations such as jigsaw and crossword puzzles, all those little eurekas along the way.

Guessing a hidden pattern fascinates us. It's part of our pleasure in complex ritual or listening to Bach, to be able to guess what comes next some of the time. It's boring when it is completely predictable, however; it's the search for how things all hang together that is so much fun. Of course, we make a lot of mistakes. Every other winter, I get fooled into thinking that a radio has been left on, somewhere in the house, and I go in search of it — only to realize that it was just the wind whistling around the house. My brain tried to make coherence out of chaos by trying out familiar word patterns on it.

Astrology, too, seems to make lots of things "all hang together." Often in science, we commit such initial errors but we are now fairly systematic about discovering and discarding them. We go on to find much better explanations for how things hang together. Finding coherence is one of our great pleasures. It would be nice to know what predisposes our brain to seek out hidden coherence.

For one thing, it might help illuminate the power of an idea — and with it, how fanaticism works.

Fundamentalist schemes that seem to make everything hang together can easily override civilization's prohibitions against murder. Inferring an enveloping coherence can create an "other" who is outside the bounds of "us." Because it seems so whole, so right, it may become okay to beat up on unbelievers — say, fans of an opposing football team, or of another religion.

For scientists and crossword fans, it's finding the coherence that is important. Then we move on. But many people, especially in the generation which follows its inventors, get trapped by a seemingly coherent worldview. Things get set in concrete; the coherent framework provides comfort, but it also creates dangerous us-and-them boundaries.

Human beings can't help but understand their world in terms of narratives. Although the theory of evolution effectively dismantled our creationist myths over a century ago, most thinking humans still harbor an attachment to the notion that we were put here, with purpose, by something. New understandings of emergence, as well as new tools for perceiving the order underlying chaos, seem to the hold the promise for a widescale liberation from the constructed myths we use to organize our experience, as well as the dangers that over-dependence on such narratives bring forth. At least I hope so.

At the very least, narratives are less dangerous when we are free to participate in their writing. I'll venture that it is qualitatively better for human beings to take an active role in the unfolding of our collective story than it is to adhere blindly to the testament of our ancestors or authorities.

But what of moving out of the narrative altogether? Is it even possible? Is our predisposition for narrative physiological, psychological, or cultural?

Is it an outmoded form of cognition that yields only bloody clashes when competing myths are eventually mistaken for irreconcilable realities? Or are stories the only way we have of interpreting our world — meaning that the forging of a collective set of mutually tolerant narratives is the only route to a global civilization?

One of the great achievements of recent history has been a dramatic reduction in absolute poverty in the world. In 1820 about 85% of the world's population lived on the equivalent of a dollar a day (converted to today's purchasing power). By 1980, that percentage had dropped to 30%, but it is now down to 20%.

But that still means 1 billion people live in absolute poverty. A further 2 billion are little better off, living on $2 a day. A quarter of the world's people never get a cup of clean water.

Part of what globalisation means is that we have a reasonable chance of assuring that a majority of the world's people will benefit from continuing economic growth, improvements in health and education, and the untapped potential of the extraordinary technologies about which most of the Edge contributors write so eloquently.

We currently lack the political will to make sure that a vast number of people are not fenced off from this optimistic future. So my question poses a simple choice. Are we content to have two, increasingly estranged world? Or do we want to find the path to a unified, healthy world?

Preliminaries

We do not know whether there are other universes. Perhaps we never shall. But I want to respond to Paul Davies' questions by arguing that "do other universes exist?" can be a genuine scientific question. Moreover, I shall outline why it is an interesting question; and why, indeed, I already suspect that the answer may be "yes".

First, a pre-emptive and trivial comment: if you define the universe as "everything there is", then by definition there cannot be others. I shall, however, follow the convention among physicists and astronomers, and define the "universe" as the domain of space-time that encompasses everything that astronomers can observe. Other "universes", if they existed, could differ from ours in size, content, dimensionality, or even in the physical laws governing them.

It would be neater, if other "universes" existed, to redefine the whole enlarged ensemble as "the universe", and then introduce some new term — for instance "the metagalaxy" — for the domain that cosmologists and astronomers have access to. But so long as these concepts remain so conjectural, it is best to leave the term "universe" undisturbed, with its traditional connotations, even though this then demands a new word, the "multiverse", for a (still hypothetical) ensemble of "universes."

Ontological Status Of Other Universes

Science is an experimental or observational enterprise, and it's natural to be troubled by assertions that invoke something inherently unobservable. Some might regard the other universes as being in the province of metaphysics rather than physics. But I think they already lie within the proper purview of science. It is not absurd or meaningless to ask "Do unobservable universes exist?", even though no quick answer is likely to be forthcoming. The question plainly can't be settled by direct observation, but relevant evidence can be sought, which could lead to an answer.

There is actually a blurred transition between the readily observable and the absolutely unobservable, with a very broad grey area in between. To illustrate this, one can envisage a succession of horizons, each taking us further than the last from our direct experience:

(i) Limit of present-day telescopes

There is a limit to how far out into space our present-day instruments can probe. Obviously there is nothing fundamental about this limit: it is constrained by current technology. Many more galaxies will undoubtedly be revealed in the coming decades by bigger telescopes now being planned. We would obviously not demote such galaxies from the realm of proper scientific discourse simply because they haven't been seen yet. When ancient navigators speculated about what existed beyond the boundaries of the then known world, or when we speculate now about what lies below the oceans of Jupiter's moons Europa and Ganymede, we are speculating about something "real" — we are asking a scientific question. Likewise, conjectures about remote parts of our universe are genuinely scientific, even though we must await better instruments to check them.

(ii) Limit in principle at present era

Even if there were absolutely no technical limits to the power of telescopes, our observations are still bounded by a horizon, set by the distance that any signal, moving at the speed of light, could have travelled since the big bang. This horizon demarcates the spherical shell around us at which the redshift would be infinite. There is nothing special about the galaxies on this shell, any more than there is anything special about the circle that defines your horizon when you're in the middle of an ocean. On the ocean, you can see farther by climbing up your ship's mast. But our cosmic horizon can't be extended unless the universe changes, so as to allow light to reach us from galaxies that are now beyond it. If our universe were decelerating, then the horizon of our remote descendants would encompass extra galaxies that are beyond our horizon today. It is, to be sure, a practical impediment if we have to await a cosmic change taking billions of years, rather than just a few decades (maybe) of technical advance, before a prediction about a particular distant galaxy can be put to the test. But does that introduce a difference of principle? Surely the longer waiting-time is a merely quantitative difference, not one that changes the epistemological status of these faraway galaxies?

(iii) Never-observable galaxies from "our" Big Bang,

But what about galaxies that we can never see, however long we wait? It's now believed that we inhabit an accelerating universe. As in a decelerating universe, there would be galaxies so far away that no signals from them have yet reached us; but if the cosmic expansion is accelerating, we are now receding from these remote galaxies at an ever-increasing rate, so if their light hasn't yet reached us, it never will. Such galaxies aren't merely unobservable in principle now — they will be beyond our horizon forever. But if a galaxy is now unobservable, it hardly seems to matter whether it remains unobservable for ever, or whether it would come into view if we waited a trillion years. (And I have argued, under (ii) above, that the latter category should certainly count as "real".)

(iv) Galaxies in disjoint universes

The never-observable galaxies in (iii) would have emerged from the same Big Bang as we did. But suppose that, instead of causally-disjoint regions emerging from a single Big Bang (via an episode of inflation) we imagine separate Big Bangs. Are space-times completely disjoint from ours any less real than regions that never come within our horizon in what we'd traditionally call our own universe? Surely not — so these other universes too should count as real parts of our cosmos, too.

This step-by-step argument (those who don't like it might dub it a slippery slope argument!) suggests that whether other universes exist or not is a scientific question. But it is of course speculative science. The next question is, can we put it on a firmer footing? What could it explain?

Scenarios For A Multiverse

At first sight, nothing seems more conceptually extravagant — more grossly in violation of Ockham's Razor — than invoking multiple universes. But this concept is a natural consequence of several different theories ( albeit all speculative). Andrei Linde, Alex Vilenkin and others have performed computer simulations depicting an "eternal" inflationary phase where many universes sprout from separate big bangs into disjoint regions of spacetimes. Alan Guth and Lee Smolin have, from different viewpoints, suggested that a new universe could sprout inside a black hole, expanding into a new domain of space and time inaccessible to us. And Lisa Randall and Raman Sundrum suggest that other universes could exist, separated from us in an extra spatial dimension; these disjoint universes may interact gravitationally, or they may have no effect whatsoever on each other.

There could be another universe just a few millimetres away from us. But if those millimetres were measured in some extra spatial dimension then to us (imprisoned in our 3-dimensional space) the other universe would be inaccessible. In the hackneyed analogy where the surface of a balloon represents a two-dimensional universe embedded in our three-dimensional space, these other universes would be represented by the surfaces of other balloons: any bugs confined to one, and with no conception of a third dimension, would be unaware of their counterparts crawling around on another balloon. Variants of such ideas have been developed by Paul Steinhardt, Neil Turok and others. Guth and Edward Harrison have even conjectured that universes could be made in some far-future laboratory, by imploding a lump of material to make a small black hole. Could our entire universe perhaps then be the outcome of some experiment in another universe? If so, the theological arguments from design could be resuscitated in a novel guise. Smolin speculates that the daughter universe may be governed by laws that bear the imprint of those prevailing in its parent universe. If that new universe were like ours, then stars, galaxies and black holes would form in it; those black holes would in turn spawn another generation of universes; and so on, perhaps ad infinitum.

Parallel universes are also invoked as a solution to some of the paradoxes of quantum mechanics, in the "many worlds" theory, first advocated by Hugh Everett and John Wheeler in the 1950s. This concept was prefigured by Olaf Stapledon, in his 1937 novel, as one of the more sophisticated creations of his Star Maker: "Whenever a creature was faced with several possible courses of action, it took them all, thereby creating many ... distinct histories of the cosmos. Since in every evolutionary sequence of this cosmos there were many creatures and each was constantly faced with many possible courses, and the combinations of all their courses were innumerable, an infinity of distinct universes exfoliated from every moment of every temporal sequence". None of these scenarios has been simply dreamed up out of the air: each has a serious, albeit speculative, theoretical motivation. However, one of them, at most, can be correct. Quite possibly none is: there are alternative theories that would lead just to one universe. Firming up any of these ideas will require a theory that consistently describes the extreme physics of ultra-high densities, how structures on extra dimensions are configured, etc. But consistency is not enough: there must be grounds for confidence that such a theory isn't a mere mathematical construct, but applies to external reality. We would develop such confidence if the theory accounted for things we can observe that are otherwise unexplained. As the moment, we have an excellent framework, called the standard model, that accounts for almost all subatomic phenomena that have been observed. But the formulae of the "standard model" involve numbers which can't be derived from the theory but have to be inserted from experiment.

Perhaps, in the 21st-century theory, physicists will develop a theory that yields insight into (for instance) why there are three kinds of neutrinos, and the nature of the nuclear and electric forces. Such a theory would thereby acquire credibility. If the same theory, applied to the very beginning of our universe, were to predict many big bangs, then we would have as much reason to believe in separate universes as we now have for believing inferences from particle physics about quarks inside atoms, or from relativity theory about the unobservable interior of black holes.

Universal Laws, Or Mere Bylaws?

"Are the laws of physics unique?" is a less poetic version of Einstein's famous question "Did God have any choice in the creation of the Universe?" The answer determines how much variety the other universes — if they exist — might display. If there were something uniquely self-consistent about the actual recipe for our universe, then the aftermath of any big bang would be a re-run of our own universe. But a far more interesting possibility (which is certainly tenable in our present state of ignorance of the underlying laws) is that the underlying laws governing the entire multiverse may allow variety among the universes. Some of what we call "laws of nature" may in this grander perspective be local bylaws, consistent with some overarching theory governing the ensemble, but not uniquely fixed by that theory.

As an analogy (one which I owe to Paul Davies) consider the form of snowflakes. Their ubiquitous six-fold symmetry is a direct consequence of the properties and shape of water molecules. But snowflakes display an immense variety of patterns because each is moulded by its micro-environments: how each flake grows is sensitive to the fortuitous temperature and humidity changes during its downward drift. If physicists achieved a fundamental theory, it would tell us which aspects of nature were direct consequences of the bedrock theory (just as the symmetrical template of snowflakes is due to the basic structure of a water molecule) and which are (like the distinctive pattern of a particular snowflake) the outcome of accidents. The accidental features could be imprinted during the cooling that follows the big bang — rather as a piece of red-hot iron becomes magnetised when it cools down, but with an alignment that may depend on chance factors. It may turn out (though this would be a disappointment to many physicists if it did) that the key numbers describing our universe, and perhaps some of the so-called constants of laboratory physics as well, are mere "environmental accidents", rather than being uniquely fixed throughout the multiverse by some final theory. This is relevant to some now-familiar arguments (explored further in my book Our Cosmic Habitat) about the surprisingly fine-tuned nature of our universe.

Fine Tuning — A Motivation For Suspecting That Our "Universe" Is One Of Many.

The nature of our universe depended crucially on a recipe encoded in the big bang, and this recipe seems to have been rather special. A degree of fine tuning — in the expansion speed, the material content of the universe, and the strengths of the basic forces — seems to have been a prerequisite for the emergence of the hospitable cosmic habitat in which we live. Here are some prerequisites for a universe containing organic life of the kind we find on Earth:

First of all, it must be very large compared to individual particles, and very long-lived compared with basic atomic processes. Indeed this is surely a requirement for any hypothetical universe that a science fiction writer could plausibly find interesting. If atoms are the basic building blocks, then clearly nothing elaborate could be constructed unless there were huge numbers of them. Nothing much could happen in a universe that was was too short-lived: an expanse of time, as well as space, is needed for evolutionary processes. Even a universe as large and long-lived as ours, could be very boring: it could contain just black holes, or inert dark matter, and no atoms at all; it could even be completely uniform and featureless. Moreover, unless the physical constants lie in a rather narrow range, there would not be the variety of atoms required for complex chemistry.

If our existence depends on a seemingly special cosmic recipe, how should we react to the apparent fine tuning? There seem three lines to take: we can dismiss it as happenstance; we can acclaim it as the workings of providence; or (my preference) we can conjecture that our universe is a specially favoured domain in a still vaster multiverse. Some seemingly "fine tuned" features of our universe could then only be explained by "anthropic" arguments, which are analogous to what any observer or experimenter does when they allow for selection effects in their measurements: if there are many universes, most of which are not habitable, we should not be surprised to find ourselves in one of the habitable ones.

Testing Specific Multiverse Theories Here And Now

We may one day have a convincing theory that tells us whether a multiverse exists, and whether some of the so called laws of nature are just parochial by-laws in our cosmic patch. But while we're waiting for that theory — and it could be a long wait — the "ready made clothes shop" analogy can already be checked. It could even be refuted: this would happen if our universe turned out to be even more specially tuned than our presence requires. Let me give two quite separate examples of how this style of reasoning can be used to refute specific hypotheses.

(i) Ludwig Boltzmann argued that our entire universe was an immensely rare "fluctuation" within an infinite and eternal time-symmetric domain. There are now many arguments against this hypothesis, but even when it was proposed one could already have noted that fluctuations in large volumes are far more improbable than in smaller volumes.

So, it would be overwhelmingly more likely, if Boltzmann were right, that we would be in the smallest fluctuation compatible with our existence (Indeed, the most probable fluctuation would be a disembodied brain that merely simulated the sensations of the external world.) Whatever our initial assessment of Boltzmann's theory, its probability would plummet if we came to accept the extravagant scale of the cosmos.

(ii) Even if we knew nothing about how stars and planets formed, we would not be surprised to find that our Earth's orbit wasn't highly eccentric: if it had been, water would boil when the Earth was at perihelion and freeze at aphelion — a harsh environment unconducive to our emergence. However, a modest orbital eccentricity (certainly up to 0.1) is plainly not incompatible with life. If it had turned out that the earth moved in a near-perfect circle (with eccentricity, say, less than 0.00001) , this would be a strong argument against a theory that postulated anthropic selection from orbits whose eccentricities had a "Bayesian prior" that was uniform in the range from zero to one.

We could apply this style of reasoning to the important numbers of physics (for instance, the cosmological constant lambda) to test whether our universe is typical of the subset that that could harbour complex life. Lambda has to be below a threshold to allow protogalaxies to pull themselves together by gravitational forces before gravity is overwhelmed by cosmical repulsion (which happens earlier if lambda is large). An unduly fierce cosmic repulsion would prevent galaxies from forming.

Suppose, for instance, that (contrary to current indications) lambda was thousands of times smaller than it needed to be merely to ensure that galaxy formation wasn't prevented. This would raise suspicions that it was indeed zero for some fundamental reason. (Or that it had a discrete set of possible values, and all the others were well about the threshold).

The methodology requires us to decide what values of a particular physical parameter are compatible with our emergence. It also requires a specific theory that gives the relative Bayesian priors for any particular value. For instance, in the case of lambda, are all values equally probable? Are low values favoured by the physics? Or is there a finite number of discrete possible values, depending on how the extra dimensions "roll up"? With this information, one can then ask if our actual universe is "typical" of the subset in which we could have emerged. If it is a grossly atypical member even of this subset (not merely of the entire multiverse) then we would need to abandon our hypothesis. By applying similar arguments to the other numbers, we could check whether our universe is typical of the subset that that could harbour complex life. If so, the multiverse concept would be corroborated.

As another example of how "multiverse" theories can be tested, consider Smolin's conjecture that new universes are spawned within black holes, and that the physical laws in the daughter universe retain a memory of the laws in the parent universe: in other words there is a kind of heredity. Smolin's concept is not yet bolstered by any detailed theory of how any physical information (or even an arrow of time) could be transmitted from one universe to another. It has, however, the virtue of making a prediction about our universe that can be checked. If Smolin were right, universes that produce many black holes would have a reproductive advantage, which would be passed on to the next generation. Our universe, if an outcome of this process, should therefore be near-optimum in its propensity to make black holes, in the sense that any slight tweaking of the laws and constants would render black hole formation less likely. (I personally think Smolin's prediction is unlikely be borne out, but he deserves our thanks for presenting an example that illustrates how a multiverse theory can in principle be vulnerable to disproof.) These examples show that some claims about other universes may be refutable, as any good hypothesis in science should be. We cannot confidently assert that there were many big bangs — we just don't know enough about the ultra-early phases of our own universe. Nor do we know whether the underlying laws are "permissive": settling this issue is a challenge to 21st century physicists. But if they are, then so-called anthropic explanations would become legitimate — indeed they'd be the only type of explanation we'll ever have for some important features of our universe.

A Keplerian Argument

The multiverse concept might seem arcane, even by cosmological standards, but it affects how we weigh the observational evidence in some current debates. Our universe doesn't seem to be quite as simple as it might have been. About 5 percent of its mass is in ordinary atoms; about 25 percent is in dark matter (probably a population of particles that survived from the very early universe contains atoms, and dark matter; and the remaining 70 percent is latent in empty space itself.

Some theorists have a strong prior preference for the simplest universe and are upset by these developments. It now looks as thought a craving for such simplicity will be disappointed. Perhaps we can draw a parallel with debates that occurred 400 years ago. Kepler discovered that planets moved in ellipses, not circles. Galileo was upset by this. In his "Dialogues concerning the two chief systems of the world" he wrote "For the maintenance of perfect order among the parts of the Universe, it is necessary to say that movable bodies are movable only circularly".

To Galileo, circles seemed more beautiful; and they were simpler — they are specified just by one number, the radius, whereas an ellipse needs an extra number to define its shape (the "eccentricic"). Newton later showed, however, that all elliptical orbits could be understood by a single unified theory of gravity. Had Galileo still been alive when Principia was published, Newton's insight would surely have joyfully reconciled him to ellipses.

The parallel is obvious. A universe with at least three very different ingredients low may seem ugly and complicated. But maybe this is our limited vision. Our Earth traces out just one ellipse out of an infinity of possibilities, its orbit being constrained only by the requirement that it allows an environment conducive for evolution (not getting too close to the Sun, nor too far away). Likewise, our universe may be just one of an ensemble of all possible universes, constrained only by the requirement that it allows our emergence. So I'm inclined to go easy with Occam's razor: a bias in favour of "simple" cosmologies may be as short-sighted as was Galileo's infatuation with circles.

What we've traditionally called "the universe" may be the outcome of one big bang among many, just as our Solar System is merely one of many planetary systems in the Galaxy. Just as the pattern of ice crystals on a freezing pond is an accident of history, rather than being a fundamental property of water, so some of the seeming constants of nature may be arbitrary details rather than being uniquely defined by the underlying theory. The quest for exact formulas for what we normally call the constants of nature may consequently be as vain and misguided as was Kepler's quest for the exact numerology of planetary orbits. And other universes will become part of scientific discourse, just as "other worlds" have been for centuries. We may one day have a convincing theory that accounts for the very beginning of our universe, tells us whether a multiverse exists, and (if so) whether some so called laws of nature are just parochial by-laws in our cosmic patch. may be vastly larger than the domain we can now (or, indeed, can ever) observe. Most physicists hope to discover a fundamental theory that will offer unique formulae for all the constants of nature. But perhaps what we've traditionally called our universe is just an atom in an ensemble — a multiverse punctuated by repeated big bangs, where the underlying physical laws permit diversity among the individual universes.

Even though some physicists still foam at the mouth at the prospects of be being "reduced" to these so-called anthropic explanations, such explanations may turn out to be the best we can ever discover for some features of our universe (just as they are the best explanations we can offer for the shape and size of Earth's orbit). Cosmology will have become more like the science of evolutionary biology. Nonetheless (and here physicists should gladly concede to the philosophers), any understanding of why anything exists — why there is a universe (or multiverse) rather than nothing — remains in the realm of metaphysics.

John McCarthy asks how animal behavior is encoded in DNA. May I sharpen the question? One of the most remarkable manifestations of inherited behavior is the way birds navigate accurately whilst migrating over vast distances. I understand that part of this skill lies with the bird's ability to use the positions of stars as beacons. Does this imply that some avian DNA contains a map of the sky? Could a scientist in principle sequence the DNA and reconstruct the constellations?

Three decades ago I began my first career working on a British television series called "Survival". Unlike the current "Survivor" series (about the politics of rejection while camping out) these were natural history documentaries on a par with the best of National Geographic and Sir David Attenborough: early recordings of humpback whales, insights on elephant behavior, the diminishing habitats of mountain gorillas and orangutans, a sweeping essay on the wildebeest migration, and my favorite, an innovative look at the ancient baobab tree.

In 2001 the "Survival" series died. It was a year when conservation efforts lagged across the board, along with other failures to take the long view. Survival programs may have told people what they could no longer bear to hear (that the human species is soiling its own den) without demonstrating constructive solutions. For example, there are precious few incentives to develop alternate energy sources despite the profound vulnerabilities that our dependence on foreign energy revealed yet again. We have no "Vision Thing," despite the many clues. "It's global warming, dude," a 28 year-old auto mechanic told The New York Times as he fished in the Hudson River; "I don't care if the whole planet burns up in a hundred years. If I can get me a fish today, it's cool by me."

Happily this provides a continuum to the question I posed at this forum in 1998:

"If tragedy + time = comedy, what is the formula for equally therapeutic music? Do (Blues) musicians reach a third person perspective similar to that found in meditation, mind-altering drugs, and genius?"

What I was reaching for with that third person perspective was a selfless overview. What I've since found is that healing dances of Native Americans and some African peoples follow the saga of a hero or heroine, much the way you or I listen to Bob Dylan or Bonnie Raitt and identify with their lyrics.

While Carl Jung delved into the healing ritual archetype among many cultures, a new science called Biomusicology suggests even more ancient origins, tracing the inspiration for human music to natural sounds (the rhythm of waves lapping at the shore, rain and waterfalls, bird song, breathing, and our mother's heartbeat when we were floating in the womb.) Songs of birds certainly influenced classical music, and the call and response patterns of birds were imitated in congregations and cotton fields, with shouts, which led to the Delta blues.

The salubrious influence of music, including research by Oliver Sacks, is featured in a Discovery Channel program that I helped research. "The Power of Music" will be broadcast in 2002, as will Sir David Attenborough's new series on a similar theme, "Songs of the Earth." But will these programs inspire viewers to relinquish their SUVs for a hydrogen-powered car? How does one convince people to address global warming when most minds are focused on the economy or terrorism?

Part one of this answer must include "An Ounce of Prevention." Richard A. Clarke, former White House director of counterterrorism, explained our ill preparedness for September 11 this way: "Democracies don't prepare well for things that have never happened before." Another senior analyst said. "Unfortunately, it takes a dramatic event to focus the government's and public's attention." Finally, efforts to prevent hijackings have been responsive, rarely proactive.

As we devise our New Year's Resolutions, how many of us will wait for a scare (positive diagnosis) before we quit smoking, drinking or sitting on our duff? Year 2002 should be the time when conservationists not only demand action, but persuade people everywhere that the demise of wild places can and should be stopped, that some of our forces of habit (unneeded air conditioning, for example) will eventually affect our quality of life in ways of greater devastation. We need people to identify with the song lyrics of others, who may live in distant lands, and feel the brunt of global warming long before we do. But first we must learn to understand their language.

In The Unbearable Lightness of Being, Milan Kundera wrote, "True human goodness, in all its purity and freedom, can come to the fore only when its recipient has no power. Mankind's true moral test, its fundamental test (which lies deeply buried from view), consists of its attitude toward those who are at its mercy: animals. And in this respect mankind has suffered a fundamental debacle, a debacle so fundamental that all others stem from it." Survival indeed.

This is, I believe, the key question on which the quantum theory of gravity and our understanding of cosmology, depends. We have made tremendous progress in the last years towards each goal, and we come to the point where we need a new answer to this question to proceed further. The basic reason for this problem is that most notions of time, change and dynamics which physics, and science more generally, have used are background dependent. This means that they define time and change in terms of fixed points of reference which are outside the system under study and do not themselves change or evolve. These external points of reference include usually the observer and clocks used to measure time. They constitute a fixed background against which time and change are defined. Other aspects of nature usually assumed to be part of the background are the properties of space, such as its dimensionality and geometry.

General relativity taught us that time and space are parts of the dynamical system of the world, that do themselves change and evolve in time. Furthermore, in cosmology we are interested in the study of a system that by definition contains everything that exists, including all possible observers. However, in quantum theory, observers seem to play a special role, which only makes sense if they are outside the system. Thus, to discover the right quantum theory of gravity and cosmology we must find a new way to formulate quantum theory, as well as the notions of time and change, to apply to a system with no fixed background, which contains all its possible observers. Such a theory is called background independent.

The transition from background dependent theories to background independent ones is a basic theme of contemporary science. Related to it is the change from describing things in terms of absolute properties intrinsic to a given elementary particle, to describing things in terms of relational properties, which define and describe any part of the universe only through its relationships to the rest.

In loop quantum gravity we have succeeded in constructing a background independent quantum theory of space and time. But we have not yet understood completely how to put the observer inside the universe. String theory, while it solves some problems, has not helped here, as it is so far a purely background dependent theory. Indeed string theory is unable to describe closed universes with a positive cosmological constant, such as observations now favor.

Among the ideas which are now in play which address this issue are Julian Barbour's proposal that time does not exist, Fotini Markopoulou's proposal to replace the single quantum theory relevant for observing a system from the outside with a whole family of quantum theories, each a description of what an observer might see from a particular event in the history of the universe and 't Hooft's and Susskind's holographic principle. This last idea says that physics cannot describe precisely what is happening inside a region of space, instead we can only talk about information passing through the boundary of the region. I believe these are relevant, but none go far enough and that we need a radical reformulation of our ideas of time and change.

As the philosopher Peirce said over a century ago, it is fundamentally irrational to believe in laws of nature that are absolute and unchanging, and have themselves no origin or explanation. This is an even more pressing issue now, because we have strong evidence that the universe, or at least the part in which we live, came into existence just a few billion years ago. Were the laws of nature waiting around eternally for a universe to be created to which they could apply? To resolve this problem we need an evolutionary notion of law itself, where the laws themselves evolve as the universe does. This was the motivation for the cosmological natural selection idea that Martin Rees is so kind to mention. That is, as Peirce understood, the notions of evolution and self-organization must apply not just to living things in the universe, but the structure of the universe and the laws themselves.

Questions? I don't ask questions. I ask answers, and then make up the questions as I see fit. I assemble vast collections of answers and while finding the questions, I make connections in the process. These connections are new answers, and depending on my mood and how much time I have at my disposal, I set about finding questions for them as well. Often, if not usually, the question I find is: "Why on earth am I wasting my time on this (project du jour)?" Once in a great while, I'll find that something I've cooked up in my multi-media cauldron "fits" just right — an appropriate gesture at a propitious moment, and it arrives with no explanation, no equation, no excuse, no reason, nothing- it just sits there — absolutely correct to itself in every possible way.

The paradigm of Question/Answer doesn't really work in my world as I've never really found Life, The Universe, and Everything (LU&E) and most (but not all) of its constituent parts and systems to be fundamentally amenable to it. From my research, I've come to a general conclusion that LU&E and most of its parts are fundamentally not knowable, or even humanly understandable in any linguistic or mathematical sense, except when framed in a more narrow set of terms, like "metaphor" or "pretend" or "just so".

A dear friend of mine once noted: "Nobody knows and you can't find out" and I largely agree with him. However, I can also say that, like being in the presence of a bucket of bricks, this is all more an experiential thing, more like a synchronistic aesthetic moment and less like a diachronistic or ahistorically definitive mathematical proposition or linguistically intelligible conclusion. So, one can't "know" it, nor can one "find out", but one can come to a sensibility that is convincing at the time and creatively informs one's behaviour and choices.

Hence, the only justice in this life is poetic, and everything else is just some tweaky form of petty revenge or (more typically in this life of entertainment and cultural anaesthesiology) dodging bullets while one waits for the big storm to blow over.

It can be infuriating (to me and most everyone else, it seems) when my work or research comes such conclusions, but since when has there been some big carved-in-stone guarantee that it's supposed to make sense in the first place? Isn't a rational conclusion a bit presumptuous and arrogant? From what I can gather it seems that the complete object of study fundamentally doesn't and shouldn't make sense (as sense seems to be a tiny subset surrounded by a vast multitude of complex forms of "nonsense"), and see that not as a shortcoming on the part of the Universe, as much as it is an indication of the limitations of human reason and the short time we get to spend on this planet.

But all this is probably not what you wanted to hear, so here's a good question that's been bugging me for years and if anyone wants to submit an answer, let me know - I'm all ears...

Mister Warwick asks:

"What comes after Science? When?"

I have shelves of books and papers by smart people who have brushed up against the edge of this question but who have seldom attacked it head on. I'm drawn to the question, and have been obsessed with it for years, because I think it's one of the big ones. It touches on everything humans do.

Fashions and fads are everywhere; in things as diverse as food, furnishings, clothes, flowers, children's names, haircuts, body image, even disease symptoms and surgical operations. Apparently, even the way we see Nature and frame questions about it is affected to some extent by fashion; at least according to those who would like to throw cold water on somebody else's theory. (In the current discussion, Paul Davies says, "Of late, it is fashionable among leading physicists and cosmologists to suppose that alongside the physical world we see lies a stupendous array of alternative realitiesŠ")

But the ubiquity of fads has not led to deep understanding, even though there are serious uses to which a working knowledge of fads could be put. A million children each year die of dehydration, often where rehydration remedies are available. What if rehydration became fashionable among those children's mothers? Public health officials have many times tried to make various behaviors fashionable. In promoting the use of condoms in the Philippines or encouraging girls in Africa to remain in school, they've reached for popular songs and comic books to deliver the message, hoping to achieve some kind of liftoff. Success has been real, but too often temporary or sporadic. Would a richer understanding of fads have helped them create better ones?

In trying to understand these phenomena, writers have been engaged in a conversation that has spanned more than a hundred years. In 1895 Gustave LeBon's speculations on "The Crowd" contained some cockeyed notions, and some that are still in use today. Ludwik Fleck, writing on "The Evolution of a Scientific Fact" in the thirties, in part inspired Thomas Kuhn's writings on the structure of scientific revolutions in the sixties. Everrett Rogers's books on the "Diffusion of Innovations" led to hundreds of other books on the subject and made terms like early adopters and agents of change part of the language. For several decades positive social change has been attempted through a practice called Social Marketing, derived in part from advertising techniques. Diffusion and social marketing models have been used extensively in philanthropy, often with success. But to my knowledge these techniques have not yet led to a description of the fad that's detailed and testable.

Malcom Gladwell was stimulating in identifying elements of the fad in The Tipping Point but we are still left with a recipe that calls for a pinch of this and a bit, but not too much, of that.

Richard Dawkins made a dazzling frontal assault on the question when he introduced the idea of memes in The Selfish Gene. The few pages he devoted to the idea have inspired a number of books and articles in which the meme is considered to be a basic building block of social change, including fads. But as far as I can tell, the meme is still a fascinating idea that urges us toward experiments that are yet to be done.

Whether memes or some other formulation turns out to be the engine of fads, the process seems to go like this: a signal of some kind produces a response that in turn acts as a signal to the next person, with the human propensity for imitation possibly playing a role. This process of signal-response-signal might then spread with growing momentum, looking something like biological contagion. But other factors may also apply, as in Steve Strogatz's examination of how things sync up with one another. Or Duncan Watt's exploration of how networks of all kinds follow certain rules of efficiency. Or the way crowds panic in a football stadium or a riot. Or possibly even the studies on the way traffic flows, including the backward generated waves that cause mysterious jams. The patterns of propagation may turn out to be more interesting than anything else.

Fads and fashions have not been taken very seriously, I think, for at least three reasons. They seem short-lived, they're often silly and they seem like a break with normal, rational behavior. But as for being short-lived, the history of fads gives plenty of examples of fads that died out only to come back again and again, eventually becoming customary, including the use of coffee, tomatoes and hot chocolate. As for silliness, some fashions are not as silly as they seem. Fashions having to do with the length of one's hair seem trivial; yet political and religious movements have often relied on the prominence or absence of hair as a rallying symbol. And fads are far from aberrational. There are probably very few people alive who, at any one time, are not under the sway of a fad or fashion, if not dozens of them. And this is not necessarily a vacation from rational behavior on our part. On the contrary, it might be essential to the way we maximize the effectiveness of our choices. Two economists in California have developed a mathematical model suggesting that in following the lead of others we may be making use of other people's experience in a way that gives us a slightly higher chance of success in adopting a new product. The economists say this may explain a burst of popularity in a new product and possibly throw light on fads themselves.

But another reason fads may not have been examined in more detail, and this could be the killer, is that at least for the moment they just seem too complicated. Trying to figure out how to track and explain change is one of the oldest and toughest of questions. Explaining change among people in groups is perhaps complex beyond measure, and may turn out to be undoable. It may forever be an art and not a science. But still, the humble fad is too tantalizing to ignore.

We take it for granted and dismiss it, even while we're in the rapture of it. This commonplace thing that sits there like the purloined letter may or may not turn out to contain a valuable message for us, but it is staring us in the face.

A mountain of research shows that our fears modestly correlate with reality. With images of September 11th lingering in their mind's eye, many people dread flying to Florida for Spring break, but will instead drive there with confidence — though, mile per mile, driving during the last half of the 1990s was 37 times more dangerous than flying.

Will yesterday's safety statistics predict the future? Even if not, terrorists could have taken down 50 more planes with 60 passengers each and — if we'd kept flying — we'd still have been ended last year safer on commercial flights than on the road. Flying may be scary, but driving the same distance should be many times scarier.

Our perilous intuitions about risks lead us to spend in ways that value some lives hundreds of times more than other lives. We'll now spend tens of billions to calm our fears about flying, while subsidizing tobacco, which claims more than 400,000 lives a year.

It's perfectly normal to fear purposeful violence from those who hate us. But with our emotions now calming a bit, perhaps it's time to check our fears against facts. To be prudent is to be mindful of the realities of how humans suffer and die.

(To see my question developed — and answered — please click here).

The universe is quantum mechanical, and its dynamics can be simulated precisely and efficiently using quantum information processing. The amount of quantum computation required to perform this simulation is finite and has been calculated. Consequently, there is no obvious way to distinguish the universe from a very large quantum logic circuit.

I am intrigued by the interplay between the following:

1) People always want a little bit more than they have.

2) The economic and political systems built on this instinct are conquering the world.

3) Yet there is no correlation between owning a little bit more and happiness. Instead, the long-term effect of everyone seeking to own a little bit more could be calamitous.

Historically, religious figures have appealed to people to overrule their greed with a concern for some higher good. In our supposed scientific age, these arguments have lost their force. Instead our public affairs are governed by the idea that people should just be free as much as possible to choose what they want.

But what if people are programmed to make choices that are not in their own best long-term interest? Suppose we discovered that what we instinctively thought would bring us happiness is an illusion created by our human-gene-built brains to induce human-gene-spreading behavior?

Today's evolutionary psychologists provide compelling arguments why this picture might be accurate. A species programmed to acquire stuff might well spread itself successfully across the globe. But evolution is blind. It has no plan regarding what might happen to that species when the globe has been conquered. And in the meantime our genes don't give a damn about our happiness. For them it's just another propagation technology... perhaps made doubly efficient by ensuring the carrot is yanked away each time it comes within reach. To achieve true happiness we may need to be a great deal wiser than the loudest demons in our head would suggest.

Will the new model of "Why We Are The Way We Are" finally convince us that our political and economic systems, and the assumptions on which they are based, are dangerously flawed. (The"problem isn't just the economists' assumption that "greed is good", or the politicians' assumption of politics that "growth is good'. We've all been brought up to believe: "natural is good". As if it weren't the most natural thing in the world for a planet to self-destruct.)

And how long will it take for the new ideas to have any impact? (What if it were to take 50 years? In an era of exponential growth, and accelerating technological change, can we afford even 10?)

More generally, can memes that have evolved in a single generation countermand the influence of genes that evolved over millions of years?

The actual day to day things that we do have been changed drastically for many people in the world over the last twenty years by the arrival of personal computers. We spend hours each day in front of a screen, typing. This was not the norm twenty years ago (although a few of us did it even then), and no one had access to the vast stores of information that are available to us on our laps now. We no longer ask for reprints or go to the library, but instead download pdf versions of papers that interest us. We no longer need to go to reference works but instead retrieve them directly on our PCs. The number of people that we correspond with has increased dramatically — granted, the medium has changed too. And chatting on the phone to people on the other side of the world is no longer expensive or an event — it is just as common and cheap as calling someone a hundred miles away. Our interaction with media is changing too — it is becoming more and more pull rather than push, even for TV and radio entertainment — we choose when and where we want to receive it, and how we will store it.

Surprisingly, neither the book, nor the movie, nor the documentary are dead. There are more of them, in fact, although the method of delivery is slowly changing. We have increased our number of options rather than supplanted the old ones.

Moore's law and the increase of telecommunications infrastructure are both continuing. What new options should we expect, and how will they change the way we work? What will be the next "web", as unimagined by most educated people today as our current one was in 1988? And what will be the impact of the new methods of delivery we can expect to be developed in the next 20 years?

Already tens of thousands of people have cochlear implants with direct electronic to neural connections to restore their hearing. Multiple groups are working on retinal implants, either into the eyeball, or interfacing to V1 at the back of the head; again to replace lost capabilities such as those resulting from macular degeneration. A few quadraplegics have direct neural connections to computer interfaces so that they can control a mouse and even type. As progress is made with these silicon/neural interfaces, pushed along by clinical pressures to cure those who are impaired, we can expect more and more "plastic surgery" applications. A direct neural typing interface first perhaps, and later data going the other way directly from the network into our brains. There are considerable challenges to be met in understanding neural "coding" to do this, but the clinical imperative is pushing this work along.

How will we all be in the world then, 20 years from now say, when we all have direct wireless connections to the Internet of that time with information services as yet unimaginable? How will our grandchildren's interaction with information change the way they work and think, in the same way that instant messaging and vast numbers of web pages have changed the way our children in elementary and high school operate today?

John McCarthy and I are from different generations (in the semester before McCarthy invented Lisp, he taught my dad FORTRAN, using punch cards on an old IBM) but our questions are nearly the same. McCarthy asks "how are behaviors encoded in DNA"?

Until recently, we were not in a position to answer this question. Few people would have even had the nerve to ask it. Many thought that most of the brain's basic organization arose in response to the environment. But we know that the mind of a newborn is far from a blank slate. As soon as they are born, babies can imitate facial gestures, connect what they hear with what they see, tell the difference between Dutch and Japanese, and distinguish between a picture of a scrambled face and a picture of a normal face. Nativists like Steven Pinker and Stanislas Dehaene suggest that infants are born with a language instinct and a "number sense". Since the function of our minds comes from the structure of our brains, these findings suggest that the microcircuitry of the brain is innate, largely wired up before birth. The plan for that wiring must come in part from the genes.

The DNA does not, however, provide a literal blueprint of a newborn's mind. We have only around 35,000 genes, but tens of billions of neurons. How does a relatively small set of genes combine to build a complex brain? As Richard Dawkins has put it, the DNA is more like a recipe than a blueprint. The genome doesn't provide a picture of a finished product, instead it provides a set of instructions for assembling an embryo. Those instructions govern basic developmental processes such as cell division and cell migration; it has long been known that such processes are essential to building bodies, and it now is becoming increasingly clear that the same processes shape our brains and minds as well.

There is, however, no master chef. In place of a central executive, the body relies on communication between cells, and communication between genes. Although the power of any one gene working on its own is small, the power of sets of genes working together is enormous. To take one example, Swiss biologist Walter Gehring has shown that the gene pax-6 controls eye development in a wide range of animals, from fruit flies to mice. Pax-6 is like any other gene in that it gives instructions for building one protein, but unlike the genes for building structural proteins like keratin and collagen because the protein that pax-6 builds serves as a signal to other genes, which in turn build proteins that serve as signals to still other genes. Pax-6 is thus a "master control gene" that launches an enormous cascade, a cascade of 2,500 genes working together to build an eye. Humans that lack it lack irises, flies that lack it lack eyes altogether. The cascade launched by pax-6 is so potent that when Gehring triggered it artificially on a fruit fly's antenna, the fly grew an extra eye, right there on its antenna. As scientists begin to work out the cascades of genes that build the brain, we will finally come to understand the role of the genes in shaping the mind.

Response to Paul Davies' reply to John McCarthy

It is hard indeed to imagine that nature would endow an organism with anything as detailed as The Cambridge Star Atlas. A typical bird probably has fewer than 50,000 genes, but, as Carl Sagan famously noted, there are billions and billions of stars.

Of course, you don't need to know all the stars to navigate. Every well trained sailor knows that Polaris marks North. A northern-hemisphere dwelling bird known as the Indigo Bunting knows something even more subtle - it doesn't just look for the brightest star (which could be lousy strategy on a cloudy night); instead it looks for how the stars rotate.

Cornell ecologist Stephen Emlen proved this experimentally, by raising buntings in a planetarium. One set of birds never got to see any stars, a second set saw the normal pattern of stars, and a third group saw a sneaky set of stars, in which everything rotated not around Polaris, but around Betelgeuse. The poor birds who didn't see any stars oriented themselves randomly (making it clear that they really did depend on the stars rather than a built-in compass). The birds who saw normal skies oriented themselves normally, and the ones who saw skies that rotated around Betelgeuse oriented themselves precisely as if they thought that Betelgeuse marked North. The birds weren't relying on specific sets of stars, they were relying on the stars' center of rotation.

You won't find the constellations in an indigo bunting's DNA, but you would find in their DNA the instructions for building a biological computer, one that can interpret the stars, taking the skies as its input and producing an estimated direction as its output. Just how the DNA can wire up such biological computers is my vote for the most important scientific question of the 21st century.

Of course this is one of the oldest philosophical questions in science but still one of the most mysterious. For most of Western history the cannonical answer has been some version of Platonism, some variation on the esentially Pythagorean idea that the matherial universe has been formed according to a set of transcendent and a priori mathematical relations or laws. These relations/laws Pythagaoras himself called the divine armonia of the cosmos, and have often been referred to since as the "cosmic harmonies" or the "music of the spheres". For Pythagoras numbers were actually gods, and the quest for mathematical relations in nature was a quest for the divine archetypes by which he believed that matter had literally been in-formed. Throughout the age of science, and even today, most physicists seem to be Platonists. Many are even Pythagoreans, implicitly (if not always with much concious reflection) making an association between the mathematical laws of nature and a transcendent being. The common association today of a "theory of everything" with "the mind of God" is simply the latest efflourescence of a two and a half millenia-old tradition which has always viewed physics as a quasi-religious activity.

Can we get beyond Platonism in our understanding of nature's undeniable propensity to realize extraordinarily sophisticated mathematical relations? Although I began my own life in science as a Platonist I have come to believe that this philosophical position is insupportable. It is not a rationally justifiable position at all, but simply a faith. Which is fine if one is prepaared to admit as much, something few physicists seem willing to do. To believe in an a priori set of laws (perhaps even a single law) by which physical matter had to be informed seems to me just a disguised version of deism — an outgrowth of Judeo-Christianity wrapped up in scientific language. I believe we should do better than this, that we should articulate (and need to articulate) a post-Platonist understanding of the so-called "laws of nature." It is a far from easy task, but not an impossible one. Just as mathematican Brian Rotman has put forward a post-Platonist account of mathematics we need to achieve a similar move for physics and our mathematical description of the world itself.

As I prepare to head for Cambridge (the Brits' one) for the conference to mark Stephen Hawking's 60th birthday, I know that the suggestion I am just about to make will strike the great and the good who are assembling for the event as my scientific suicide note. Suggesting time does not exist is not half as dangerous for one's reputation as questioning the expansion of the universe. That is currently believed as firmly as terrestrial immobility in the happy pre-Copernican days. Yet the idea that the universe in its totality is expanding is odd to say the least. Surely things like size are relative? With respect to what can one say the universe expands?

When I put this question to the truly great astrophysicists of our day like Martin Rees, the kind of answer I get is that what is actually happening is that the intergalactic separations are increasing compared with the atomic scales. That's relative, so everything is fine. Some theoreticians give a quite different answer and refer to the famous failed attempt of Hermann Weyl in 1917 to create a genuinely scale-invariant theory of gravity and unify it with electromagnetism at the same time. That theory, beautiful though it was, never made it out of its cot. Einstein destroyed it before it was even published with the simple remark that Weyl's theory would make the spectral lines emitted by atoms depend on their prior histories, in flagrant contradiction to observation. Polite in public, Einstein privately called Weyl's theory 'geistreicher Unfug' [inspired nonsense].

Ever since that time it seems to have been agreed that, for some inscrutable reason, the quantum mechanics of atoms and elementary particles puts an absolute scale into physics. Towards the end of his life, still smarting from Einstein's rap, Weyl wrote ruefully "the facts of atomism teach us that length is not relative but absolute" and went one to bury his own cherished ambition with the words "physics can never be reduced to geometry as Descartes had hoped".

I am not sure the Cartesian dream is dead even though the current observational evidence for expansion from a Big Bang is rather impressive. The argument from quantum mechanics, which leads to the identification of the famous Planck length as an absolute unit, seems to me inconclusive. It must be premature to attempt definitive statements in the present absence of a theory of quantum gravity or quantum cosmology. And the argument about the relativity of scale being reflected in the changing ratio of the atomic dimensions to the Hubble scale is vulnerable.

To argue this last point is the purpose of my contribution, which I shall do by a much simpler example, for which, however, the principle is just the same. Consider N point particles in Euclidean space. If N is greater than three, the standard Newtonian description of this system is based on 3N + 1 numbers. The 3N (=3xN) are used to locate the particles in space, and the extra 1 is the time. For an isolated dynamical system, such as we might reasonably conjecture the universe to be, three of the numbers are actually superfluous. This is because no meaning attaches to the three coordinates that specify the position of the centre of mass. This is a consequence of the relativity principle attributed to Galileo, although it was actually first cleanly formulated by Christiaan Huygens (and then, of course, brilliantly generalized by Einstein). The remaining 3N - 2 numbers constitute an oddly heterogeneous lot. One is the time, three describe orientation in space (but how can the complete universe have an orientation?), one describes the overall scale, and the remaining 3N - 7 describe the intrinsic shape of the system. The only numbers that are not suspect are the last: the shape variables.

Developing further ideas first put forward in 1902 in his Science and Hypothesis by the great French mathematician Poincare [ascii does not allow me to put the accent on his e], I have been advocating for a while a dynamics of pure shape. The idea is that the instantaneous intrinsic shape of the universe and the sense in which it is changing should be enough to specify a dynamical history of the universe. Let me spell this out for the celebrated 3 body problem of Newtonian celestial mechanics. In each instant, the instantaneous triangle that they form has a shape that can be specified by two angles, i.e., just two numbers. These numbers are coordinates on the space of possible shapes of the system. By the 'sense' in which the shape is changing I mean the direction of change of the shape in this two-dimensional shape space. That needs only one number to specify it. So a dynamics of pure shape, one that satisfies what I call the Poincare criterion, should need only three essential numbers to set up initial conditions. That's the only ideal that, in Poincare's words, would give the mind satisfaction. It's the ideal that inspired Weyl (though he attacked the problem rather differently).

Now how does Newtonian dynamics fare in the light of the Poincare criterion? Oddly enough, despite centuries of dynamical studies, this question hardly seems to have been addressed by anyone. However, during the last year, working with some N-body specialists, I have established that Newtonian mechanics falls short of the ideal of a dynamics of pure shape by no fewer than five numbers. Seen from the rational perspective of shape, Newtonian dynamics is very complicated. This is why the study of the Moon (which forms part of the archetypal Earth-Moon-Sun three-body problem) gave Newton headaches. Among the five trouble makers (which I won't list in full or discuss here), the most obstreperous is the one that determines the scale or size. The same five trouble makers are present for all systems of N point particles for N equal to or greater than 3. Incidentally, the reason why 3-body dynamics is so utterly different from 2-body dynamics is that shape only enters the picture when N = 3. Most theoretical physicists get their intuition for dynamics from the study of Newtonian 2-body dynamics (the Kepler problem). It's a poor guide to the real world.

The point of adding up the number of the variables that count in the initial value problem is this. The Newtonian three-body problem can be expressed perfectly well in terms of ratios. One can consider how the ratios of the individual sides to the perimeter of the triangle change during the evolution. This is analogous to following the evolution of the ratio of the atomic-radii to the Hubble radius in cosmology. To see if scale truly plays no role, one must go further. One must ask: do the observable ratios change in the simplest way possible as dictated by a dynamics of pure shape, or is the evolution more complicated? That is the acid test. If it is failed, absolute scale is playing its pernicious role. The Poincare criterion is an infallible test of purity.

Both Newtonian dynamics and Einstein's general relativity fail it. The fault is not in quantum mechanics but in the most basic structure of both theories. Scale counts. In fact, seen from this dynamical perspective Einstein's theory is truly odd. As James York, one of John Wheeler's students in Princeton, showed 30 years ago (in a beautiful piece of work that I regard as the highest point achieved to date in dynamical studies), the most illuminating way to characterize Einstein's theory is that it describes the mutual interaction of infinitely many degrees of freedom representing the pure shape of the universe with one single solitary extra variable that describes the instantaneous size of the universe (i.e., its 3-dimensional volume in the case of a closed universe). From Poincare's perspective, this extra variable, to put frankly, stinks, but the whole of modern cosmology hangs on it: it is used to explain the Hubble red shift.

There, I have stuck my neck out in good Popperian fashion. Current observations suggest I will have my head chopped off and Einstein will be vindicated. Certainly all the part of his theory to do with pure shape is philosophically highly pleasing and is supported by wonderful data. But even if true dynamical expansion is the correct explanation of the Hubble red shift, why did nature do something so unaesthetic? As I hope to show very shortly on the Los Alamos bulletin board, dynamics of pure shape can mimic a true Hubble expansion. The fact is that Einstein's theory allows red shifts of two kinds: one is due to stretching (expansion) of space, while the other is the famous gravitational red shift that makes clocks on the Earth run at a now observable amount slower than clocks in satellites. It is possible to eliminate scale from Einstein's theory, as Niall O'Murchadha and I have shown. This kills the stretching red shift but leaves the other intact. It is just possible that this could explain the Hubble red shift.

Let me conclude this possibly premature (but I feel justified, since all dogmas need to be challenged) contribution by pointing out that according to the standard Big-Bang scenario two things have been happening simultaneously since something lit the fuse: the universe has been expanding from an extraordinarily uniform and isotropic compressed state and it has simultaneously been getting more and more clumpy. Inflationists claim to have explained why we observe such a uniform Big Bang, but sceptics (which include me) have the uncomfortable feeling that an observational cosmic coincidence is merely being described, rather than explained, by theoretical fine tuning of an adjustable parameter. In a self-respecting universe that dismisses size as opposed to shape as a fiction, sharper predictions must be possible. In a dynamics of pure shape, the only thing that can happen is change of shape. That must explain the Hubble red shift. Merely by observing the rate at which matter and the universe in general becomes more clumpy, above all the rate of formation of gravitationally collapsed objects, astronomers ought to be able to predict the value of the Hubble constant.

So my challenge to the theoreticians is this: Are you absolutely sure Einstein got it exactly right? Prove me wrong in my hunch that the universe obeys a dynamics of pure shape subtly different from Einstein's theory. If size does count, why should nature do something so puzzling to the rational mind?

Could our lack of theoretical insight in some of the most basic questions in biology in general, and consciousness in particular, be related to us having missed a third aspect of reality, which upon discovery will be seen to always have been there, equally ordinary as space and time, but so far somehow overlooked in scientific descriptions?

Is the arena of physics, constructed out of space and time with matter/energy tightly interwoven with space and time, sufficient to fully describe all of our material world? The most fundamental debates in cognitive science take a firm "yes" for granted. The question of the nature of mind then leaves open only two options: either a form of reductionism, or a form of escapism. The latter option, a dualist belief in a separate immaterial mental realm has fallen out of favor, largely because of the astounding successes of natural science. The former, reductionism, is all that is left, whether it is presented in a crude form (denial of consciousness as real or important) or in a more fancy form (using terms like emergence, as if that would have any additional explanatory power).

The question I ask myself is whether there could not be another equally fundamental aspect to reality, on a par with space and time, and just as much part of the material world?

Imagine that some tribe had no clear concept of time. Thinking only in terms of space, they would have a neat way to locate everything in space, and they would scoff at superstitious notions that somehow there would be "something else", wholly other than space and the material objects contained therein. Of course they would see things change, but both during and after each change everything has its location, and the change would be interpreted as a series of purely spatial configurations.

Yet such a geometric view of the world is not very practical. In physics and in daily life we use time in an equally fundamental way as space. Even though everything is already "filled up" with space, similarly everything participates in time. Trying to explain that to the people of the no-time tribe may be difficult. They will see the attempt at introducing time as trying to sneak in a second type of space, perhaps a spooky, ethereal space, more refined in some way, imbued with different powers and possibilities, but still as a geometric something, since it is in these terms that they are trained to think. And they probably would see no need for such a parallel pseudo-space.

In contrast, we do not consider time to be in any way less "physical" than space. Neither time nor space can be measured as such, but only through what they make possible: distances, durations, motion. While space and time are in some sense abstractions, and not perceivable as such, they are enormously helpful concepts in ordering everything that is perceivable into a coherent picture. Perhaps our problems in coming up with a coherent picture of mental phenomena tells us that we need another abstraction, another condition of possibility for phenomena in this world, this very material world we have always lived in.

Could it be that we are like that tribe of geometers, and that we have so far overlooked a third aspect of reality, even though it may be staring us in the face? Greek mathematicians used time to make their mathematical drawings and construct their theories, yet they disregarded time as non essential in favor of a Platonic view of unchanging eternal truths. It took two thousand years until Newton and Leibniz invented infinitesimal calculus, which opened the door for time to finally enter mathematics, thus making mathematical physics possible.

To reframe my question: could our lack of theoretical insight in some of the most basic questions in biology in general, and consciousness in particular, be related to us having missed a third aspect of reality, which upon discovery will be seen to always have been there, equally ordinary as space and time, but so far somehow overlooked in scientific descriptions?

Although I don't know the answer, I suspect we will stumble upon it through a trigger that will come from engineering. Newton did not work in a vacuum. He built upon what Galileo, Descartes, Huygens and others had discovered before him, and many of those earlier investigations were triggered by concrete applications, in particular the construction of powerful canons calling for better ways to compute ballistic orbits. Another example is the invention of thermodynamics. It took almost two centuries for Newtonian mechanics to come to grips with time irreversibility. Of course, every physicist had seen how stirring sugar in a cup of tea is not reversible, but until thermodynamics and statistical mechanics came along, that aspect of reality had mostly been ignored. The engineering problems posed by the invention of steam engines were what forced a deeper thinking about time reversibility.

Perhaps current engineering challenges, from quantum computers to robotics to attempts to simulate large-scale neural interactions, will trigger a fresh way of looking at the arena of space and time, perchance finding that we have been overlooking an aspect of material reality that has been quietly with us all along.

What do we actually know about the physical world after the scientific revolution of the last century? Before the XXth century, the picture of the physical world was simple: matter formed by particles (and fields) moving in time over the stage of space, pushed and pulled by forces, according to deterministic equations, which we could write down. That's it.. But the 20th Century has changed all that in depth. Matter has quantum properties: particles can be delocalized -as if they were clouds- although they manifest themselves always as a single point when interacting with us. Space and time are not just curved: they are dynamical entities very much like the electric and magnetic field. Is there a new consistent picture of the physical world, that takes all this new knowledge into account?

The most remarkable aspect of quantum theory is its relational character: elementary quantum events (such as a certain quantum particle being "here") only happen in interactions, and, in a precise sense they are only "real" with respect to, or in relation with, another system. Indeed, I can see the particle "here", but at the same time the particle and I can be in a quantum superposition in which the particle has no precise localization. Thus, a quantum particle is not just "here", but only "here for me".

On the other hand, the most remarkable property of general relativity is that localization in space and time are not defined. Things are only localized with respect to other things. In fact, the spacetime coordinates have no meaning in general relativity, and only quantities that are independent of these coordinates (such as relative localizations) have physical meaning.

Now the question is: are the quantum relationalism (quantum systems have definite properties only in nteracting with other systems) and the general relativistic relationalism (position is only relative) connected to each other? Are they indeed two aspects of the same relationalism?

There is clearly some deep connection. In order to interact quantum mechanically, two systems must be close in space and time, and, viceversa, spacetime contiguity can only be checked via a quantum interaction. So, is perhaps spacetime just the geography of the net of the quantum interactions? Is the world just made of relations?

We are far from understanding all this, and the current highly speculative physical theories haven't even started addressing this kind of questions. But until we address these questions -which are the interesting ones in physics for me- the great revolution of the 20th century is not over. We have lost the old picture of the physical world, but we haven't a new credible one yet.

By “life on Earth” I mean the variety of life, the multitude of species, the dazzling array of ecosystems they create from the permanent snow fields of the Himalayas to steamy jungles, and coral reefs, and the variety of including ourselves including and the 6000+ languages we speak and our cultures that they largely define.

There are two answers: no and yes.

A median estimate is that a third of all the species will be on the fast track to extinction within the next quarter century. Over 90% of all languages will be gone by then, because languages spoken by fewer than a million people are rarely taught to children. Most tropical forests will be gone by 2025 and with them, their species and peoples. Global warming will ensure that the species that survive do so in the wrong place. Coral reefs will be cooked alive in too-warm oceans, tropical glaciers will long have been only a memory preserved in the National Geographic photo collection.

So what will it mean for humanity to live in such a biological impoverished world? I always think of Orange County, California, with an airport named after an actor. A fake cowboy/war hero (delete as appropriate) to introduce you to a desert world with nitrogen-enriched green lawns, no sidewalks, golf courses, imported water. Instant gratification reigns. The future? Don’t worry be happy. Enough people like that world; property values are high.

But suppose we saved the variety of life on Earth, grabbed the nettle of global warming, and, in general thought about our human futures. What would that tell us about ourselves — and what we are capable of achieving? What would it take to accomplish that?

Answer the life-on-Earth question and whatever answer one picks, so much about ourselves must be revealed.

Despite monumental advances in brain and behavioral sciences, nothing like a science of human potential and the good life has yet emerged. This seems ironic in an age of unprecedented wealth, yet one that also has chronically high levels of stress and life dissatisfaction.

My hunch is that there's not yet a science of human potential and the good life because such concerns are only just now moving from the realm of humanistic thinking to ones being informed by science. Much of my research lies at the interface between humanities and brain science, as my collaborators and I address basic issues regarding how enduring questions about the quality of human life can be informed by brain science.

In my primary research, I ask, what is the neural basis of human intelligence, and how can our understanding of brain development and plasticity be used to construct more effective learning environments? With Gabrielle Starr, an English professor at NYU and Anne Hamker here at Caltech, we are asking, what is the brain basis of aesthetic experience, and how can such an understanding be used to deepen our emotional life? With Michael Dobry, co-director of the graduate industrial design program at the Art Center College of Design, we are asking, what is the relation between design and the brain, and how can the design of daily life be more in line with the brain's capacities?

Ultimately, a science of human potential and of the good life must help explain how these human capacities can be actualized in contexts that confer significance and dignity to individual life.

The question of what is "real," defined here as the physical universe, acquires special subtlety from the perspective of brain and cognitive science. The question goes beyond semantic quibbling about the difference between physical stimuli and our perception of them. (Consider the old question, "If a tree falls in the forest, was a sound made if no one is present to hear it?" The answer is "no," because a sound is a sensation that must be perceived by an observer, and no observer was present to hear it.) The startling truth is that we live in a neurologically generated, virtual cosmos that we are programmed to accept as the real thing. The challenge of science is to overcome the constraints of our kludgy, neurological wetware, and understand a physical world that we know only second-hand. In fact, we must make an intuitive leap to accept the fact that there is a problem at all. Common sense and the brain that produces it evolved in the service of our hunter-gatherer ancestors, not scientists.

Sensory science provides the most obvious discrepancies between the physical world and our neurological model of it. Consider these physical to perceptual transformations: photons stimulate the sensations of light and color; chemicals produce tastes and odors; and pressure changes become sounds. Yet, there is no "light" or "color" in the wave or photon structure of electromagnetic radiation, no "sweet" in the molecular structure of sugar, no "sound" in pressure changes, etc. The brain produced these sensory attributes. Sensation is the arbitrary experience that is correlated with a physical stimulus, but is not the physical stimulus itself. Our brain manages these psychophysical transformations in such a convincing manner that we seldom consider that we are sensing a neurological simulation, not physical reality. When do we question the physical meaning of "blue," "pain," or "B-flat?" Consider also the apparent seamlessness of the reality illusion. Using a visual metaphor, our sensory environment is like that of a person trapped in a tiny house, through which the universe must be viewed through peep-holes, one per each sensory channel, such as vision, taste, hearing, etc. From this limited, peep hole vista, we synthesize a seamless, noisy, bright, flavorful, smelly, three dimensional panorama that is an hypothesis of reality. The peep-hole predicament is invisible to us. (Some animals have peep-holes we lack, such as those associated with electric or magnetic field perception.)

Sensory examples are instructive because the nature of the psychophysical linkage is relatively clear. It's easy to imagine sensory limits of bandwidth (the size of our "peephole"), absolute sensitivity, or even modes of sensitivity (our "peep-holes"). Neurological limits on thinking may be as common as those on sensing, but they are more illusive — it's hard to think about what you can't think about. A good example from physics is our difficulty in understanding the space-time continuum — our intellect fails us when we move beyond the dimensions of height, width, and depth. Other evidence of our neurological reality-generator is revealed by its malfunction in illusions, hallucinations, and dreams, or in brain damage, where the illusion of reality does not simply degrade, but often splinters and fragments.

Why am I interested in this question? As a neuroscientist, I want to understand how the brain evolved, developed, and functions. As a biologist, I believe that all organisms are a theory of their environment, and it's necessary to understand that environment. As an amateur astronomer and cosmologist, I want to know the universe in which I live. To me, physics, biology, neuroscience and psychology are different approaches to a similar set of perceptual problems. It's no coincidence that Herman Helmholtz, a great physicist of the past century, appreciated that you can never separate the observer from the observed, and became a founder of experimental psychology. The distinction between psychology and physics is one of emphasis. The time has come for experimental psychologists to return the favor and remind physicists that they should be wary of confusing the physical world with their neurologically generated model of it. The frontiers of physics may be an exciting playground for the adventurous cognitive scientist. Ultimately, physics is a study of the behavior of physicists, scientists trying as best they can to understand the physical world. The intellectual prostheses of mathematics, computers, and instrumentation loosen but do not free our species of the constraints of its neurological heritage. We do not build random devices to detect stimuli that we cannot conceive, but build outward from a base of knowledge. A neglected triumph of science is how far we have come with so flawed an instrument as the human brain and its sensoria.

Try this question on any man: All you'll get for an answer is a shrugging of shoulders along with a puzzled facial expression. The one thing neither rocket scientists nor astrophysicists will ever be able to comprehend is how women think and feel. Bill Watterson's eternal six-year old Calvin (from "Calvin & Hobbes"), no smart scholar, but the epitome of the self-assured yet forever puzzled boy, summarizes his incomprehension of the opposite gender: "What is it like to be a girl? Is it like being a bug? I imagine bugs and girls have a dim perception that nature has played a cruel trick on them, but they lack the intelligence to really comprehend the magnitude of it!"

In reality it is, of course, the other way around. Nature has played a cruel trick on men – rather than on women. Men's minds, for the most part, work along a single longitudinal path: A triggers B, B triggers C and so forth. They consider themselves to be smart, because they are barely able to grasp causal chains. Men's intelligence is expressed by the extent to which they can estimate or predict a sequence of steps in a chain reaction. Like chess players, some men can think one or two steps ahead, some seven or eight. Alternatives to their one-dimensional, allegedly "logical" path of thinking are beyond their imagination.

Womens minds, on the other hand, are much more complex. Women embrace several different natures in their personality. In addition to the men's straightforward "logical" way of thinking, they (according to C. G. Jung) incorporate a personification of the unconscious counter-sexual image, in other words the inner man in a woman. This archetype encompasses a number of instincts that are quite useful in supplementing a woman's emotions. In addition, women's minds embrace a third governing force, the so-called "shadow", a counter-image of their true character. The working-type woman, for instance, can identify with the feelings of a spoiled tootsie. A woman who has run expeditions in Ethiopia, Somalia and Afghanistan all her life, can suddenly become flustered at the run of a nylon stocking. What makes women so unfathomable to men is that they can leap in a split second from one level of their personality to the other. As a consequence, that charming lady you are flirting with suddenly turns into a sharp-tongued businesswoman, only to react like a helpless college girl in the next moment. It would be asking too much of a man's mind, being merely a simplified, incomplete version of a woman's mind, to be able to comprehend this kind of complexity in the opposite gender.

Of course, one might argue that men also incorporate an anima and a shadow in their personality. So what? The effect of all three personalities is still the same: A unilateral drive towards ambition, competition and ultimately triumph. Let's face it: We men are pathetically simple minded. How simple minded? Swiss author Melina Moser knows the answer. She lists the only three things men need to be happy: Admiration, oral sex and freshly pressed orange juice.

"What will happen when the increasing speed of communication, the driving force behind cultural progress since the introduction of husbandry, suddenly becomes irrelevant?"

I am convinced that there is a predominant driving force behind cultural progress and that this driving force is speed of communications. The ancestors of modern humans lived in caves and hunted large mammals on essentially the same cultural level for over two million years. The entire history of civilization is limited only to the past 10,000 years.

In my opinion it began when, at the end of the Ice Age, sea level rose, thereby drowning estuaries and creating innumerable natural harbours. A high sea level invited people to climb aboard boats and cross the sea, thus accelerating the exchange of information between different peoples. Knowledge about new discoveries and achievements spread more rapidly and the advance of culture received its first major boost.

Since then, the acceleration of information exchange has driven cultural progress. The wheel, sailing ships, trains, planes, telephones, fax machines followed suit. Finally, the invention of the Worldwide Web caused one of the biggest hysterias in world economics. Today, we can transfer five thousand copies of the entire Encyclopaedia Britannica from (almost) any place on earth to (almost) any other place on earth in only one second ­ and at the maximum possible speed, the speed of light.

After ten thousand years of cultural progress mankind is now reaching the point at which any amount of information can be transferred to any place at the speed of light. The increasing speed of communication, the driving force behind cultural progress since the introduction of husbandry, suddenly becomes irrelevant.

What will happen to progress as this threshold is crossed?

This question is based on what I call, tongue in cheek, "Shermer's Last Law," that any sufficiently advanced extra-terrestrial intelligence is indistinguishable from God.

As scientist extraordinaire (most profoundly as inventor of the communications satellite) and author of an empire of science fiction books and films (most notably 2001: A Space Odyssey), Arthur C. Clarke is one of the most far-seeing visionaries of our time. Thus, his pithy quotations tug harder on our collective psyches for their inferred insights into humanity and our place in the cosmos. And none do so more than his famous three laws:

Clarke's First Law: "When a distinguished but elderly scientist states that something is possible he is almost certainly right. When he states that something is impossible, he is very probably wrong."

Clarke's Second Law: "The only way of discovering the limits of the possible is to venture a little way past them into the impossible."

Clarke's Third Law: "Any sufficiently advanced technology is indistinguishable from magic."

This last observation stimulated me to think more on the relationship of science and religion, particularly the impact the discovery of an Extra-Terrestrial Intelligence (ETI) would have on both traditions. To that end I would like to immodestly propose Shermer's Last Law (I don't believe in naming laws after oneself, so as the good book warns, the last shall be first and the first shall be last): "Any sufficiently advanced ETI is indistinguishable from God".

God is typically described by Western religions as omniscient and omnipotent. Since we are far from the mark on these traits, how could we possibly distinguish a God who has them absolutely, from an ETI who has them in relatively (to us) copious amounts? Thus, we would be unable to distinguish between absolute and relative omniscience and omnipotence. But if God were only relatively more knowing and powerful than us, then by definition it "would" be an ETI! Consider two observations and one deduction:

1. Biological evolution operates at a snail's pace compared to technological evolution (the former is Darwinian and requires generations of differential reproductive success, the latter is Lamarckian and can be implemented within a single generation). 2. The cosmos is very big and space is very empty ("Voyager I", our most distant spacecraft hurtling along at over 38,000 mph, will not reach the distance of even our sun's nearest neighbor, the Alpha Centauri system that it is "not" even headed toward, for over 75,000 years). Ergo, the probability of an ETI who is only slightly more advanced than us and also makes contact is virtually nil. If we ever do find ETI it will be as if a million-year-old "Homo erectus" were dropped into the middle of Manhattan, given a computer and cell phone and instructed to communicate with us. ETI would be to us as we would be to this early hominid — godlike.

Science and technology have changed our world more in the past century than it changed in the previous hundred centuries. It took 10,000 years to get from the cart to the airplane, but only 66 years to get from powered flight to a lunar landing. Moore's Law of computer power doubling every eighteen months continues unabated and is now down to about a year. Ray Kurzweil, in The Age of Spiritual Machines, calculates that there have been thirty-two doublings since World War II, and that the Singularity point may be upon us as early as 2030. The Singularity (as in the center of a black hole where matter is so dense that its gravity is infinite) is the point at which total computational power will rise to levels that are so far beyond anything that we can imagine that they will appear near infinite and thus, relatively speaking, be indistinguishable from omniscience (note the suffix!).

When this happens the world will change more in a decade than it did in the previous thousand decades. Extrapolate that out a hundred thousand years, or a million years (an eye blink on an evolutionary time scale and thus a realistic estimate of how far advanced ETI will be, unless we happen to be the first space-faring species, which is unlikely), and we get a gut-wrenching, mind-warping feel for just how godlike these creatures would seem.

In Clarke's 1953 novel Childhood's End, humanity reaches something like a Singularity (with help from ETIs) and must make the transition to a higher state of consciousness in order to grow out of childhood. One character early in the novel opines that "Science can destroy religion by ignoring it as well as by disproving its tenets. No one ever demonstrated, so far as I am aware, the nonexistence of Zeus or Thor, but they have few followers now."

Although science has not even remotely destroyed religion, Shermer's Last Law predicts that the relationship between the two will be profoundly effected by contact with ETI. To find out how we must follow Clarke's Second Law, venturing courageously past the limits of the possible and into the unknown. Ad astra!

Plato believed that human knowledge was inborn. Kant and Peirce agreed that much of knowledge had to exist prior to birth or it would be impossible to understand or learn anything. Until quite lately, psychologists were almost uniformly opposed to this notion, insisting that only process not content could be part of our native equipment. Piaget was typical (and highly influential) in asserting that only learning skills and inferential procedures such as deductive rules and schemes for induction and causal analysis were native. He also maintained that these were identical for all people with undamaged minds, and that development of such processes ended with adolescence. Content could be almost infinitely variable because these processes operate on different inputs for different people in different situations and cultures.

But recent work by psychologists provides evidence that some content is universal and native. Theories of mechanics are present by the age of three months and highly elaborated theories of mind and make their appearance before the age of four, are universal, and may also be native. Some anthropologists maintain that schemes for understanding the biological world and even some for understanding the social world are universal and native, as are some knowledge structures for representing the spirit world.

Psychologists ­ and philosophers in this case as well ­ may turn out to be wrong in assuming that all mental processes are universal, native and unalterable. Though early in the 20th century there were claims by Soviet psychologists Vygotsky and Luria that cognitive processes were historically rooted, differentiated by culture, and alterable by education, they were largely ignored. But findings have cropped up from time to time that fit these assertions. Deductive rules may be a trick learned in the process of Western-style education; rational choice procedures may be applied primarily by economists and only in very limited domains by lay people; statistical rules (Piaget's "probability schema") may be used only to a very slight extent by non-Western peoples.

Authors of this year's questions have asked how radical the differences among universes, mathematical systems, and kinds of life might be. How radical could the differences among humans be in basic knowledge structures and inferential procedures? What has to be shared or even inborn? What can be allowed to vary?

There are, it seems to me, just two fundamental scientific questions that, for very different reasons, we may have no possibility of answering with any certainty.

One question is so fundamental that it is arguably not a scientific question at all: It's the big how and why question of existence itself. Although there are many technical questions still to be answered, as a mathematician, I find myself broadly content with science's explanation of how the physical universe — including time itself — sprang into being: the symmetry breaking, primordial fireball we call the Big Bang, followed by the subsequent evolution into the universe we see today. But that is simply an explanation of the mechanics of the universe of our experience and perception. It leaves us with a lingering question of how, and perhaps why, the framework arose in which the Big Bang took place in the first place — be that framework one in which our universe is the only one there is and has ever been, or one that cycles in "universe time" (whatever that is), or maybe some kind of multiple universe scenario.

I accept that this is not really a scientific question. Science only addresses the how of our own universe, starting just after the Big Bang. But my curiosity, both as a scientist and more generally just as a thinking person, cannot help but dwell from time to time on the biggest question of all — the question that for those having a deep religious faith seems to find an answer in the phrase "God made it that way." (An answer that I find even more incomprehensible in a world where millions of human beings believe that that same God authorizes his chosen emissaries to fly jet airliners full of humans into buildings full of other humans.)

My second fundamental question is clearly a genuine scientific matter. In fact, it is a technical question about evolution by natural selection. Exactly how and why did a species (namely, us) develop that has the capacity to think abstractly, that possesses language, and that can reflect on its own existence? Like the big existence issue, this is a question that has enormous significance for us, as humans. And that makes it the more frustrating that we may find ourselves unable ever to answer it with any certainty.

In my recent book The Math Gene, I summarized arguments to show that the possession of language (i.e., a symbolic communication system with a recursive grammatical structure allowing for the production and comprehension of meaningful utterances of unlimited length) and the ability for "offline" thinking (reasoning about the world in the absence of direct input from the environment and without the automatic generation of a physical response) are two sides of the same coin. Implicit in that argument is that this ability also brings with it the capacity for self-reflective, conscious thought. (I also argued that such a mental capacity also yields the potential for mathematical thought.) Thus, we are talking here about the capacity that makes us human, and in so doing makes us very different from any other species on Earth.

The best evidence we have from anthropology is that our ancestors acquired this capacity some time between 75,000 and 200,000 years ago. (The evidence is in the form of manufactured artifacts that early humans left behind, which indicate such a level of abstract thinking and communication.) But how — and in terms of natural selection, why — did our ancestors acquire this capacity? All we know for sure is that it came at the end of a three-and-a-half-million year period in which the average brain size of our ancestors grew to roughly its present level, approximately nine times larger than is normal for a mammal of our body size and about twice that of a present-day ape.

What makes this question particularly hard is that, at least in terms of functionality (as opposed to brain structure), the acquisition of syntactic structure (i.e., the structure that enables us to create complex sentences or to reason abstractly about the world) is an all-or-nothing event. As linguists have pointed out, you cannot have "half a grammar". True, in theory you can have grammars without, say, passive constructions, but there is no chain of gradually more complex grammars that starts with protolanguage — simple subject-predication utterances — and leads continuously to the grammatical structure that is common to all human languages. The chain has to start with a sudden jump. Although the acquisition of language was a major functional change in brain capacity, there is no reason why that jump was not the result of a tiny structural change in the brain. But what propelled the brain to reach a stage where such a change could occur? And what exactly was that small structural change? This would surely be a minor technical question about one detail, among thousands, of evolutionary history, were it not for the fact that it was this single change that made us human — that made it possible for us to ask these how and why questions, and to care about the answers.

One oft-repeated suggestion for the natural selection advantage that language provides is that it enabled the communication of more complex thoughts and ideas than was previously possible. But that suggestion falls down immediately when you realize that such communication can only arise when the brain that is doing the communicating is able to form those complex thoughts and ideas in the first place, and that capacity itself requires a brain having grammatical structure.

It seems likely that the two sides of this particular coin, thinking complex thoughts and communicating them, arose at the same time, and indeed it could have taken both aspects together to spur the development that led to their acquisition. But we are still left with the tantalizing question that the obvious natural selection advantages this capacity provides only came into play after the capacity was in place. Just what led to and prompted that jump remains a mystery.

There has been, as you might imagine, no shortage of attempts to provide an explanation, but so far I haven't seen one that I find convincing, or even close to convincing. (I mention some in The Math Gene, and give pointers to further reading on the matter.) And even if someone produces a compelling explanation, it seems we will never know for sure. When our early ancestors died, their brains rapidly rotted away, leaving nothing but the skulls that contained them. And even if, by some fluke, we found an intact brain from some early ancestor, buried deep in the ice of a glacier somewhere, how could that help us? Dissecting an object as complex as the human brain tells us virtually nothing about what that brain did — how it thought and what it thought about.

Our higher brain functions could just have been an accident. Of course, all evolutionary changes are accidents. What I mean here is that it may be purely accidental that the structural change in the brain that gave us language and abstract, symbolic thought did in fact have that effect. It might just be, as some have suggested, that the brain grew in complexity as a device for cooling the blood, and that language and symbolic thought are mere accidental by-products of the body's need to maintain a certain temperature range. (Certainly, the brain is an extremely efficient cooling device, as illustrated by the fact that putting on a hat is an extremely efficient way of staying warm when we go skiing.) Personally, I don't buy the cooling mechanism explanation. But unless and until someone comes up with something more convincing, I see no way we can rule it out.

For all our huge success in telling the story of how life began and evolved to its present myriad of forms, it seems likely that we may never know for certain exactly what it was that gave us the one thing we value above all else, and the thing that makes us human: our minds. If there is one question I would like to answer above all others, it is this one.

Precollegiate education has been remarkably consistent over the decades: literacy in the primary years, initial mastery of a few major subject areas (math, science, history, language, perhaps in the arts) in middle and secondary school. We could take the position that we know how to do this and should just stick to our guns. I don't agree.

Because of globalization, the capacity to think across disciplines, to synthesize wide ranges of information efficiently and accurately, to deal with individuals and institutions with which one has no personal familiarity, to adjust to the continuing biological and technological revolutions, are at a far greater premium. And because of the events of September 11, we need to think much more deeply about the nature of democratic institutions and the threats to them, the role and limits of tolerance and civil liberties, the fate of scarce resources, profound gaps across religions and cultures, just to name a few.

The time has come where we need to rethink what we teach, how we teach, what young people learn on their own, how they interact, how they relate to mass culture, etc. The question we must then ask is: Do we have to continue to be reactive or can we plan proactively the education that is needed for our progeny in this new world?

The world is caught up in a paroxysm of change. Key words: globalism, multinational corporations, ethical influences in business, explosive growth of science-based technology, fundamentalism, religion and science, junk science, alternative medicines, rich vs. poor gap, who supports research, where is it done, how is it used, advances in cognition science, global warming, the disconnect between high school and college....these and other influences are undergoing drastic changes and all will have some impact on science, mathematics and technology and therefore on how our schools must change to produce graduates who can function in the 21st century...function and assume positions of leadership. Is it conceivable that the standard curriculum in science and math, crafted in 1893, will still be maintained in the 26,000 high schools of this great nation?

This is a question that obsesses me in my daily activities. I have been agonizing over it along with a few colleagues around Fermilab, University of California, and the students, staff and trustees of the Illinois Math Science Academy (IMSI), a three year public residential high school for gifted students, I was involved in founding some 16 years ago.

It differs in countless ways, most of them poorly understood. It generally deals with individuals rather than analyses or averages, with motives and reasons rather than movements and causes. It has a point of view rather than a "view" from nowhere. As the writer's maxim says, it shows rather than tells, contains dialogue rather than only declarative sentences, relies on context rather than raw data alone, is open-ended and metaphorical rather than determinate and literal, is tied to a particular time rather than being timeless, and deals with emotions rather than impersonal facts. Furthermore, narrative logic must deal with the notion of "common knowledge," whereby two or more people know something, know that the others know it, know that the others know that others know, and so on. In short, narrative logic is much harder than mathematical logic.

In everyday "story logic," how "we," the story-tellers, characterize an event or person is crucial. If a man touches his hand to his eyebrow, for example, we may see this as an indication he has a headache. We may also see the gesture as a signal from a baseball coach to the batter. Then again, we may infer that the man is trying to hide his anxiety by appearing nonchalant, that it is simply a habit of his, that he is worried about getting dust in his eye, or indefinitely many other things depending on indefinitely many perspectives we might have and on the indefinitely many human contexts in which we might find ourselves. A similar open-endedness characterizes the use of probability and statistics in surveys and studies.

Furthermore, unlike mathematical logic, story logic does not allow for substitutions. In mathematical contexts, for example, the number 3 can always be substituted for the square root of 9 or the largest whole number smaller than the constant without affecting the truth of the statement in which it appears. By contrast, although Lois Lane knows that Superman can fly, and even though Superman equals Clark Kent, the substitution of one for the other can't be made. Oedipus is attracted to the woman Jocasta, not to the extensionally equivalent person who is his mother. In the impersonal realm of mathematics, one's ignorance or one's attitude toward some entity does not affect the validity of a proof involving it or the allowability of substituting equals for equals.

Recent events around the world remind us of historical phenomena observed since the dawn of civilizations: wars, genocides, oppression, conquests, occupations, and, of course, killings in the name of some God. Although the underlying principles are the same, modern killings are more sophisticated, spectacular, and effective than those in the past. In a matter of hours, you can now hijack a plane and crush it against an office building killing thousands, or you can (as it was done more than 50 years ago) drop an atomic bomb over a city killing hundreds of thousands of civilians. You can see all that on TV.

Studying non-human animals, contemporary biology, evolutionary theory, and modern ethology have gathered enough knowledge to respond to questions regarding the nature of aggression, social power, alliance formation, hierarchical domination, and attack-defense behavior. Psychology, anthropology and cognitive science have added important pieces extending this knowledge into human animals. From these studies contemporary science has got some deep understanding about what peace is about. In a nutshell, the moral is that there is no absolute, ideal or ultimate peace in the animal kingdom. Peace turns out to be a fragile local phenomenon that depends on circumstances, population density, biological needs, availability of resources, and so on. If you value peace, the best you can do is to provide conditions for peace, not to "install" peace itself.

So, if we have good scientific knowledge about the nature of peace, how come we don't have peace on earth? Well, because we don't want to accept that we are animals. We prefer to continue believing that we are the protégées of our own created Gods, and that we are, in a transcendental sense, different from a chimpanzee. Peace for humans is taken to be something profound, spiritual and pure, not a bio-social emerging phenomenon. Our created Gods provide the moral values that define what the absolute and ultimate peace is supposed to be, and who is supposed to impose it. There is no surprise then if we see intransigent world and religious leaders calling for holy wars, fighting the Evil in the name of the Good, and justifying in the name of peace, the bombing of civilians, the construction of missile shields, or the occupation of foreign territories.

If we really value peace (but I am not sure this is what some world powers really want!), what we need is to provide sustainable conditions for peace. And for this, it would be much easier to know how to do it, if we assume once for all, that we are indeed animals.

We know that genes play an important role in the shaping of our personality and intellects. Identical twins separated at birth (who share all their genes but not their environments) and tested as adults are strikingly similar-though far from identical-in their intellects and personalities. Identical twins reared together (who share all their genes and most of their environments) are much more similar than fraternal twins reared together (who share half their genes and most of their environments). Biological siblings (who share half their genes and most of their environments) are much more similar than adopted siblings (who share none of their genes and most of their environments).

Many people are so locked into the theory that the mind is a Blank Slate that when they hear these findings they say, "So you're saying it's all in the genes!" If genes have any effect at all, it must be total. But the data show that genes account for about only about half of the variance in personality and intelligence (25% to 75%, depending on how things are measured). That leaves around half the variance to be explained by something that is not genetic.

The next reaction is, "That means the other half of the variation must come from how we were brought up by our parents." Wrong again. Consider these findings. Identical twins separated at birth are not only similar; they are "no less" similar than identical twins reared together. The same is true of non-twin siblings — they are no more similar when reared together than when reared apart. Identical twins reared together — who share all their genes and most of their family environments-are only about 50% similar, not 100%. And adopted siblings are no more similar than two people plucked off the street at random. All this means that growing up in the same home — with the same parents, books, TVs, guns, and so on — does not make children similar.

So the variation in personality and intelligence breaks down roughly as follows: genes 50%, families 0%, something else 50%. As with Bob Dylan's Mister Jones, something is happening here but we don't know what it is.

Perhaps it is chance. While in the womb, the growth cone of an axon zigged rather than zagged, and the brain gels into a slightly different configuration. If so, it would have many implications that have not figured into our scientific or everyday way of thinking. One can imagine a developmental process in which millions of small chance events cancel one another out, leaving no difference in the end product. One can imagine a different process in which a chance event could derail development entirely, making a freak or monster. Neither of these happens. The development of organisms must use complex feedback loops rather than blueprints. Random events can divert the trajectory of growth, but the trajectories are confined within an envelope of functioning designs for the species defined by natural selection.

Also, what we are accustomed to thinking of as "the environment" — namely the proportion of variance that is not genetic — may have nothing to do with the environment. If the nongenetic variance is a product of chance events in brain assembly, yet another chunk of our personalities and intellects would be "biologically determined" (though not genetic) and beyond the scope of the best laid plans of parents and society.

Many human skills enable an individual to do something with less physiological effort. If you are good at skiing (and I am not) it takes less energy to climb that mountain. One can even argue forcefully that a mental "understanding" of a phenomenon allows one to perceive it with less increase in brain metabolism.
But not all skills are directed at a reduction of the expenditure. Many creative activities involve a huge effort to explore new issues or phenomena. The better skier goes beyond the first mountain. New worlds and ideas are explored. Why do we bother — or why do some of us bother?

One could argue that we explore new phenomena to produce skilful insights that will in the future allow us to visit the same phenomena again with less effort. But is that really enough? Can such a functional explanation of creativity as an initial effort devoted to enable a future reduction of the effort really capture the reasons for people to involve themselves in lifelong efforts to understand the world of ants or the intricacy of ski dope?

It seems that president John F. Kennedy captured an essential element in creative efforts when he, in his famous speech at Rice University in 1962, argued for the decision to create the Apollo program: "We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills..."

Indeed, the most important outcome of Apollo — offering earthlings an outside view of their planet, visualizing the vulnerability of the Earth and its biosphere — was an unintended result of doing a major effort. It did pay off to do something hard. Somehow we know that doing something hard, rather than something easy, is fruitful. But we also know that doing it the hardest way possible (like when I ski) is not a very efficient way of getting anywhere.

We want to be efficient, but also to do difficult things. Why? In a sense this is a rephrasing of Brian Eno's question in Edge 11: "Why Culture"? Many different approaches can be taken involving different disciplines such as economy, anthropology, psychology, evolutionary biology etc.

An idea currently explored in both economy and evolutionary biology could be relevant: Costly signals. They provide the answer to the question: How does one advertise one's own hidden qualities (in the genes or in the bank) in a trustworthy way? By giving a signal that is very costly to produce. One has to have a strong bank account, a very good physiology (and hence good genes) or a strong national R&D programme to do costly things. The more difficult, the better the advertising.

Perhaps we bother because we want to show that we are strong and worthy of mating? Culture is all about doing something that is so difficult that only a healthy individual or society could do it.

If so, it's not at all about reducing the effort, it's all about expanding the effort.

For the past four centuries, the attempt to answer this question has been the main driving force of world history ­ not only the history of ideas, but also the history of politics and collective violence. This is true for two reasons:

1. It is impossible for people to live without constructing some cognitive structure (which philosophers call practical reason) that asks and answers questions concerning how to live and what to do ­ traditionally, by formulating them in moral or ethical terms as how we should live and what we ought to do.

2. When humanity made the transition, at the time of the scientific revolution of the 17th century, to a new and higher stage of its collective cognitive development by progressing from theology and philosophy to science, it became more and more difficult for people to see how it could be possible to answer the old pre scientific theological and philosophical questions, "what is good and what is evil?" Those questions came to be seen as unanswerable and hence meaningless because what the scientific revolution showed, above all, was that what we call "knowledge" (scientia) is possible when, and only when, it can be framed in the form of hypotheses that can be confirmed or disconfirmed by means of experience, i.e., empirical data and observations.

That entailed, for example, the conclusion that metaphysical knowledge (knowledge of Absolute Reality, or God, as It, He or She exists independently of our perceptual and conceptual apparatus) is unattainable. (Nietzsche called this the "death of God.") But that was not an insuperable problem, because metaphysics was immediately replaced by physics, which had far greater cognitive power to predict, explain and control the phenomena being cognized anyway.

What has been an insuperable problem, up to now, has been the unavailability of any cognitively adequate replacement for ethics. Moral knowledge is unattainable because there is, in principle and by definition, no conceivable moral hypothesis that could possibly be proved or disproved by means of any conceivable type of empirical data, test or experiment. That is true, among other reasons, because moral statements do not take the form of empirically testable hypotheses, or hypothetical imperatives ("If you want X, then you can get it by doing Y" -­ but with no guidance as to whether you should want X in the first place). Moral statements take the form of value judgments and categorical imperatives (i.e., commandments or orders as to what you should do or want). Commandments can never be true or false, so they cannot communicate knowledge. And value judgments are incapable of communicating knowledge about the external world; the only thing they can express are subjective wishes, tastes and preferences which are, from a logical and epistemological point of view, completely non-rational and arbitrary, matters of whim, about which we can only say De gustibus non disputandum est.

Of course, it has always been known that beauty exists in the eye of the beholder. What had not been seen so clearly, until the scientific revolution, was that the same was true of good and evil. The first modern personality, Hamlet, expressed this clearly in 1601 when he said "There is nothing either good or bad but thinking makes it so." I.e., good and evil are words for subjective preferences, sentiments of approval or disapproval, that exist only in the mind of the beholder. They do not exist as objective realities whose validity can be known or tested, proved or disproved. And Hamlet's fate shows how confused, paralyzed, violent and self-destructive people can become when they have recognized that it is impossible to know what one "should" do, but have not yet discovered how to replace that question with one that is answerable.

Thus, it is not only God (and the Devil) that are dead; more importantly, so are Good and Evil, the abstract philosophical concepts of which the former are the concrete mythological and theological incarnations. As Ivan Karamazov put it (speaking for those for whom God is the only credible and legitimate source of moral authority), "without God anything is possible, everything is permitted." But even those who, following Kant or Rawls, would like to place their faith in pure (a priori) reason, and would trust it to take the place of God as the source of moral knowledge, are doomed to disappointment and ignorance; for even Kant made it clear that moral knowledge was unattainable. As he put it, "I must destroy knowledge in order to make room for faith (Glaube, also translatable as "belief")." That is, even the most dedicated champion of pure (a priori) practical reason as the source of moral knowledge had to admit that moral knowledge is unattainable; all he could put in its place was faith. And by the time he wrote those words, the Age of Faith had long since been dead and buried. Indeed, the whole history of modern science was one long demonstration that knowledge was attainable when, and only when, one replaced faith with its opposite, the attitude of universal doubt, and refused to believe any proposition that had not been tested against empirical evidence.

One inescapable consequence that followed from all this was the loss of credibility of the traditional sources of moral authority (God and pure reason). Why did that create such a crisis that most of human history since the 17th century has been a series of attempts to come to terms with it, both in theory and in practice? Because human nature abhors a cognitive vacuum, especially in the sphere of practical reason. For without some way of answering the questions that practical reason asks, concerning how to live and what to do, humans are totally disoriented and without direction, a condition that is intolerable and panic-inducing. Once they have discovered the cognitive inadequacies of the moral way of formulating those questions and answers, as they have to an increasing extent since the scientific revolution of the 17th century, and have not yet discovered how to progress to a more cognitively adequate form of practical reason, many people will regress to a more intellectually primitive and politically reactionary set of questions and answers. In the 20th century these took the form of political totalitarianism, which led to genocide; more recently, they have taken the form of religious fundamentalism, which has increasingly led to apocalyptic terrorism. Given the existence of weapons of mass destruction, it hardly needs to be stressed how much both of these ideologies potentially threaten the survival of our species.

These political/ideological movements have been widely, and correctly, interpreted as rebellions or reactions against modernity (whether modernity is conceived of as Western civilization, Jewish science, modern technology, religious unbelief, freedom to express any opinion, or whatever), though usually without specifying what it is about modernity that threatens our very existence and survival. The deepest threat, I would maintain, is cognitive chaos in the realm of practical reason, and thus nihilism in the realm of morality, anomie in the realm of law, and anarchy in the realm of politics. The paradox is that the political movements that have been most widely interpreted as nihilistic and "evil" ­- Nazi, Stalinist and theocratic totalitarianism and their sequelae, genocide and terrorism ­ in fact originated as desperate (and misguided) attempts to ward off nihilism and what their adherents consider "evil." To them, the greatest evil is modernity, on in other words, the modern scientific mentality, which replaces certainty with doubt, dogmatism with skepticism, authority with evidence, faith with agnosticism, coercion with persuasion, violence with words and ideas, and hierarchy with democracy and equality of opportunity ­ all of which fills them with overwhelming dread and terror, amounting to a kind of existential or moral panic.

In fact, to the totalitarian/fundamentalist mind, modernity not only represents absolute evil; it represents something even worse than that, namely, the total absence and delegitimation of any standards of good and evil whatsoever ­ the total death of good and evil, a state of complete anomie and nihilism. For without knowing what is good and evil, how can one know what to do? And without knowing what to do, how can one live (not only biologically, but even mentally)? How can one maintain any mental, emotional, social, cultural or political coherence and order? As Kenneth Tynan remarked, "Hell is not the place of evil; rather, Hell is the absence of any standards at all." That condition is so intolerable to humans that many will regress to even the most irrational and destructive ideology if they cannot find some more epistemologically powerful cognitive structure with which to replace the old moral way of thinking, once its cognitive inadequacy has been so deeply perceived that its credibility has been irreversibly destroyed.

Cognitive growth occurs by finding better and better answers to existing questions. Cognitive development occurs only when one begins to ask a new and different set of questions. We do this only when we notice that our current questions are meaningless because they are unanswerable, so that they need to be replaced with a different set of questions that can be answered. By this point, in the 21st century, we now realize that it is impossible to answer the moral (and legal and political) questions, "How should we live and what ought we to do?" The only questions that are meaningful, in that they can lead to answers that possess cognitive content or knowledge, are the questions "How can we live? i.e., what biological, psychological and social forces, processes and behavior patterns promote, protect and preserve life, and which ones cause death?" For that question can be answered, by means of empirical investigation as to the causes and prevention of the extinction of species (including our own, as by nuclear holocaust or unrestrained devastation of our natural environment), the extermination of social groups (through epidemics of collective violence, such as war, genocide, poverty, famine, etc.), and the deaths of individuals (by means of homicide, suicide, obesity, alcoholism, etc.). In other words, the only possible replacement for ethics or morality that is progressive rather than regressive is the human sciences ­ human biology, psychology and psychiatry, and the social sciences.

Unfortunately, the modern human sciences, unlike the natural sciences, had not yet been invented when the scientific revolution of the 17th century first showed that moral knowledge was unattainable. And even today, the ability of the human sciences to predict, explain and control the objects of their scrutiny (human behavior) is extremely limited, whether compared with that which the natural sciences possess with respect to their objects of study, or with the degree of cognitive power that the human sciences will need to attain if we are to gain the ability to avert the headlong rush to species-wide self-destruction that we currently seem to be embarked upon. In other words, to paraphrase Winston Churchill's remark about democracy, the human sciences are the worst (the least cognitively adequate) of all possible forms of practical reason ­ except for all the others (such as moralism, fundamentalism and totalitarianism)! What that implies is that nothing is more important for the continued survival of the human species than a stupendously increased effort to make progress in the further development of the human sciences, so as to increase our understanding of the causes of the whole range of our own behaviors, from life-threatening (violent) to life-enhancing.

Here is a paradox for cognitive neuroscientists: We're trying to understand the brain with the very mental resources that are afforded by our brains. We hope that the brain is simple enough that we can understand it; but it needs to be complex enough for us to be able to understand it.

This is not completely unrelated to Gödel's theorem, which states -roughly- that in any sufficient complex formal system, there exists truths that are inaccessible to formal demonstration. Strictly speaking, Gödel's theorem does not apply to the brain because the brain is not a formal system of rules and symbols. Still, however, it is a fact that the tightly constrained structure of our nervous system constrains the thoughts that we are able to conceive. Our mathematics, for instance, is founded on a small set of basic objects: a number sense, an intuition of space, a simple symbol-manipulation system... Will this small set of representations, crafted by evolution for a very different purpose, suffice to understand ourselves?

I see at least two reasons for hope. First, we seem to have a remarkable capacity for constructing new mental representations through culture. Through metaphor, we are able to connect old representations together in new ways, thus building new mathematical objects that extend our brain's representational power (e.g. Cartesian coordinates, a blend between number and space concepts). Second, and conversely, Nature's bag of tricks doesn't seem so huge. Indeed, this is perhaps the biggest unanswered question: how is it that with a few simple mathematical objects, we are able to understand the outside physical world in such detail? The mystery of this "unreasonable efficacy of mathematics", as Wigner put it, suggests a remarkable adaptation of our brain to the structure of the physical world. Will this adaptation suffice for the brain to understand itself?

Women of a previous generation said that their own mothers had missed out on the fruits of feminism. Like many women in my cohort, I discovered that my mother was born too early for postfeminism.

Of course, postfeminism makes sense only when basic legal and civil rights exist for both sexes — it's an irrelevant luxury for too many women on this planet. Letitia Baldrige, the dean of American manners (among other things), recently defined her own position as that of a "conservative feminist." It makes sense, for the restless privileged daughters of Western feminism, to become moderate postfeminists — not centrists, exactly, but realists.

Feminism is a seductive, useful and powerful ideology, provoking reaction and rebellion whenever it becomes an established player. When will postfeminism be a viable option the world over? Will it ever be possible? And, in those cultures where postfeminism plays an important role in women's lives, what's the next step? Is postfeminism a toy or a tool?

It is a bit embarrassing to admit a preoccupation with this gigantic old question, but it is human, I suppose. Tackling it straight on seems to be an exercise in hubris, but if you stick to science, you soon realize that we are still struggling to figure out what the question is. It helps, I think, to distinguish four separate questions.

The first question is why capacities for suffering exist at all. Why do organisms care if they are injured? Why do they try so hard to avoid dying? Why do they fight just to have sex? Why do we experience a certain kind of pain just from being ignored? Such motives, behaviors, and experiences are made possible by brain mechanisms shaped by natural selection. While many individual experiences of suffering arise because something has gone wrong, either in person's life or brain, the capacities for suffering and pleasure exist because they are useful, at least for the genes that make them possible. This is terribly sobering. Many people still confuse the question of why capacities for suffering exist, with the very different question of what causes suffering in individual instances. I have called this the "clinician's fallacy" because doctors and therapists so often treat defenses as if they were diseases. Eventually the distinction will become clear.

The second question is why we so often continue to do things that make us miserable. Why do we pursue goals we can't reach given that this causes so much unhappiness? Why we can't take Buddha's advice and transcend our desires? The answer is that people who have given up difficult goals have had fewer children. These goals are not just wealth, power and sex. Trying without success to protect and help one's children causes intense suffering and everyone recognizes why we can't give up this goal. The evolutionary origins of our motives do not make us helpless puppets but they can help us to understand why controlling our desires is difficult.

The third question is why we treat others the way we do. It is silly to say that people are innately generous or selfish, but the fact of poverty is universal. I spent this week on call where the truth hits you in the face; for all the riches of our society, millions of people have no job, no money, few friends and not even a warm place to sleep. Politicians enact policies that make it even easier for the rich to keep their riches. This is nothing new, but neither is it unalterable. Any improvement, however, needs to start from the realities of human nature.

The fourth question is very different. The other three ask why people are mostly the same, but this one instead asks why people are different. The explanations for differences in suffering include differences in genes, experiences, personalities, and social settings. Most of our efforts to understand suffering have been here. This research provides genuine knowledge, but only part of a complete answer.

Big problems often motivate proposals for grand quick solutions that give rise to horrendous unanticipated consequences. A gradual deepening of our evolutionary understanding of ourselves offers more modest but surer hope. Many misgivings about evolutionary approaches to human behavior come from a simple misconception. Natural selection explains how the competitive struggles of life shaped us, but this does not mean that life is only a struggle nor does not mean that life cannot be made better. Quite the contrary. If we want to prevent social catastrophes and gradually improve our world, we had better start with a real understanding of why we are the way we are. Negative psychology tells us why some people are unhappy and how bad this is for them. In another corner, positive psychology tells us why some people are happier than others and how good this is for them. What we need now is "diagonal psychology" that investigates the costs of experiencing positive emotions when they are not warranted, and the benefits of capacities for suffering. This will offer a real foundation for understanding why the world is so full of suffering.

To my mind, by far the most important question concerns the way in which our currently non-sustainable course gets resolved in the next several decades. Our present course with regards to many of our demands on the environment cannot be sustained for more than several decades. Those demands include atmospheric change, deforestation, fresh water use, global warming, overfishing, production of toxic materials, utilization of available photosynthetic capacity, and utilization of topsoil. Hence the interesting question is whether these non-sustainable developments become halted in pleasant ways of our choice, or in unpleasant ways not of our choice.