"I recommend Nonzero to any and all readers as a marvelous summary and interpretation of what is now known and surmised about biological and human history on our planet. For an author so well informed scientifically, perhaps the book's most unusual feature is the fact that Wright does not flinch from closing with a chatty, informal yet incisive argument about cosmic meaning and purpose behind the story he unfolds. . . . I greatly admire the book. [Wright] knows so much and has thought so clearly; and allows his imagination to range so freely!"--William H. McNeill, professor emeritus of history, University of Chicago, and author of The Rise of the West

"This is the book to read to start off the millennium. Leaping from mountaintop to mountaintop, this integrative and inspiring volume is brimming with hope for a positive human future. Religions are made of such stuff."--Martin Seligman, professor of psychology, University of Pennsylvania, and author of Learned Optimism

"Wright's chapters on the evolution of biological complexity and intelligence--in addition to being beautifully written and scientifically sound--are a welcome corrective to current trendy views that understate natural selection's creative power. There is, indeed, as Darwin said, a grandeur in this view of life."--James Gould, professor of biology, Princeton University, and author of Biological Science

"A fiercely intelligent, beautifully written, and engrossingly original book. Wright writes with a consistent, irreverent wit that does not hide a heartfelt seriousness of purpose."--New York Times Book Review

A great many internal and external portents (political and social upheaval, moral and religious unease) have caused us all to feel, more or less confusedly, that something tremendous is at present taking place in the world. But what is it?

The Nobel laureate Steven Weinberg once ended a book on this note: "The more the universe seems comprehensible, the more it also seems pointless." Far be it from me to argue with a great physicist about how depressing physics is. For all I know, Weinberg's realm of expertise, the realm of inanimate matter, really does offer no evidence of overarching purpose. But when we move into the realm of animate matter -- bacteria, cellular slime molds, and, most notably, human beings -- the situation strikes me as different. The more closely we examine the drift of biological evolution and, especially, the drift of human history, the more there seems to be a point to it all. Because in neither case is "drift" really the right word. Both of these processes have a direction, an arrow. At least, that is the thesis of this book.

People who see a direction in human history, or in biological evolution, or both, have often been dismissed a mystics or flakes. In some ways, it's hard to argue that they deserve better treatment. The philosopher Henri Bergson believed that organic evolution is driven forward by a mysterious "élan vital," a vital force. But why posit something so ethereal when we can explain evolution's workings in the wholly physical term of natural selection? Pierre Teilhard de Chardin, the Jesuit theologian, saw human history moving toward "Point Omega." But how eriously could he expect historians to take him, given that Point Omega is "outside Time and Space"?

On the other hand, you have to give Bergson and Teilhard de Chardin some credit. Both saw that organic evolution has a tendency to create forms of life featuring greater and greater complexity. And Teilhard de Chardin, in particular, stressed a comparable tendency in human history: the evolution, over the millennia, of ever more vast and complex social structures. His extrapolations from this trend were prescient. Writing at the middle of this century, he dwelt on telecommunications, and the globalization it abets, before these subjects were all the rage. (Marshall McLuhan, coiner of "global village," had read Teilhard.) With his concept of the "noosphere," the "thinking envelope of the Earth," Teilhard even anticipated in a vague way the Internet -- more than a decade before the invention of the microchip.

Can the trends rightly noted by Bergson and Teilhard -- basic tendencies in biological evolution and in the technological and social evolution of the human species -- be explained in scientific, physical terms? I think so; that is largely what this book is about. But the concreteness of the explanation needn't, I believe, wholly drain these pattern of the spiritual content that Bergson and Teilhard imputed to them. If directionality is built into life -- if life naturally moves toward a particular end -- then this movement legitimately invites speculation about what did the building. And the invitation is especially strong, I'll argue, in light of the phase of human history that seems to lie immediately ahead -- a social, political, and even moral culmination of sorts.

As readers not drawn to theological questions will be delighted to hear, such speculation constitutes a small portion of this book: a few cosmic thoughts toward the end, necessarily tentative. Mostly this book is about how we got where we are today, and what this tells us about where we're heading next.

On the day James Watson and Francis Crick discovered the structure of DNA, Crick, as Watson later recalled it, walked into their regular lunch place and announced that they had "found the secret of life." With all due respect for DNA, I would like to nominate another candidate for the secret of life. Unlike Francis Crick, I can't claim to have discovered the secret I'm touting. It was discovered -- or, if you prefer, invented -- about half a century ago by the founders of game theory, John von Neumann and Oskar Morgenstern.

They made a basic distinction between "zero-sum" games and "non-zero-sum" games. In zero-sum games, the fortunes of the players are inversely related. In tennis, in chess, in boxing, one contestant's gain is the other's loss. In non-zero-sum games, one player's gain needn't be bad news for the other(s). Indeed, in highly non-zero-sum games the players' interests overlap entirely. In 1970, when the three Apollo 13 astronauts were trying to figure out how to get their stranded spaceship back to earth, they were playing an utterly non-zero-sum game, because the outcome would be either equally good for all of them or equally bad. (It was equally good.)

Back in the real world, things are usually not so clear-cut. A merchant and a customer, two members of a legislature, two childhood friends sometimes -- but not always -- find their interests overlapping. To the extent that their interests do overlap, their relationship is non-zero-sum; the outcome can be win-win or lose-lose, depending on how they play the game. (For elaboration on non-zero-sum logic, and discussion of the classic non-zero-sum game "the prisoner's dilemma," see appendix 1.

Sometimes political scientists or economists break human interaction down into zero-sum and non-zero-sum components. Occasionally, evolutionary biologists do the same in looking at the way various living systems work. My contention is that, if we want to see what drives the direction of both human history and organic evolution, we should apply this perspective more systematically. Interaction among individual genes, or cells, or animals, among interest groups, or nations, or corporations, can be viewed through the lenses of game theory. What follows is a survey of human history, and of organic history, with those lenses in place. My hope is to illuminate a kind of force -- the non-zero-sum dynamic -- that has crucially shaped the unfolding of life on earth so far.

The survey of organic history is brief, and the survey of human history not so brief. Human history, after all, is notoriously messy. But I don't think it's nearly as messy as it's often made out to be. Indeed, even if you start the survey back when the most complex society on earth was a hunter-gatherer village, and follow it up to the present, you can capture history's basic trajectory by reference to a core pattern: New technologies arise that permit or encourage new, richer form of non-zero-sum interaction; then (for intelligible reasons grounded ultimately in human nature) social structures evolve that realize this rich potential -- that convert non-zero-sum situations into positive sums.* Thus does social complexity grow in scope and depth.

[* This and all subsequent asterisks refer to elaborative notes that can be found in the Notes section at the end of the book.]

This isn't to say that non-zero-sum games always have win-win outcomes and never have lose-lose outcomes. (Badly governed societies are littered with losses, and history is littered with the remains of badly governed societies.) Nor is it to say that the powerful and the treacherous never exploit the weak and the naïve; exploitation -- ranging from clear-cut parasitism to subtler inequity -- is often possible in non-zero-sum games, and history offer plenty of examples. Still, on balance, over the long run, non-zero-sum situations produce more positive sums than negative sums, and more mutual benefit than parasitism. As a result, people become embedded in larger and richer webs of interdependence.

This basic sequence -- the conversion of non-zero-sum situations into mostly positive sums -- had started happening at least as early as 15,000 years ago. Then it happened again. And again. And again. Until -- voilà! -- here we are, riding in airplanes, sending e-mail, living in a global village.

I don't mean to minimize the interesting details that populate most history books: Sumerian kings, barbarian hordes, medieval knights, the Protestant Reformation, nascent nationalism, and so on. In fact, I try to give all of these their due (along with such too-often-neglected exemplars of the human experience as native American hunter-gatherers, Polynesian chiefdoms, Islamic commercial innovations, African kingdoms, Aztec justice, and precocious Chinese technology). But I do intend to show how these details, though important in their own right, are ultimately part of a larger story -- to show how they fit into a framework that make thinking about human history easier.

After surveying human history, I will briefly apply to organic history the same organizing principle. Through natural selection, there arise new "technologies" that permit richer forms of non-zero-sum interaction among biological entities: among genes, or cells, or animals, or whatever. And the rest, as they say, is organic history.

In short, both organic and human history involve the playing of evermore-numerous, ever-larger, and ever-more-elaborate non-zero-sum games. It is the accumulation of these games -- game upon game upon game -- that constitutes the growth in biological and social complexity that people like Bergson and Teilhard de Chardin have talked about. I like to refer to this accumulation as an accumulation of "non-zero-sumness." Non-zero-sumness is a kind of potential -- a potential for overall gain, or for overall loss, depending on how the game is played. The concept may sound ethereal in the abstract, but I hope it will feel concrete by the end of this book. Non-zero-sumness, I'll argue, is something whose ongoing growth and ongoing fulfillment define the arrow of the history of life, from the primordial soup to the World Wide Web.

You might even say that non-zero-sumness is a nuts-and-bolts, materialist version of Bergson's immaterial élan vital; it gives a certain momentum to the basic direction of life on this planet. It explains why biological evolution, given enough time, was very likely to create highly intelligent life -- life smart enough to generate technology and other forms of culture. It also explains why the ensuing evolution of technology, and of culture more broadly, was very likely to enrich and expand the social structure of that intelligent species, carrying social organization to planetary breadth. Globalization, it seems to me, has been in the cards not just since the invention of the telegraph or the steamship, or even the written word or the wheel, but since the invention of life. The current age, in which relations among nations grow more non-zero-sum year by year, is the natural outgrowth of several billion years of unfolding non-zero-sum logic.

Any book with a subtitle as grandiose as "The Logic of Human Destiny" is bound to have some mealy-mouthed qualification somewhere along the way. We might as well get it over with.

How literally do I mean the word "destiny"? Do I mean that the exact state of the world today has been inevitable for eons? No, on two counts.

First, I'm talking not about the world's exact, detailed state, but about its broad contours, such as the scope and nature of its political and economic structures. Second, I'm not talking about something that was literally inevitable -- 100 percent guaranteed ever since the dawn of history, or the dawn of life, or whatever. Still, I am talking about something whose chances of transpiring were very high -- something that was "in the cards" in the sense that the deck was stacked heavily in its favor.

Some people may consider it cheating to use the word "destiny" when you mean not "inevitable" but "exceedingly likely." Would you consider it cheating to say that the destiny of a poppy seed is to become a poppy? Obviously, a given poppy seed may not become a poppy. Indeed, the destiny of some poppy seeds seems -- in retrospect, at least -- to have been getting baked onto a bagel. And even poppy seeds that have escaped this fate, and landed on soil, may still get eaten (though not at brunch) and thus never become flower.

Still, there are at least three reasons that it seems defensible to say that the "destiny" of a poppy seed is to become a poppy. First, this is very likely to happen under broadly definable circumstances. Second, from the seed's point of view, the only alternative to this happening is catastrophe -- death, to put a finer point on it. Third, if we inspect the essence of a poppy seed -- the DNA it contains -- we find it hard to escape the conclusion that the poppy seed is programmed to become a poppy. Indeed, you might say the seed is designed to become a poppy, even though it was "designed" not by a human designer, but by natural selection. For anything other than full-fledged poppyhood to happen to a poppy seed -- for it to get baked onto a bagel or eaten by a bird -- is for the seed's true expression to be stifled, its naturally imbued purpose to go unrealized.

It is for reasons roughly analogous to these that I will make an argument for human destiny. Of course, the human-poppy analogy gets most contentious when we ponder the third reason: Is it fair to say that our species has some larger "purpose"? Is there some grand goal that life on earth was "designed" to realize? I think the reasons for answering yes are stronger than many people -- especially many scientists and social scientists -- realize. Still, as I've already suggested, this question is slippery, and answers to it must be speculative. In contrast, destiny in the more modest sense of the word -- a likely outcome, an outcome that history naturally move toward -- is a fairly concrete proposition, more clearly open to empirical appraisal. This book is a full-throated argument for destiny in this sense of "direction," along with a more reticent argument for destiny in the sense of "purpose."

Neither biological evolution nor human history is a smooth, steady process. Both pass through thresholds; they can leap from one equilibrium to a new, higher-level equilibrium. To some people, the current era has the aura of a threshold; it has that unsettling, out-of-control feeling that can portend a major shift. Technological, geopolitical, and economic change seem ominously fast, and the fabric of society seems somehow tenuous.

For instance: World currency markets are rocked by the turbulent force of electronically lubricated financial peculation. Weapons of mass destruction are cultivated by rogue regimes and New Age cults. Nations seem less cohesive than before, afflicted by ethnic or religious or cultural faction. Health officials seriously discuss the prospect of a worldwide plague -- the unspeakably gruesome Ebola virus, perhaps, or some microbe we don't yet know about, spread around the world by jet-propelled travelers. Even tropical storms seem to have grown more intense in recent decades, arguably a result of global warming.

It sounds apocalyptic, and some religiously minded people think it literally is. They have trouble imagining that this rash of new threats could be mere coincidence -- especially coming, as it has, at the end of a millennium. Some fundamentalist Christians cite growing global chaos as evidence that Judgment Day is around the corner. A whole genre of best-selling novels envisions "the Rapture," the day when true believers, on the way to heaven, meet Christ in midair, while others, down below, find a less glamorous fate.

In a sense, these fundamentalists are right. No, I don't mean about the Rapture. I just mean that growing turmoil does signify, by my lights, a distinct step in the unfolding of what you could call the world's destiny. We are indeed approaching a culmination of sorts; our species seems to face a kind of test toward which basic forces of history have been moving us for millennia. It is a test of political imagination -- of our ability to accept basic, necessary changes in structures of governance -- but also a test of moral imagination.

So how will we do on this test? Judging by history, the current turbulence will eventually yield to an era of relative stability, an era when global political, economic, and social structures have largely tamed the new forms of chaos. The world will reach a new equilibrium, at a level of organization higher than any past equilibrium. And the period we are now entering will, in retrospect, look like the storm before the calm.

Or, on the other hand, we could blow up the world. Remember, even poppy seeds don't always manage to flower.

Indeed, at this moment in history, when social organization approaches the global level, and technologies of destruction reach commensurate scope, the arrow of history starts to quiver. Though getting to this threshold has long been so probable as to border on the inevitable, whether we successfully pass through it is another question altogether. And, while I'm basically optimistic, an extremely bleak outcome is obviously possible.

For that matter, even if we avoid blowing up the world, several moderately bleak outcomes are possible. One can imagine, within the bounds of possibility suggested by the trajectory of the past, future political structures that grant more freedom or less, more privacy or less, that foster more order or less, more wealth or less. One purpose of this book is to aid in exploring this "wiggle room" --in choosing among such alternative futures and in realizing the choice.

At least as big as the question of where exactly our future path leads is how chaotically it leads there. History, even if its basic direction is good, can proceed at massive, wrenching human cost. Or it can proceed more smoothly -- with costs, to be sure, but with more tolerable costs.

All told, our menu of options is rich, ranging from self-annihilation to graceful adaptation, and emphatically including the middle prospect of a long and turbulent adjustment full of strife and suffering. It is the destiny of our species -- and this time I mean the inescapable destiny, not just the high likelihood -- to choose.