The immense, overpowering blackness is relieved here and there by a faint point of light—which, upon closer approach, is revealed to be a mighty sun, blazing with thermonuclear fire and warming a small surrounding volume of space. The Universe is, almost entirely, black emptiness, and yet the number of suns is staggering. The neighborhoods immediately encompassing these suns represent an insignificant fraction of the vastness of the Cosmos, but many, perhaps most, of those cheerful, bright, clement circumstellar regions are occupied by worlds. In the Milky Way galaxy alone there may be a hundred billion of them—neither too close by, nor too distant from, the local sun, around which they orbit in silent gravitational homage.

This is a story about one such world, perhaps not very different from many others—a story, especially, about the beings that evolved upon it, and one kind in particular.

Just to be alive billions of years after the origin of life, a being must be tough, resourceful, and lucky: There have been so many hazards along the way. Lifeforms endure by being patient, say, or ravenous, or solitary and camouflaged, or profligate with offspring, or fearsome hunters, or able to fly away to safety, or sleek swimmers, or burrowers, or sprayers of noxious, disorienting liquids, or masters at infiltrating into the very genetic material of other, unsuspecting, beings; or by accidentally being elsewhere when the predators stalk or the river is poisoned or the food supply dwindles. The creatures with which we are particularly concerned were, not so long ago, gregarious to a fault, noisy, quarrelsome, arboreal, bossy, sexy, clever, tool-using, with prolonged childhoods and tender regard for their young. One thing led to another, and in a twinkling their descendants had multiplied all over the planet, killed off all their rivals, devised world-transforming technologies, and posed a mortal danger to themselves and the many other beings with whom they shared their small home. At the same time, they set off to visit the planets and the stars.

——

Who are we? Where do we come from? Why are we this way and not some other? What does it mean to be human? Are we capable, if need be, of fundamental change, or do the dead hands of forgotten ancestors impel us in some direction, indiscriminately for good or ill, and beyond our control? Can we alter our character? Can we improve our societies? Can we leave our children a world better than the one that was left to us? Can we free them from the demons that torment us and haunt our civilization? In the long run, are we wise enough to know what changes to make? Can we be trusted with our own future?

Many thoughtful people fear that our problems have become too big for us, that we are for reasons at the heart of human nature unable to deal with them, that we have lost our way, that the dominant political and religious ideologies are unable to halt an ominous, long-term drift in human affairs—indeed, that they have helped cause that drift through rigidity, incompetence, and the inevitable corruption of power. Is this true, and if it is, can we do anything about it?

In attempting to understand who we are, every human culture has invented a corpus of myth. The contradictions within us are ascribed to a struggle between contending but equally matched deities; or to an imperfect Creator; or, paradoxically, to a rebellious angel and the Almighty; or to the even more unequal struggle between an omnipotent being and disobedient humans. There have also been those who hold that the gods have nothing to do with it. One of them, Nanrei Kobori, late Abbot of the Temple of the Shining Dragon, a Buddhist sanctuary in Kyoto, said to us

Had life and humans first come to be hundreds or even thousands of years ago, we might know most of what’s important about our past. There might be very little of significance about our history that’s hidden from us. Our reach might extend easily to the beginning. But instead, our species is hundreds of thousands of years old, the genus Homo millions of years old, primates tens of millions of years old, mammals over 200 million years old, and life about 4 billion years old. Our written records carry us only a millionth of the way back to the origin of life. Our beginnings, the key events in our early development, are not readily accessible to us. No firsthand accounts have come down to us. They cannot be found in living memory or in the annals of our species. Our time-depth is pathetically, disturbingly shallow. The overwhelming majority of our ancestors are wholly unknown to us They have no names, no faces, no foibles. No family anecdotes attach to them. They are unreclaimable, lost to us forever. We don’t know them from Adam. If an ancestor of yours of a hundred generations ago—never mind a thousand or ten thousand—came up to you on the street with open arms, or just tapped you on the shoulder, would you return the greeting? Would you call the authorities?

We ourselves, the writers of this book, have so short a reach into our family histories that we can peer clearly only two generations back, dimly three, and almost not at all beyond that. We do not know even the names—much less the occupations, countries of origin, or personal histories—of our great-great-grandparents. Most people on Earth, we think, are similarly isolated in time. For most of us, no records have preserved the memories of our ancestors of even a few generations back.

A vast chain of beings, human and nonhuman, connects each of us with our earliest predecessors Only the most recent links are illuminated by the feeble searchlight of living memory. All the others are plunged into varying degrees of darkness, more impenetrable the farther from us they are in time. Even those fortunate families who have managed to keep meticulous records range no more than a few dozen generations into the past. And yet a hundred thousand generations ago our ancestors were still recognizably human, and ages of geological time stretch back before them. For most of us, the searchlight progresses forward as the generations do, and as the new ones are born, information about the old ones is lost. We are cut off from our past, separated from our origins, not through some amnesia or lobotomy, but because of the brevity of our lives and the immense, unfathomed vistas of time that separate us from our coming to be.

We humans are like a newborn baby left on a doorstep, with no note explaining who it is, where it came from, what hereditary cargo of attributes and disabilities it might be carrying, or who its antecedents might be. We long to see the orphan’s file.

Repeatedly, in many cultures, we invented reassuring fantasies about our parents—about how much they loved us, about how heroic and larger than life they were.³ As orphans do, we sometimes blamed ourselves for having been abandoned. It must have been our fault. We were too sinful, perhaps, or morally incorrigible. Insecure, we clung to these stories, imposing the strictest penalties on any who dared to doubt them. It was better than nothing, better than admitting our ignorance of our own origins, better than acknowledging that we had been left naked and helpless, a foundling on a doorstep.

As the infant is said to feel it is the center of its Universe, so we were once sure, not just of our central position, but that the Universe was made for us. This old, comfortable conceit, this safe view of the world has been crumbling for five centuries. The more we understood of how the world is put together, the less we needed to invoke a God or gods, and the more remote in time and causality any divine intervention had to be. The cost of coming of age is giving up the security blanket. Adolescence is a roller coaster ride.

When, beginning in 1859, our very origins, it was suggested, could be understood by a natural, unmystical process—requiring no God or gods—our aching sense of isolation became nearly complete. In the words of the anthropologist Robert Redfield, the Universe began to “lose its moral character” and became “indifferent, a system uncaring of man.”⁴

Moreover, without a God or gods and the attendant threat of divine punishment, will not humans be as beasts? Dostoyevsky warned that those who reject religion, however well-intentioned they may be, “will end by drenching the earth with blood.”⁵ Others have noted that drenching has been in progress since the dawn of civilization—and often in the name of religion.

The distasteful prospect of an indifferent Universe—or worse, a meaningless Universe—has generated fear, denial, ennui, and the sense that science is an instrument of alienation. The cold truths of our scientific age are uncongenial to many. We feel stranded and alone. We crave a purpose to give meaning to our existence. We do not want to hear that the world was not made for us. We are unimpressed with moral codes contrived by mere mortals; we want one handed down from on high. We are reluctant to acknowledge our relatives. They are strangers to us still. We feel ashamed: After imagining our Antecedent as King of the Universe, we are now asked to accept that we come from the lowest of the low—mud, and slime, and mindless beings too small to be seen with the naked eye.

Why concentrate on the past? Why upset ourselves with painful analogies between humans and beasts? Why not simply look to the future? These questions have an answer. If we do not know what we’re capable of—and not just a few celebrity saints and notorious war criminals—then we do not know what to watch out for, which human propensities to encourage, and which to guard against. Then we haven’t a clue about which proposed courses of human action are realistic, and which are impractical and dangerous sentimentality. The philosopher Mary Midgley writes,

The study of the history of life, the evolutionary process, and the nature of the other beings who ride this planet with us has begun to cast a little light on those past links in the chain. We have not met our forgotten ancestors, but we begin to sense their presence in the dark. We recognize their shadows here and there. They were once as real as we are. We would not be here if not for them. Our natures and theirs are indissolubly linked despite the aeons that may separate us. The key to who we are is waiting in those shadows.

——

When we began this search into our origins, using the methods and findings of science, it was almost with a sense of dread. We were afraid of what we might find. We found instead not just room but reason for hope, as we begin to explain in this book.

The real orphan’s file is long. We humans have uncovered bits and pieces, occasionally a few consecutive pages, nothing as elaborate as a complete chapter. Many of the words are blurred Most have been lost.⁷

Here then is one version of some of the early pages of the orphan’s file, the missing note that should have accompanied the foundling on the doorstep, something of our beginnings and the forgotten ancestors that are central to the outcome of our story. Like most family stories, it begins in the dark—so long ago and far away, in circumstances so unpromising, that no one could have guessed where it all would lead.

We are about to trace the history of life, and the path that led to us—how we got to be the way we are. It is fitting that we begin at the beginning. Or a little earlier.