This book is written for a wide readership. For clarity, we have sometimes stressed the same point more than once, or in more than one context. We have tried to indicate qualifications and exceptions. The pronoun “we” is used sometimes to mean the authors of this book, but usually to mean the human species; the context should make clear which is meant. For those who wish to dig deeper, references to other works, popular and technical—keyed to superscripts in the text—are in the back of the book. Also to be found there are additional comments, notes, and clarifications. Although the two works have little else in common, the haunting 1964 film by Sergei Parajanov gave us our title.
As for essential inspiration and a heightened sense of urgency, it was during the years of preparation of this book that we became the parents of Alexandra Rachel and Samuel Democritus—beloved namesakes of unforgettable ancestors.
CARL SAGAN
ANN DRUYAN
June 1, 1992
Ithaca, N.Y.
Prologue
THE
ORPHAN’S
FILE
Having seen a small part of life, swift to die,
men rise and fly away like smoke, persuaded
only of what each has met with … Who then
claims to find the whole?
EMPEDOCLES
On Nature1
Who are we? The answer to this question is not
only one of the tasks, but the task of science.
ERWIN SCHRÖDINGER
Science and Humanism2
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 usGod is an invention of Man. So the nature of God is only a shallow mystery. The deep mystery is the nature of Man.
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.