Shadows of Forgotten Ancestors (60 page)

Even in the fossil remains of the earliest lifeforms, there is unmistakable evidence of communal living arrangements and mutual cooperation. We humans have been able to design effective cultures that for hundreds of thousands of years have fostered one set of inborn characteristics and discouraged another. From brain anatomy, human behavior, personal introspection, the annals of recorded history, the fossil record, DNA sequencing, and the behavior of our closest relatives, a clear lesson emerges: There is more than one side to human nature. If our greater intelligence is the hallmark of our species, then we should use it as all the other beings use their distinctive advantages—to help ensure that their offspring prosper and their heredity is passed on. It is our business to understand that some predilections we bear as remnants of our evolutionary history, when coupled with our intelligence—especially with intelligence in the subordinate role—might threaten our future. Our intelligence is imperfect, surely, and newly arisen; the ease with which it can be sweet-talked, overwhelmed, or subverted by other hardwired propensities—sometimes themselves disguised as the cool light of reason—is worrisome. But if intelligence is our only edge, we must learn to use it better, to sharpen it, to understand its limitations and deficiencies—to use it as cats use stealth, as walking sticks use camouflage, to make it the tool of our survival.

SHADOWS OF FORGOTTEN ANCESTORS

T
he evolutionary process has made the Earth brim over with life. There are beings that walk, jump, hop, fly, glide, float, slither, burrow, stride on the water’s surface, canter, waddle, brachiate, swim, tumble, and patiently wait. Damsel flies molt, deciduous trees bud, great cats stalk, antelopes take fright, birds chatter, nematodes worry a grain of humus, perfect insect imitations of leaves and twigs rest incognito on a branch, earthworms entwine themselves in passionate bisexual embrace, algae and fungi are comfortable roommates in the lichen partnership, great whales sing their plaintive
songs
as they traverse the world ocean, willows suck moisture from unseen underground aquifers, and a universe of microbes swarms in every thimbleful of muck. There is hardly a clod of soil, a drop of water, a breath of air that is not teeming with life. It fills every nook and cranny of our planet’s surface. There are bacteria in the upper air, jumping spiders at the tops of the highest mountains, sulfur-metabolizing worms in the deep ocean trenches, and heat-loving microbes kilometers below the surface of the land. Almost all these beings are in intimate contact. They eat and drink one another, breathe each other’s waste gases, inhabit one another’s bodies, disguise themselves to look like one another, construct intricate networks of mutual cooperation, and gratuitously fiddle with each other’s genetic instructions. They have generated a web of mutual dependence and interaction that embraces the planet.

By 3 billion years ago, life had changed the color of the inland seas; by 2 billion years ago, the gross composition of the atmosphere; by 1 billion years ago, the weather and the climate; by a third of a billion years ago, the geology of the soil; and in the past few hundred million years the close-up appearance of the planet. These profound changes, all brought about by forms of life we tend to consider “primitive,” and of course by processes we describe as natural, mock the concerns of those who hold that humans, through their technology, have now
achieved “the end of Nature.” We are rendering many species extinct; we may even succeed in destroying ourselves. But this is nothing new for the Earth. Humans would then be just the latest in a long sequence of upstart species that arrive on-stage, make some alterations in the scenery, kill off some of the cast, and then themselves exit stage-left forever. New players appear in the next act. The Earth abides. It has seen all this before.

Life has penetrated only a thin surface layer, bounded by the heavens above and something very much like hell below. The planet itself—rotating once a day, revolving about the Sun once a year, circumnavigating the center of the Milky Way Galaxy once every quarter billion years, this world of rock and metal with its deep convection currents that make and destroy continents and generate the planet’s magnetic field—the planet knows nothing of life. The Earth would continue on its way as readily without life as with it. The Earth is indifferent, and all but that shallow clement zone at its very surface is impervious to anything life has been able to serve up.

——

Our family tree was rooted when the Earth was just emerging from a time of massive, obliterating impacts, molten red-hot landscapes, and pitch-black skies; when the oceans and the stuff of life were still falling in from space; when our connection with the Universe around us was manifest. The orphan’s file began in epic style.

The family tree of a few rare individuals of our species, we’ve argued, can be traced back perhaps as much as two or three dozen generations. Most of us, in contrast, are able to penetrate only three or four generations into the past before the record fades and is lost. With a rare exception here and there, all earlier ancestors are the merest phantoms. But hundreds of generations link us to the time that civilization was invented, thousands of generations run to the origin of our species, and a hundred thousand generations lie between us and the first member of the genus
Homo
. How many generations link us back through our non-human primate, mammal, reptile, amphibian, fish, and still earlier ancestors to the microbes of the primeval sea, and how many generations before that to the first organic molecules able to make crude copies of themselves is unfathomed—but it might approach 100 billion. The family tree of each of us is graced by
all those great inventors: the beings who first tried out self-replication, the manufacture of protein machine tools, the cell, cooperation, predation, symbiosis, photosynthesis, breathing oxygen, sex, hormones, brains, and all the rest—inventions we use, some of them, minute-by-minute without ever wondering who devised them and how much we owe to these unknown benefactors, in a chain 100 billion links long.

Many have construed our clear kinship with the other animals as an affront to human dignity. But any one of us is much more closely related to Einstein and Stalin, to Gandhi and Hitler than to any member of another species. Shall we think more or less of ourselves in consequence? The discovery of a deep connection between human nature,
all
of human nature, and the other living things on Earth comes not a moment too soon. We are helped to know ourselves.

In acknowledging our ties of kinship, we are forced to reconsider the morality (as well as the prudence) of our conduct: wiping out another species every few minutes, night and day, all over the planet. Over the last few decades we have caused the extinction of something like a million species—some providing potential new foods, some desperately needed medicines, but all unique DNA sequences, tortuously evolved over 4 billion years of the evolution of life and all now lost forever. We have been faithless heirs, squandering the family inheritance with little thought for the generations to come.

We must stop pretending we’re something we are not. Somewhere between romantic, uncritical anthropomorphizing of the animals and an anxious, obdurate refusal to recognize our kinship with them—the latter made tellingly clear in the still-widespread notion of “special” creation—there is a broad middle ground on which we humans can take our stand.

If the Universe really were made for us, if there really is a benevolent, omnipotent, and omniscient God, then science has done something cruel and heartless, whose chief virtue would perhaps be a testing of our ancient faiths. But if the Universe is heedless of our aspirations and our destiny, science provides the greatest possible service by awakening us to our true circumstances. In accord with the unforgiving principle of natural selection, we are charged with our own preservation—under penalty of extinction.

And yet we go from massacre to massacre; and as our technology becomes more powerful, the magnitude of the potential tragedy
grows. The many sorrows of our recent history suggest that we humans have a learning disability. We might have thought that the horrors of World War II and the Holocaust were enough to innoculate us against the toxins there revealed and unleashed. But our resistance quickly fades. A new generation gladly abandons its critical and skeptical faculties. Old slogans and hatreds are dusted off. What was only recently muttered guiltily is now offered as political axiom and agenda. There are renewed appeals to ethnocentrism, xenophobia, homophobia, racism, sexism, and territoriality. And with a sigh of relief we are apt to surrender to the will of the alpha, or long for an alpha we can surrender to.

Ten thousand generations ago, when we were divided into many small groups, these propensities may have served our species well. We can understand why they are almost reflexive, why they should be so easy to evoke, why they are the stock in trade of every demagogue and hack politician. But we cannot wait for natural selection to further mitigate these ancient primate algorithms. That would take too long. We must work with what tools we have—to understand who we are, how we got to be that way, and how to transcend our deficiencies. Then we can begin to create a society less apt to bring out the worst in us.

Still, from the perspective of the last ten thousand years extraordinary transformations have lately been playing themselves out. Consider how we humans organize ourselves. Dominance hierarchies requiring debasing submission and obedience to the alpha male, as well as hereditary alphahood, were once the global standard of human political structure, justified as right and proper and divinely ordained by our greatest philosophers and religious leaders. These institutions have now almost vanished from the Earth. Chattel slavery—likewise long defended by revered thinkers as preordained and deeply consonant with human nature—has been nearly abolished worldwide. Just a minute ago, all over the planet, with only a few exceptions, women were subordinate to men and denied equal status and power; this also was thought predetermined and inevitable. Here too, clear signs of change are now evident nearly everywhere. A common appreciation of democracy and what are called human rights is, with some backsliding, sweeping the planet.

Taken together, these dramatic societal shifts—often in ten generations
or less—provide a compelling refutation of the claim that we are condemned, without hope of reprieve, to live out our lives in a barely disguised chimpanzee social order. Moreover, the shifts are occurring so swiftly that they cannot possibly be due to natural selection. Instead, our culture must be drawing forth propensities and predispositions that already reside deep within us.

We humans hold at least 99.9% of our DNA sequences in common. We are far more closely related to one another than we are to any other animal. By the similarity standards we use in other matters, humans—even of the most disparate cultures and ethnic origins—are essentially identical in our heredities. Of the immense number of possible beings, realized and unrealized, we all are cut from the same cloth, made on the same pattern, granted the same strengths and weaknesses, and will ultimately share the same fate. Given the reality of our mutual interdependence, our intelligence, and what is at stake, are we really unable to break out of behavior patterns evolved to benefit our ancestors of long ago?