Ever Since Darwin
Reflections in Natural History
Ever Since Darwin
Reflections in Natural History
Stephen Jay Gould
W. W. NORTON & COMPANY. NEWYORK.LONDON
FOR MY FATHER
Who took me to see the
Tyrannosaurus when I was five
Contents
Prologue
1 | DARWINIANA
1 Darwin’s Delay
2 Darwin’s Sea Change, or Five Years at the Captain’s Table
3 Darwin’s Dilemma: The Odyssey of Evolution
4 Darwin’s Untimely Burial
2 | HUMAN EVOLUTION
5 A Matter of Degree
6 Bushes and Ladders in Human Evolution
7 The Child as Man’s Real Father
8 Human Babies as Embryos
3 | ODD ORGANISMS AND EVOLUTIONARY EXEMPLARS
9 The Misnamed, Mistreated, and Misunderstood Irish Elk
10 Organic Wisdom, or Why Should a Fly Eat Its Mother from Inside
11 Of Bamboos, Cicadas, and the Economy of Adam Smith
12 The Problem of Perfection, or How Can a Clam Mount a Fish on Its Rear End?
4 | PATTERNS AND PUNCTUATIONS IN THE HISTORY OF LIFE
13 The Pentagon of Life
14 An Unsung Single-Celled Hero
15 Is the Cambrian Explosion a Sigmoid Fraud?
16 The Great Dying
5 | THEORIES OF THE EARTH
17 The Reverend Thomas’ Dirty Little Planet
18 Uniformity and Catastrophe
19 Velikovsky in Collision
20 The Validation of Continental Drift
6 | SIZE AND SHAPE, FROM CHURCHES TO BRAINS TO PLANETS
21 Size and Shape
22 Sizing Up Human Intelligence
23 History of the Vertebrate Brain
24 Planetary Sizes and Surfaces
7 | SCIENCE IN SOCIETY—A HISTORICAL VIEW
25 On Heroes and Fools in Science
26 Posture Maketh the Man
27 Racism and Recapitulation
28 The Criminal as Nature’s Mistake, or the Ape in Some of Us
8 | THE SCIENCE AND POLITICS OF HUMAN NATURE
Race, Sex, and Violence
29 Why We Should Not Name Human Races—A Biological View
30 The Nonscience of Human Nature
31 Racist Arguments and IQ
Part B Sociobiology
32 Biological Potentiality vs. Biological Determinism
33 So Cleverly Kind an Animal
Epilogue
Bibliography
Index
OTHER TITLES BY STEPHEN JAY GOULD PUBLISHED
OTHER TITLES BY STEPHEN JAY GOULD
Copyright
Prologue
“ONE HUNDRED YEARS without Darwin are enough,” grumbled the noted American geneticist H.J. Muller in 1959. The remark struck many listeners as a singularly inauspicious way to greet the centenary of the Origin of Species, but no one could deny the truth expressed in its frustration.
Why has Darwin been so hard to grasp? Within a decade, he convinced the thinking world that evolution had occurred, but his own theory of natural selection never achieved much popularity during his lifetime. It did not prevail until the 1940s, and even today, though it forms the core of our evolutionary theory, it is widely misunderstood, misquoted, and misapplied. The difficulty cannot lie in complexity of logical structure, for the basis of natural selection is simplicity itself—two undeniable facts and an inescapable conclusion:
1.Organisms vary, and these variations are inherited (at least in part) by their offspring.
2.Organisms produce more offspring than can possibly survive.
3.On average, offspring that vary most strongly in directions favored by the environment will survive and propagate. Favorable variation will therefore accumulate in populations by natural selection.
These three statements do ensure that natural selection will operate, but they do not (by themselves) guarantee for it the fundamental role that Darwin assigned. The essence of Darwin’s theory lies in his contention that natural selection is the creative force of evolution—not just the executioner of the unfit. Natural selection must construct the fit as well; it must build adaptation in stages by preserving, generation after generation, the favorable part of a random spectrum of variation. If natural selection is creative, then our first statement on variation must be amplified by two additional constraints.
First, variation must be random, or at least not preferentially inclined toward adaptation. For, if variation comes prepackaged in the right direction, then selection plays no creative role, but merely eliminates the unlucky individuals who do not vary in the appropriate way. Lamarckism, with its insistence that animals respond creatively to their needs and pass acquired traits to offspring, is a non-Darwinian theory on this account. Our understanding of genetic mutation suggests that Darwin was right in maintaining that variation is not predirected in favorable ways. Evolution is a mixture of chance and necessity—chance at the level of variation, necessity in the working of selection.
Secondly, variation must be small relative to the extent of evolutionary change in the foundation of new species. For if new species arise all at once, then selection only has to remove former occupants to make way for an improvement that it did not manufacture. Again, our understanding of genetics encourages Darwin’s view that small mutations are the stuff of evolutionary change.
Thus, Darwin’s apparently simple theory is not without its subtle complexities and additional requirements. Nonetheless, I believe that the stumbling block to its acceptance does not lie in any scientific difficulty, but rather in the radical philosophical content of Darwin’s message—in its challenge to a set of entrenched Western attitudes that we are not yet ready to abandon. First, Darwin argues that evolution has no purpose. Individuals struggle to increase the representation of their genes in future generations, and that is all. If the world displays any harmony and order, it arises only as an incidental result of individuals seeking their own advantage—the economy of Adam Smith transferred to nature. Second, Darwin maintained that evolution has no direction; it does not lead inevitably to higher things. Organisms become better adapted to their local environments, and that is all. The “degeneracy” of a parasite is as perfect as the gait of a gazelle. Third, Darwin applied a consistent philosophy of materialism to his interpretation of nature. Matter is the ground of all existence; mind, spirit, and God as well, are just words that express the wondrous results of neuronal complexity. Thomas Hardy, speaking for nature, expressed his distress at the claim that purpose, direction, and spirit had been banished:
When I took forth at dawning, pool,
Field, flock, and lonely tree,
All seem to gaze at me
Like chastened children sitting silent in a school;
Upon them stirs in lippings mere
(As if once clear in call,
But now scarce breathed at all)—
“We wonder, ever wonder, why we find us here!”
Yes, the world has been different ever since Darwin. But no less exciting, instructing, or uplifting; for if we cannot find purpose in nature, we will have to define it for ourselves. Darwin was not a moral dolt; he just didn’t care to fob off upon nature all the deep prejudices of Western thought. Indeed, I suggest that the true Darwinian spirit might salvage our depleted world by denying a favorite theme of Western arrogance—that we are meant to have control and dominion over the earth and its life because we are the loftiest product of a preordained process.
In any
case, we must come to terms with Darwin. And to do this, we must understand both his beliefs and their implications. All the disparate essays of this book are devoted to the exploration of “this view of life”—Darwin’s own term for his new evolutionary world.
These essays, written from 1974–77, originally appeared in my monthly column for Natural History Magazine, entitled “This View of Life.” They range broadly from planetary and geological to social and political history, but they are united (in my mind at least) by the common thread of evolutionary theory—Darwin’s version. I am a tradesman, not a polymath; what I know of planets and politics lies at their intersection with biological evolution.
I am not unmindful of the journalist’s quip that yesterday’s paper wraps today’s garbage. I am also not unmindful of the outrages visited upon our forests to publish redundant and incoherent collections of essays; for, like Dr. Seuss’ Lorax, I like to think that I speak for the trees. Beyond vanity, my only excuses for a collection of these essays lie in the observation that many people like (and as many people despise) them, and that they seem to cohere about a common theme—Darwin’s evolutionary perspective as an antidote to our cosmic arrogance.
The first section explores Darwin’s theory itself, especially the radical philosophy that inspired H.J. Muller’s complaint. Evolution is purposeless, nonprogressive, and materialistic. I approach the heavy message through some entertaining riddles: who was the Beagle’s naturalist (not Darwin); why didn’t Darwin use the word “evolution”; and why did he wait twenty-one years to publish his theory?
The application of Darwinism to human evolution forms the second section. I try to stress both our uniqueness and our unity with other creatures. Our uniqueness arises from the operation of ordinary evolutionary processes, not from any predisposition toward higher things.
In the third section, I explore some complex issues in evolutionary theory through their application to peculiar organisms. On one level, these essays are about deer with giant antlers, flies that eat their mother from inside, clams that evolve a decoy fish on their rear end, and bamboos that only flower every 120 years. On another level, they treat the issues of adaptation, perfection, and apparent senselessness.
The fourth section extends evolutionary theory to an exploration of patterns in the history of life. We find no story of stately progress, but a world punctuated with periods of mass extinction and rapid origination among long stretches of relative tranquility. I focus upon the two greatest punctuations—the Cambrian “explosion” that ushered in most complex animal life about 600 million years ago, and the Permian extinction that wiped out half the families of marine invertebrates 225 million years ago.
From the history of life, I move to the history of its abode, our earth (fifth section). I discuss both the ancient heros (Lyell) and the modern heretics (Velikovsky) who wrestled with the most general questions of all—does geological history have a direction; is change slow and stately, or rapid and cataclysmic; how does the history of life map the history of the earth? I find a potential resolution to some of these questions in the “new geology” of plate tectonics and continental drift.
The sixth section attempts to be comprehensive by looking in the small. I take a single, simple principle—the influence of size itself upon the shapes of objects—and argue that it applies to an astonishingly broad range of developmental phenomena. I include the evolution of planetary surfaces, the brains of vertebrates and the characteristic differences in shape between small and large medieval churches.
The seventh section may strike some readers as a break in the sequence. I have built laboriously from general principles down to their specific applications, and up again to their working in major patterns for life and the earth. Now I move to the history of evolutionary thought, particularly to the impact of social and political views upon supposedly “objective” science. But I see it as more of the same—another needle in scientific arrogance, with an added political message. Science is no inexorable march to truth, mediated by the collection of objective information and the destruction of ancient superstition. Scientists, as ordinary human beings, unconsciously reflect in their theories the social and political constraints of their times. As privileged members of society, more often than not they end up defending existing social arrangements as biologically foreordained. I discuss the general message in an obscure debate within eighteenth century embryology, Engels’s views on human evolution, Lombroso’s theory of innate criminality, and a twisted tale from the catacombs of scientific racism.
The final section pursues the same theme, but applies it to contemporary discussions of “human nature”—the major impact of misused evolutionary theory upon current social policy. The first subsection criticizes as political prejudice the biological determinism that has recently deluged us with killer apes as ancestors, innate aggression and territoriality, female passivity as the dictate of nature, racial differences in IQ, etc. I argue that no evidence supports any of these claims, and that they represent just the latest incarnation of a long and sad story in Western history—blaming the victim with a stamp of biological inferiority, or using “biology as an accomplice,” as Condorcet put it. The second subsection treats both my pleasure and unhappiness with the recently christened study of “Sociobiology,” and its promise of a new, Darwinian account of human nature. I suggest that many of its specific claims are unsupported speculations in the determinist mode, but I find great value in its Darwinian explanation of altruism—as support for my alternate preference that inheritance has given us flexibility, not a rigid social structure ordained by natural selection.
These essays have suffered only minor alteration from their original status as columns in Natural History Magazine—errors corrected, parochialisms eliminated, and information updated. I have tried to attack the bugbear of essay collections, redundancy, but have retreated when my editorial knife threatened the coherence of any individual piece. At least I never use the same quote twice. Finally, my thanks and affection for editor-in-chief Alan Ternes, and for his copy editors Florence Edelstein and Gordon Beckhorn. They have supported me through a rash of cranky letters, and have shown the finest forebearance and discretion by using the lightest of editorial hands. Blame Alan, however, for all the really catchy titles—particularly for the sigmoid fraud of essay 15.
Sigmund Freud expressed as well as anyone the ineradicable impact of evolution upon human life and thought when he wrote:
Humanity has in course of time had to endure from the hands of science two great outrages upon its naive self-love. The first was when it realized that our earth was not the center of the universe, but only a speck in a world-system of a magnitude hardly conceivable.… The second was when biological research robbed man of his particular privilege of having been specially created, and relegated him to a descent from the animal world.
I submit that the knowledge of this relegation is also our greatest hope for continuity on a fragile earth. May “this view of life” flower during its second century and help us to comprehend both the limits and the lessons of scientific understanding—as we, like Hardy’s fields and trees, continue to wonder why we find us here.
1 | Darwiniana
1 | Darwin’s Delay
FEW EVENTS INSPIRE more speculation than long and unexplained pauses in the activities of famous people. Rossini crowned a brilliant operatic career with William Tell and then wrote almost nothing for the next thirty-five years. Dorothy Sayers abandoned Lord Peter Wimsey at the height of his popularity and turned instead to God. Charles Darwin developed a radical theory of evolution in 1838 and published it twenty-one years later only because A. R. Wallace was about to scoop him.
Five years with nature aboard the Beagle destroyed Darwin’s faith in the fixity of species. In July, 1837, shortly after the voyage, he started his first notebook on “transmutation.” Already convinced that evolution had occurred, Darwin sought a theory to explain its mechanism. After much preliminary speculation and a
few unsuccessful hypotheses, he achieved his central insight while reading an apparently unrelated work for recreation. Darwin later wrote in his autobiography:
In October 1838 … I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long continued observation of the habits of animals and plants, it at once struck me that under these circumstances favorable variations would tend to be preserved and unfavorable ones to be destroyed. The result of this would be the formation of new species.
Darwin had long appreciated the importance of artificial selection practiced by animal breeders. But until Malthus’s vision of struggle and crowding catalyzed his thoughts, he had not been able to identify an agent for natural selection. If all creatures produced far more offspring than could possibly survive, then natural selection would direct evolution under the simple assumption that survivors, on the average, are better adapted to prevailing conditions of life.
Darwin knew what he had achieved. We cannot attribute his delay to any lack of appreciation for the magnitude of his accomplishment. In 1842 and again in 1844 he wrote out preliminary sketches of his theory and its implications. He also left strict instructions with his wife to publish these alone of his manuscripts if he should die before writing his major work.
Why then did he wait for more than twenty years to publish his theory? True, the pace of our lives today has accelerated so rapidly—leaving among its victims the art of conversation and the game of baseball—that we may mistake a normal period of the past for a large slice of eternity. But the span of a man’s life is a constant measuring stick; twenty years is still half a normal career—a large chunk of life even by the most deliberate Victorian standards.
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