The Human Instinct: How We Evolved to Have Reason, Consciousness, and Free Will - Hardcover

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Kenneth R. Miller is professor of biology at Brown University and the critically acclaimed bestselling author of Only a Theory, Finding Darwin’s God, and The Human Instinct. He has appeared frequently on radio and television as a public advocate for evolution. In 2005 he was the lead expert witness for the victorious plaintiffs in the landmark Kitzmiller v. Dover trial, where he testified in favor of evolution and against “intelligent design.” Among his honors are the Stephen Jay Gould Prize from the Society for the Study of Evolution, the Laetare Medal from the University of Notre Dame, and the Award for Public Engagement with Science from the American Association for the Advancement of Science.

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The Human Instinct

Chapter 1

Grandeur

I think Charles Darwin might have seen his critics coming. Unlike most nineteenth-century works of science, On the Origin of Species is still read today. Much of that attention has been earned by the logical power and simplicity of Darwin’s argument. He begins with a chapter on variation among domestic animals and plants, something that every animal and plant breeder in the England of his time would have been familiar with. Chapter 2 points out that similar variation exists in wild species. Having established that individual members of a species vary in their characteristics, chapter 3 then describes a “struggle for existence” occurring everywhere in the natural world, producing forces that work remarkably like the hand of a breeder to shape the characteristics of every living species. At that point, the stage is set for the theory of evolution by natural selection, which he introduced by name in chapter 4. The remaining ten chapters enlarge and expand upon the evidence for this theory. The book has been called “one long argument,” and so it is. A powerful and elegant argument.

But there is another reason The Origin is not only read today, but also widely quoted. While much of the book is mired in scientific minutiae and arcane speculation, as it moves toward a conclusion, The Origin shines with a clarity—even a kind of poetry—rarely seen in a scientific document. In particular, having brought his many arguments to their logical conclusions, Darwin seems compelled to tell us what a wonderful vision of nature he has set before us:

When I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Silurian system was deposited, they seem to me to become ennobled.1

And why are they “ennobled”? To Darwin, it is because living species are linked to an almost endless history of struggle and success, often against great odds. So distant is that past, so persistent are the triumphs of those shaped by natural selection, that we may look at them with pride, confident of an equally long and glorious future.

As all the living forms of life are the lineal descendants of those which lived long before the Silurian epoch, we may feel certain that the ordinary succession by generation has never once been broken, and that no cataclysm has desolated the whole world. Hence, we may look with some confidence to a secure future of equally inappreciable length. And as natural selection works solely by and for the good of each being, all corporeal and mental endowments will tend to progress towards perfection.2

Every day, in every way, they’re getting better and better—and so are we. The future is secure, and we’re getting closer to perfection. Fine words, even though most biologists today, myself included, would argue that evolution never produces “perfection.” In fact, it never even gets close. Success in the struggle for existence is all that matters, so being just good enough to get by is good enough. Always has been, always will be. But Darwin spun things differently.

As stirring as these words about perfection may have seemed to nineteenth-century readers, the final paragraph of The Origin reaches even higher. Darwin wants us to find beauty in the apparent chaos of nature, using the metaphor of a tangled bank alongside a stream to represent the creativity of the evolutionary process:

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us.3

And finally, just in case his readers might be a bit distressed by the realizations that they are merely the products of “laws acting around us,” he assures us that there is indeed something special, something glorious about the whole process:

There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.4

It’s a stirring sentence. I have often quoted it in my own writings and lectures, and I’m not alone. But if his ideas were on such firm footing, as they clearly were, why did Darwin find it necessary to describe his vision as one of “grandeur”? I think it may have been because he recognized full well that many, if not most, of his readers would surely think otherwise. If we find our origin in the natural world by means of natural laws, then how can we possibly consider humankind as something apart from the beasts of the field, or even the slimy critters of the soil? Punch, the humor magazine, picked up on this much later with a satirical cartoon on its cover, stating “Man is but a worm.”5 Building on Darwin’s own writings, the cartoon depicted an earthworm-like creature first arising out of chaos, then morphing into a series of monkeys, next a cave man, then an English aristocrat, and finally into Darwin himself. Hardly a vision rooted in grandeur.

Darwin clearly realized that a little polishing of the human ego would go a long way toward encouraging acceptance of his ideas, and that is exactly what we see in the concluding paragraphs of The Origin. He understood that most would not find this vision “grand” and decided to do what he could to convince them otherwise. But I’m not sure this appeal to his readers to recognize the “grandeur” of evolution ever took hold. And I believe that remains the case today, even among many who fully accept the evolutionary story of our origins.

In Ian McEwan’s novel Saturday, his contemporary protagonist begins the single day of the story’s title by contemplating Darwin’s use of that very word. As Henry Perowne, a London neurosurgeon, rises, the phrase comes to him over and over again: There is grandeur in this view of life. Three times he repeats those words, and then remembers why. Last night, in the bath after a tiring day, he had skimmed a biography of Darwin sent him by his “all too literate” poet daughter, Daisy. He doesn’t remember much—he’d never actually read Darwin himself—but that phrase stuck with him. Musing to himself, he contemplates the forces that drove the great naturalist to compose the final sentence of his masterwork:

Kindly, driven, infirm Charles in all his humility, bringing on the earthworms and the planetary cycles to assist him with a farewell bow. To soften the message, he also summoned up a Creator in later editions, but his heart was never really in it. Those five hundred pages deserved only one conclusion: endless and beautiful forms of life, such as you see in a common hedgerow, including exalted beings like ourselves, arose from physical laws, from war of nature, famine, and death. This is the...