|It Ain't Necessarily So|
|The Dream of the Human Genome and Other Illusions|
by Richard Lewontin
Posted: July 28, 2000
Sportin' Life, the dashing scoundrel who sings "It Ain't Necessarily So" in Porgy and Bess, aims to convince his devout, churchgoing listeners that "the Bible you're readin' is often misleadin'." Richard Lewontin, author of the nine sparkling essays in this book, seeks to debunk a different sort of holy writ, the widely held belief that biology, and in particular genetics and genomics, canand soon willexplain human behavior and human nature.
This deterministic faith pervades current discussion of issues as diverse as gender roles, the nature of individuality, the origins of intelligence, and the causes of disease. It arises from a few essential tenets. The first is that more "basic" processes, such as those that occur in molecules, account for the less "basic" ones that happen in minds, hearts and relationships. Second, the most "basic" processes of all occur in DNA, giving genes the power to determine what each organism becomes. Third, evolution by natural selection has precisely molded our species' genome, finely adapting our inclinations and abilities to the environment that produced them.
Lewontin will have none of this "vulgar Darwinism" (p. 52). For him, this creed represents not science but "simplistic scientism" and reveals basic confusion about how organisms develop and the world works (p. xxiv). "Natural scientists, in their overweening pride, have come to believe that everything about the natural world is knowable and that eventually everything we want to know will be known," he writes. "This is not true" (p. xxv). He doubts, for instance, that there will ever be "world enough or time" for us to fully understand our own nervous systems. He suspects that we can never pin down the exact selective forces that shaped us. He is quite sure that mapping the human genome will not hold up to homo sapiens a mirror revealing our humanity.
If you haven't encountered Lewontin before, you may by now be wondering whether he is some fundamentalist preacher who considers Darwin in league with the Devil. But the Alexander Agassiz Research Professor at Harvard University is no obscurantist fanatic, but a leading evolutionary biologist. In a long and distinguished career studying in detail the interplay of genetics and development, he has rejected neither molecular biology nor evolutionary theory, only to the way that many people, including some of his fellow scientists, distort and misconstrue them. "The great successes of molecular biology in understanding the machinery of the cell have left the impression that no problem is beyond the analytical power of biologists and that complete knowledge of the organism is just around the corner." (p. 104).
But, he insists, such a conclusion ignores the enormous, essential, and probably unknowable influence of environment and experience on what each of us becomes. "An organism does not compute itself from its DNA," he explains. "A living organism at any moment in its life is the unique consequence of a developmental history" affected by both "internal and external forces." And "the external forces, what we usually think of as 'environment'" themselves result in part from the organism's own actions. "Organisms do not find the world in which they develop," he observes. "They make it" (pp. 147-48).
Besides his own research, Lewontin has spent a simultaneous, and equally distinguished, career as a critic of biological pretension and excess, aiming a stream of witty, lucid, profound, and often controversial writings not at a small circle of fellow experts but at a wide reading public. He favors a subtle and sophisticated Darwinism expressed in language non-specialists can understand. Nine of his essays, all previously published in The New York Review of Books, make up this volume. Each takes on a biodeterministic dogma and reduces it to intellectual rubble.
No, he demonstrates, inheritance does not explain intelligence, character traits or social customs. No, he shows, natural selection does not work on all our genes equally. No, he establishes, human clones would not lack individuality. No, he verifies, "DNA has no power to reproduce itself," but is in fact a product of the enzymes in living cells (p. 142). And, most importantly of all: No, he repeatedly proves, science is not the wholly objective search for truth celebrated in legend and lore, but a human endeavor reflecting the biases and assumptions of the people who practice it.
Lewontin is so skilled a thinker and writer that he makes deep and difficult scientific and philosophical arguments not just clear, but vivid and even funny, peppering his penetrating observations with references to folk tales, Agatha Christie mysteries and Broadway musicals. Like Sportin' Life, he dazzles and captivates his audience. But unlike that sly seducer, he leads you not into mindless cynicism but toward greater understanding.