Human Natures: Genes, Cultures, and the Human Prospect

It's common to blame "human nature" for some of the unpleasant facts of life--road rage, say, or murder, or war. The problem with this convenient out, argues the distinguished scientist Paul Ehrlich, is that there really is no single human nature. Humans, it's true, share a common genetic code with remarkably few large-scale differences (if all but native Africans disappeared from the planet, he notes, "humanity would still retain somewhat more than 90 percent of its genetic variability"); and evolution has endowed us with capabilities shared by no other species. But for all that, he adds, our separation into haves and have-nots, weak and strong, and other such categories is more often than not a product of cultural evolution, a process far more complex than the mere mutation and adaptation of a few genes. And, in any event, those genes "do not shout commands to us about our behavior," Ehrlich says. "At the very most, they whisper suggestions."

In this wide-ranging survey of what it is that has made and that continues to make us human, Ehrlich touches on a number of themes--among them, his recurrent observation that science has taught us little about how genes influence human behavior. (Instead, he notes wryly, "science tells us that we are creatures of accident clinging to a ball of mud hurtling aimlessly through space. This is not a notion to warm hearts or rouse multitudes.") He urges that scientists take a larger, interdisciplinary view that looks beyond mere genetics to the larger forces that shape our lives, a view for which Human Natures makes a handy, and highly accessible, primer. --Gregory McNamee