THE MEANING OF HUMAN EXISTENCE

By Edward O. Wilson

Liveright.

207 pp. $23.95

Where did we come from, with our two-legged stance, horizon-scanning eyes and teeming brain? Human cultures have answered this question by telling stories — about gardens and gods, about sacred places and shaping spirits. For a century and a half, ever since Darwin published his distressing theory, biologists have been insisting that all those creation stories, however comforting and flattering, are false.

In our own day, no biologist has been more persistent or eloquent in correcting our misapprehensions about human origins than Edward O. Wilson. At age 85, author of more than 20 books, twice winner of the Pulitzer Prize, recipient of numerous major awards for science and public service, he could easily rest on his laurels. He might be content with having made pioneering contributions in the study of entomology, biodiversity, sociobiology, island biogeography and environmental psychology, along with having popularized the term “biophilia” to describe our fascination with the living world.

‘The Meaning of Human Existence’ by Edward O. Wilson (Liveright/Liveright)

Instead, Wilson tries yet again, in “The Meaning of Human Existence,” to convince ordinary readers of the scientific view that humans have evolved, along with millions of other species, from earlier life forms, entirely by natural processes, without guidance from any supreme being. He has his work cut out for him. According to the most recent Pew Research Center poll, roughly two-thirds of Americans reject this view of evolution, which undergirds all of modern medicine and the life sciences.

Ironically, the religious faiths that are the chief source of this skepticism are themselves a product of evolution, Wilson tells us in this slender volume, which has been short-listed for this year’s National Book Award in nonfiction. Following Darwin’s lead, he argues that natural selection operates not only at the individual level but also at the level of groups. Throughout our evolutionary history, those groups that bonded most firmly against outsiders enjoyed greater reproductive success — and religion is the most potent binding force that human cultures have produced.

Wilson acknowledges the benefits that arise from religious faith, including moral codes that instruct believers to relieve suffering and care for the vulnerable. One of his previous books, “The Creation: An Appeal to Save Life on Earth” (2006), took the form of a letter addressed to a Southern Baptist minister, seeking common ground in the effort to preserve biodiversity by invoking the stewardship ethic implicit in the Bible. In his new book, however, perhaps in response to the sectarian strife that engulfs so many nations, Wilson laments that “the great religions are also, and tragically, sources of ceaseless and unnecessary suffering. They are impediments to the grasp of reality needed to solve most social problems in the real world. Their exquisitely human flaw is tribalism.”

Tribalism is only one consequence of what Wilson calls the “Paleolithic Curse: genetic adaptations that worked very well for millions of years of hunter-gatherer existence but are increasingly a hindrance in a globally urban and technoscientific society.” Among other ways in which our genetic adaptations ill suit us for contemporary conditions, he notes our penchant for racism, our refusal to curb population growth, our failure to cooperate with one another on a scale commensurate with the challenges we face and our devastation of the natural environment.

Having become the dominant species on the planet, are we doomed to self-destruct? Calling himself “at heart a congenital optimist,” Wilson answers with a qualified no. We can avoid undermining the natural conditions on which civilization depends by drawing on our “social intelligence,” another legacy of our evolutionary journey. The abilities to communicate, collaborate through division of labor and behave altruistically within organized groups are traits that have arisen “on only twenty known occasions in the history of life,” principally among insects, such as termites and ants.

While he draws parallels between the behavior of ants — on which he is the world’s leading authority — and human social behavior, Wilson is careful to say that we are not slaves of instinct, as insects are. As he has done since his early and controversial book “On Human Nature” (1978), he argues here that our “behavior has a strong genetic component,” which shapes but does not determine our actions. Unlike insects, we can think about the consequences of our behavior and choose to act differently. We can choose, for example, to bring fewer children into the world, stop burning coal, plant trees faster than we cut them down, judge people by their character rather than by the color of their skin.

To posit such a power to choose, as Wilson does repeatedly in “The Meaning of Human Existence,” raises a conundrum that he never squarely addresses, not even in the chapter titled “Free Will.” He predicts that neuroscientists will soon identify the physical basis of consciousness, revealing the material processes that give rise to our emotions and thoughts. If what we call mind is only a side effect of material processes, which proceed from a skein of cause-and-effect that reaches back to the big bang, then the conscious “self” may believe that it freely chooses how to behave, but that belief, Wilson implies, is an illusion.

“Confidence in free will is biologically adaptive,” Wilson argues. It protects us from fatalism. Reassured by imagining that we exert conscious control over our lives, we keep on reproducing our kind. But in a material universe governed entirely by physical laws, he concedes, free will does not exist “in ultimate reality.” Then what is the point of exhorting readers to embrace the theory of evolution, to preserve the Earth’s wealth of living things, to overcome bigotry and put an end to war? How could we, by conscious effort, change our actions or beliefs?

Despite this seemingly fatal flaw in his enterprise, we should be grateful that Wilson, so late in his illustrious career, still appeals to reason and imagination in hopes of enlightening us about our nature and inspiring us to change our destructive ways.

Scott Russell Sanders is the author, most recently, of “Earth Works: New & Selected Essays” and “Divine Animal: A Novel.”