There is plenty of theoretical ambition where humanists and public intellectuals meet the global ecological crisis. On a well-stocked bookstore shelf, you can find calls for interspecies democracy, “post-humanism,” and a revival of ancient Stoicism to learn “how to die in the Anthropocene,” the new era in which human powers shape the planet alongside geological forces. But philosophical radicalism doesn’t have much practical payoff. Some eco-theorists are vegetarians, some like to take their pets for walks, and pretty much all would support a carbon tax but have no special insight on how to get it passed.

So it is exciting that Edward O. Wilson, the Harvard evolutionary theorist and two-time Pulitzer winner, has devoted his new book, Half-Earth, to an audacious and concrete proposal: We should set aside half the planet’s surface for nonhuman life. Rain forests, savannas, deserts, alpine meadows, and many more places should be preserved, mostly undisturbed, perhaps visited occasionally and observed at home through a few aptly placed web cams. Wilson would consecrate to nonhuman life as much of the planet as you can see from space, as much as the sun shines on.

Half-Earth completes the 86-year-old Wilson’s valedictory trilogy on the human animal and our place on the planet. The first in the series, The Social Conquest of Earth (2012), is an accessible summa of Wilson’s lifetime of work on evolution, human nature, war, religion, and the relationship between science and the humanities. The Meaning of Human Existence (2014) argues for telling new stories about nature, making the most of our status as “the mind of the biosphere.” All of this extends well beyond the core of Wilson’s scientific work—for many decades he has been a leading authority on ants—but since he published two sweepingly ambitious books in the late 1970s, Sociobiology and On Human Nature (the latter the occasion of his first Pulitzer), Wilson has dedicated much of his energy to arguments about what, exactly, we are. A passionate conservationist, he has also always asked how our strange species fits among the other kinds of lives that we often threaten or exterminate.

Considering that Wilson’s proposal to preserve half the earth is addressed to the species busily consuming all of it—it is now estimated that humans’ ecological demands well outstrip the planet’s long-term carrying capacity—the interesting question is how he imagines we might be persuaded to adopt his radical proposal to limit our reach. The wild nature Wilson studies and loves depends on human nature because to save the earth people would have to achieve a new level of self-restraint. How does Wilson imagine the human side of nature can be marshaled to save the wild one? 

Wilson argues that humans dominate the planet because of our social nature, our gift for cooperation. We are among the handful of species that build their own environments, along with termites, ants, and the naked mole rat. Other highly social species work through caste divisions and instinct; worker ants, soldier ants, and queens are differently shaped cogs in a biological machine. Humans, instead, cooperate through high levels of social intelligence: emotional perception and mirroring that cue trust and mistrust, narrative thinking that enables us to lay plans, and language, that great and supple connector of minds.

HALF-EARTH: OUR PLANET’S FIGHT FOR LIFE by Edward O. WilsonLiveright, 272 pp., $25.95

For Wilson, we are torn between instincts that lead us to cooperate and follow social codes, on the one hand, and selfish impulses on the other. Wilson is in the minority among evolutionary theorists in arguing that human nature is split because evolution itself is split between two levels of selection: individual selection, which favors selfish genes, and group selection, which favors families and tribes with a propensity to cooperate. Whether or not you accept Wilson’s version of its Darwinian origins, his picture of people is a gloss on an old and universal insight: Humanity is at once angel and beast, world-preserving Vishnu and world-destroying Shiva, loyal and ever generous and also an untrustworthy pain in the ass. Much of social and political theory is an archive of navigators’ charts portraying these treacherous shoals.

Wilson understands religion and culture as basically side effects of social intelligence. For him, humans are obsessive storytellers who instinctively use narrative to imagine other minds and map out social scenarios. We make up stories about gods and spirits because narrative is how we build a navigable world. We find it comforting to tell stories even when the characters are imaginary—a point that religious skeptics have been making at least since Epicurus and Lucretius. In literature and drama we map, remap, and bedazzle the fault lines and back alleys of our divided nature. Antigone, Macbeth, Encyclopedia Brown: All are narrative dioramas of our mixed nature.

For Wilson, science contributes to the humanities by showing the parochial character of our stories. Most of the world is outside our perception: the ultraviolet light that some animals see, the complex smells that plants and insects use to communicate, the electromagnetic fields that guide migrating birds, the many registers of sound where elephants and whales are chatting. We are, Wilson evocatively suggests, like blind and deaf people walking in New York City, feeling an occasional rumble from the subway or gust of wind, but missing most of the noise, conversation, signs, and sights. For that matter, most of our stories take place within the timelines of human life and history; but science points us to deep time, the stories of old species, galaxies, continents. It suggests imagining the inner lives of other kinds of animals than ourselves.

Wilson hopes to inspire an imaginative leap, informed by science but powered by the humanities, into a cultural attitude in which people would explore the experience of other species and the perspective, so to speak, of ecosystems and even of the planet. (In other writing he has set stories among the ants.) Nowhere in this trilogy does he come close to narrating an enriched and expanded consciousness of life’s many forms, but that is a tall order. Other writers, whom Wilson does not mention, point the way: Aldo Leopold’s A Sand County Almanac tells the story of an atom that lived out parts of its life as grass, in the body of a buffalo, as part of a human body, and in a long sleep on a Southern riverbank. Barry Lopez’s Arctic Dreams includes a wondrous meditation on the feeling of being a narwhal, a creature for which undersea sound is everything, which steers by vibration in a three-dimensional sonic world. While Wilson celebrates all the humanities as the free play of human nature, this is the frontier that matters most to him—above all because it fosters the kind of imagination that might embrace the half-earth project.

How does Wilson imagine that such change happens, not on the evolutionary scale, but on the political timeline where his proposal will succeed or fail? He doesn’t really say, but he gives a few clues. Discussing the future of population, he notes one of the most hopeful statistics of recent history: When women achieve literacy and a modicum of empowerment, the birthrate falls enough that global population should begin dropping—on current projections this will happen in most countries by the end of the century. There is no stronger evidence that human freedom and progress are compatible with long-term planetary health. Wilson says of this change that “population growth has begun to decelerate autonomously, without pressure one way or the other from law or custom,” and he calls it “an unintended consequence of human nature, namely the flip from r-strategy reproduction”—large numbers of poorly resourced offspring—“to K-strategy reproduction”—small numbers of well-resourced offspring—“in favorable environments.” Missing from that picture are the lives women want to live by having fewer children; the laws and policies that establish or undermine sexual equality and personal autonomy; three waves of modern feminism; and the thought of, among others, Mary Wollstonecraft, Harriet Taylor Mill, and John Stuart Mill.

Wilson’s optimism about economic growth is also rooted in a naturalized logic of history. Here the driver is the “evolution of the free market system” toward energy-efficient, eco-friendly technologies. Wilson exudes confidence that lightening our ecological footprint is just what markets organically do as they evolve. But of course there is no scenario in which such change happens without a massive political decision to build ecological “costs” into the price of energy and other technologies; otherwise, markets will continue to “evolve” dysfunctionally by treating the global atmosphere as a free dumping ground.

Even this is just a standard technocratic fix, which gives political regulation a central place but aims to “make markets work.” Is that enough? Wilson writes cheerily that, “Almost all of the competition in a free market, other than in military technology, raises the average quality of life.” This is a rather faith-based assertion for a man of science. There are plausible, and darker, ways to see things. There is growing evidence that competition can amplify economic inequality, concentrate market power in oligopolies and monopolies, and foster industries with dubious public benefit, such as much of high finance. If we want what Wilson urges, a move toward an economy of “quality” rather than “quantity,” it may be that the current market economy is perfectly counterproductive: By producing insecurity at every point, from anxious and unequal education to a precarious job market to uncertain retirement, it ensures that no one ever really has enough. That is the microeconomics of an economy of endless appetite for more, what Wilson would call an economy of quantity. A shift to “quality,” meaning, for instance, valuing the natural world for its own sake, might have a fighting chance after a move to a more secure, more humane social order. Wilson gives no hint of having considered this wrinkle in the “evolution of the free market system.”

A more interesting approach was possible. Wilson argues that human nature is flexible, but not infinitely so. Universal templates—solidarity, sympathy, self-interest, storytelling, a sense of beauty, the impulse to transcendence—get expressed in some of many possible forms. But how do we select among the expressions? Surely by creating the institutional and legal architecture—our far more complex version of the ant colony and its roles—in which people learn to fear or trust one another, form sympathetic bonds with parts and places of the natural world, and develop the social repertoires, cosmologies, and forms of judgment that guide them through the world. In other words, human nature is a political creation—not, of course, at the deepest biological level, but at the level that counts, the one that can make a difference where we live.

Although Wilson aims for the vantage of the universe—who else today calls a book The Meaning of Human Existence?—the strengths and limitations of his standpoint are those of a mind formed in the twentieth-century United States. He believes that nature is generally benign and is at its purest in wilderness; he is distressed that children today are less exposed to remnants of the wild than he was in his Alabama childhood of the 1930s and 1940s, but he does not seem to have imagined how it would feel to be radically more vulnerable to nature, whether in the form of a drought, an epidemic, or a predator, as many were a century or two earlier. Wilson imagines markets as natural things, born organically from human rationality and social intelligence. He has the indifference to serious political thought of someone who has always been able to take good-enough government for granted. And he has a kind of revivalist, post-Transcendentalist sense that if “we” could just get the problem of human consciousness right, history would pivot at last in the right direction.

This is a book of grand ambition without much to say. The glimmer of an important argument is here, but it is not much developed beyond the title. Wilson has given us a shambles, a smudgy and diminished case for a big idea. Half-Earth, The Meaning of Human Existence, and The Social Conquest of Earth repeat themes and arguments, and the habit gets more frequent with each new book. Instead of drawing a speculative map of which half of the earth would be saved and proposing what the path to preserving it might be, Wilson fills 18 pages with one-paragraph sketches of some naturalists’ favorite places on earth, which get mired in repetitious breathlessness. He tells us that he and other naturalists take joy in nature, but admits this is a feeling “I can’t explain in words to you.” This turns out to be true.

Half-Earth also feels poorly balanced. Approaching his final argument, Wilson veers off for several pages into the prospect of artificial intelligence, then doesn’t explain why, except repeating that we humans need to think about our place in the world. He devotes polemical chapters to the word “Anthropocene,” the geological portmanteau term for “the age of humanity” which Wilson calls “the most dangerous worldview.” It isn’t. He argues (asserts, really) that the word implies arrogance, human selfishness, and ecological complacency. It doesn’t. All of this is a distraction. The Anthropocene is a useful name for the reality that the future of the planet is, for better or worse, substantially in human hands, and that we need forms of thought and politics that can make our choices more deliberate and generous. Half-Earth is an Anthropocene argument through and through, and Wilson wastes time attacking the idea of “the Anthropocene” when he should be making his case.

The Senegalese ecologist Baba Dioum said in 1968, “In the end, we will conserve only what we love, we will love only what we understand, and we will understand only what we are taught.” Although Wilson does not repeat Dioum’s much-quoted adage, he offers himself as a teacher, explaining the world in order to save it. Unfortunately, his well-intended book is a victim of his parochial understanding of the human beings who are both its audience and its topic. It will take something different to save the earth even halfway.