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.