Conventional wisdom has it that the way to avert global ecological disaster is to persuade people to change their selfish habits for the common good. A more sensible approach would be to tap a boundless and renewable resource: the human propensity for thinking mainly of short term self-interest

At 82, the famed biologist E. O. Wilson arrived in Mozambique last summer with a modest agenda—save a ravaged park; identify its many undiscovered species; create a virtual textbook that will revolutionize the teaching of biology. Wilson’s newest theory is more ambitious still. It could transform our understanding of human nature—and provide hope for our stewardship of the planet.