“It suggests to us that behavior of complex animals can change very rapidly, and not always for the better. It suggests that behavior can cease to be responsive to the environment, and lead to decline and death. It suggests that animals may stop adapting. Is this what happened to the dinosaurs? Is this the true cause of their disappearance? We may never know. But it is no accident that human beings are so interested in dinosaur extinction. The decline of the dinosaurs allowed mammals—including us—to flourish. And that leads us to wonder whether the disappearance of the dinosaurs is going to be repeated, sooner or later, by us as well. Whether at the deepest level the fault lies not in blind fate—in some fiery meteor from the skies—but in our own behavior. At the moment, we have no answer.”