From the back of the room, a young man in his early thirties stood. "Actually," the man said, "an observation."

The speaker was dark and thin, dressed in khaki shirt and shorts, precise in his movements and manner. Malcolm recognized him as a paleontologist from Berkeley named Levine, who was spending the Summer at the Institute. Malcolm had never spoken to him, but he knew his reputation: Levine was generally agreed to be the best paleobiologist of his generation, perhaps the best in the world. But most people at the Institute disliked him, finding him pompous and arrogant.

"I agree," Levine continued, "that the fossil record is not helpful in addressing extinction. Particularly if your thesis is that behavior is the cause of extinction - because bones don't tell us much about behavior. But I disagree that your behavioral thesis is untestable. In point of fact, it implies an outcome. Although perhaps you haven't yet thought of it."

The room was silent. At the podium, Malcolm frowned. The eminent mathematician was not accustomed to being told he had not thought through his ideas. "What's your point," he said.

Levine appeared indifferent to the tension in the room. "Just this," he said. "During the Cretaceous, Dinosauria were widely distributed across the planet, We have found their remains on every continent, and in every climatic zone - even in the Antarctic. Now. If their extinction was really the result of their behavior, and not the consequence of a Catastrophe, or a disease, or a change in plant life, or any of the other broad-scale explanations that have been proposed, then it seems to me highly unlikely that they all changed their behavior at the same time, everywhere. And that in turn means that there may well be some remnants of these animals still alive on the earth. Why couldn't you look for them?"

"You could," Malcolm said coldly, "if that amused you. And if you had no more compelling use for your time."