“Our main difference from chimps and gorillas is that over the last 3 million years or so, we have been shaped less and less by nature, and more and more by culture. We have become experimental creatures of our own making. This experiment has never been tried before. And we, its unwitting authors, have never controlled it. The experiment is now moving very quickly and on a colossal scale. Since the early 1900s, the world’s population has multiplied by four and its economy — a rough measure of the human load on nature — by more than forty. We have reached a stage where we must bring the experiment under rational control, and guard against present and potential dangers. It’s entirely up to us. If we fail — if we blow up or degrade the biosphere so it can no longer sustain us — nature will merely shrug and conclude that letting apes run the laboratory was fun for a while but in the end a bad idea.”