Humanity's comforting sense of the performance of the natural world is the result of a subtly warped perspective. Total changes in the natural world can now happen during the lifetime of a person. Without recognizing it, humanity has already stepped over the threshold of such a change and has reached the end of nature, namely the end of that set of human ideas about the world and man's place in it. The death of these ideas began with definite changes in the reality of the natural world -- changes which can be measured. With increasing frequency such changes will clash with man's perceptions until finally the mistaken sense of nature as eternal and separate will no longer be tenable.