Historians are wont to name technological advances as the great milestones of culture, among them the development of the plow, the discovery of smelting and metalworking, the invention of the clock, printing press, steam power, electric engine, lightbulb, semiconductor, and computer. But possibly even more transforming than any of these was the recognition by Greek philosophers and their intellectual descendants that human beings could examine, comprehend, and eventually even guide or control their own thought process, emotions, and resulting behavior. With that realization we became something new and different on earth: the only animal that, by examining its own cerebration and behavior, could alter them. This, surely, was a giant step in evolution. Although we are physically little different from the people of three thousand years ago, we are culturally a different species. We are the psychologizing animal.
