Though psychology is a relatively modern discipline, we can look back to our old friends the Greek philosophers and see that the genesis of psychological thinking began back then. Plato's myth of the cave, wherein we the cave dwellers only see shadows of reality while the Truth is forever obscured to all save brave inquiring minds, can also be a metaphor for the unconscious. Our conscious selves are only the tip of the iceberg, a mere fraction of the totality that makes us tick.

The ancient philosophers and medical men also tried to come to terms with the problems of insanity. In the earliest speculations, demonic possession and other supernatural forces took the blame. Later thinkers sought to find physical causes for mental illness. Plato and Socrates believed that insanity arose when man's animal nature overwhelmed his logical mind. This is a precursor to the twentieth-century concepts of the Id and the shadow. An early physician named Galen came up with the idea that bodily fluids, or humours, regulated the emotions. If the four humours were out of balance, mental illness occurred. The four humours identified by Galen are blood and the unappetizing sounding black bile, yellow bile, and phlegm.

It wasn't until the late nineteenth century that psychology came into its own as a separate discipline. And perhaps the most famous of the fledgling psychiatrists was Sigmund Freud.