Shouldn't we all wonder where humans get their ideas? Here's what I mean --

Human brains are so-o-o enormous that they are capable of taking in an enormous number of impressions. However, human brains are incapable of sorting through all those impressions in real time, so some of them are stored to be accessed later, if at all. The storage locker is popularly called "the unconscious," as apart from the "conscious" which actually deals with *selected* impressions. Therefore, the answer to my question is this: Humans get their ideas from the enormous number of impressions stored in their unconscious.

Some stored impressions, however, are mis-impressions, i.e., mistaken impressions. Those mistaken impressions lead nowhere or to mistaken conclusions, including what we call "mental illness." The difference between "mistakes" and "mental illness" is merely a matter of degree, as Freud noted. In the long run, then, we're always on the precipice -- all of us. It's just a matter of degree.