Sigmund Freud — "The aim of all life is to find pleasure and avoid pain."

"The tendency to aggression is an innate, independent, instinctual disposition in man."

"I have found little that is 'good' about human beings on the whole. In my experience most of them are trash, no matter whether they publicly subscribe to this or that ethical doctrine or to none at al…"

"The insane are not without reason, but they are without a certain kind of reason."

"The path to happiness is through the fulfillment of the pleasure principle."

"The more the fruits of knowledge become accessible to men, the more widespread is the decline of religious belief."