Psychology

The Savage interrupted him. "But isn't it natural to feel there's a God?"
"You might as well ask if it's natural to do up one's trousers with zippers," said the Controller sarcastically. "You remind me of another of those old fellows called Bradley. He defined philosophy as the finding of bad reason for what one believes by instinct. As if one believed anything by instinct! One believes things because one has been conditioned to believe them. Finding bad reasons for what one believes for other bad reasons–that's philosophy. People believe in God because they've been conditioned to.
"But all the same," insisted the Savage, "it is natural to believe in God when you're alone–quite alone, in the night, thinking about death …"
"But people never are alone now," said Mustapha Mond. "We make them hate solitude; and we arrange their lives so that it's almost impossible for them ever to have it."

One of the symptoms of an approaching nervous breakdown is the belief that one’s work is terribly important.

Unlike the physicist, the psychologist … investigates processes that belong to the same order — perception, learning, thinking — as those by which he conducts his investigation.