"My mind seems to have become a kind of machine for grinding general laws out of large collections of facts, but why this should have caused the atrophy of that part of the brain alone, on which the hi…"

"At some future period, not very distant as measured by centuries, the civilized races of man will almost certainly exterminate and replace the savage races throughout the world."

"Ignorance more frequently begets confidence than does knowledge."

"The greatest discovery of all is that the world is not as we thought it was."

"If I had my life to live over again, I would have made a rule to read some poetry and listen to some music at least once every week."