"As a proof of the admirable power of the mind, I may mention that I have been for some years training my mind to reject the evidence of my senses when they do not square with my preconceived notions."

"I am not apt to follow blindly the lead of other men."

"Man in his arrogance thinks himself a great work, worthy of the interposition of a deity. More humble and I believe truer to consider him created from animals."

"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…"

"It is a wonderful fact that we can understand so much."