Charles Darwin — "He who understands baboon would do more towards metaphysics than Locke."

"Blushing is the most peculiar and most human of all expressions."

"The expression of the emotions in man and animals is a study of the utmost interest."

"I am almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable."

"My mind seems to have become a kind of machine for grinding general laws out of large collections of facts."

"Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by sc…"