"The difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind."

"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…"

"What a book a Devil's Chaplain might write on the clumsy, wasteful, blundering, low, and horridly cruel works of nature!"

"But I am very poorly today & very stupid & I hate everybody & everything. One lives only to make blunders."

"I confess I am not much interested in the future, for I am too much occupied with the present."