"We can come to look upon the deaths of our enemies with as much regret as we feel for those of our friends, namely, when we miss their existence as witnesses to our success."

"A man can be himself only so long as he is alone."

"It is with trifles, and when he is off guard, that a man best reveals his character."

"The doctor sees all the weakness of mankind; the lawyer all the wickedness, the theologian all the stupidity."

"For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring."

"The nineteenth century believed in science but the twentieth century does not."

"Science and religion are the two most powerful forces in the world. Having them at odds... is not productive."

"The universe speaks in the silent dialect of universal natural laws."