“The ultimate test of man's conscience may be his willingness to sacrifice something today for future generations whose words of thanks will not be heard.”

“Not the criticism of individual contemporaries will decide the truth or falsity of these discoveries, but future generations. There are things that are not yet true today, perhaps we dare not find them true, but tomorrow they may be. So every man whose fate it is to go his individual way must proceed with hopefulness and watchfulness, ever conscious of his loneliness and its dangers.”

“Conscience. Conscience is the ultimate measure of a man.”

“A man's conscience and his judgment are the same thing, and, as the judgment, so also the conscience may be erroneous”

“Man has come to dominate the planet thanks to two essential traits. One is intelligence. The other has been the absolute willingness to kill anyone and anything that gets in his way.”

“Don't judge a man's conscience by looking at his face cause he may have a bad heart.”