"The question that will decide our destiny is not whether we shall expand into space. It is: shall we be one species or a million? A million species will not exhaust the ecological niches that are awaiting the arrival of intelligence."
"Few people even scratch the surface, much less exhaust the contemplation of their own experience."
"Only the really plain people know about love - the very fascinating ones try so hard to create an impression that they soon exhaust their talents."
"Although you may spend your life killing, You will not exhaust all your foes. But if you quell your own anger, your real enemy will be slain."