"The intellectual is, quite simply, a human being who has a pencil in his or her hand when reading a book."
"For all things difficult to acquire, the intelligent man works with perseverance."
"We on Earth have just awakened to the great oceans of space and time from which we have emerged. We are the legacy of 15 billion years of cosmic evolution. We have a choice: We can enhance life and come to know the universe that made us, or we can squander our 15 billion-year heritage in meaningless self-destruction. What happens in the first second of the next cosmic year depends on what we do, here and now, with our intelligence and our knowledge of the cosmos."
"An enlightened public opinion can only be generated by the efforts of those who desire that it should exist."
"To be able to fill leisure intelligently is the last product of civilization, and at present very few people have reached this level."
"Nothing in all the world is more dangerous than sincere ignorance and conscientious stupidity."
"The poet only asks to get his head into the heavens. It is the logician who seeks to get the heavens into his head. And it is his head that splits."
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
"A great deal of intelligence can be invested in ignorance when the need for illusion is deep."