Every creature alive on the earth today represents an unbroken line of life that stretches back to the first primitive organism to appear on this planet; and that is about three billion years.

Our challenge is to give what account we can of what becomes of life in the solar system, this corner of the universe that is our home; and, most of all, what becomes of men-all men, of all nations, colors, and creeds. This has become one world, a world for all men. It is only such a world that can now offer us life, and the chance to go on.

Since we have had a history, men have pursued an ideal of immortality.

A scientist lives with all reality. There is nothing better. To know reality is to accept it, and eventually to love it.

There's life all over this universe, but the only life in the solar system is on earth, and in the whole universe we are the only men.

I have often had cause to feel that my hands are cleverer than my head. That is a crude way of characterizing the dialectics of experimentation. When it is going well, it is like a quiet conversation with Nature. One asks a question and gets an answer, then one asks the next question and gets the next answer. An experiment is a device to make Nature speak intelligibly. After that, one only has to listen.

Dropping those atomic bombs on Hiroshima and Nagasaki was a war crime.