The trouble with most of the things that people want is that they get them.

The Vietnamese have a secret weapon. It's their willingness to die beyond our willingness to kill. In effect, they've been saying, You can kill us, but you'll have to kill a lot of us; you may have to kill all of us. And, thank heaven, we are not yet ready to do that.

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

About two million years ago, man appeared. He has become the dominant species on the earth. All other living things, animal and plant, live by his sufferance. He is the custodian of life on earth, and in the solar system. It's a big responsibility.

Our business is with life, not death.

When you have no experience of pain, it is rather hard to experience joy.

Not all living creatures die. An amoeba, for example, need never die; it need not even, like certain generals, fade away. It just divides and becomes two new amoebas.