Four elements, Hydrogen, carbon, oxygen and nitrogen, also provide an example of the astonishing togetherness of our universe. They make up the "organic" molecules that constitute living organisms on a planet, and the nuclei of these same elements interact to generate the light of its star. Then the organisms on the planet come to depend wholly on that starlight, as they must if life is to persist. So it is that all life on the Earth runs on sunlight. [Referring to photosynthesis]

One has only to contemplate the magnitude of this task to concede that the spontaneous generation of a living organism is impossible. Yet here we are-as a result, I believe, of spontaneous generation.

Civilization will end within 15 or 30 years unless immediate action is taken against problems facing mankind.

I tell my students to try early in life to find an unattainable objective.

If the germ plasm wants to swim in the ocean, it makes itself a fish; if the germ plasm wants to fly in the air, it makes itself a bird. If it wants to go to Harvard, it makes itself a man. The strangest thing of all is that the germ plasm that we carry around within us has done all those things. There was a time, hundreds of millions of years ago, when it was making fish. Then ... amphibia ... reptiles ... mammals, and now it's making 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.

Our business is with life, not death.