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.

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.

Death seems to have been a rather late invention in evolution. One can go a long way in evolution before encountering an authentic corpse.

A scientist is in a sense a learned small boy. There is something of the scientist in every small boy. Others must outgrow it. Scientists can stay that way all their lives.

The thought that we're in competition with Russians or with Chinese is all a mistake, and trivial. We are one species, with a world to win.

[Attributing the origin of life to spontaneous generation.] However improbable we regard this event, it will almost certainly happen at least once.... The time... is of the order of two billion years.... Given so much time, the "impossible" becomes possible, the possible probable, and the probable virtually certain. One only has to wait: time itself performs the miracles.

The only use for an atomic bomb is to keep somebody else from using one. It can give us no protection - only the doubtful satisfaction of retaliation...