The discoveries of yesterday are the truisms of tomorrow, because we can add to our knowledge but cannot subtract from it.

The moment of truth, the sudden emergence of a new insight, is an act of intuition. Such intuitions give the appearance of miraculous flushes, or short-circuits of reasoning. In fact they may be likened to an immersed chain, of which only the beginning and the end are visible above the surface of consciousness. The diver vanishes at one end of the chain and comes up at the other end, guided by invisible links.

Adolescence is a kind of emotional seasickness. Both are funny, but only in retrospect.

Faith is a wondrous thing; it is not only capable of moving mountains, but also of making you believe that a herring is a race horse.

The fact is: I no longer believe in my own infallibility. That is why I am lost.

Most of us were not afraid of death, only of the act of dying; and there were times when we overcame even this fear. At such moments we were free-men without shadows, dismissed from the ranks of the mortal; it was the most complete experience of freedom that can be granted a man.

Hitherto man had to live with the idea of death as an individual; from now onward mankind will have to live with the idea of its death as a species.