"To have security against atomic bombs and against the other biological weapons, we have to prevent war, for if we cannot prevent war every nation will use every means that is at their disposal; and in spite of all promises they make, they will do it. At the same time, so long as war is not prevented, all the governments of the nations have to prepare for war, and if you have to prepare for war, then you are in a state where you cannot abolish war."

Source: Address to the symposium The Social Task of the Scientist in the Atomic Era at the Institute for Advanced Study in Princeton, New Jersey, November 17, 1946.