Despite the vision and farseeing wisdom of our wartime heads of state, the physicists have felt the peculiarly intimate responsibility for suggesting, for supporting, and in the end, in large measure, for achieving the realisation of atomic weapons. Nor can we forget that these weapons as they were in fact used dramatised so mercilessly the inhumanity and evil of modern war. In some sort of crude sense which no vulgarity, no humour, no overstatement can quite extinguish, the physicists have known sin; and this is a knowledge which they cannot lose.
— J Robert Oppenheimer (22 April 1904 – 18 February 1967), American physicist and the scientific director of the Manhattan Project.
Physics in the Contemporary World, Lecture at M.I.T. (25 November 1947)