Joseph Rotblat walked away from the atomic bomb

Person: Joseph Rotblat
Lived: 1908–2005
Field: Physics, disarmament
From: Polish-British

The story

Joseph Rotblat was born in Warsaw in 1908 into a Polish-Jewish family and received his early education in a cheder taught by a local rabbi. He trained as an electrician before becoming a physicist, and before the Second World War he showed that neutrons are emitted in nuclear fission and worked out that a fast enough chain of fissions would cause an explosion. In 1939 he went to Liverpool to work with James Chadwick. His wife, Tola, who was to follow him, was trapped in Poland by the German invasion and was later murdered at Belzec.

Rotblat was troubled by the morality of building an atomic bomb, but he feared that Nazi Germany would build one first and believed the Allies needed the ability to retaliate. In February 1944 he went to Los Alamos with the British mission to the Manhattan Project. He declined to take British or American citizenship, and the usual requirement was waived for him.

By the end of 1944 it was clear that Germany had abandoned its bomb programme. For Rotblat the only justification for the work had vanished, and he asked to leave on grounds of conscience, returning to Liverpool. He was the only scientist to quit the Manhattan Project for moral reasons. He felt betrayed when the bombs were used against Japan in 1945, and he resolved that his own research would serve only peaceful ends, turning to medical physics at St Bartholomew’s Hospital in London.

He spent the rest of his long life working to abolish the weapons he had helped to create: as a signatory of the Russell–Einstein Manifesto in 1955, as a founder and leader of the Pugwash Conferences on Science and World Affairs, and as a co-founder of the Campaign for Nuclear Disarmament. He shared the 1995 Nobel Peace Prize with Pugwash, and he argued that scientists need their own equivalent of the Hippocratic Oath. His Nobel lecture ended: “Above all, remember your humanity.”

Why it matters

Rotblat’s decision remains the best-known example of a scientist refusing weapons work on moral grounds, and it inspires today’s debates about scientists’ responsibility for how their discoveries are used.

About Joseph Rotblat

Warsaw-born Jewish physicist, the only scientist to quit the Manhattan Project on grounds of conscience, who led the Pugwash movement for nuclear arms control. Nobel 1995.

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Joseph Rotblat

1908–2005 · Physics, disarmament

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