Joseph Rotblat was one of the great men of the 20th century. He was a man of science and peace. Born in Warsaw, Poland in 1908, he was one of those rare individuals who, like Rosa Parks or Nelson Mandela, comes to an intersection with history and courageously forges a new path. In Joseph’s case, the intersection with history arrived in 1944 while he was working on the Manhattan Project, the US project to develop an atomic bomb.

Joseph had worked as a scientist toward the creation of an atomic weapon, first in the UK at the University of Liverpool and then at Los Alamos, New Mexico. When he learned in late 1944 that Germany would not succeed in developing an atomic bomb, he believed there was no longer reason to continue work on creating a US bomb. For him, there was only one reason to create an atomic weapon, and that was to deter the German use of such a weapon during World War II. If the Germans would not have an atomic weapon, then there was no reason for the Allies to have one. Joseph was the only scientist to leave the Manhattan Project on moral grounds.

He was the last living signer of the 1955 Russell-Einstein Manifesto, one of the great documents of the 20th century, and he often quoted its final passage: “We appeal, as human beings, to human beings: Remember your humanity and forget the rest. If you can do so, the way lies open for a new paradise; if you cannot, there lies before you the risk of universal death.”

He was convinced that countries needed to abolish nuclear weapons and he devoted his life to achieving this goal, as well as the goal of ending war as a human institution. Just prior to his 90th birthday, he said that he still had two great goals in life. “My short-term goal,” he said, “is the abolition of nuclear weapons, and my long-term goal is the abolition of war.”

Joseph was for many years the General Secretary of the Pugwash Conferences on Science and World Affairs, and later served as president of the Pugwash Conferences. In his work with Pugwash, he was instrumental in bringing together scientists from East and West, so that they could find common ground for ending the Cold War with its mad nuclear arms race. In 1995, Joseph and the Pugwash Conferences were joint recipients of the Nobel Peace Prize.

He began his Nobel acceptance speech by saying, “At this momentous event in my life…I want to speak as a scientist, but also as a human being. From my earliest days I had a passion for science. But science, the exercise of the supreme power of the human intellect, was always linked in my mind with benefit to people. I saw science as being in harmony with humanity. I did not imagine that the second half of my life would be spent on efforts to avert a mortal danger to humanity created by science.”

In his speech, he reasoned that a nuclear weapon-free world would be safer than a world with nuclear weapons, but the danger of “ultimate catastrophe” would still exist. He concluded that war must be abolished: “The quest for a war-free world has a basic purpose: survival. But if in the process we learn how to achieve it by love rather than by fear, by kindness rather than compulsion; if in the process we learn to combine the essential with the enjoyable, the expedient with the benevolent, the practical with the beautiful, this will be an extra incentive to embark on this great task.”

When Joseph came to Santa Barbara in 1997 to receive the Nuclear Age Peace Foundation’s Lifetime Achievement Award for Distinguished Peace Leadership, I asked him, “What gives you hope for the future?” He responded, “My hope is based on logic. Namely, there is no alternative. If we don’t do this [eliminate nuclear weapons and engender more responsibility by scientists as well as citizens in general], then we are doomed. The whole existence of humankind is endangered. We are an endangered species now and we have to take steps to prevent the extinguishing of the human species. We owe an allegiance to humanity. Since there is no other way, then we must proceed in this way. Therefore, if we must do it, then there is hope that it will be done.”

Earlier this year, Joseph made an appeal to the delegates to the nuclear Non-Proliferation Treaty Review Conference, held in May at the United Nations in New York. “Morality,” he wrote, “is at the core of the nuclear issue: are we going to base our world on a culture of peace or on a culture of war? Nuclear weapons are fundamentally immoral: their action is indiscriminate, affecting civilians as well as military, innocents and aggressors alike, killing people alive now and generations as yet unborn. And the consequence of their use could bring the human race to an end.” He ended his appeal with his oft-repeated plea, “Remember your humanity.”

I visited Joseph at his home in London just a few months ago. He had been slowed down by a stroke and was disturbed that he wasn’t able to be as active as he’d been accustomed. But his spirit was strong, and he was still smiling and looking forward. He was as committed as ever to his dual goals of achieving a world without nuclear weapons and without war – goals to which he had devoted the full measure of his energy, intellect and wisdom.

Joseph has left behind a strong legacy of peace. It is our job now to pick up the baton that he carried so well and passionately for so long, and continue his legacy.

David Krieger is president of the Nuclear Age Peace Foundation ( and the Deputy Chair of the International Network of Engineers and Scientists for Global Responsibility (