Carl Friedrich von Weizsäcker, the German physicist and philosopher who died on Saturday at age 94, was the last surviving member of the team that tried and failed to develop atomic weapons for the Nazis during World War II; later he dedicated his life to pacifism and philosophy.

A protégé of Werner Heisenberg, who headed Germany’s wartime nuclear program, Weizsäcker attended a crucial meeting at Army headquarters in September 1939 to launch the German atomic weapons project. But when, toward the end of the war, the Americans captured Weizsäcker’s laboratory at Strasbourg and seized his papers, it emerged that the Germans had never come close to developing a weapon.

After being captured in July 1945, Weizsäcker and his fellow scientists were briefly interned near Cambridge, where their conversations were secretly recorded. In one Weizsäcker remarked, on hearing that America had dropped atom bombs on Hiroshima and Nagasaki: “If they were able to finish it by summer ’45, then with a bit of luck we could have been ready in winter ’44-45.”

Historians are divided over how much effort was put into Hitler’s nuclear program. Some believe the scientists’ failure reflected a desire not to succeed because they feared the consequences of the Nazis having a nuclear capability.

Weizsäcker himself encouraged this view in interviews with Robert Jungk for his book “Brighter Than a Thousand Suns” (1957), implying that the team stalled on the technical grounds. While there had been no conspiracy not to make the bomb, there had, he claimed, been “no passion” to press ahead.

The truth emerged only in 1993, when transcripts of secretly recorded conversations between Weizsäcker, Heisenberg and others were published. These had been recorded at a village called Farm Hall, where the scientists were interned.

The “Farm Hall transcripts” revealed that Weizsäcker had taken the lead in arguing for an agreement among the group that they would claim they had never wanted to develop a German bomb. This story — which they knew to be untrue — was known within their circle as die Lesart (the Version).

Carl Friedrich von Weizsäcker was born in the north German port of Kiel on June 28, 1912, into a prominent family of jurists and theologians. After studying physics, mathematics, and astronomy in Leipzig, Berlin, and Göttingen, he went on to become a professor of physics and, later, philosophy. His brother Richard later served as German president between 1984 and 1994.

In 1937, Carl Friedrich made a name for himself as an atomic physicist, through the so-called Weizsäcker Formula, which concerns the energetic substance of atomic cells and the point at which they melt.

He claimed to have worked on the atomic bomb during World War II as a way of avoiding being conscripted into the army; but in later interviews he insisted he was grateful that the Nazis were never able to use the technology they were researching.

After the war Weizsäcker dedicated his energies to philosophy, becoming a professor at the University of Hamburg.

He also remained a physicist, conducting research for the Max Planck Institute.

In 1957, he joined 17 other leading German physicists to form the Göttinger 18, who protested against equipping the West German army with nuclear weapons and urged the state to declare its rejection of nuclear arms.

Influenced by his experiences under the Nazi regime, Weizsäcker also developed an interest in ethics and responsibility.

He wrote several books analyzing the dangers of war in the modern world; translated into a dozen languages, they included “The World View of Physics “(1946), “The Unity of Nature” (1971), and “The Politics of Peril” (1978).

A Christian, he was fascinated by the idea of seeking the hand of God in the laws of physics, concluding that religion and science are not opposites but complements of a fundamental unity.

Weizsäcker’s later works were recognized with the Max Planck Medal in 1957, the Peace Prize of the German Booksellers in 1963 and the Theodor-Heuss Prize for Religion and Integration in Europe in 1988.