Carl Friedrich von Weizsäcker A Scientist Faced with “The Ambivalence of Progress”

As a young physicist, he was involved in developing a nuclear bomb, and later founded a peace research institute. First he was a physicist, then a philosopher, and finally a political intellectual: Carl Friedrich von Weizsäcker’s path through the twentieth century was a long and convoluted one. He was born 100 years ago.

Carl Friedrich von Weizsäcker; © Lorenz Vierecke Carl Friedrich von Weizsäcker | © Lorenz Vierecke He proposed a theoretical interpretation of quantum physics and a theory about how planets had formed from clouds of gas. He taught philosophy and, in his own words, felt “at home” with Plato. He visited the Ashram of Pondicherry, admired Buddhism and meditated regularly. His books deal with The Unity of Nature, The Structure of Physics, peace politics and Der Mensch in seiner Geschichte (i.e. Man in his History).

Carl Friedrich von Weizsäcker, who was born in Kiel on 28 June 1912 and died at Lake Starnberg on 28 April 2007, appears to be something of a postmodern universal genius. He himself, however, explained his broad spectrum of works more modestly, saying that he was “mathematically too stupid” to be a successful pure physicist.

An elite German family

In a television interview, Carl Friedrich von Weizsäcker once made great play of his family’s background as millers – his name, after all, is derived from people who lugged around sacks of wheat, or Weizensäcke. That is quite a few generations ago, however. By the nineteenth century, the Weizsäckers were already an elite German family, influenced by science and politics. A great-grandfather of Carl Friedrich was a professor of theology in Tübingen, while his grandfather Carl was given a hereditary peerage as prime minister of the Kingdom of Württemberg.

His father, Ernst Heinrich, had been in the diplomatic service since 1925: to the present day, there is controversy surrounding his career path, which saw him advance from the Weimar Republic’s League of Nations consul to state secretary under Hitler and, in the last years of the war, to ambassador to the Vatican. Just recently, the historians’ report commissioned by the Federal Foreign Office revealed the active role he played in stripping Thomas Mann of his German citizenship. Carl Friedrich always defended his father, who was convicted after the war and spent a year in prison, saying that he was an anti-Nazi within the apparatus whose hope had always been “to prevent even worse things from happening”.

Carl Friedrich’s uncle was a neurologist who is regarded as a co-founder of psychosomatic medicine. His brother Richard became a politician in the Christian Democratic Union (CDU) party, ultimately rising to the office of Federal President. His son has also continued in the family tradition: a physicist and biologist, he was president of the Wuppertal Institute for Climate, Environment and Energy until 2000.

A diplomat’s child turns researcher

Carl Friedrich von Weizsäcker’s path was already given decisive impetus in 1927 when 14-year-old Carl – the child of a diplomat in Copenhagen – met Werner Heisenberg, a co-founder of quantum theory. He advised Carl, his junior by ten years, to study physics, and a few years later made him his student. Thus Weizsäcker gained access to the world of avant-garde physics led by Niels Bohr and Otto Hahn, at whose Berlin institute he worked from 1937 – initially under its director Lise Meitner, an Austrian Jew who was forced into exile in 1938.

Weizsäcker focused on nuclear physics, which he initially regarded as pure basic research: “technology did not much interest me.” In early 1939, just a few months before the outbreak of World War Two, Otto Hahn discovered nuclear fission. A small group of experts immediately recognized its practical implications.

From bomb patent to bomb protest

Just what role Weizsäcker played in the development of a German nuclear bomb remains unclear to this day. On the one hand, Weizsäcker claimed in the post-war years that Heisenberg and he had intentionally not pushed forward the project with any great vigour, yet on the other hand he conceded that it had been “divine grace” that they had not succeeded in building the bomb. Recorded comments by Bohr which were later published cast doubt on the claim by Heisenberg and Weizsäcker that they had wanted during the war to warn Niels Bohr in Copenhagen and thus the outside world about the atomic bomb project. What is more, letters from Heisenberg, not published until 2010, reveal that he himself did not trust his pupil’s fervour – who after all entirely on his own had filed a patent in the summer of 1942 for a “process to generate energy and neutrons by an explosion, e.g. in a bomb”. When he was arrested by American and British military forces in 1945, von Weizsäcker was still working, on behalf of the “Uranverein” (i.e. Uranium Club), on an experimental reactor in Haigerloch. Together with Heisenberg and other physicists, he was interned in England until 1946.

Later, in his memoirs entitled “Im Garten des Menschlichen” (translated into English as “The Ambivalence of Progress”), Weizsäcker described his attitude during National Socialism as “reluctant conformism” and admitted that he had emerged from the denazification process with an “undeservedly clean bill of health”. In the post-war era he reacted to this by adopting a markedly non-conformist stance: when German Chancellor Konrad Adenauer (CDU) considered equipping the German Army with so-called “tactical nuclear weapons”, Weizsäcker in 1957 organized the “Göttingen Manifesto”, a declaration by 18 nuclear scientists who wished to protest against nuclear armament and refused to take part in any sort of military nuclear research.

In 1970, Weizsäcker established the “Max Planck Institute for the Research of Living Conditions in the World of Science and Technology” in Starnberg, where he focused primarily on peace research while his co-director Jürgen Habermas addressed sociology and Klaus Michael Meyer-Abich devoted himself to ecological issues. In this form, the institute existed only until Weizsäcker retired in 1980.

The happy philosopher

Weizsäcker remained a professor of physics in Göttingen until he was 45, when he moved to a chair in philosophy in Hamburg in 1957 for twelve years. Looking back, Weizsäcker described that time as “the best years of my life”. As a philosopher, Weizsäcker’s preferred area of study was ancient Greek philosophy; apparently, he could effortlessly translate Plato to the world of quantum mechanics: “What we call matter are ideas released into the three-dimensional world.” For Weizsäcker, Platonism and modern physics have in common the fact that they both go beyond a superficial way of thinking in terms of substances: consciousness and matter, subject and object are not opposites but manifestations of one and the same reality.

On the other hand, Weizsäcker sought in philosophy not only to confirm and reflect upon science but also to go beyond it. He believed that natural science is wrong when it sets itself absolute boundaries. The crisis of humankind which Weizsäcker the peace researcher studied during the Cold War was found by Weizsäcker the philosopher to have its roots in occidental thought, whose aim is to gain control over humans and nature. “The way humans deal with power is always one of the biggest problems”, said Weizsäcker, who knew what he was talking about here.