Cheryl Misak in Aeon:
Vienna in the 1920s was an exciting place. Politically, it was the time of Red Vienna, when the municipal government experimented with radical democratic reforms in housing, healthcare, education and worker’s rights. There was optimism in the air, despite postwar hyperinflation and rising conservatism. It was also an exciting time intellectually, for one of the most influential movements in the history of philosophy was in full swing: the Vienna Circle.
They were a group of philosophers, mathematicians and physicists who gathered around the German philosopher Moritz Schlick, and included luminaries such as Rudolf Carnap, Otto Neurath and Herbert Feigl. The Circle put forward an ambitious programme that would have all knowledge constructed out of an objective foundation of observation and deductive logic. Their ‘verifiability principle’ would assert that a meaningful sentence had to be reducible, via truth-preserving logic, to a basic language of observation statements. Metaphysics, ethics, religion and aesthetics were either to be revised so as to be stated in this scientific language, or else declared meaningless – mere nonsense. These new scientific philosophers were socially progressive, at home in Red Vienna, and they saw themselves as intellectually progressive as well. Unfortunately, others all too readily concurred, such as the fascist student who gunned down Schlick on the steps of the University of Vienna in 1936.
Theirs was an idea whose time had come. A similar group was developing in Berlin, with Hans Reichenbach and Carl Hempel as its most prominent members. In Cambridge, Bertrand Russell had also been arguing that philosophy must proceed by a logical analysis that bottoms out in simple, metaphysically fundamental existents in the world. But it was Russell’s Viennese student Ludwig Wittgenstein who most intrigued the Circle with his first book, written mostly during the First World War on the perilous Eastern and Italian fronts, where he was ultimately taken as a prisoner of war.
More here.