Above all, philosophy was materialist -- though not materialistic. Medieval philosophy had been the handmaiden of theology; in the twentieth century, it was to perform the same service for science. Mach's remarkable book Die Mechanik in ihrer Entwicklung (The Science of Mechanics) exercised a decisive influence on Einstein by denying Newton's notion of absolute time and space, so paving the way for relativity. The introduction to the first edition of Die Mechanik in 1883 describes its tendency as "an enlightening one or, to put it more clearly, an anti-metaphysical one". That was also the motto of the Vienna Circle.
A key aspect of Mach's philosophy was his deconstruction of the unity of the self. In his major work, Die Analyse der Empfindungen (The Analysis of the Sensations, first published in 1885), Mach declared: "Das Ich ist unrettbar." ("The self is beyond saving.") Following the ideas of Hume, underpinned by experimental evidence, Mach's materialism depicted man as a bundle of sense data. Not only did the self have to go, but the soul and anything beyond the senses with it.
Some reacted to this bleak but bracing vision with despair. Vienna's leading poet, Hugo von Hofmannsthal, wrote a key Modernist text, The Lord Chandos Letter, incorporating Mach's ideas in a self-portrait of an Elizabethan nobleman whose personality is disintegrating. Lenin was so appalled that he wrote an entire book, Materialism and Empirio-criticism, to refute "Machist gentlemen" like Hofmannsthal. Lenin's book later became the bible of Soviet philosophers -- so much so that when, decades later, the FBI visited Philipp Frank, one of the Vienna Circle, in his Harvard exile to ask about his alleged communist connections, he was able to show the two detectives a passage in Materialism and Empirio-Criticism in which Frank was denounced by Lenin as a Machist. The FBI men "practically saluted him, and left speedily and satisfied".
As Mach's successor, Schlick was the natural leader of what, in the mid-1920s, had become known as the Wiener Kreis, the Vienna Circle: a motley gathering of thinkers from various fields, united by their commitment to a wissenschaftliche Weltauffassung, or "scientific world conception", which Edmonds, following academic usage, calls logical empiricism, but is better known as "logical positivism". Their public face was the Ernst Mach Society, which held open meetings and lectures, but the Circle was by invitation only. And the invitation had to come from Schlick. He saw their common goal of ushering in a new Enlightenment as a blessing for humanity, not least by countering the rising irrationalism of the day, but he was resolutely apolitical.
Schlick followed the gospel according to Wittgenstein. It was an ascetic aestheticism, given physical embodiment in the Palais Stonborough, the house he built for his sister Margaret on the Kindmanngasse. Austere beauty of the Modernist kind does not always make for comfort. Though the mysterious, wandering scholar never actually attended the Circle or any of the international conferences organised in its name, his early philosophy was embodied in the only book he ever allowed to be published, written during the war: the Logisch-Philosophische Abhandlung, later translated as Tractatus Logico-Philosophicus. In this austere, introspective world of pure logic, there could be no place for systems of philosophy, let alone for politics. "Whereof one cannot speak, thereof one must be silent."
For Schlick, the Tractatus had the status of holy writ; accordingly, the Circle treated it as such. In his own remarkable little book, Problems of Ethics (published in the Circle series Schriften zur wissenschaftlichen Weltauffassung in 1930), Schlick bases his ethics not on the Kantian foundation of absolute duty -- then fashionable in Austro-German culture -- but on probability: "Moral rules, too, must refer to the average."
