PEIRCE TO STRAWSON much a riddle as this one ‘God does not reveal himself in the world,’ Wittgenstein wrote; ‘it is not how things are in the world that is mystical, but that it exists’ (TLP 6.432, 6.44) Philosophy can very little for us What it can do, however, had been done once for all by the Tractatus—or so Wittgenstein believed With perfect consistency, having published the book he gave up philosophy and took up a number of more humdrum jobs On the death of Karl Wittgenstein in 1912 Ludwig like his siblings had inherited a large fortune, but on returning from the war he renounced his share, and supported himself instead as a gardener in a monastery or a schoolmaster in rural schools In 1926 a charge of sadistic punishment was brought against him on behalf of one of his pupils, and though he was acquitted this brought his schoolteaching career to an end Logical Positivism Wittgenstein returned to Vienna, and had a hand in designing the architecture of a new house for his sister He was introduced by her to Moritz Schlick, since 1922 Professor of the Philosophy of Science at Vienna University, with whom he resumed his philosophical inquiries The two met on Monday evenings in 1927 and 1928, and were joined by others, including Rudolf Carnap and Friedrich Waismann In 1929 Wittgenstein went to Cambridge to work on a philosophical manuscript (published posthumously as Philosophische Bemerkungen) During his absence the discussion group developed into a self-conscious philosophical movement and issued a manifesto, the Wissenschaftliche Weltauffassung der Wiener Kreis, which launched a campaign against metaphysics as an outdated system that must give way to a scientific world-view The anti-metaphysical programme exploited some of the ideas of Wittgenstein’s Tractatus, and proclaimed that necessary truths were necessary only because they were tautologies This enabled them to accept that mathematical truths were necessary while denying that they told us anything about the world Knowledge about the world could be gained only by experience, and propositions had meaning only if they could be either verified or falsified by experience The thesis that the meaning of a proposition was its mode of its verification, the verification principle, was 58