Early school of analytic philosophy , inspired by Bertrand Russell and Alfred North Whitehead , and Ludwig Wittgenstein 's Tractatus (1921).
The school, formally instituted at the University of Vienna in a seminar of Moritz Schlick (1882–1936) in 1922, continued there as the Vienna Circle until 1938. It proposed several revolutionary theses: (1) All meaningful discourse consists either of (a) the formal sentences of logic and mathematics or (b) the factual propositions of the special sciences; (2) Any assertion that claims to be factual has meaning only if it is possible to say how it might be verified; (3) Metaphysical assertions, including the pronouncements of religion, belong to neither of the two classes of (1) and are therefore meaningless. Some logical positivists, notably A.J. Ayer , held that assertions in ethics (e.g., "It is wrong to steal") do not function logically as statements of fact but only as expressions of the speaker's feelings of approval or disapproval toward some action. See also Rudolf Carnap ; {{link=emotivism">emotivism ; verifiability principle .