The Vienna Circle (or Ernst Mach Society) was a group of German-speaking scientists, mathematicians and philosophers based around the University of Vienna from 1922 until the mid-1930s, and included the following:
Moritz Schlick (1882–1936)Hans Hahn, Otto Neurath, and Rudolf Carnap wrote the manifesto of the Vienna Circle in 1929, but, as noted above, the group had existed since 1922.
Rudolf Carnap (1891–1970), from 1926
Otto Neurath (1882–1945)
Friedrich Waismann (1896–1959)
Gustav Bergmann (1906–1987)
Hans Hahn (1879–1934)
Victor Kraft (1880–1975)
Karl Menger (1902–1985)
Philipp Frank (1884–1966)
Olga Hahn-Neurath (1882-1937)
The members of the Vienna Circle had drawn inspiration from Ludwig Wittgenstein’s (1889–1951) book the Tractatus Logico-Philosophicus (Logical-Philosophical Treatise), which was first published in German in 1921, and then in an English translation prepared in Cambridge of 1922.
From 1926, Wittgenstein himself attended meetings of the Vienna Circle, although relations were not exactly amicable, not only because Wittgenstein did not get along with Rudolf Carnap (Schwartz 2012: 51), but also because of philosophical disagreements.
The importance of the Tractatus (as it is usually called) lies in the realm of philosophy of language, how language represents the world (Schwartz 2012: 52), and particularly in the picture theory of meaning. While the world is composed of all kinds of things and states of affairs, our language represents reality, and there is a fundamental structure embodied in formal logic that gives us an isomorphic relationship between our language (which we use in thought) and reality (Schwartz 2012: 52).
A simple and independent, or “atomic,” proposition represents a simple fact about the world, and larger complex or compound propositions are built up out of the truth functions of atomic propositions (Schwartz 2012: 53).
The fundamental logical concepts we call tautologies and self-contradictions are recognisable by the formal use of truth tables (Schwartz 2012: 53). Wittgenstein thought that tautologies are without meaning in the sense that they contain no new information (Schwartz 2012: 53). Thus the necessary truth they provide is “empty and formal,” so that Wittgenstein also saw mathematics as being tautological (Schwartz 2012: 53–54).
Wittgenstein also held that the “totality of true propositions is the whole of natural science,” so that philosophy itself is not science, but merely a technique aiming at “logical clarification of thoughts” (Schwartz 2012: 58).
The upshot of all this was the epistemologically revolutionary view (at least at the time) that analytic propositions, while they are certain, are tautologies and provide no informative new knowledge (Schwartz 2012: 54). This view invigorated the radical empiricism of the Vienna Circle, and led to the emergence of logical positivism.
The logical positivists came to think that there are ultimately two sources of human knowledge: (1) logical reasoning (yielding analytic a priori knowledge) and (2) empirical experience (yielding synthetic a posteriori knowledge). Like Frege, they rejected the existence of Kantian synthetic a priori knowledge, and saw mathematics as analytic tautologies (Schwartz 2012: 61).
The unusual twist in logical positivist epistemology is the verification criterion of meaningfulness, which, in the form stated by Ayer, holds that any non-analytic proposition must be empirically verifiable, either in practice or at least in principle, to be meaningful (Schwartz 2012: 60–61). If a proposition is not verifiable, then it is meaningless or without cognitive content. The logical positivists used the verification principles to reject metaphysics, theology and ethics as meaningless (Schwartz 2012: 61), a rather extreme view to say the least.
At the heart of the logical positivist program was the belief that many of the traditional issues of metaphysics are just confusions caused by improper use or misunderstanding of language (Schwartz 2012: 63). One of the most important of these confusions was the idea that existence is a property, when it is not a property at all, but simply expressed by the logic of quantifiers (Schwartz 2012: 63).
Logical positivism was spread to the English-speaking world by A. J. Ayer in his now classic book Language, Truth, and Logic (1936). Ayer had visited the Vienna Circle in 1933, and learned the principles of the logical positivists, though perhaps oversimplified them in process (Schwartz 2012: 59).
Ayer’s logical positivism had these seven tenets:
(1) that metaphysics, theology, ethics and aesthetics are meaningless by the verification principle;After the 1930s, however, many of the leading logical positivists came to modify or reject many of their core beliefs, and other philosophers such as the later Wittgenstein and the “ordinary language” philosophers at Oxford came to attack its principles (Schwartz 2012: 69).
(2) metaphysical issues are pseudo-problems caused by unclear or informal and misleading use of language;
(3) logic and mathematics are formal truths but tautologies;
(4) all propositions are divided into two classes: (i) analytic, a priori and necessarily true, but tautologous, and (ii) synthetic, a posteriori and contingent;
(5) the idea that all science forms a single unified system, and social sciences use the same methods as the natural sciences;
(6) reductionism (either phenomenalist or physicalist), and
(7) that ethical statements have no cognitive content, but express attitudes and emotions (Schwartz 2012: 61–67).
Curiously, in 1932 – the year before Ayer’s own visit to Vienna – Willard Van Orman Quine had also visited the logical positivists, but, while Ayer was to become a leading exponent of logical positivism, Quine emerged after WWII as a severe critic.
“Ludwig Wittgenstein,” Stanford Encyclopedia of Philosophy, 2002 (rev. 2009)
Duncan J. Richter, “Ludwig Wittgenstein (1889–1951),” Internet Encyclopedia of Philosophy, 2004
“Vienna Circle,” Stanford Encyclopedia of Philosophy, 2006 (rev. 2011),
Mauro Murzi, “Vienna Circle,” Internet Encyclopedia of Philosophy, 2004
“Logical Empiricism,” Stanford Encyclopedia of Philosophy, 2011 (rev. 2011)
Mauro Murzi, “Rudolf Carnap (1891–1970),” Internet Encyclopedia of Philosophy, 2001
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“Russell’s Logical Atomism,” Stanford Encyclopedia of Philosophy, 2005 (rev. 2009)
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“Logical Atomism,” Wikipedia
Ayer, A. J. 1936. Language, Truth, and Logic. Gollancz Ltd, London.
Schwartz, Stephen P. 2012. A Brief History of Analytic Philosophy: From Russell to Rawls. Wiley-Blackwell, Chichester, UK.