Vienna Circle

The Vienna Circle (in German: der Wiener Kreis) was a group of philosophers and scientists from various disciplines who gathered around Moritz Schlick when he was called to the Vienna University in 1922. (Loosely associated with the Circle was the Verein Ernst Mach (Ernst Mach Society), as a forum for popular dissemination of its ideas.) The Vienna Circle became the main center of what was later called logical positivism. Among its members were Moritz Schlick, chairman of the Ernst Mach Society, Gustav Bergmann, Rudolf Carnap, Herbert Feigl, Philipp Frank, Kurt Gödel, Hans Hahn, Felix Kaufmann, Victor Kraft, Karl Menger, Marcel Natkin, Otto Neurath, Olga Hahn-Neurath, Theodor Radakovic, Friedrich Waismann. It was long thought that the members of the Vienna Circle had a uniform philosophical view, but recent research has emphasized its internal disagreements and controversies. Most members shared a certain basic empiricism as well as a preference for construing philosophical problems as technical problems of logic or mathematics.

History of the Vienna Circle

The prehistory of the Vienna Circle began with meetings on the philosophy of science and epistemology from 1907 on, promoted by Philipp Frank, Hans Hahn, Richard von Mises, and Otto Neurath.

Hans Hahn, the eldest of the three (1879-1934), was a mathematician. He received his degree in mathematics in 1902. Afterwards he studied under the direction of Ludwig Boltzmann in Vienna and David Hilbert, Felix Klein and Hermann Minkowski in Göttingen. In 1905 he received the Habilitation in mathematics. He taught at Innsbruck (1905-1906) and Vienna (from 1909).

Otto Neurath (1882-1945) studied sociology, economics and philosophy in Vienna and Berlin. From 1907 to 1914 he taught in Vienna at the Neuen Wiener Handelsakademie (Viennese Commercial Academy). Neurath married Olga, Hahn’s sister, in 1911.

Philipp Frank, the younger of the group (1884-1966), studied physics at Göttingen and Vienna with Ludwig Boltzmann, David Hilbert and Felix Klein. From 1912, he held the chair of theoretical physics in the German University in Prague.

Their meetings were held in Viennese coffeehouses from 1907 onward. Frank remembered:

After 1910 there began in Vienna a movement which regarded Mach’s positivist philosophy of science as having great importance for general intellectual life […] An attempt was made by a group of young men to retain the most essential points of Mach's positivism, especially his stand against the misuse of metaphysics in science. […] To this group belonged the mathematician H. Hahn, the political economist Otto Neurath, and the author of this book [i.e. Frank], at the time an instructor in theoretical physics in Vienna. […] We tried to supplement Mach’s ideas by those of the French philosophy of science of Henri Poincaré and Pierre Duhem, and also to connect them with the investigations in logic of such authors as Couturat, Schröder, Hilbert, etc. (cited from Uebel, Thomas, 2003, p.70).

Presumably the meetings stopped in 1912, when Frank went to Prague, where he held the chair of theoretical physics left vacant by Albert Einstein. Hahn left Vienna during the World War I and returned in 1921. The following year Hahn, with the collaboration of Frank, arranged to bring into the group Moritz Schlick, who held the chair of philosophy of the inductive sciences at the University of Vienna. Schlick had already published his two main works Raum und Zeit in die gegenwärtigen Physik (Space and Time in contemporary Physics) in 1917 and Allgemeine Erkenntnislehre (General Theory of Knowledge) in 1918. A central frame of reference for the newly founded discussion group was the Logisch-Philosophische Abhandlung (Tractatus Logico-Philosophicus), published by Ludwig Wittgenstein in 1918.

Under the direction of Schlick, a new regular series of meetings began. In 1926 Schlick and Hahn arranged to bring in Rudolf Carnap at the University of Vienna. In 1928 the Verein Ernst Mach (Ernst Mach Society) was founded, with Schlick as chairman. In 1929 the Vienna Circle manifesto Wissenschaftliche Weltauffassung. Der Wiener Kreis (The Scientific Conception of the World. The Vienna Circle) was published. The pamphlet is dedicated to Schlick, and its preface was signed by Hahn, Neurath and Carnap. In the appendix there is the list of the members of the Vienna Circle.

Moritz Schlick was killed in 1936 by a deranged student whose doctoral dissertation had been rejected. The rest of the Vienna Circle left Austria after the Anschluss. Many of its members emigrated to the United States, where they taught at several universities.

The Vienna Circle manifesto

In 1929 the Vienna Circle published its central manifesto Wissenschaftliche Weltauffassung. Der Wiener Kreis (The Scientific Conception of the World: The Vienna Circle). It states the scientific world-conception of the Vienna Circle, which is characterized “essentially by two features. First it is empiricist and positivist: there is knowledge only from experience […] Second, the scientific world-conception is marked by the application of a certain method, namely logical analysis.” (The Scientific Conception of the World. The Vienna Circle in Sarkar, Sahotra, 1996, p. 331 – hereinafter VC).

Logical analysis is the method of clarification of philosophical problems; it makes an extensive use of the symbolic logic and distinguishes the Vienna Circle empiricism from earlier versions. The task of philosophy lies in the clarification - through the method of logical analysis - of problems and assertions.

Logical analysis shows that there are two different kinds of statements: one kind includes statements reducible to simpler statements about the empirically given; the other kind includes statements which cannot be reduced to statements about experience and thus devoid of meaning. Metaphysical statements belong to this second kind and therefore they are meaningless. Hence many philosophical problems are rejected as pseudo-problems which arise from logical mistakes, while others are re-interpreted as empirical statements and thus becomes the subject of scientific inquiries.

The Vienna Circle holds that the ambiguity of natural language is often the source for the logical mistakes of metaphysics. “Ordinary language for instance uses the same part of speech, the substantive, for things (‘apple’) as well as for qualities (‘hardness’), relations (‘friendship’), and processes (‘sleep’); therefore it misleads one into a thing-like conception of functional concepts” (VC p. 329). Another source of mistakes is “the notion that thinking can either lead to knowledge out of its own resources without using any empirical material, or at least arrive at new contents by an inference from given states of affair” (VC p. 330). The latter notion is typical in Kantian philosophy, according to which there are synthetic a priori statements that expand knowledge without experience. Synthetic a priori knowledge is rejected by the Vienna Circle. Mathematics, which at a first sight seems an example of necessarily valid synthetic knowledge derived from pure reason alone, has instead a tautological character, that is its statements are analytical statements, thus very different from Kantian synthetic a priori statements. The only two kinds of statements accepted by the Vienna Circle are synthetic a posteriori statements (i.e. scientific statements) and analytic a priori statements (i.e. logical and mathematical statements).

However, the persistence of metaphysics is connected not only with logical mistakes but also with “social and economical struggles” (VC p. 339). Metaphysics and theology are allied to traditional social forms, while the group of people who “faces modern times, rejects these views and takes its stand on the ground of empirical sciences” (VC p. 339). Thus the struggle between metaphysics and scientific world-conception is not only a struggle between different kinds of philosophies, but it is also—and perhaps primarily—a struggle between different political, social, and economical attitudes. Of course, as the manifesto itself acknowledged, “not every adherent of the scientific world-conception will be a fighter” (VC p. 339). Many historians of the Vienna Circle see in the latter sentence an implicit reference to a contrast between Moritz Schlick and the so-called "left wing" of the Vienna Circle, mainly represented by Otto Neurath and Rudolf Carnap. The aim of the left wing was to facilitate the penetration of the scientific world-conception in “the forms of personal and public life, in education, upbringing, architecture, and the shaping of economic and social life” (VC p. 339-340). Schlick, on the contrary, was primarily interested in the theoretical study of science and philosoph. Perhaps the sentence “Some, glad of solitude, will lead a withdrawn existence on the icy slopes of logic” (VC p. 339) is an ironic reference to Schlick.

Unified Science

A goal pursued by the Vienna Circle was unified science. In the beginning this goal meant the construction of a "constitutive system" in which every legitimate statement is reduced to the concepts of lower level which refer directly to the given experience. "The endeavour is to link and harmonise the achievements of individual investigators in their various fields of science" (VC p. 328). The idea of this constitutional system can also be found in Carnapűs Aufbau. From this aim follows the search for clarity, neatness, intersubjectivity, and for a neutral symbolic language that eliminates the problems arising from the ambiguity of natural language. Later, Carnap's interests changed form a constitutional system to a universal language. As an influence of Neurath this language was the physicalistic language. In Carnap's conception translatability to physical language was the basis of unified science. Neurath later emphasised that his concept of unity is not any strictly formal system. In Nuerath's view the unity of science means a "mosaic of everything".

The Vienna Circle published a collection, called Einheitswissenschaft (Unified science), edit by Rudolf Carnap, Philipp Frank, Hans Hahn, Otto Neurath, Joergen Joergensen (after Hahn's death) and Charles Morris (from 1938), the aim of which was to present an unified vision of science. With the start of World War II, the authors suspended the project. They had published seven monographs between 1933 and 1939. In 1938, American philosophers started a new series of publications called the International Encyclopedia of Unified Science, and while an ambitious project it was never completely devoted to unified science. Only the first section. Foundations of the Unity of Sciences, was published. It contains two volumes for a total of twenty monographs published from 1938 to 1969. As remembered by Rudolf Carnap and Charles Morris in the Preface to the 1969 edition:

The Encyclopedia was in origin the idea of Otto Neurath. It was meant as a manifestation of the unity of science movement […] Original plans for the Encyclopedia were ambitious. In addition to the two introductory volumes, there was to be a section on the methodology of the sciences, one on the existing state of the unification of sciences, and possibly a section on the application of the sciences. It was planned that the work in its entirety would comprise about twenty-six volumes (260 monographs) (Foundations of the Unity of Sciences, vol. 1, The University of Chicago Press, 1969, p. vii).

Thomas Kuhn’s well-known The Structure of Scientific Revolutions was published in this Encyclopedia in 1962 as the number two in the second volume.

The elimination of metaphysics

The attitude of Logical Positivism towards metaphysics in the eraly period is well expressed by Carnap in the article 'Überwindung der Metaphysik durch Logische Analyse der Sprache' in Erkenntnis, vol. 2, 1932 (English translation 'The Elimination of Metaphysics Through Logical Analysis of Language' in Sarkar, Sahotra, ed., Logical empiricism at its peak: Schlick, Carnap, and Neurath, New York : Garland Pub., 1996, pp. 10-31).

A language – says Carnap – consists of a vocabulary, i.e. a set of meaningful words, and a syntax, i.e. a set of rules governing the formation of sentences from the words of the vocabulary. Pseudo-statements, i.e. sequences of words that at first sight resemble statements but in reality have no meaning, are formed in two ways: either meaningless words occur in them, or they are formed in an invalid syntactical way. According to Carnap, pseudo-statements of both kinds occur in metaphysics.

In the late 30's Carnap emphasyzed the distinction of formal and material mode of speech. Metaphisics was characterized in this era by Carnap as sentences, formulated in material mode of speech, which usually can be corrected by putting them in formal mode of speech.

Later, in Empiricism, Semantics and Ontollogy Carnap developed a theory of frameworks. He distingishued external and internal questions relative to the framwework. According to Carnap internal theoretical questions can be answered. Fopr example in arithmetic, one can decide and prove that "there exists no even prime number larger than 2". On the other hand the question "Are numbers really existing?" is not an internal question. This question as an external theoreticasl question is meaningles and usually these are the methaphysical questions.

External questions however can be put as practical questions "is the system of arythmetic useful in science? I.e. shall we accept the system as a tool?"

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