Skip to main content

Vienna Circle

Logical Positivism

By Karl Popper, logical positivism, Moritz Schlick, Rudolf Carnap, Vienna Circle, Wittgenstein

Moritz Schlick

The phenomenon known as logical positivism (or logical empiricism) originated in the Vienna Circle, a 1920s group of thinkers led by the German philosopher (and physicist) Moritz Schlick (1882-1936). Other prominent members were Rudolf Carnap, Herbert Feigl, Otto Neurath, Philipp Frank, and Friedrich Waismann. The Circle met regularly at the University of Vienna, during the period 1924-36.
Herbert Feigl  (1902-89) was an Austrian. “Like most analytic philosophers, Feigl thought philosophical problems were reducible to problems of language” (information). Reductionism is not always advisable. Neurath (1882-1945) was a Hungarian political economist with another confining agenda.  “He denied any value to philosophy over and above the pursuit of work on science, within science and for science” However, “his views on the language, method and unity of science were led throughout by his interest in the social life of individuals and their well-being” (Jordi Cat, Stanford Encyclopedia of Philosophy).
The ultimate origins of the Vienna  Circle were a little earlier, from about 1908 onwards, when the philosophy of science was debated by mathematician Hans Hahn, Otto Neurath, and physicist Philipp Frank. These men favoured the positivism of the Austrian physicist Ernst Mach (d.1916).

In addition to the Vienna Circle, there was a similar gathering in Germany known as the Berlin Circle, inspired by Hans Reichenbach. However, the Vienna Circle gained more fame, assisted by the publication in 1929  of a German pamphlet often known as the Vienna Circle manifesto. The English translation of the pamphlet title is The Scientific Conception of the World: The Vienna Circle.

This document amounted to a summary of the formulations favoured, including a reliance upon empiricism or “knowledge gained by experience.” There was strong opposition to metaphysics and the doctrine of synthetic a priori truths associated with Immanuel Kant. The contention here is that a uniform scientific language should be the medium for all knowledge. The manifesto defers to the Tractatus of Wittgenstein, a book originally published in German as Logisch-philosophische Abhandlung (1921). 

The contribution of Wittgenstein was here problematic. The logical positivists favoured his critique of language; ironically, some of them are said to have disliked the Tractatus, deeming that work to be metaphysical. On his own part, Wittgenstein transpired to be in reaction to logical positivism in his later career.

In 1924, Schlick contacted Wittgenstein, who eventually agreed to meet him (and Waismann) to discuss the Tractatus. However, Wittgenstein subsequently concluded that the Vienna Circle were not representing his ideas correctly (Stadler 2015:219ff). He refused to attend further meetings, although he maintained a correspondence with Schlick.

The logical analysis, in favour with Schlick and his colleagues, deemed metaphysical statements to be meaningless. Such statements were said to be irreducible to statements about experience, i.e., not empirically verifiable. This meant that many traditional philosophical problems were rejected as fallacies resulting from mistakes in logical and verbal applications. However, other “problems” were awarded a reinterpretation as empirical statements, and thus deemed worthy of scientific investigation. The Vienna Circle validated statements in accord with their logical and mathematical code of “materialist” rationalism. They insisted upon a criterion of “verifiability” to determine the relevance of meaning.

A tragedy occurred when the Nazis gained power in Germany and Austria. Science could not compete with Fascism at this juncture. The Vienna Circle dispersed, a fair number of the members emigrating to America, where they became influential in universities. Schlick chose to stay in Austria, where he was murdered in 1936 by a fanatical student at the University of Vienna (Stadler 2015:597ff). The killer later became a member of the Austrian Nazi party.

Meanwhile, Friedrich Waismann (1896-1959) had extensive conversations with Wittgenstein, who influenced him to some extent. Nevertheless, Waismann came to believe that Wittgenstein had betrayed logical positivism with a diverging argument. Waismann became a lecturer at Oxford University. He is noted for his radical paper of 1956 entitled How I See Philosophy. In this article, Waismann arrived at the conclusion that philosophy is “very unlike science in that in philosophy there are no proofs, no theorems and no questions that can be decided.”

Philosophy cannot accurately be reduced to either science or language, despite many attempts of conceptualists in those directions. A question may be resolved in ways that are elusive of association with scientific procedure and not determined by modes of language.


Rudolf Carnap

The German philosopher Rudolf Carnap (1891-1970) was especially influential amongst the logical positivists. His early book Pseudoproblems in Philosophy (1928) maintained that many traditional “philosophical problems” were meaningless, being the result of faulty language. Carnap advocated the elimination of metaphysics from philosophical discourse, an emphasis which became a characteristic of his circle. He envisaged a new democratic and rational society enlightened by scientific knowledge (Carus 2007).

Carnap met Wittgenstein in the 1920s. In his autobiography, Carnap describes his encounter with the Tractatus author at Vienna: 

The impression he made on us was as if insight came to him as through a divine inspiration, so that we could not help feeling that any sober rational comment or analysis of it would be a profanation. Thus, there was a striking difference between Wittgenstein’s attitude to philosophical problems and that of Schlick and myself….Wittgenstein, on the other hand, tolerated no critical examination by others, once the insight had been gained by an act of inspiration. (David Auerbach, Carnap Meets Wittgenstein)

In The Logical Syntax of Language (1934), Carnap reformulated the concept of logical syntax proposed in the Tractatus. Carnap stressed philosophy as “the logic of the sciences,” which some critics say is too narrow a definition. His subsequent book Philosophy and Logical Syntax (1935) again rejected metaphysics, favouring the concept of verifiability in strict positivist idiom (see further Schilpp 1963).

Carnap emigrated to America, for many years being a Professor of Philosophy at the University of Chicago. “Since ordinary language is ambiguous, Carnap asserted the necessity of studying philosophical issues in artificial languages, which are governed by the rules of logic and mathematics” (see Mauro Murzi, “Rudolf Carnap,” Internet Encyclopedia of Philosophy).

After Wittgenstein, the second complication for logical positivism was the contribution of Karl Popper, who became famous as a critic of the positivists. His early work Logik der Forschung (1934) disputed the verifiability criterion, urging that this should be replaced by a criterion of falsifiability to compensate for excesses. This conflict has been much discussed; strong arguments are lodged against Popper’s tendency to diminish the importance of induction. However, Popper was nevertheless concerned to separate scientific from pseudoscientific statements, without insisting that metaphysical statements are necessarily meaningless.

In his autobiography, Popper says that he heard about the Vienna Circle in 1926 or 1927. He read the books of Carnap as these were published. “They [the Circle] were trying to find a criterion which made metaphysics meaningless nonsense, sheer gibberish, and any such criterion was bound to lead to trouble, since metaphysical ideas are often the forerunners of scientific ones” (Popper 1992:80). 

Popper preferred the guideline that “scientific theories always remain hypotheses or conjectures” (ibid:81). He furnished an illustration via the Einsteinian revolution in physics, which “had shown that not even the most successfully tested theory, such as Newton’s, should be regarded as more than a hypothesis, an approximation to the truth” (ibid).

In contrast, Carnap became noted for asserting that metaphysicists are like musicians with no musical ability. Metaphysics was here relegated to the status of an art, not a science, and one amounting to poetry.

Is the relegated art in all cases the same poetry? Are dogmatic theologians really demonstrating the same artistry as metaphysical philosophers like Plotinus and Spinoza, or a linguistic “contemplative” such as the aphoristic Wittgenstein? Certainly, the Tractatus was at the root of logical positivism; this ambiguous work  can be interpreted as an opposing factor to the format upon which it was grafted.

At the opposite extreme are those who deny all relevance to logical positivism, a significant minority movement of scientific intellectuals, attempting to negotiate Kantian and Hegelian arguments (positivists did not reject all the Kantian repertory by any means). Logical positivism was the ideological counter to Fascism, losing out to “ordinary language,” afterwards surviving in the intellectual language of analytical philosophy.


Ayer, Alfred J., Logical Positivism (Glencoe, Illinois: Free Press, 1959).

Carnap, Rudolf, The Logical Syntax of Language, trans. R. Smeaton (London: Kegan Paul, Trench Trubner, 1937).

Carus, A. W., Carnap and Twentieth Century Thought: Explication as Enlightenment (Cambridge University Press, 2007).

McGuinness, Brian, ed. and trans., Wittgenstein and the Vienna Circle: Conversations Recorded by Friedrich Waismann (Oxford: Blackwell, 1979).

Popper, Karl, Logik der Forschung (Vienna, 1935), trans. as The Logic of Scientific Discovery (London: Hutchinson, 1959).

——–Unended Quest: An Intellectual Autobiography (1974; new edn, London: Routledge, 1992).

Schilpp, Paul A., ed., The Philosophy of Rudolf Carnap (La Salle, Illinois: Open Court, 1963).

Stadler, Friedrich, The Vienna Circle: Studies in the Origins, Development, and Influence of Logical Empiricism (2001; new edn, Vienna: Springer, 2015).

Waissmann, Friedrich, Philosophical Papers, ed., B. McGuinness (Vienna: Springer, 1977).

Wittgenstein, Ludwig, Tractatus Logico-Philosophicus, trans. D. F. Pears and B. F. McGuinness (London: Routledge, 1961).


Kevin R. D. Shepherd
January 16th 2010 (modified 2021)

ENTRY no. 9

Copyright © 2021 Kevin R. D. Shepherd. All Rights Reserved.

Ludwig Wittgenstein

By J. P. Stern, Tractatus, Vienna Circle, Wittgenstein

Ludwig Wittgenstein, 1930

One of the most celebrated modern philosophers is Ludwig Wittgenstein (1889-1951). He early wrote the Tractatus Logico-Philosophicus (1921), believing that he had solved all the outstanding problems of philosophy in this compact work. The Tractatus was much favoured by the Vienna Circle, a group of scientists and philosophers who pioneered logical positivism, and who interpreted Wittgenstein in that light. The Vienna Circle emphasised language, in terms of a presiding insistence that the only meaningful statements are those which are empirically verifiable. In other words, what you cannot prove, never state, because such a statement is worthless. Metaphysics, for instance, is out of bounds.

The Vienna Circle survived their diaspora in the face of the Nazi regime. Logical positivism lived on in America and Britain, later  becoming influential. This contingent made a relevant critique of Fascist propaganda, a form of political rhetoric saturating Germany and other countries during  the 1930s and early 1940s.

Wittgenstein was born in Austria, coming from a wealthy industrialist family, his father being a steel magnate. However, he became a British citizen,  one strongly linked to Cambridge University. When I was a young man (and a resident of Cambridge), the dons would discuss “what Wittgenstein really meant.” There were permutations of this during my temporary employment under Professor J. P. Stern, who enthused about Kant, Wittgenstein, and Nietzsche in our conversations dating to 1973. These talks occurred in his book-lined study, overlooking a panoramic garden in a select area of Cambridge.

Professor Stern (who taught German at London University) was an expert on Nietzsche. I found great difficulty in conceding the importance of Nietzsche. I also found the Tractatus a  disconcerting work, though in a different way to Thus Spake Zarathustra. Professor Stern pressed upon me the Tractatus when he grasped that I had an interest in philosophy. He expected me to enthuse over the treatise, as many undergraduates did at that time. I was a citizen exception to the intellectual fashion. I never did find the Tractatus inspiring; to me, the format was obscurantist. That book is generally considered significant in the history of philosophy.

Stern was one of the more liberal academics in Cambridge. Even he could not understand my citizen viewpoint on some matters. He assumed that one had to elevate Wittgenstein and Kant for the purpose of gaining intellectual clarity. I merely regarded these thinkers as interesting, not as figureheads of an ultimate philosophy. In some Cambridge colleges, there was an attitude of semi-worship attaching to Wittgenstein, despite his own aversion to such trends. 

Wittgenstein had early read Schopenhauer, whose worldview he apparently believed was to some extent correct. He was impressed by his predecessor’s theory of the “world as idea,” but not the “world as will.” Schopenhauer therefore needed “adjustments and clarifications” (Anscombe 1959:11ff). “Schopenhauer’s influence on Wittgenstein was considerable, but for the most part indirect and negative” (Severin Schroeder, Schopenhauer’s Influence on Wittgenstein, p. 23, online). Nevertheless, Wittgenstein assimilated Schopenhauer’s division between the noumenal and the phenomenal, himself emphasising the phenomenal world in his Tractatus (Magee 1997:310ff). Schopenhauer was acknowledging a theme of Immanuel Kant (1724-1804), who earlier defined the noumenal as the unknowable, using the terminology of Thing-in-Itself (Ding an Sich). In contrast, the Vienna Circle believed that only the phenomenal world existed, seeing support for their ideology in the Tractatus.

Wittgenstein conveyed that any metaphysical reality is beyond conceptual grasp, and therefore a factor of which nothing can be said. Only the phenomenal world can be described. Various objections have been lodged against this perspective. However, in the 1970s, the exegesis of Wittgenstein was very much in the ascendant at Cambridge. When meeting incredulity from academics (as I sometimes did), there is nothing that can usefully be said.

Wittgenstein himself demonstrated a dissatisfaction with the Tractatus at a later phase of his career. By then he knew that he had not solved all the problems of philosophy. The Tractatus had been influenced by theories of the mathematician Gottlob Frege and the author’s own tutor Bertrand Russell. Critics say that the Tractatus is ambiguous and contradictory; they even urge that Wittgenstein’s format of logic made nonsense of his own propositions. He maintained that philosophical problems arose from a failure to understand the logic of language.

Amongst the academic philosophers, Wittgenstein is the one who came closest to being a citizen philosopher. In 1912 he became an undergraduate at Cambridge, but reacted to the example of his tutor Bertrand Russell, who at this time authored The Problems of Philosophy (1912).

“ ‘How few there are who do not lose their own soul,’ remarked Wittgenstein one day. Russell felt obliged to tell Wittgenstein that he would not get his degree unless he learnt to write ‘imperfect things,’ a constraint which incurred the junior’s displeasure.” (Shepherd, Meaning in Anthropos, Cambridge 1991, p. 149)

Neglecting the degree, Wittgenstein moved back to the Continent. At this time he became a rich man, gaining the fortune of his deceased father, an industrialist tycoon. Yet he retired to Norway, building himself an isolated hut near Skjolden, his intention being to live in complete seclusion. The First World War changed his plans; he then volunteered to join the Austrian army, and fought on the Russian front. After the war, he became a schoolmaster, teaching at various remote villages in Austria. At a school in Otterthal, he gained a reputation for administering severe corporal punishment to pupils finding difficulty with mathematics, in which he was himself very competent. He subsequently became a gardener and an architect. He later expressed a discontent with scientism.

Two of his friends criticised the Tractatus. Wittgenstein is said to have abandoned his earlier views. In 1929 he returned to Cambridge, quickly acquiring a Ph.D. (on the basis of the Tractatus) after his lengthy absence of sixteen years in obscurity. He thereafter did much writing, but without publishing the result, apparently because he did not wish to be misunderstood. Dr. Wittgenstein was noted for his unconventional lectures uttered in a mood of deep concentration.

The advantages of his transition to academic status are not totally convincing. He remained a virtual alien within academic life; his aversion to appearing in the college dining room is a well known detail. Wittgenstein regarded all the talking as superficial. He frequently visited the local cinema in an effort to suspend his prolonged concentration on philosophy; he could appear quite desperate not to be distracted while watching the film (he was partial to Hollywood westerns and musicals). During the 1930s, he escaped for nearly a year to his distant hut in Norway. In 1947, he ceased to lecture at Cambridge, instead moving to Ireland, where for a time he lived alone in a hut beside the sea in Galway (for a partisan account, see Malcolm 1958; for a more detailed biography, see Monk 1990).

Some critics accuse Wittgenstein of being idiosyncratic, self-absorbed, suicidal, and homosexual. He certainly possessed a strong personality; he criticised both himself and colleagues.  “His sexuality was ambiguous but he was probably gay; how actively so is still a matter of controversy” (Duncan J. Richter, “Ludwig Wittgenstein,” Internet Encyclopaedia of Philosophy).

After his death, many of his writings surfaced in print. The most famous of these later works became his Philosophical Investigations (1953). Wittgenstein was here committed to what is known as linguistic philosophy. He emphasised language as a tool, and introduced the concept of “language game.” A number of differing interpretations of his ambiguous output have emerged. Wittgenstein regarded philosophy as a therapeutic activity for dispelling linguistic confusions. Critics say that his treatment of philosophy as language can be considered more of a philosophical problem than a solution.

The meaning of life remains a mystery to much contemporary philosophical language. Wittgenstein failed to describe his own notable striving for experiential equipoise. The new language philosophy did not describe, for instance, the hut in Norway or his recurring thought of entering a monastery. His frustration with artificial surface discourse is evident. Wittgenstein is unusual in this respect.

The intrinsic struggle to penetrate “philosophical problems” is a feature of mind rather than language. This factor appears to be confirmed by what Rudolf Carnap described as “an act of inspiration,” referring to the manner in which Wittgenstein communicated:

When he started to formulate his view on some specific problem, we often felt the internal struggle that occurred in him at that very moment, a struggle by which he tried to penetrate from darkness to light under an intensive and powerful strain, which was even visible on his most expressive face. (Carnap Meets Wittgenstein)


Anscombe, G. E. M., An Introduction to Wittgenstein’s Tractatus (London: Hutchinson, 1959).

Frongia, Guido, and Brian McGuinness, Wittgenstein: A Bibliographical Guide (Oxford: Blackwell, 1990).

Klagge, James C., ed., Wittgenstein: Biography and Philosophy (Cambridge University Press, 2001).

Magee, Bryan, The Philosophy of Schopenhauer (1983; revised edn, Oxford University Press, 1997).

Malcolm, Norman, Ludwig Wittgenstein: A Memoir (Oxford University Press, 1958).

McGuinness, Brian, Wittgenstein: A Life, The Young Ludwig, 1889-1921 (University of California Press, 1988).

Monk, Ray, Ludwig Wittgenstein: The Duty of Genius (London: Cape, 1990).

Redpath, Theodore, Ludwig Wittgenstein: A Student’s Memoir (London: Duckworth, 1990).

Sluga, Hans, and David G. Stern, eds., The Cambridge Companion to Wittgenstein (second edn, Cambridge University Press, 2018).

Wittgenstein, Ludwig, Tractatus Logico-Philosophicus, trans. D. F. Pears and B. F. McGuinness (London: Routledge, 1961).

——–Philosophical Investigations, trans. G. E. M. Anscombe (Oxford: Blackwell, 1963).


Kevin R. D. Shepherd
November 17th 2009  (modified 2021)

ENTRY no. 2

Copyright © 2021 Kevin R. D. Shepherd. All Rights Reserved.