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Logical positivism (also known as logical empiricism, scientific philosophy, and neo-positivism) is a philosophy that combines empiricism—the idea that observational evidence is indispensable for knowledge—with a version of rationalism incorporating mathematical and logico-linguistic constructs and deductions of epistemology. It may be considered as a type of analytic philosophy.[1]

Logical positivism, in the formal sense, began from discussions of a group known as the First Vienna Circle which gathered during the earliest years of the 20th century in Vienna at the Café Central. After World War I, Hans Hahn, a member of that early group, helped bring Moritz Schlick to Vienna. Schlick's Vienna Circle, along with Hans Reichenbach's Berlin Circle, propagated the new doctrines more widely during the 1920s and early 1930s. It was Otto Neurath's advocacy that made the movement self-conscious and more widely known. A 1929 pamphlet written by Neurath, Hahn, and Rudolf Carnap summarized the doctrines of the Vienna Circle at that time. The doctrines included the opposition to all metaphysics, especially ontology and synthetic a priori propositions; the rejection of metaphysics not as wrong but as having no meaning; a criterion of meaning based on Ludwig Wittgenstein's early work; the idea that all knowledge should be codifiable by a single standard language of science; and above all the project of rational reconstruction, in which ordinary-language concepts were gradually to be replaced by more precise equivalents in that standard language.

It was an important philosophical development for psychologists as it contributed to supporting the development of behaviorism [2] although the strength of this relationship can be overstated. [3]


During the late 1920s, '30s, and '40s, Bertrand Russell and Ludwig Wittgenstein's formalism was developed by a group of philosophers in Vienna and Berlin, who formed the Vienna Circle and Berlin Circle into a doctrine known as logical positivism (or logical empiricism). Logical positivism used formal logic to underpin an empiricist account of our knowledge of the world.[4] Philosophers such as Rudolf Carnap and Hans Reichenbach, along with other members of the Vienna Circle, claimed that the truths of logic and mathematics were tautologies, and those of science were verifiable empirical claims. These two constituted the entire universe of meaningful judgements; anything else was nonsense. The claims of ethics and aesthetics were subjective preferences. Theology and other metaphysics were pseudo-statements, neither true nor false, simply meaningless nonsense.

Karl Popper's insistence upon the role of falsification in the philosophy of science was a reaction to the logical positivists.[5] With the rise of Adolf Hitler and National Socialism in Germany and Austria, some members of the Vienna and Berlin Circles fled Germany, mainly to Britain and the USA, which helped to reinforce the dominance of logical positivism and analytic philosophy in the Anglophone world.[6]

Logical positivists typically considered philosophy as having a very limited function. For them, philosophy is concerned with the organization of thoughts, rather than having distinct topics of its own. The positivists adopted the principle of verificationism, according to which every meaningful statement is either analytic or is capable of being verified by experience. This caused the logical positivists to reject many traditional problems of philosophy, especially those of metaphysics or ontology, as meaningless.

Origins Edit

The chief influences on the early logical positivists were Ernst Mach and Ludwig Wittgenstein.


Wittgenstein's Tractatus was a text of great importance for the positivists. The use of the tools of modern logic for linguistic reform, the conception of philosophy as a "critique of language," and the possibility of drawing a theoretically principled distinction between intelligible and nonsensical discourse were all appealing to the logical positivists. Many positivists adopted a correspondence theory of truth similar to that of the Tractatus, although some, like Otto Neurath, preferred a form of coherentism. Wittgenstein's influence is further evident in certain formulations of the verification principle. Compare, for example, Proposition 4.024 of the Tractatus, where Wittgenstein asserts that we understand a proposition when we know what happens if it is true, with Schlick's assertion that "To state the circumstances under which a proposition is true is the same as stating its meaning".[7] The tractarian doctrine that the truths of logic are tautologies was widely held among the logical positivists. Wittgenstein also influenced the logical positivists' interpretation of probability. It should be noted that not all logical positivists' reactions to the Tractatus were positive; according to Neurath, it was full of metaphysics.[8]

Contemporary developments in logic and the foundations of mathematics, especially Russell and Whitehead's monumental Principia Mathematica, impressed the more mathematically minded logical positivists such as Hans Hahn and Rudolf Carnap. "Language-planning" and syntactical techniques derived from these developments were used to defend logicism in the philosophy of mathematics and various reductionist theses. Russell's theory of types was employed to explosive effect in Carnap's early anti-metaphysical polemics.[9]

Immanuel Kant was something of a punching bag in many of the logical positivists' early debates, but his influence shows through. His doctrine of synthetic a priori truths was the view to overthrow, and his notion of the thing in itself commanded its fair share of attention. More positively, Kantian views about the nature of physical objects pervade the "protocol sentence" debate[10], and the positivists all shared somewhat Kantian views about the relationship between philosophy and science.[11]

Basic tenets Edit



Another characteristic feature of logical positivism is the commitment to "Unified Science"; that is, the development of a common language or, in Neurath's phrase, a "universal slang" in which all scientific propositions can be expressed.[15] The adequacy of proposals or fragments of proposals for such a language was often asserted on the basis of various "reductions" or "explications" of the terms of one special science to the terms of another, putatively more fundamental one. Sometimes these reductions took the form of set-theoretic manipulations of a handful of logically primitive concepts;[16] sometimes these reductions took the form of allegedly analytic or a priori deductive relationships.[17]. A number of publications over a period of thirty years would attempt to elucidate this concept.


The Vienna Circle published a collection called Einheitswissenschaft (Unified Science)—edited by Rudolf Carnap, Philipp Frank, Hans Hahn, Otto Neurath, Jorgen Jorgensen (after Hahn's death) and Charles Morris—the aim of which was to present a unified vision of science. The collection was dismissed, after the publication of several monographies, because of the problems arising from World War II. The list of philosophers and scientists who contributed to these works is impressive. The complete list of contributors is given here for the historical record.

Einheitswissenschaft (Unified Science), edited by Carnap, Frank, Hahn, Neurath, Jorgensen (after Hahn's death), and Morris (from 1938):

These works are translated in Unified Science: The Vienna Circle Monograph Series, originally edited by Otto Neurath:, Kluwer, 1987.

International Encyclopedia of Unified ScienceEdit

In 1938 the publication of the International Encyclopedia of Unified Science started under the auspice of logical positivists. It was an ambitious project, and never completed. Only the first section, Foundations of the Unity of Sciences, was published; it contained two volumes, for a total of twenty monographs published from 1938 to 1969:

Perhaps the most famous work published in the International Encyclopedia of Unified Science is Thomas Kuhn's The Structure of Scientific Revolutions. However, every entry in the encyclopedia is of substantial scientific and philosophical value.

Monographs on the Scientific World-ConceptionEdit

A third collection was published by the Vienna Circle from 1928 to 1937. This collection was entitled Schriften zur wissenschaftlichen Weltauffassung (Monographs on the Scientific World-Conception), and was edited by Schlick and Frank. Scientists and philosophers such as Karl Popper contributed. The contributors and monographs were:

  • Richard von Mises, Wahrscheinlichkeit, Statistik und Wahrheit, 1928 (Probability, Statistics, and Truth, New York: MacMillan Company, 1939)
  • Rudolf Carnap, Abriss der Logistik, 1929
  • Otto Neurath, Empirische Soziologie, 1931
  • Philipp Frank, Das Kausalgesetz und seine Grenzen, 1932 (The Law of Causality and its Limits, Dordrecht; Boston: Kluwer, 1997)
  • Otto Kant, Zur Biologie der Ethik, 1932
  • Josef Schächeter, Prolegomena zu einer kritischen Grammatik, 1935 (Prolegomena to a Critical Grammar, Dordrecht; Boston: D. Reidel Pub. Co., 1973)
  • Victor Kraft, Die Grundlagen einer wissenschaftliche Wertlehre, 1937 (Foundations for a Scientific Analysis of Value, Dordrecht; Boston: D. Reidel Pub. Co., 1981)

Philosophers associated with logical positivism Edit

There is an extensive list of philosophers who are associated to some degree with logical positivism.

The Vienna CircleEdit

  • The physicist and philosopher Moritz Schlick, one of the first philosophers interested in the theory of relativity. He taught at the University of Vienna, where he held the chair of theory of inductive science. In Vienna, he organized the discussion group known as the Vienna Circle. Schlick can be regarded as the father of logical positivism, both for his organizational skills and for his philosophical ideas. He formulated the verifiability principle.
  • Rudolf Carnap, one of the major philosophers of the twentieth century, a leading exponent of logical positivism, and co-author of the Vienna Circle manifesto. He made contributions to the philosophy of science, the philosophy of language, the theory of probability, and classical, inductive and modal logic. Since ordinary language is ambiguous, Carnap asserted the necessity to study philosophical issues in artificial languages, governed by the rules of logic and mathematics. In such languages he dealt with problems like the meaning of a statement, the distinction between analytic and synthetic, a priori and a posteriori, necessity and contingency, the different interpretations of probability, and the nature of explanation. Carnap taught at the University of Prague, the University of Vienna, the University of Chicago, Harvard University, and the University of California at Los Angeles.
  • The philosopher of science Herbert Feigl, who encouraged Karl Popper to write the book Logik der Forschung. His 1931 article with A. E. Blumberg, "Logical Positivism: A New Movement in European Philosophy" in The Journal of Philosophy, was one of the first reports on logical positivism published in the United States, and promoted the spread of logical positivism. He taught at the University of Iowa and at the University of Minnesota, where in 1953 he founded the Minnesota Center for the Philosophy of Science, the oldest center for the philosophy of science in the world.
  • The physicist Philipp Frank, a student of David Hilbert and Ludwig Boltzmann, who was an editor of the series Monographs on the Scientific World-Conception and Unified Science; he contributed to the International Encyclopedia of Unified Science with the 1946 work "Foundations of physics".. He taught at Harvard University and wrote about the theory of relativity.
  • The logician and mathematician Kurt Gödel attended meetings of the Vienna Circle weekly between 1926 and 1928, but, although he is sometimes mistaken for a positivist, and his greatest achievements "are still often tallied among positivism's greatest success stories"[18], he was actually committed to Platonism and many of his core ideas were diametrically opposed to those of the rest of the Circle.[18] Gödel proved the completeness of first-order logic and the incompleteness of formal arithmetic. Gödel also worked on set theory and non-classical logics, such as intuitionistic logic and modal logic. He proved that the continuum hypothesis is consistent with the axioms of classical set theory. He was interested in the mathematical aspects of the theory of relativity, and proved the existence of solutions of Einstein’s relativistic equations in which time travel to the past is possible.
  • The mathematician Hans Hahn, co-author of the Vienna Circle manifesto, who taught at Innsbruck, Bonn and Vienna; among his students there were Karl Popper and Kurt Gödel.
  • The philosopher and sociologist Otto Neurath, who played an important role in the development of logical positivism. He was co-author of the manifesto of the Vienna Circle (it is supposed that he was indeed the principal author), planned and directed the International Encyclopedia of Unified Science, was an editor of the journal Erkentnnis and of the series Unified Science, and founded and directed the International Foundation for Visual Education.
  • The philosopher Friedrich Waismann, who was one of the few members of the Vienna Circle admitted to the meetings with Wittgenstein. He taught philosophy of mathematics and philosophy of science at the University of Cambridge and at the University of Oxford.

Germany and the Berlin CircleEdit

In Germany, members of the Berlin Circle contributed in an essential way to the development of logical empiricism:


  • As early as 1930 Scandinavian philosophers were interested in logical positivism. Finnish Eino Kaila employed for the first time the expression "logical neopositivism" for denoting the new philosophical movements (E. Kaila, "Der logistische Neupositivismus" in Annales Universitatis Aboensis, 1930). Eino Kaila published in 1939 a work pervaded by the principles of logical positivism (The human knowledge, in Finnish). He taught philosophy at the University of Helsinki. Among his students was Georg Henrik von Wright, who published a study about logical positivism (The Logical Empiricism, 1943, in Finnish). Wright contributed to the development of modal logic and deontic logic. Finn Jaakko Hintikka, who had Wright as a teacher, pursued Carnap's studies on inductive logic. Hintikka's article "A two-dimensional continuum of inductive methods" in Aspects of inductive logic (eds. J. Hintikka and P. Suppes, 1966), extended the methods Carnap used in The Continuum of Inductive Methods, 1952. Swedish philosopher Åke Petzäll (author of Der logistische Neupositivismus, 1931) was mainly influenced by the Vienna Circle and in 1930 or 1931 he went to Vienna, where he took part in theVienna Circle's meetings. Later he founded a new journal, Theoria, published in Göteborg; in that journal Hempel published his very first description of the paradoxes of confirmation (Le problème de la vérité, 1937).
  • Danish philosopher Jørgen Jørgensen very actively collaborated with neopositivists. After Hans Hahn's death in 1934, Jørgensen became an editor of the Vienna Circle's series Unified Science; later he collaborated on the International Encyclopedia of Unified Science, to which he contributed the 1951 essay The Development of Logical Empiricism.
  • In Norway, the young Arne Naess was strongly influenced by logical positivism, especially so in his doctorate Erkenntnis und wissenschaftliches Verhalten (1936). This lead to a forceful postivist bent for parts of Norwegian philosophy.

United Kingdom Edit

Poland Edit

Italy Edit

Relations between Italian philosophy and logical positivism developed in the early stages of logical positivism.

  • The Italian mathematician and philosopher of science Federigo Enriques took part in the congresses on scientific philosophy and collaborated on the International Encyclopedia, and Neurath and Carnap contributed articles to the journal Scientia edited by Enriques.
  • In 1934, Ludovico Geymonat published a work on logical positivism: La Nuova Filosofia della Natura in Germania. Geymonat had the opportunity to study with Schlick, Reichenbach, Carnap, and Waismann. He later held the first chair in Italy of philosophy of science.
  • The interest of Italian philosophy in logical positivism was primarily directed towards historical research. Francesco Barone distinguished himself with his work Il Neopositivismo Logico, 1953, a detailed and up-to-date historical and philosophical analysis of logical positivism.

Criticism and influencesEdit



Karl Popper, a well-known critic of logical positivism, published the book Logik der Forschung in 1934 (translated by himself as The Logic of Scientific Discovery published 1959). In it he presented an influential alternative to the verifiability criterion of meaning, defining scientific statements in terms of falsifiability. First, though, Popper's concern was not with distinguishing meaningful from meaningless statements, but distinguishing "scientific" from "metaphysical" statements. He did not hold that metaphysical statements must be meaningless; neither did he hold that a statement that in one century was "metaphysical" while unfalsifiable (like the ancient Greek philosophy about atoms), could not in another century become "falsifiable" and thus "scientific". About psychoanalysis he thought something similar: in his day it offered no method for falsification, and thus was not falsifiable and not scientific. However, he did not exclude it being meaningful, nor did he say psychoanalysts were necessarily "wrong" (it only couldn't be proven either way: that would have meant it was falsifiable), nor did he exclude that one day psychoanalysis could evolve into something falsifiable, and thus "scientific". He was, in general, more concerned with scientific practice than with the logical issues that troubled the positivists. Second, although Popper's philosophy of science enjoyed great popularity for some years, if his criterion is construed as an answer to the question the positivists were asking, it turns out to fail in exactly parallel ways. Negative existential claims ("there are no unicorns") and positive universals ("all ravens are black") can be falsified, but positive existential and negative universal claims cannot, although Popper thought himself these could be deemed as verifiable[19].





Footnotes Edit

  1. See, e.g.,  : "Vienna Circle" in Stanford Encyclopedia of Philosophy
  2. Kock, S (1`964). Psychology and emerging conceptions of knowledge as unitary. In T. Wann (ed) Behaviorism and Phenomenolgy (pp1-45) Chicago:University of Chicago Press
  3. Smith, L.D. (1986). Behaviourism and logical positivism.:A reassessment of the alliance. Stanford:Stanford University Press
  4. Carnap, R. (1928). 'The Logical Structure of the World', ?.
  5. Popper, Karl R. (2002). 'The Logic of Scientific Discovery', Routledge.
  6. Prominent amongst these were Ludwig Wittgenstein and Rudolf Carnap. Karl Popper might also be included, since despite his rejection of the term his method has much in common with the analytic tradition.
  9. Carnap, op. cit.
  10. See the essays by Carnap and Neurath in Ayer's Logical Positivism.
  12. For a classic survey of other versions of verificationism, see Hempel, Carl. "Problems and Changes in the Empiricist Criterion of Meaning." Revue Internationale de Philosophie 41 (1950), pp 41-63.
  13. For the classic expression of this view, see Carnap, Rudolf. "The Elimination Of Metaphysics Through Logical Analysis of Language." Erkenntnis 2 (1932). Rpt. in Logical Positivism. Ed. Alfred Jules Ayer. New York: Free Press, 1959. 60-81. Moritz Schlick, a key figure in the logical positivist movement, did not believe ethical (or aesthetic) sentences to be cognitively meaningless. See Schlick, Moritz. "The Future Of Philosophy." The Linguistic Turn. Ed. Richard Rorty. Chicago: University of Chicago Press, 1992. 43-53.
  16. As in Carnap's (1928) Logical Structure of the World.
  17. As in Carnap's Testability and Meaning
  18. 18.0 18.1 Goldstein, Rebecca (February 2005). Incompleteness: The Proof and Paradox of Kurt Godel, 74-75, W. W. Norton.
  19. Popper, K., The Logic of Scientific Discovery, chapter 13

Further reading Edit


See also Edit



Other philosophical movementsEdit

External links Edit

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