Logical positivism

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Template:Cleanup-date Logical positivism (later referred to as logical empiricism, rational empiricism, and also neo-positivism) is a philosophy that combines positivism with a version of apriorism.

It originated in the Vienna Circle in the 1920s, where Rudolf Carnap, Otto Neurath, et al. (see 'philosophers associated with logical positivism' below) divided statements into those which are analytic (true a priori) and those which are synthetic (verified by sensory experience). This was perhaps presaged by Hume's fork. Logical positivism holds that philosophy should aspire to the same sort of rigor as science. Philosophy should provide strict criteria for judging sentences true, false and meaningless.

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Assertions and Origins of logical positivism

Although the logical positivists held a wide range of beliefs on many matters, they all shared an interest in science and deep skepticism of the theological and metaphysical. Following Wittgenstein, many subscribed to the correspondence theory of truth, although some, like Neurath, believed in coherentism. They believed that all knowledge should be based on logical inference from simple "protocol sentences" grounded in observable facts. Hence many supported forms of realism, materialism, philosophical naturalism, and empiricism.

The logical positivists were very much influenced by and were great admirers of the early Ludwig Wittgenstein (from the period of the Tractatus). Wittgenstein himself was not a logical positivist, although he was on friendly terms with many members of the Vienna Circle while in Vienna, especially fellow aristrocrat Moritz Schlick. However, Wittgenstein's relations were not entirely amicable after he left Vienna. While Wittgenstein worked mostly in cooperation for nearly a decade with Circle member Friedrich Waismann to impose form and structure on his often oracular utterances, using him as a secretary and speaking of cooperating on a book with him, when Waismann came to Cambridge in 1937 Wittgenstein barely acknowledged him.

Logical positivism is perhaps best known for the verifiability criterion of meaning, which asserts that a statement is meaningful if and only if it is empirically verifiable. One intended consequence of the verification criterion is that all non-empirical forms of discourse, including ethics and aesthetics, are not "literally" or "cognitively" meaningful, and so belong to "metaphysics".

Logical positivism was essential to the development of early analytic philosophy. It was disseminated throughout the European continent and, later, in American universities by the members of the Vienna Circle. A.J. Ayer is considered responsible for the spread of logical positivism to Britain. The term subsequently came to be almost interchangeable with "analytic philosophy" in the first half of the twentieth century. Logical positivism was immensely influential in the philosophy of language and represented the dominant philosophy of science between World War I and the Cold War. Many subsequent commentators on "logical positivism" have attributed to its proponents a greater unity of purpose and creed than they actually shared, overlooking the complex disagreements among the logical positivists themselves.

Unified Science

An important objective pursued by logical positivism was Unified Science, that is the construction of a 'constitutive system' in which every legitimate statement is reduced to the concepts of lower level which refer directly to a given experience. 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), whose aim was to present an unified vision of science. The collection was dismissed, after the publication of several monographies, because of the problems arising from the World War II. In 1938 the publication of the International Encyclopedia of Unified Science started under the auspice of logical positivists. It was an ambitious project never completed devoted to the unification of 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.

The list of philosophers and scientists who contributed to those works is impressive. The complete list of contributors is given here for the historical record.

Einheitswissenschaft (Unified Science), edit by Carnap, Frank, Hahn, Neurath, Joergensen (after Hahn's death), Morris (from 1938):

  • Hans Hahn, Logik, Mathematik und Naturerkennen, 1933
  • Otto Neurath, Einheitswissenschaft und Psychologie, 1933
  • Rudolf Carnap, Die Aufgabe der Wissenschaftlogik, 1934
  • Philipp Frank, Das Ende der mechanistischen Physik, 1935
  • Otto Neurath, Was bedeutet rationale Wirtschaftsbetrachtung, 1935
  • Otto Neurath, E. Brunswik, C. Hull, G. Mannoury, J. Woodger, Zur Enzyklopädie der Einheitswissenschaft. Vorträge, 1938
  • Richard von Mises, Ernst Mach und die empiristische Wissenschaftauffassung, 1939

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

Monographs, arranged in chronological order

Published in the International Encyclopedia of Unified Science:

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 has a very high scientific and philosophical level.

A third collection was publish by Vienna Circle from 1928 to 1937. This collection was entitled Schriften zur wissenschaftlichen Weltauffassung (Monographs on the Scientific World-Conception), and was edit by Schlick and Frank. Scientists and philosopher contributed; between them, we can remember Karl Raimund Popper with Logik der Forschung. Here the complete list of contributors.

  • Richard von Mises, Wahrscheinlichkeit, Statistik und Wahrheit, 1928 (Probability, Statistics, and Truth, New York : Macmillan company, 1939)
  • Rudolf Carnap, Abriss der Logistik, 1929
  • Moritz Schlick, Fragen der Ethik, 1930 (Problems of Ethics, New York : Prentice-Hall, 1939)
  • Otto Neurath, Empirische Soziologie, 1931
  • Philipp Frank, Das Kausalgesetz und seine Grenzen, 1932 (The Law of Causality and its Limits, Dordrecth ; Boston : Kluwer, 1997)
  • Otto Kant, Zur Biologie der Ethik, 1932
  • Rudolf Carnap, Logische Syntax der Sprache, 1934 (The Logical Syntax of Language, New York : Humanities, 1937)
  • Karl Raimund Popper, Logik der Forschung, 1934 (The Logic of Scientific Discovery, New York : Basic Books, 1959)
  • Josef Schächeter, Prolegomena zu einer kritischen Grammatik, 1935 (Prolegomena to a Critical Grammar, Dordrecth ; Boston : D. Reidel Pub. Co., 1973)
  • Victor Kraft, Die Grundlagen einer wissenschaftliche Wertlehre, 1937 (Foundations for a Scientific Analysis of Value, Dordrecth ; Boston : D. Reidel Pub. Co., 1981)

Philosophers associated with logical positivism

The list of philosophers associated, sometimes in different ways, to logical positivism is long. There are the members of Vienna Circle:

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

Ludwig Wittgenstein's Tractatus Logico-Philosophicus exerted a great influence on Vienna Circle; many meetings were dedicated to a punctual analysis of that work. Not all logical positivists' reactions to Tractatus were positive: according to Neurath it was full of metaphysics. Carnap (in his Autobiography published in The philosophy of Rudolf Carnap) said that Wittgenstein's influence on Vienna Circle was overestimated. Moreover, Wittgenstein did not take part to Vienna Circle's discussions; there were separate meetings between him, Schlick, Carnap and Waismann, but soon Carnap was not admitted to those meetings. Wittgenstein's influence is evident in the formulation of the verifiability principle. See for example Proposition 4.024 of Tractatus, where Wittgenstein asserts that we understand a proposition when we know what happens if it is true and compare it with Schlick's assertion "The definition of the circumstances under which a statement is true is perfectly equivalent to the definition of its meaning". Wittgenstein influenced also the logical positivist's interpretation of probability.

As early as 1930 Scandinavian philosophers were interested in logical positivism. Two of them, Swedish Ake Petzäll and Finnish Eino Kaila, employed for the first time the expression 'logical neopositivism' for denoting the new philosophical movements (A. Petzäll, Der logistische Neupositivismus, 1930 and E. Kaila, 'Der logistische Neupositivismus' in Annales Universitatis Aboensis, 1930). Petzäll was mainly influenced by the Vienna Circle and in 1930-31 he went to Vienna, where he took part to Vienna 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). 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 George 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. Finnish Jaakko Hintikka - among his teachers was Wright - pursued Carnap's studies on inductive logic. Hintikka's article 'A two-dimensional continuum of inductive methods' in Aspects of inductive logic (ed. by J. Hintikka and P. Suppes), 1966, extended the methods Carnap used in The Continuum of Inductive Methods, 1952.

Danish philosopher Joergen Joergensen very actively collaborated with neopositivists. After Hans Hahn's death (1934) he 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 essay The Development of Logical Empiricism, 1951.

English philosopher Alfred Jules Ayer played an important role in the spreading of logical positivism. His work Language, Truth and Logic, 1936, gained an immediate success. In that book, he completely accepted both the verifiability principle and the distinction between analytic and synthetic statements; hence he asserted that metaphysical sentences are meaningless.

Logical positivism had extensive contacts with the group of Polish logicians who developed several branches of contemporary logic. Polish philosophy was greatly influenced by Kazimierz Twardowski, who studied at the University of Vienna and taught at Lwow; he is the founder of Polish analytic philosophy. He taught to several Polish philosophers and logicians; among them were:

The Polish logician Alfred Tarski, who developed the theory of semantics in formal language, took part to the congresses on scientific philosophy organized by Vienna Circle and Berlin Circle; he greatly influenced Carnap's philosophy of language: in a first time, Carnap was interested in logical syntax but, after the publication of Tarski's works, he turned to semantics.

Criticisms

Critics of Logical Positivism say that its fundamental tenets could not themselves be formulated in a way that was clearly consistent. The verifiability criterion of meaning did not seem verifiable; but neither was it simply a logical tautology, since it had implications for the practice of science and the empirical truth of other statements. This presented severe problems for the logical consistency of the theory. Another problem was that, while positive existential claims (There is at least one human being) and negative universals (Not all ravens are black) allow for clear methods of verification (find a human or a non-black raven), negative existential claims and positive universal claims do not.

Universal claims could apparently never be verified: How can you tell that all ravens are black, unless you've hunted down every raven ever, including those in the past and future? This led to a great deal of work on induction, probability, and "confirmation," (which combined verification and falsification; see below).

Karl Popper, a well known critic of Logical Positivism, published the book Logik der Forschung (Eng.:The Logic of Scientific Discovery) in 1934. 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 (by the 20th century atoms would become part of science). About psychoanalysis he thought something similar: in his day it offered no method for falsification, and thus was not falsifiable and not scientific, but he didn't 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.

Logical positivists' response to the first criticism is that Logical Positivism, like all other philosophies of science, is a philosophy of science, not an axiomatic system that can prove its own consistency (see Gödel's incompleteness theorem). Secondly, a theory of language and mathematical logic were created to answer what it really means to say things like "all ravens are black".

A response to the second criticism was provided by A. J. Ayer in Language, Truth and Logic, in which he sets out the distinction between 'strong' and 'weak' verification. "A proposition is said to be verifiable, in the strong sense of the term, if, and only if, its truth could be conclusively established by experience." (Ayer 1946:50) It is this sense of verifiable that causes the problem of verification with negative existential claims and positive universal claims. However, the weak sense of verification states that a proposition is "verifiable... if it is possible for experience to render it probable." (ibid) After establishing this distinction, Ayer goes on to claim that "no proposition, other than a tautology, can possibly be anything more than a probable hypothesis" (Ayer 1946:51) and therefore can only be subject to weak verification. This defence was controversial among Logical Positivists, some of whom stuck to strong verification, and claimed that general propositions were indeed nonsense.

Subsequent philosophy of science tends to make use of the better aspects of both of these approaches. Work by W. V. O. Quine and Thomas Kuhn has convinced many that it is not possible to provide a strict criterion for good or bad scientific method outside of the science we already have. But even this sentiment was not unknown to the logical positivists: Otto Neurath famously compared science to a boat which we must rebuild on the open sea.

References

  • Achinstein, Peter and Barker, Stephen F. The Legacy of Logical Positivism: Studies in the Philosophy of Science. Baltimore: Johns Hopkins Press, 1969.
  • Ayer, Alfred Jules. Logical Positivism. Glencoe, Ill: Free Press, 1959.
  • Barone, Francesco. Il neopositivismo logico. Roma Bari: Laterza, 1986.
  • Bergmann, Gustav. The Metaphysics of Logical Positivism. New York: Longmans Green, 1954.
  • Cirera, Ramon. Carnap and the Vienna Circle: Empiricism and Logical Syntax. Atlanta, GA: Rodopi, 1994.
  • Edmonds, David & Eidinow, John; Wittgenstein's Poker, ISBN 0066212448
  • Friedman, Michael, Reconsidering Logical Positivism. Cambridge, UK: Cambridge University Press, 1999.
  • Gadol, Eugene T. Rationality and Science: A Memorial Volume for Moritz Schlick in Celebration of the Centennial of his Birth. Wien: Springer, 1982.
  • Geymonat, Ludovico. La nuova filosofia della natura in Germania. Torino, 1934.
  • Giere, Ronald N. and Richardson, Alan W. Origins of Logical Empiricism. Minneapolis: University of Minnesota Press, 1997.
  • Hanfling, Oswald. Logical Positivism. Oxford: B. Blackwell, 1981.
  • Jangam, R. T. Logical Positivism and Politics. Delhi: Sterling Publishers, 1970.
  • Janik, Allan and Toulmin, Stephen. Wittgenstein's Vienna. London: Weidenfeld and Nicolson, 1973.
  • Kraft, Victor. The Vienna Circle: The Origin of Neo-positivism, a Chapter in the History of Recent Philosophy. New York: Greenwood Press, 1953.
  • McGuinness, Brian. Wittgenstein and the Vienna Circle: Conversations Recorded by Friedrich Waismann. Trans. by Joachim Schulte and Brian McGuinness. New York: Barnes & Noble Books, 1979.
  • Mises von, Richard. Positivism: A Study in Human Understanding. Cambridge: Harvard University Press, 1951.
  • Parrini, Paolo. Empirismo logico e convenzionalismo: saggio di storia della filosofia della scienza. Milano: F. Angeli, 1983.
  • Parrini, Paolo; Salmon, Wesley C.; Salmon, Merrilee H. (ed.) Logical Empiricism - Historical and Contemporary Perspectives, Pittsburgh: University of Pittsburgh Press, 2003.
  • Rescher, Nicholas. The Heritage of Logical Positivism. Lanham, MD: University Press of America, 1985.
  • Salmon, Wesley and Wolters, Gereon (ed.), Logic, Language, and the Structure of Scientific Theories: Proceedings of the Carnap-Reichenbach Centennial, University of Konstanz, 21-24 May 1991, Pittsburgh: University of Pittsburgh Press, 1994.
  • Sarkar, Sahotra. The Emergence of Logical Empiricism: From 1900 to the Vienna Circle. New York: Garland Publishing, 1996.
  • Sarkar, Sahotra. Logical Empiricism at its Peak: Schlick, Carnap, and Neurath. New York: Garland Pub., 1996.
  • Sarkar, Sahotra. Logical Empiricism and the Special Sciences: Reichenbach, Feigl, and Nagel. New York: Garland Pub., 1996.
  • Sarkar, Sahotra. Decline and Obsolescence of Logical Empiricism: Carnap vs. Quine and the Critics. New York: Garland Pub., 1996.
  • Sarkar, Sahotra. The Legacy of the Vienna Circle: Modern Reappraisals. New York: Garland Pub., 1996.
  • Spohn, Wolfgang (ed.), Erkenntnis Orientated: A Centennial Volume for Rudolf Carnap and Hans Reichenbach, Boston: Kluwer Academic Publishers, 1991.

See also

Institution

Other philosophical movements

External links

About Logical positivism

About philosophical subjects pertinent to logical positivism

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