Moritz Schlick

Friedrich Albert Moritz Schlick (/ʃlɪk/; German: [ʃlɪk] (listen); April 14, 1882 – June 22, 1936) was a German philosopher, physicist, and the founding father of logical positivism and the Vienna Circle.

Moritz Schlick
Schlick sitting
Moritz Schlick around 1930
Friedrich Albert Moritz Schlick

April 14, 1882
DiedJune 22, 1936 (aged 54)
Alma materUniversity of Heidelberg
University of Lausanne
University of Berlin
Era20th-century philosophy
RegionWestern philosophy
SchoolAnalytic philosophy
Vienna Circle
Logical positivism
Main interests
Logic, philosophy of science, philosophy of mathematics, ethics
Notable ideas
General theory of knowledge
Observational statement (Beobachtungssatz)[2]
Internal and application rules of grammar[3]

Early life and works

Schlick was born in Berlin to a wealthy family, his father was Ernst Albert Schlick and his mother was Agnes Arndt. He studied physics at the University of Heidelberg, the University of Lausanne, and, ultimately, the University of Berlin under Max Planck. In 1904, he completed his dissertation essay, "Über die Reflexion des Lichts in einer inhomogenen Schicht" ("On the Reflection of Light in a Non-Homogeneous Medium"). After a year as Privatdozent at Göttingen, he turned to the study of Philosophy in Zurich. In 1907, he married Blanche Hardy. [5] In 1908, he published Lebensweisheit ("The Wisdom of Life"), a slim volume about eudaemonism, the theory that happiness results from the pursuit of personal fulfillment as opposed to passing pleasures. His habilitation essay, "Das Wesen der Wahrheit nach der modernen Logik" ("The Nature of Truth According to Modern Logic"), was published in 1910. Several essays about aesthetics followed, whereupon Schlick turned his attention to problems of epistemology, the philosophy of science, and more general questions about science. In this last category, Schlick distinguished himself by publishing a paper in 1915 about Einstein's special theory of relativity, a topic only ten years old. He also published Raum und Zeit in der gegenwärtigen Physik ("Space and Time in Contemporary Physics"), which extended his earlier results by applying Poincaré's geometric conventionalism to explain Einstein's adoption of a non-Euclidean geometry in the general theory of relativity.

The Vienna Circle and Wittgenstein

After early appointments at Rostock and Kiel, in 1922 Schlick assumed the chair of Naturphilosophie at the University of Vienna which had previously been held by Ludwig Boltzmann and Ernst Mach. Schlick displayed an unusual success in organizing talented individuals in the philosophical and scientific spheres. When Schlick arrived in Vienna, he was invited to lead a group of scientists and philosophers who met regularly (on Thursday evenings in the Chemistry Building) to discuss philosophical topics in the sciences. Early members included the mathematician Hans Hahn and, within a few years, they were joined by Rudolf Carnap, Herbert Feigl, Kurt Gödel, Otto Neurath, Friedrich Waismann and others. They initially called themselves the Ernst Mach Association, but they eventually became best known as the Vienna Circle. In the years 1925-1926, the Thursday night group discussed recent work in the foundations of mathematics by Gottlob Frege, Bertrand Russell, and Ludwig Wittgenstein. Wittgenstein's book, Tractatus Logico-Philosophicus, was a work that advanced, among other things, a logical theory of symbolism and a "picture" or "model" theory of language. Schlick and his group were impressed by the work, devoting considerable time to its study and, even when it was no longer the principal focus of their discussion, it was mentioned in discussion. Eventually Wittgenstein agreed to meet with Schlick and other Circle members to discuss the Tractatus and other ideas but he later found it necessary to restrict the visitors to sympathetic interlocutors. Through Schlick's influence, Wittgenstein was encouraged to consider a return to philosophy after some ten years away from the field. Schlick and Waismann's discussions with Wittgenstein continued until the latter felt that germinal ideas had been used without permission in an essay by Carnap, a charge of dubious merit. But he continued discussions in letters to Schlick after he no longer met with other Circle members.

General Theory of Knowledge and later works

Schlick had worked on his Allgemeine Erkenntnislehre (General Theory of Knowledge) between 1918 and 1925, and, though later developments in his philosophy were to make various contentions of his epistemology untenable, the General Theory is perhaps his greatest work in its acute reasoning against synthetic a priori knowledge. This critique of synthetic a priori knowledge argues that the only truths which are self-evident to reason are statements which are true as a matter of definition, such as the statements of formal logic and mathematics. The truth of all other statements must be evaluated with reference to empirical evidence. If a statement is proposed which is not a matter of definition, and not capable of being confirmed or falsified by evidence, that statement is "metaphysical", which is synonymous with "meaningless", or "nonsense". This is the principle upon which members of the Vienna Circle were most clearly in agreement — with each other, as well as with Wittgenstein.

Problems of Ethics

Between 1926 and 1930, Schlick labored to finish Fragen der Ethik (Problems of Ethics'), in which he surprised some of his fellow Circlists by including ethics as a viable branch of philosophy. In his 1932-33 contribution to Erkenntnis, "Positivism and Realism",[6] Schlick offered one of the most illuminating definitions of positivism as every view "which denies the possibility of metaphysics" (Schlick [1932-1933], p. 260). Accordingly he defined metaphysics as the doctrine of “true being”, “thing in itself” or “transcendental being”, a doctrine which obviously "presupposes that a non-true, lesser or apparent being stands opposed to it" (Ibid). Therefore in this work he bases the positivism on a kind of epistemology which holds that the only true beings are givens or constituents of experience. Also during this time, the Vienna Circle published The Scientific View of the World: The Vienna Circle as a homage to Schlick. Its strong anti-metaphysical stance crystallized the viewpoint of the group.

Comment on Wittgenstein's Tractatus

Carnap, in his book Logical Syntax of Language, included a comment by Schlick on Wittgenstein 's Tractatus.

Schlick ( [Wende] p.8 ) interprets Wittgenstein's position as follows: philosophy "is that activity by which the meaning of propositions is established or discovered" ; it is a question of "what the propositions actually mean. The content, soul, and spirit of science naturally consist in what is ultimately meant by its sentences; the philosophical activity of rendering significant is thus the alpha and omega of all scientific knowledge".

— Carnap, p.284, Logical Syntax of Language

Schlick's murder

With the rise of the Nazis in Germany and Austrofascism in Austria, many of the Vienna Circle's members left for the United States and the United Kingdom. Schlick, however, stayed on at the University of Vienna. When visited by Herbert Feigl in 1935, he expressed dismay at events in Germany. On June 22, 1936, Schlick was ascending the steps of the University for a class when he was confronted by a former student, Johann Nelböck, who killed Schlick with a pistol. The court declared Nelböck to be fully compos mentis, he confessed to the act, was detained without any resistance, but was unrepentant. The delinquent used the judicial proceedings as a chance to present himself and his ideology in the public. He claimed that Schlick's anti-metaphysical philosophy had "interfered with his moral restraint". In another version of the events, the murderer covered up all political causes and claimed that he was motivated by jealousy over his failed attachment to the female student Sylvia Borowicka, leading to a paranoid delusion about Schlick as his rival and persecutor. Nelböck was tried and sentenced, but the event became a distorted cause célèbre around which crystallized the growing nationalist and anti-Jewish sentiments in the city. (The fact that Schlick was not Jewish did not seem to matter to propagandists capitalizing on the crime.) After the annexation of Austria into Nazi Germany in 1938 the assassin was released on probation after serving two years of a 10-year sentence.[7][8][9][10][11][12]


Schlick's enduring contribution to the world of philosophy is as the fount of logical positivism. His humanity, good will, gentleness, and especially his encouragement have been documented by many of his peers. Herbert Feigl and Albert Blumberg, in their introduction to the General Theory of Knowledge, wrote,

No other thinker was so well prepared to give new impetus to the philosophical questings of the younger generation. Though many of his students and successors have attained a higher degree of exactitude and adequacy in their logical analyses of problems in the theory of knowledge, Schlick had an unsurpassed sense for what is essential in philosophical issues.

— Feigl and Blumberg, Introduction, General Theory of Knowledge, p. xxi


  • Lebensweisheit. Versuch einer Glückseligkeitslehre. Munich, Becksche Verlagsbuchhandlung 1908[13]
  • Das Wesen der Wahrheit nach der modernen Logik, in: Vierteljahrsschrift für wissenschaftliche Philosophie und Soziologie, Jg. 34, 1910, p. 386-477
  • Die philosophische Bedeutung des Relativitätsprinzips, in: Zeitschrift für Philosophie und philosophische Kritik, 159, 1915, S. 129-175
  • Raum und Zeit in der gegenwärtigen Physik. Berlin: Verlag von Julius Springer 1917 (4th ed. 1922)
  • Hermann von Helmholtz. Schriften zur Erkenntnistheorie (Publishers: Moritz Schlick & Paul Hertz). Berlin: Springer 1921[14]
  • Allgemeine Erkenntnislehre. Berlin: Verlag von Julius Springer 1918 (2nd edition 1925)[15]
  • Kritizistische oder empiristische Deutung der neuen Physik?, in: Kant-Studien, 26, 1921, p. 96-111[16]
  • Einsteins Relativitätstheorie. In: Mosse Almanach, 1921, S. 105-123.[17][18]
  • Erleben, Erkennen, Metaphysik, in: Kant-Studien, 31, 1926, p. 146-158[19]
  • Vom Sinn des Lebens, in: Symposion. Philosophische Zeitschrift für Forschung und Aussprache, Jg. 1, 1927, p. 331-354[20]
  • Fragen der Ethik. Vienna: Verlag von Julius Springer 1930[21]
  • Gibt es ein Materiales Apriori?, 1930
  • "Die Wende der Philosophie". Erkenntnis. 1: 4–11. 1930. doi:10.1007/BF00208605.
  • "Über das Fundament der Erkenntnis". Erkenntnis. 4: 79–99. 1934. doi:10.1007/BF01793485.
  • Unanswerable Questions, 1935
  • Meaning and Verification, 1936
  • Gesammelte Aufsätze 1926-1936. Vienna: Gerold & Co. 1938
  • Die Probleme der Philosophie in ihrem Zusammenhang. Frankfurt: Suhrkamp Verlag 1986
  • Moritz Schlick Gesamtausgabe. Vienna/New York: Springer Verlag 2006. — Almost complete author copy of Vol. I/1, I/2, I/3, I/5, I/6


  1. ^ Ted Poston, "Foundationalism" (Internet Encyclopedia of Philosophy)
  2. ^ Hans Günther Ruß, Wissenschaftstheorie, Erkenntnistheorie und die Suche nach Wahrheit. Stuttgart, Kohlhammer 2004, p. 71.
  3. ^ Thomas Oberdan, Protocols, Truth and Convention, Rodopi, 1993, p. 110.
  4. ^ B. F. McGuinness (2013). Moritz Schlick. pp. 336–7. Once again, one has to understand Schlick's world conception, which he took over from Schopenhauer's world as representation and as will. … “To will something” – and here Schlick is heavily influenced by Schopenhauer –
  5. ^ Biography at Vienna University
  6. ^ Erkenntnis vol. 3, 1932/33. English: translated by David Rynin (PDF). Retrieved 2013-03-11.
  7. ^ Stadler, Friedrich (2001). Documentation: The Murder of Moritz Schlick, in: Friedrich Stadler (ed.). The Vienna Circle. Studies in the Origins, Development, and Influence of Logical Empiricism. Vienna, New York: Springer. pp. 866–909. ISBN 978-3-211-83243-1.
  8. ^ Silverman, Lisa (2012). Becoming Austrians: Jews and culture between the World Wars. New York: Oxford University Press. pp. 60–65. ISBN 978-0-19-979484-3.
  9. ^ Lotz-Rimbach, Renata (2009). Mord verjaehrt nicht: Psychogramm eines politischen Mordes, in: Friedrich Stadler, Fynn Ole Engler (eds.). Stationen: dem Philosophen und Physiker Moritz Schlick zum 125. Geburtstag. Vienna, New York: Springer. pp. 81–104. ISBN 978-3-211-71580-2.
  10. ^ Csendes, Peter (2006). Wien: Von 1790 bis zur Gegenwart. Vol. 3. Vienna: Boehlau. pp. 499f. ISBN 978-3-205-99268-4.
  11. ^ Stadler, Friedrich (1997). Die andere Kulturgeschichte am Beispiel von Emigration und Exil der oesterreichischen Intellektuellen 1930-1940, in: Rolf Steininger, Michael Gehler (eds.). Oesterreich im 20. Jahrhundert. Ein Studienbuch in zwei Baenden. Von der Monarchie bis zum Zweiten Weltkrieg. Wien, Köln, Weimar: Boehlau. pp. 535–553. ISBN 978-3-205-98310-1.
  12. ^ Malina, Peter (1988). Tatort: Philosophenstiege, in: Michael Benedikt, Rudolf Burger (eds.). Bewusstsein, Sprache und Kunst. Vienna: Boehlau. pp. 231–253.
  13. ^ Reprinted in Vol. I/3 of the Moritz Schlick Gesamtausgabe
  14. ^ Editors' preface reprinted in Vol. I/5 of the Moritz Schlick Gesamtausgabe, p.255-264
  15. ^ Reprinted as Vol. I/1 of the Moritz Schlick Gesamtausgabe
  16. ^ Reprinted in Vol. I/5 of the Moritz Schlick Gesamtausgabe, p.223-250
  17. ^ Contribution to a competition of Scientific American; for background information see p.31ff in: Fynn Ole Engler, Moritz Schlick und Albert Einstein, MPI for the History of Science, 2006
  18. ^ Reprinted in Vol. I/5 of the Moritz Schlick Gesamtausgabe, p.157-178
  19. ^ Reprinted in Vol. I/6 of the Moritz Schlick Gesamtausgabe, p.33-56
  20. ^ Reprinted in Vol. I/6 of the Moritz Schlick Gesamtausgabe, p.99-128
  21. ^ Reprinted in Vol. I/3 of the Moritz Schlick Gesamtausgabe


  • Edmonds, David and John Eidinow. Wittgenstein's Poker. New York: HarperCollins, 2001.
  • Fynn Ole Engler, Mathias Iven. Moritz Schlick. Leben, Werk und Wirkung. Berlin: Parerga 2008. ‹See Tfd›(in German)
  • Schlick, Moritz. Positivism and Realism. Originally appeared in Erkenntnis 111 (1932/33); translated by Peter Heath and reprinted in Moritz Schlick: Philosophical Papers, Volume II (1925–1936) from Vienna Circle Collection, edited by Henk L. Mulder (Kluwer, 1979), pp. 259–284.

Further reading

  • Holt, Jim, "Positive Thinking" (review of Karl Sigmund, Exact Thinking in Demented Times: The Vienna Circle and the Epic Quest for the Foundations of Science, Basic Books, 449 pp.), The New York Review of Books, vol. LXIV, no. 20 (21 December 2017), pp. 74–76.

External links

1936 in philosophy

1936 in philosophy


Foundationalism concerns philosophical theories of knowledge resting upon justified belief, or some secure foundation of certainty such as a conclusion inferred from a basis of sound premises. The main rival of the foundationalist theory of justification is the coherence theory of justification, whereby a body of knowledge, not requiring a secure foundation, can be established by the interlocking strength of its components, like a puzzle solved without prior certainty that each small region was solved correctly.Identifying the alternatives as either circular reasoning or infinite regress, and thus exhibiting the regress problem, Aristotle made foundationalism his own clear choice, positing basic beliefs underpinning others. Descartes, the most famed foundationalist, discovered a foundation in the fact of his own existence and in the "clear and distinct" ideas of reason, whereas Locke found a foundation in experience. Differing foundations may reflect differing epistemological emphases—empiricists emphasizing experience, rationalists emphasizing reason—but may blend both.In the 1930s, debate over foundationalism revived. Whereas Moritz Schlick viewed scientific knowledge like a pyramid where a special class of statements does not require verification through other beliefs and serves as a foundation, Otto Neurath argued that scientific knowledge lacks an ultimate foundation and acts like a raft. In the 1950s, foundationalism fell into decline – largely due to the influence of Willard Van Orman Quine, whose ontological relativity found any belief networked to one's beliefs on all of reality, while auxiliary beliefs somewhere in the vast network are readily modified to protect desired beliefs.

Classically, foundationalism had posited infallibility of basic beliefs and deductive reasoning between beliefs—a strong foundationalism. About 1975 weak foundationalism emerged. Thus recent foundationalists have variously allowed fallible basic beliefs, and inductive reasoning between them, either by enumerative induction or by inference to the best explanation. And whereas internalists require cognitive access to justificatory means, externalists find justification without such access.

Francis Skinner

Sidney George Francis Guy Skinner (1912 – 11 October 1941) was a friend, collaborator, and lover of the Austrian philosopher Ludwig Wittgenstein.

Gustav Bergmann

Gustav Bergmann (May 4, 1906 – April 21, 1987) was an Austrian-born American philosopher. He studied at the University of Vienna and was a member of the Vienna Circle. Bergmann was influenced by the philosophers Moritz Schlick, Friedrich Waismann, and Rudolf Carnap who were members of the Circle. In the United States, he was a professor of philosophy and psychology at the University of Iowa.

Index of analytic philosophy articles

This is a list of articles in analytic philosophy.

A. C. Grayling

A.P. Martinich

Abstract particulars


Alfred Jules Ayer


Analytic-synthetic distinction

Analytic philosophy

Analytic reasoning

Arda Denkel

Arthur Danto

Australian Realism

Avrum Stroll


Berlin Circle

Bernard Williams

Bertrand Russell


Breaking the Spell: Religion as a Natural Phenomenon

C. D. Broad

Cahiers pour l'Analyse

Carl Gustav Hempel

Ramsey sentence

Charles Sanders Peirce

Chinese room

Cognitive synonymy

Contemporary Pragmatism

Contrast theory of meaning

Cooperative principle

Cora Diamond

Daniel Dennett

Darwin's Dangerous Idea

David Braine (philosopher)

David Kellogg Lewis


Descriptivist theory of names


Direct reference theory

Doctrine of internal relations

Donald Davidson (philosopher)

Doxastic logic

Elbow Room (book)

Elliott Sober


Ernst Mach

Eternal statement

F. C. S. Schiller

Family resemblance

Felicity conditions

Form of life (philosophy)

Frank P. Ramsey

Freedom Evolves

Friedrich Waismann

G. E. M. Anscombe

George Edward Moore

Gilbert Ryle

Gottlob Frege

Gricean maxims

Gustav Bergmann

Hans Hahn

Hans Reichenbach

Hans Sluga

Harvey Brown (philosopher)

Herbert Feigl


Hypothetico-deductive model

Indeterminacy of translation

Introduction to Mathematical Philosophy

Isaiah Berlin

J. L. Austin

Jeff Malpas

Jerry Fodor

John Hick

John Rawls

John Searle

John Wisdom

Jules Vuillemin

Karl Menger

Kit Fine

Kurt Grelling

Kwasi Wiredu

Language, Truth, and Logic

Logical atomism

Logical form

Logical positivism

Lorenzo Peña

Ludwig Wittgenstein

Mark Addis

Mark Sacks

Max Black

Mental representation

Metaphor in philosophy

Michael Dummett

Michael Tye (philosopher)

Modal realism

Moritz Schlick

Naming and Necessity

Nelson Goodman



Norman Malcolm

Oets Kolk Bouwsma

Olaf Helmer

Olga Hahn-Neurath

On Certainty

On Denoting

Ordinary language philosophy

Original proof of Gödel's completeness theorem

Ostensive definition

Otto Neurath

P. F. Strawson

Paradox of analysis

Paul Churchland

Paul Grice

Per Martin-Löf

Peter Hacker

Peter Simons

Philipp Frank

Philippa Foot

Philosophical analysis

Philosophical Investigations

Philosophy of engineering

Philosophy of technology

Pieranna Garavaso

Postanalytic philosophy


Principia Ethica

Principia Mathematica

Private language argument

Process philosophy

Radical translation

Richard von Mises

Robert Audi

Rose Rand

Round square copula

Rudolf Carnap

Rupert Read

Ryle's regress

Speech act

Stephen Laurence

Susan Stebbing

The Bounds of Sense

The Logic of Scientific Discovery

The Mind's I

Theodore Drange

Þorsteinn Gylfason

Tore Nordenstam

Tractatus Logico-Philosophicus

Two Dogmas of Empiricism

UCLA Department of Philosophy

Use–mention distinction

Verification theory


Victor Kraft

Vienna Circle

Wilfrid Sellars

Willard Van Orman Quine

William James Lectures

William L. Rowe

William W. Tait

Wolfgang Stegmüller

Word and Object

Zeno Vendler

Index of philosophy of language articles

This is an index of articles in philosophy of language

A.P. Martinich


Adolph Stöhr

Alexis Kagame

Alfred Jules Ayer

Alphabet of human thought


Analytic-synthetic distinction


Andrea Bonomi

Applicative Universal Grammar

Archie J. Bahm

Arda Denkel


Artificial intelligence

Association for Logic, Language and Information

Avrum Stroll

Barry Loewer

Berlin Circle

Bertrand Russell

Bob Hale (philosopher)

Calculus ratiocinator

Carl Gustav Hempel

Ramsey sentence


Category mistake

Causal theory of reference

César Chesneau Dumarsais

Cheung Kam Ching

Circular definition

Claude Lévi-Strauss

Cognitive synonymy

Colloquial language

Computational humor


Concept and object

Conceptual metaphor

Context-sensitive grammar

Context principle


Contrast theory of meaning


Cooperative principle

Cora Diamond


Dagfinn Føllesdal

David Efird

David Kellogg Lewis

De dicto and de re



Descriptivist theory of names

Direct reference theory

Direction of fit

Discourse ethics

Disquotational principle

Donald Davidson (philosopher)

Donkey pronoun


Duns Scotus

Empty name

Engineered language

Enumerative definition


Ethics and Language

Eugen Rosenstock-Huessy

European Summer School in Logic, Language and Information


Extensional definition

F. H. Bradley

Family resemblance

Felicity conditions

Ferdinand Ebner

Failure to refer

Form of life (philosophy)

Franz Rosenzweig

Frege's Puzzle

Friedrich Waismann

Function and Concept

G. E. M. Anscombe

Gareth Evans (philosopher)

Genus–differentia definition

George Orwell

Gilbert Ryle

Gordon Park Baker

Gottlob Frege


Hans Kamp

Hector-Neri Castañeda

Henri Bergson

Ideal speech situation

Illocutionary act


Indeterminacy (philosophy)

Indeterminacy of translation


Indirect self-reference

Inferential role semantics

Ingeborg Bachmann


Intensional definition

Internalism and externalism

Interpretation (logic)

J. L. Austin

Jacques Bouveresse

James F. Conant

Jody Azzouni

John Etchemendy

John McDowell

Jonathan Bennett (philosopher)

Journal of Logic, Language and Information

Karl-Otto Apel

Katarzyna Jaszczolt

Keith Donnellan

Kent Bach

Kit Fine


Language and thought

Language of thought

Language, Truth, and Logic

Latitudinarianism (philosophy)

Lexical definition

Lexis (Aristotle)

Linguistic determinism

Linguistic relativity

Linguistic turn

Linguistics and Philosophy

List of philosophers of language

Logical atomism

Logical form

Logical positivism

Ludwig Wittgenstein

Marilyn Frye

Martian scientist

Max Black

Meaning (linguistics)

Meaning (non-linguistic)

Meaning (philosophy of language)

Meaning (semiotics)

Mediated reference theory

Meinong's jungle

Mental representation

Mental space


Metaphor in philosophy

Michael Devitt

Michael Dummett

Modal property


Modularity of mind

Moritz Schlick

Mumbo Jumbo (phrase)

Naming and Necessity

Nelson Goodman

New Foundations

Nino Cocchiarella

Noam Chomsky



Non-rigid designator


Norm (philosophy)

Object language

On Denoting

Ontological commitment

Operational definition

Ordinary language philosophy

Ostensive definition

Otto Neurath

P. F. Strawson

Paradigm-case argument


Paul Boghossian

Paul Grice

Performative contradiction

Performative text

Performative utterance

Persuasive definition

Peter Abelard

Peter Millican

Philosophical interpretation of classical physics

Philosophical Investigations

Philosophy and literature

Philosophy of language

Pirmin Stekeler-Weithofer

Plato's Problem

Port-Royal Grammar


Precising definition

Principle of charity

Principle of compositionality

Private language argument

Proper name (philosophy)




Radical translation

Rational reconstruction

Redundancy theory of truth


Relevance theory

Rhetoric of social intervention model

Richard von Mises

Rigid designator

Robert Brandom

Robert Maximilian de Gaynesford

Robert Stalnaker

Round square copula

Rudolf Carnap

S. Morris Engel

Saul Kripke

Scalar implicature

Scientific essentialism

Sebastian Shaumyan

Secondary reference


Semantic externalism

Semantic holism




Sense and reference

Sense and Sensibilia (Austin)



Singular term

Slingshot argument

Social semiotics

Speech act


Stanley Cavell

Statement (logic)

Stipulative definition


Supposition theory

Susan Stebbing




Symbol grounding


The Naturalization of Intentionality

Theoretical definition

Theory of descriptions

Þorsteinn Gylfason

Tractatus Logico-Philosophicus

Transparency (linguistic)

True name

Truth-conditional semantics

Truth-value link


Two Dogmas of Empiricism

Type physicalism

Universal grammar

Universal language

Universal pragmatics

Use–mention distinction


Verification theory


Vienna Circle

Virgil Aldrich

Walter Benjamin

Willard Van Orman Quine

William Alston

William C. Dowling

William Crathorn

Wittgenstein on Rules and Private Language

Word and Object

Word sense

Yehoshua Bar-Hillel

Zeno Vendler


Institute Vienna Circle

The Institute Vienna Circle (IVC) (Society for the Advancement of the Scientific World Conception), founded in October 1991 is an international nonprofit organization which is dedicated to the work and influence of the Vienna Circle of Logical Empiricism. Since 2011 the IVC is also a subunit of the Faculty of Philosophy and Education at the University of Vienna. The Institute’s founder and scientific director is Friedrich Stadler.

Johann Nelböck

Johann "Hans" Nelböck (May 12, 1903 – February 3, 1954) was an Austrian former student and murderer of Moritz Schlick, the founder of the group of philosophers and scientists known as the Vienna Circle.

After attending the gymnasium in Wels, Nelböck studied philosophy at the University of Vienna from 1925 on with Moritz Schlick, who was his doctoral advisor, and graduated as a Doctor of Philosophy on March 21, 1931, with the doctoral thesis "The Importance of Logic in Empirism and Positivism". Twice Nelböck was sent to a mental hospital with the diagnosis of schizoid personality disorder. He had threatened to kill Schlick.

On June 22, 1936, Nelböck shot Schlick in the chest, killing him on one of the central staircases of the University of Vienna. The substantiation of the judgment of the Provincial Court for Criminal Matters of Vienna (dated May 26, 1937) summed up:

The court declared Nelböck to be fully compos mentis, he confessed to the act, was detained without any resistance, but was unrepentant. He used the judicial proceedings as a chance to present himself and his ideology in the public. A significant part of his defence was the claim that Schlick's anti-metaphysical philosophy had undermined his native moral restraints, a line of thought which Austrian Nazis, asserting Schlick's Jewish connections within the Vienna Circle, quickly developed and exploited. In another version of the events Nelböck covered all political causes up and claimed, that he was motivated by jealousy over his failed attachment to the female student Sylvia Borowicka, leading to a paranoid delusion about Schlick as his rival and persecutor.

Nelböck was found guilty and sentenced, but in the event he became a distorted cause célèbre, around which crystallized the growing nationalist and anti-Jewish sentiments in the city. Although a German Protestant from minor Prussian nobility, Schlick was subsequently characterized in the press as a pivotal figure in disaffected Jewish circles, and the murder was applauded by Vienna's austrofascists.

On May 26, 1937, Nelböck was sentenced to ten years' imprisonment, but only two years later - after the annexation of Austria into Nazi Germany in 1938 - asked for a pardon. In his application he pointed out "that by his act and the result elimination of a Jewish teacher who propagated doctrines alien and detrimental to the nation he rendered National Socialism a service and also suffered for National Socialism as a consequence of his act. Since the world-view, the rightness of which he recognized even then and out of which he committed his act, is now the ruling national ideology, he considers it a hardship if he still has to remain in a disadvantaged position because of an act which sprang from his world-view."

Because the Senior Public Prosecutor concluded that Nelböck's act was accompanied primarily by personal motives, Nelböck was only released on probation on October 11, 1938.From 1938 on, Nelböck worked in the geological department of the wartime economic oil authority. When the period of probation ended in 1943, he worked as a technical employee in the Main Measurement Office.

In 1951, Nelböck sued Victor Kraft, a member of the Vienna Circle, who had called Nelböck a "paranoid psychopath" in his (Kraft's) book Der Wiener Kreis. Kraft agreed to an out-of-court settlement.

Josef Schächter

Josef Schächter (* September 16, 1901 in Kundrynce, Galicia, † March 27, 1994 Haifa) was an Austrian rabbi, philosopher and member of the Vienna Circle from 1925 to 1936.

Language game (philosophy)

A language-game (German: Sprachspiel) is a philosophical concept developed by Ludwig Wittgenstein, referring to simple examples of language use and the actions into which the language is woven. Wittgenstein argued that a word or even a sentence has meaning only as a result of the “rule” of the “game” being played. Depending on the context, for example, the utterance “Water!” could be an order, the answer to a question, or some other form of communication.

List of philosophers of science

This is a chronological list of philosophers of science. For an alphabetical name-list, see Category:Philosophers of science.

Logical determinism

Logical determinism is the view that a proposition about the future is either necessarily true, or its negation is necessarily true. The argument for this is as follows. By excluded middle, the future tense proposition (‘There will be a sea-battle tomorrow’) is either true now, or its negation is true. But what makes it (or its negation true) is the present existence of a state of affairs – a truthmaker. If so, then the future is determined in the sense that the way things are now – namely the state of affairs that makes ‘There will be a sea-battle tomorrow’ or its negation true – determines the way that things will be. Furthermore, if the past is necessary, in the sense that a state of affairs that existed yesterday cannot be altered, then the state of affairs that made the proposition ‘There will be a sea-battle tomorrow’ true cannot be changed, and so the proposition or its negation is necessarily true, and it is either necessarily the case that there will be a sea-battle tomorrow, or necessarily not the case.

The term ‘logical determinism’ (Logischer Determinismus) was introduced by Moritz Schlick.Logical determinism seems to present a problem for the conception of free will which requires that different courses of action are possible, for the sea-battle argument suggests that only one course is possible, because necessary. In trying to resolve the problem, the 13th century philosopher Duns Scotus argued in an early work that a future proposition can be understood in two ways: either as signifying something in reality that makes something be true in the future, or simply as signifying that something will be the case. The second sense is weaker in that it does not commit us to any present state of affairs that makes the future proposition true, only a future state of affairs.

Marcel Boll

Marcel Boll (15 September 1886, Paris – 12 August 1971, Paris) was a French positivist, educationalist who played a prominent role in promoting the Vienna Circle in France. He was professor of Chemistry and Electricity at HEC Paris.

He translated works by Rudolph Carnap, Phillip Frank, Hans Reichenbach, and Moritz Schlick into French.

Remarks on Colour

Remarks on Colour (German: Bemerkungen über die Farben) was one of Ludwig Wittgenstein's last works, written during a visit to Vienna in 1950 while dying of cancer. Believing that philosophical puzzles about colour can only be resolved through attention to the involved language games, he considers Goethe's propositions in the Theory of Colours, and the observations of Philipp Otto Runge in an attempt to clarify the use of language about colour.

Wittgenstein was interested in the fact that some propositions about colour are apparently neither empirical nor exactly a priori, but something in between: phenomenology, according to Goethe. However, he took the line that 'There is no such thing as phenomenology, though there are phenomenological problems.' He was content to regard Goethe's observations as a kind of logic or geometry. Wittgenstein took his examples from the Runge letter included in the "Farbenlehre", e.g. "White is the lightest colour", "There cannot be a transparent white", "There cannot be a reddish green", and so on. The logical status of these propositions in Wittgenstein's investigation, including their relation to physics, was discussed in Jonathan Westphal's Colour: a Philosophical Introduction (1991).

Although Remarks on Colour is considered difficult on account of its fragmentation, his last work, On Certainty (German: Über Gewissheit) is considered to be his most lucid.

Some Remarks on Logical Form

Some Remarks on Logical Form (German: Bemerkungen über logische Form) was the only academic paper ever published by Ludwig Wittgenstein, and contained Wittgenstein's thinking on logic and the philosophy of mathematics immediately before the rupture that divided the early Wittgenstein of the Tractatus Logico-Philosophicus from the later Wittgenstein. The approach to logical form in the paper reflected Frank P. Ramsey's critique of Wittgenstein's account in the Tractatus, and has been analyzed by G.E.M. Anscombe and Jaakko Hintikka, among others.


Verificationism, also known as the verification principle or the verifiability criterion of meaning, is the philosophical doctrine that only statements that are empirically verifiable (i.e. verifiable through the senses) are cognitively meaningful, or else they are truths of logic (tautologies).

Verificationism thus rejects as cognitively "meaningless" statements specific to entire fields such as metaphysics, theology, ethics and aesthetics. Such statements may be meaningful in influencing emotions or behavior, but not in terms of conveying truth value, information or factual content. Verificationism was a central thesis of logical positivism, a movement in analytic philosophy that emerged in the 1920s by the efforts of a group of philosophers who sought to unify philosophy and science under a common naturalistic theory of knowledge.

Vienna Circle

The Vienna Circle (German: Wiener Kreis) of Logical Empiricism was a group of philosophers and scientists drawn from the natural and social sciences, logic and mathematics who met regularly from 1924 to 1936 at the University of Vienna, chaired by Moritz Schlick.

The Vienna Circle's influence on 20th-century philosophy, especially philosophy of science and analytic philosophy, is immense up to the present day.

Among the members of the inner circle were Moritz Schlick, Hans Hahn, Philipp Frank, Otto Neurath, Rudolf Carnap, Herbert Feigl, Richard von Mises, Karl Menger, Kurt Gödel, Friedrich Waismann, Felix Kaufmann, Viktor Kraft and Edgar Zilsel. In addition, the Vienna Circle was occasionally visited by Alfred Tarski, Hans Reichenbach, Carl Gustav Hempel, Willard Van Orman Quine, Ernest Nagel, Alfred Jules Ayer, Oskar Morgenstern and Frank P. Ramsey. Ludwig Wittgenstein and Karl Popper were in close contact to the Vienna Circle, but never participated in the meetings of the Schlick Circle.The philosophical position of the Vienna Circle was called logical empiricism (German: logischer Empirismus), logical positivism or neopositivism. It was influenced by Ernst Mach, David Hilbert, French conventionalism (Henri Poincaré and Pierre Duhem), Gottlob Frege, Bertrand Russell, Ludwig Wittgenstein and Albert Einstein. The Vienna Circle was pluralistic and committed to the ideals of the Enlightenment. It was unified by the aim of making philosophy scientific with the help of modern logic. Main topics were foundational debates in the natural and social sciences, logic and mathematics; the modernization of empiricism by modern logic; the search for an empiricist criterion of meaning; the critique of metaphysics and the unification of the sciences in the unity of science.The Vienna Circle appeared in public with the publication of various book series – Schriften zur wissenschaftlichen Weltauffassung (Monographs on the Scientific World-Conception), Einheitswissenschaft (Unified Science) and the journal Erkenntnis – and the organization of international conferences in Prague; Königsberg (today known as Kaliningrad); Paris; Copenhagen; Cambridge, UK, and Cambridge, Massachusetts. Its public profile was provided by the Ernst Mach Society (German: Verein Ernst Mach) through which members of the Vienna Circle sought to popularize their ideas in the context of programmes for national education in Vienna.

During the era of Austrofascism and after the annexation of Austria by Nazi Germany most members of the Vienna Circle were forced to emigrate. The murder of Schlick in 1936 by a former student put an end to the Vienna Circle in Austria.

Zettel (Wittgenstein)

Zettel (German: "slip(s) of paper") is a collection of assorted remarks by Ludwig Wittgenstein, first published in 1967.

It contains several discussions of philosophical psychology and of the tendency in philosophy to try for a synoptic view of phenomena. Analyzed subjects include sense, meaning, thinking while speaking, behavior, pretense, imagination, infinity, rule following, imagery, memory, negation, contradiction, calculation, mathematical proof, epistemology, doubt, consciousness, mental states, and sensations.Editions include a parallel text English/German edition edited by Elizabeth Anscombe and Georg Henrik von Wright first published by Blackwell (UK) and University of California Press (USA) in 1967.

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