Rudolf Carnap
Metaphysical claims are not false but meaningless, and philosophy should become the logical analysis of the language of science.
Placement
Logical empiricism: overcoming metaphysics through the logical analysis of language.
Key ideas
- The Logical Structure of the World
- Verification principle
- Principle of tolerance
Teachers: Gottlob Frege
Students: Carl Gustav Hempel
Influence
Influenced by 10
Immanuel Kant
influenced by ✓
Carnap kept a Kantian synthetic a priori for the topological structure of intuitive space (Der Raum, 1922); Friedman reads the Aufbau (1928) as recasting neo-Kantian constitution. R. Carnap, Der Raum (1922); Der logische Aufbau der Welt (1928); M. Friedman, Reconsidering Logical Positivism (1999); SEP “Rudolf Carnap”
Immanuel Kant › 1724–1804
Ernst Mach
influenced by ✓
Carnap built the Aufbau (1928) on an autopsychological basis of experiences, in the line of Mach’s analysis of sensations, but took elementary experiences, not sensation elements, as basic. R. Carnap, Der logische Aufbau der Welt (1928); E. Mach, Die Analyse der Empfindungen (1886); SEP “Ernst Mach”; SEP “Rudolf Carnap”
Ernst Mach › 1838–1916
Edmund Husserl
influenced by ✓
Carnap grounded intuitive space on Husserl’s eidetic intuition (Wesensschau) in his dissertation (Der Raum, 1922) and attended Husserl’s seminars in Freiburg (1924–25). R. Carnap, Der Raum. Ein Beitrag zur Wissenschaftslehre (1922); SEP “Rudolf Carnap”
Edmund Husserl › 1859–1938
Bertrand Russell
influenced by
Carnap set Russell’s maxim to replace inferred entities by logical constructions as motto of the Aufbau (1928); reading Our Knowledge of the External World (1914) had launched it. R. Carnap, Der logische Aufbau der Welt (1928); “Intellectual Autobiography”, in P. A. Schilpp (ed.), The Philosophy of Rudolf Carnap (1963); B. Russell, Our Knowledge of the External World (1914); SEP “Rudolf Carnap”
Evidence: also in InPhO · InPhO
Bertrand Russell › 1872–1970
Ludwig Wittgenstein
influenced by ✓
Carnap took from the Tractatus, read in the Vienna Circle, the view that logic consists of tautologies and metaphysics of pseudo-sentences, and met Wittgenstein in 1927–29. R. Carnap, “Intellectual Autobiography”, in P. A. Schilpp (ed.), The Philosophy of Rudolf Carnap (1963); “Überwindung der Metaphysik durch logische Analyse der Sprache” (1932); SEP “Rudolf Carnap”; SEP “Vienna Circle”
Evidence: also in Wikidata · Wikidata
Ludwig Wittgenstein › 1889–1951
Alfred Tarski
influenced by ✓
After talks with Tarski from 1930, Carnap adopted Tarski’s semantic concept of truth and turned from logical syntax to semantics (Introduction to Semantics, 1942). R. Carnap, Introduction to Semantics (1942); “Intellectual Autobiography”, in P. A. Schilpp (ed.), The Philosophy of Rudolf Carnap (1963); SEP “Rudolf Carnap”; SEP “Tarski’s Truth Definitions”
Evidence: also in Wikidata · Wikidata
Alfred Tarski › 1901–1983
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Gottlob Frege studied with
studied with ✓
Carnap attended Frege’s courses in Jena – Begriffsschrift I and II (1910–11, 1913) and Logic in Mathematics (1914) – as one of very few students; he later recalled them as his introduction to modern logic. R. Carnap, “Intellectual Autobiography”, in P. A. Schilpp (ed.), The Philosophy of Rudolf Carnap (1963)
Evidence: AI draft
Gottlob Frege › 1848–1925
Otto Neurath
influenced by
Carnap adopted Neurath’s physicalism, making physical language the universal language of science (1932), and came round to his view that protocol sentences are revisable. R. Carnap, “Die physikalische Sprache als Universalsprache der Wissenschaft”, Erkenntnis 2 (1932); “Über Protokollsätze”, Erkenntnis 3 (1932); O. Neurath, “Protokollsätze”, Erkenntnis 3 (1932); SEP “Otto Neurath”
Evidence: AI draft
Otto Neurath › 1882–1945
Janina Hosiasson-Lindenbaum
influenced by
Carnap took up Hosiasson-Lindenbaum’s axioms for a degree of confirmation (‘On Confirmation’, 1940) in his inductive logic (Logical Foundations of Probability, 1950). R. Carnap, Logical Foundations of Probability (1950); J. Hosiasson-Lindenbaum, “On Confirmation”, Journal of Symbolic Logic 5 (1940)
Evidence: AI draft
Janina Hosiasson-Lindenbaum › 1899–1942
Kurt Gödel
influenced by
Carnap used Gödel’s arithmetisation to state the syntax of a language within that language and, after the incompleteness results, separated derivability from consequence (Logische Syntax der Sprache, 1934). R. Carnap, Logische Syntax der Sprache (1934); K. Gödel, “Über formal unentscheidbare Sätze der Principia Mathematica und verwandter Systeme I”, Monatshefte für Mathematik und Physik 38 (1931); SEP “Rudolf Carnap”
Evidence: AI draft
Kurt Gödel › 1906–1978
Influenced 6
Carl Gustav Hempel taught
taught
Hempel studied with Carnap, Schlick and Waismann in Vienna in the autumn semester of 1929 and in 1937–38 worked with Carnap at the University of Chicago; his doctorate (Berlin, 1934) was taken elsewhere. SEP “Carl Hempel”
Evidence: AI draft
Carl Gustav Hempel › 1905–1997
A. J. Ayer
influenced ✓
Ayer took up Carnap’s elimination of metaphysics by logical analysis of language and his view of philosophy as a department of logic (Language, Truth and Logic, 1936). A. J. Ayer, Language, Truth and Logic (1936); R. Carnap, “Überwindung der Metaphysik durch logische Analyse der Sprache”, Erkenntnis 2 (1932); SEP “Alfred Jules Ayer”
Evidence: also in Wikidata · Wikidata
A. J. Ayer › 1910–1989
Wilfrid Sellars
influenced
Sellars developed Carnap’s logical syntax and semantics into a ‘pure pragmatics’ of rule-governed language, the frame of his later epistemology (‘Pure Pragmatics and Epistemology’, 1947). W. Sellars, “Pure Pragmatics and Epistemology”, Philosophy of Science 14 (1947); “Autobiographical Reflections” (1975); SEP “Wilfrid Sellars”
Evidence: also in InPhO · InPhO
Wilfrid Sellars › 1912–1989
Donald Davidson
influenced ✓
Davidson worked through Carnap’s semantics of extension and intension (Schilpp volume, 1963) before replacing meanings with a Tarskian theory of truth (‘Truth and Meaning’, 1967). D. Davidson, “The Method of Extension and Intension”, in P. A. Schilpp (ed.), The Philosophy of Rudolf Carnap (1963); “Truth and Meaning”, Synthese 17 (1967); SEP “Donald Davidson”
Evidence: also in Wikidata · Wikidata
Donald Davidson › 1917–2003
Hilary Putnam
influenced
Putnam, who worked with Carnap on inductive logic (1953–54), illustrated his conceptual relativity with a ‘Carnapian’ world of three individuals (The Many Faces of Realism, 1987). H. Putnam, The Many Faces of Realism (1987); “‘Degree of Confirmation’ and Inductive Logic”, in P. A. Schilpp (ed.), The Philosophy of Rudolf Carnap (1963); SEP “Rudolf Carnap”
Evidence: AI draft
Hilary Putnam › 1926–2016
David Lewis
influenced
Lewis adapted the Ramsey–Carnap method for theoretical terms to define mental states by their causal roles (‘How to Define Theoretical Terms’, 1970; ‘Psychophysical and Theoretical Identifications’, 1972). D. Lewis, “How to Define Theoretical Terms”, Journal of Philosophy 67 (1970); “Psychophysical and Theoretical Identifications”, Australasian Journal of Philosophy 50 (1972); SEP “David Lewis”
Evidence: also in InPhO · InPhO
David Lewis › 1941–2001
Criticism
Criticized by 4
Susan Stebbing
criticised by
Stebbing rejected Carnap’s logically constructed systems and methodological solipsism, objecting that the positivists put the question of meaning before that of truth (‘Logical Positivism and Analysis’, 1933). L. S. Stebbing, “Logical Positivism and Analysis”, Proceedings of the British Academy 19 (1933); SEP “Susan Stebbing”, §§ 3–4
Evidence: AI draft
Susan Stebbing › 1885–1943
Eino Kaila
criticised by
In Der logistische Neupositivismus (1930) Kaila argued against Carnap’s Aufbau (1928) that the concepts of science cannot all be constructed from elementary experiences. E. Kaila, Der logistische Neupositivismus. Eine kritische Studie (1930); R. Carnap, Der logische Aufbau der Welt (1928)
Evidence: AI draft
Eino Kaila › 1890–1958
Karl Popper
criticised by
Popper rejected Carnap’s verifiability criterion of meaning and inductive logic, proposing falsifiability as a criterion of demarcation, not of meaning (‘The Demarcation between Science and Metaphysics’, 1963). K. Popper, Logik der Forschung (1934), §§ 4–6; “The Demarcation between Science and Metaphysics”, in P. A. Schilpp (ed.), The Philosophy of Rudolf Carnap (1963), with Carnap’s reply
Evidence: AI draft
Karl Popper › 1902–1994
W. V. O. Quine influenced
influenced
Quine met Carnap in Prague (1933), read Logische Syntax in typescript and presented it in Harvard lectures (1934); he called Carnap his teacher (‘Homage to Rudolf Carnap’, 1970). W. V. Quine, “Lectures on Carnap” (1934), in R. Creath (ed.), Dear Carnap, Dear Van (1990); “Homage to Rudolf Carnap” (1970); SEP “Willard Van Orman Quine”
Evidence: also in InPhO · InPhO
criticised by
In ‘Two Dogmas of Empiricism’ (1951) Quine rejected Carnap’s analytic–synthetic distinction and reductionism: statements face the tribunal of experience only as a corporate body. W. V. O. Quine, “Two Dogmas of Empiricism”, Philosophical Review 60 (1951), 20–43; “Carnap and Logical Truth” (1963)
Evidence: AI draft
W. V. O. Quine › 1908–2000
Criticizes 1
Martin Heidegger
criticised
Carnap declared sentences such as Heidegger’s ‘The Nothing itself nothings’ pseudo-statements without cognitive content (‘Überwindung der Metaphysik durch logische Analyse der Sprache’, Erkenntnis, 1931/32). R. Carnap, “Überwindung der Metaphysik durch logische Analyse der Sprache”, Erkenntnis 2 (1931/32), 219–241, § 5; M. Heidegger, Was ist Metaphysik? (1929)
Evidence: AI draft
Martin Heidegger › 1889–1976
Works
A rational reconstruction of all concepts from what is given in experience.
The manifesto of the Vienna Circle, signed by Hans Hahn, Otto Neurath and Rudolf Carnap: unified science, logical analysis, no metaphysics – and an alliance with social reform.
“The nothing nothings” as a textbook example of a pseudo-statement.
Position
Carnap wanted to make philosophy as precise as mathematics. In The Logical Structure of the World he attempted to reconstruct all concepts of science step by step from elementary experiences. Metaphysical sentences such as Heidegger’s “Nothing nothings” he declared not false but meaningless: they look like statements yet cannot be checked by any experience. Later his “principle of tolerance” gave the program a liberal turn: one may choose among different logical languages, and the choice is a practical question of usefulness, not of truth. With his work on logical syntax, semantics and inductive probability, Carnap became the central figure of logical empiricism and a teacher of a whole generation of American philosophers, Quine among them.
Life & context
Carnap was born in 1891 near Wuppertal and studied in Jena, where he heard Gottlob Frege’s lectures on logic. From 1926 he taught in Vienna and became a leading member of the Vienna Circle, then moved to Prague in 1931. In 1935 he emigrated to the United States, teaching in Chicago and later at UCLA until his death in 1970.
Further main works
- The Logical Syntax of Language (1934)
- Meaning and Necessity (1947)
- Empiricism, Semantics, and Ontology (1950)
Appears in
- Journey ‘The Linguistic Turn’ · Stop 4 of 10
- Debate ‘Carnap, Heidegger and the Nothing’
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