Logical positivism
A philosophy of the scientific workshop: physicists, logicians and mathematicians gathered in Vienna to separate, in everything that is said, the statements that have meaning from those that only seem to.
c. 1924 – c. 1960
was born in Vienna around , whose seminar brought together philosophers, physicists and mathematicians from 1924 on. The group, which became the Vienna Circle, gave itself a programme in 1929 with the manifesto The Scientific Conception of the World, written by Hans Hahn, and and dedicated to Schlick. Heir to and armed with the logic of and , it read 's in a verificationist sense; Wittgenstein himself tried out formulas of that kind around 1929-1930, in his conversations with Schlick and , without turning them into a doctrine. In Berlin, a group gathered around pursued a closely related programme. The school was not monolithic: Schlick looked for a foundation of knowledge in immediate experience, whereas Neurath held that a statement can only ever be compared with other statements; Carnap came to adopt a principle of tolerance that leaves the choice of linguistic framework open; in ethics, Schlick treated morality as an empirical science of motives, while and Carnap saw in it only the expression of attitudes. Ayer gave the school its most forceful English statement in 1936, Language, Truth and Logic. The rise of Nazism, Schlick's murder (1936) and then the Anschluss (1938) scattered the Circle: Carnap and Reichenbach went to the United States, while Neurath ended his exile in Britain. Under the name of logical empiricism, the movement dominated American philosophy of science until the 1950s; 's criticisms (1951), followed by a more historically minded philosophy of science, marked its decline. The period recorded here ends around 1960: the school faded as such, but its work went on and its method left a lasting mark on the philosophy of science.
Philosophy is not a doctrine but an activity: it discovers no truths of its own, it establishes the meaning of our statements, and it is for the sciences to say whether they are true.
There is no knowledge outside science: metaphysics is not false, it is meaningless.
All knowledge of the world comes from experience; logic and mathematics say nothing about it, they are true by their form or the meaning of their terms.
Justification
For the Circle, philosophy is not a doctrine but an activity: calls this the “turning point” of philosophy (1930). It adds no truths to those of the sciences; it clarifies what our statements mean. The criterion of meaning supplies the tool for this sorting: a statement is cognitively meaningful if it is analytic, true or false by its form and the meaning of its terms alone, or if it can be tested by experience; otherwise it is a pseudo-statement, to be set aside rather than refuted. In Carnap, the early demand for strict verification soon gives way to the looser one of confirmation. The criterion does not itself meet its own demand; its defenders reply that it is a rule proposed for language, not a truth about the world. The reforming side of the manifesto, championed by Neurath, extends this clarification without turning it into a philosophy of transforming the world.
Schlick, “The Turning Point in Philosophy” (Erkenntnis, 1930) · Ayer, Language, Truth and Logic (1936), ch. I
Justification
argues (1932) that metaphysical sentences lack cognitive meaning: “the Nothing itself nothings”, which he borrows from , imitates the grammar of a statement while violating logical syntax. 's programme of the unity of science extends this division: a single language, that of the sciences, for everything that can be known. The value stops short of the extreme: the Circle does not expect science to replace metaphysics by answering its questions; it holds those questions to be ill-formed, and leaves to art the expression of the attitude toward life that metaphysics expressed badly.
Carnap, “The Elimination of Metaphysics through Logical Analysis of Language” (Erkenntnis, 1932) · Hahn, Neurath, Carnap, The Scientific Conception of the World: The Vienna Circle (1929)
Justification
The Circle radicalizes against : there is no synthetic a priori judgement. The logic of and , reread through the , makes it possible to treat logical and mathematical truths as analytic: true by virtue of their form or of the meaning of their terms alone, they teach nothing about the world. Rationalism thereby loses its best example, that of certain knowledge obtained without experience. This empiricism concerns the justification of knowledge of the world, not the psychological origin of ideas: it assumes no “blank slate”.
Hahn, Neurath, Carnap, The Scientific Conception of the World (1929) · Ayer, Language, Truth and Logic (1936), ch. IV
2 more
dismisses theism and atheism alike: since “God exists” cannot be verified, the sentence has no meaning, and its negation has none either. had already counted the metaphysical use of the word “God” among pseudo-concepts (1932). This is therefore not atheism but the refusal of the alternative itself.
regards the quarrel between realism and idealism as a pseudo-problem: two geographers, one a realist and the other an idealist, will describe the same mountain in the same way, and no experience could decide between them (Pseudoproblems in Philosophy, 1928). reaches the same conclusion in “Positivism and Realism” (1932).
Lineages
See on the friezeAll lineages↑ Influences received
- ContinuesEmpiricismThe 1929 manifesto counts Hume among its avowed ancestors: what passes on is the thesis that all knowledge of the world comes from experience.Read
- ReinterpretsPositivismThe Vienna Circle's manifesto (1929) lists Comte among its precursors, alongside Hume and Mill.Read
- ReinterpretsWittgensteinThe Circle read the Tractatus line by line in the mid-1920s and found two weapons in it: logical truths as tautologies, and the boundary between what can and cannot be said.Read
- Reacts againstOrdinary language philosophyAustin takes apart Ayer's theory of sense data by showing that the philosopher wrenches ordinary words, « illusion », « appear », « real », away from their precise use.Read
↓ Influence exerted
- challenged byWillard Van Orman QuineA pupil and friend of Carnap, Quine attacked the two pillars of logical empiricism: the distinction between analytic and synthetic truths, and the idea that each statement is verified in isolation.Read