Vienna Circle in the context of "Philosophy of language"

German philosophy, meaning philosophy in the German language or philosophy by German people, in its diversity, is fundamental for both the analytic and continental traditions. It covers figures such as Gottfried Wilhelm Leibniz, Immanuel Kant, Georg Wilhelm Friedrich Hegel, Karl Marx, Friedrich Nietzsche, Martin Heidegger, Ludwig Wittgenstein, the Vienna Circle, and the Frankfurt School, who now count among the most famous and studied philosophers of all time. They are central to major philosophical movements such as rationalism, German idealism, Romanticism, dialectical materialism, existentialism, phenomenology, hermeneutics, logical positivism, and critical theory. The Danish philosopher Søren Kierkegaard is often also included in surveys of German philosophy due to his extensive engagement with German thinkers.

Verificationism, also known as the verification principle or the verifiability criterion of meaning, is a doctrine in philosophy and the philosophy of language which holds that a declarative sentence is cognitively meaningful only if it is either analytic or tautological (true or false in virtue of its logical form and definitions) or at least in principle verifiable by experience. On this view, many traditional statements of metaphysics, theology, and some of ethics and aesthetics are said to lack truth value or factual content, even though they may still function as expressions of emotions or attitudes rather than as genuine assertions. Verificationism was typically formulated as an empiricist criterion of cognitive significance: a proposed test for distinguishing meaningful, truth-apt sentences from "nonsense".

As a self-conscious movement, verificationism was a central thesis of logical positivism (or logical empiricism), developed in the 1920s and 1930s by members of the Vienna Circle and their allies in early analytic philosophy. Drawing on earlier empiricism and positivism (especially David Hume, Auguste Comte and Ernst Mach), on pragmatism (notably C. S. Peirce and William James), and on the logical and semantic innovations of Gottlob Frege and the early Wittgenstein, these philosophers sought a "scientific" conception of philosophy in which meaningful discourse would either consist in empirical claims ultimately testable by observation or in analytic truths of logic and mathematics. The verification principle was intended to explain why many traditional metaphysical disputes seemed irresolvable, to demarcate science from pseudo-science and speculative metaphysics, and to vindicate the special status of the natural sciences by taking empirical testability as the paradigm of serious inquiry.

Rudolf Carnap (/ˈkɑːrnæp/; German: [ˈkaʁnaːp]; 18 May 1891 – 14 September 1970) was a German philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism.

Friedrich Albert Moritz Schlick (/ʃlɪk/; German: [ʃlɪk] ; 14 April 1882 – 22 June 1936) was a German philosopher, physicist, and the founding father of logical positivism and the Vienna Circle. He was murdered by a former student, Johann Nelböck, in 1936.

Otto Karl Wilhelm Neurath (/ˈnɔɪrɑːt/; Austrian German: [ˈɔtoː ˈnɔʏraːt]; 10 December 1882 – 22 December 1945) was an Austrian-born philosopher of science, sociologist, and political economist. He was also the inventor of the ISOTYPE method of pictorial statistics and an innovator in museum practice. Before he fled his native country in 1934, Neurath was one of the leading figures of the Vienna Circle.

Hans Hahn (/hɑːn/; German: [haːn]; 27 September 1879 – 24 July 1934) was an Austrian mathematician and philosopher who made contributions to functional analysis, topology, set theory, the calculus of variations, real analysis, and order theory. In philosophy he was among the main logical positivists of the Vienna Circle.