Friedrich Waismann (March 21, 1896 - November 4, 1959) was an Austrian mathematician, physicist, and philosopher. He is best known for being a member of the Vienna Circle and one of the key theorists in logical positivism 1896 was a leap year starting on Wednesday (see link for calendar). ... 1959 was a common year starting on Thursday (link will take you to calendar). ... The Vienna Circle was a group of philosophers and scientists organized in Vienna under Moritz Schlick. ... Logical positivism (later referred to as logical empiricism) holds that philosophy should aspire to the same sort of rigor as science. ...

Born in Vienna, Waismann was educated in mathematics and physics at the University of Vienna. In 1922, he began to study philosophy under the tutelage of Moritz Schlick, the founder of the Vienna Circle. He emigrated to the United Kingdom in 1938. He was a reader in philosophy of science at the University of Cambridge from 1937 to 1939, and lecturer in philosophy of mathematics at the University of Oxford from 1939 until his death. 1922 was a common year starting on Sunday (see link for calendar). ... Moritz Schlick (April 14, 1882–June 22, 1936) was a German philospher and the founding father of logical positivism and the Vienna Circle. ... 1938 was a common year starting on Saturday (link will take you to calendar). ... The philosophy of science is the branch of philosophy which studies the philosophical foundations, presumptions and implications of science both of the natural sciences like physics and biology and the social sciences such as psychology and economics. ... The University of Cambridge is the second-oldest in the English-speaking world, after Oxford University. ... 1937 was a common year starting on Friday (link will take you to calendar). ... 1939 was a common year starting on Sunday (link will take you to calendar). ... Philosophy of mathematics is that branch of philosophy which attempts to answer questions such as: why is mathematics useful in describing nature?, in which sense, if any, do mathematical entities such as numbers exist? and why and how are mathematical statements true?. The various approaches to answering these questions will... The University of Oxford, situated in the city of Oxford in England, is the oldest university in the English-speaking world. ... 1939 was a common year starting on Sunday (link will take you to calendar). ...

Intermittently, from 1927 until 1936, Waismann had extensive conversations with Ludwig Wittgenstein about topics in philosophy of mathematics and philosophy of language. These conversations, recorded by Waismann, were published in Ludwig Wittgenstein and the Vienna Circle (1979, ed. B.F. McGuinness). Other members of the Circle (including Schlick, Rudolf Carnap, and Herbert Feigl) also spoke with Wittgenstein, but not to Waismann's extent. At one point in 1934, Wittgenstein and Waismann considered collaborating on a book, but these plans fell through after their philosophical differences became apparent. 1927 was a common year starting on Saturday (link will take you to calendar). ... 1936 was a leap year starting on Wednesday (link will take you to calendar). ... Ludwig Wittgenstein (1889-1951), pictured here in 1930, made influential contributions to logic and the philosophy of language, critically examining the task of conventional philosophy and its relation to the nature of language. ... Philosophy of language is the branch of philosophy that studies language. ... 1979 is a common year starting on Monday. ... Rudolf Carnap (May 18, 1891 - September 14, 1970) was a German philosopher. ... Herbert Feigl (December 14, 1902 - June 1, 1988) was an Austrian philosopher and a member of the Vienna Circle. ... 1934 was a common year starting on Monday (link will take you to calendar). ...

In Introduction to Mathematical Thinking: The Formation of Concepts in Modern Mathematics (1936), Waismann argued that mathematical truths are true by convention rather than being necessarily (or verifiably) true. His collected lectures, The Principles of Linguistic Philosophy (1965), and How I See Philosophy (1968, ed. R. Harré), a collection of papers, were published posthumously. 1936 was a leap year starting on Wednesday (link will take you to calendar). ... 1965 was a common year starting on Friday (the link is to a full 1965 calendar). ... 1968 was a leap year starting on Monday (the link is to a full 1968 calendar). ...