# Friedrich Waismann

Friedrich Waismann (/ˈvaɪsmən/; German:; 21 March 1896 – 4 November 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.

## Biography

Born to a Jewish family in Vienna, Austria-Hungary, 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 due to the annexation of Austria by Nazi Germany.
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. He died in Oxford.

## Relationship with Wittgenstein

Schlick first met Wittgenstein in 1927 and did so several times before the latter would agree to be introduced to some of his colleagues. From 1927 to 1928 Wittgenstein met with small groups that included Schlick, almost always Waismann, sometimes Carnap, and sometimes Feigl and his future wife Maria Kesper. But is doubtful that Wittgenstein ever attended any meetings of the Vienna Circle proper. And from 1929, Wittgenstein's contact with the Circle would be restricted to meetings with Schlick and Waismann only.
Conversations from these later meetings (December 1929 up to March 1932) were recorded by Waismann, and eventually published in English translation in Ludwig Wittgenstein and the Vienna Circle (1979). By the time these conversations began, Schlick had tasked Waismann with writing an exposition of Wittgenstein's philosophy. This project would undergo radical transformation but the final text, inspired by WIttgenstein but very much Waismann's own work, was published posthumously in English as The Principles of Linguistic Philosophy in 1965. Further material and notes from the period were published in English under the editorship of Gordon Baker in 2003.
Waismann later accused Wittgenstein of obscurantism because of what he considered to be his betrayal of the project of logical positivism and empirically-based explanation.

## Linguistic philosophy and logical positivism

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 papers were published posthumously in How I See Philosophy (1968, ed. R. Harré) and Philosophical Papers (1976, ed. B. F. McGuinness).

## Porosity and verifiability

Waismann introduced the concept of open texture to describe the universal possibility of vagueness in empirical statements. He had coined the phrase “Die Porosität der Begriffe” ('the porosity of concepts') for this purpose and credits William Kneale for suggesting the English term that he then adopted.
It is probably based, Brian Bix suggests, "on a constructivist view of language Wittgenstein put forward in the early 1930s." According to Waismann, even after measures have been taken to ensure that a statement is precise, there remains an inexhaustible source of vagueness due to an indefinite number of possibilities. Waismann's notion of vagueness is slightly different from his concept of open texture―he explained that open texture is more like the possibility of vagueness; vagueness can also be remedied so that it can be made more precise, while open texture cannot.
Open texture has been found in legal philosophy through the writings of H. L. A. Hart (see Hart's "Formalism and Rule Scepticism" in The Concept of Law). According to Hart, vagueness constitutes a fundamental feature of legal languages. It is claimed, however, that Waismann's conceptualization has limited practical application, since it is more for the extraordinary, while Hart's view of open texture concerns the more mundane, approaching the term in the context of a particular norm.

## Selected Bibliography
### Articles

* "Die Natur des Reduzibilitätsaxioms", Monatshefte für Mathematik und Physik 35, 1928, pp. 143–146.
** translated as "The Nature of the Axiom of Reducibility" in Philosophical Papers (1976)
* "Logische Analyse des Wahrscheinlichkeitsbegriffs", Erkenntnis, Vol. 1 (1930/1931), pp. 228-248.
** translated as "A Logical Analysis of the Concept of Probability" in Philosophical Papers (1976)
* "Über den Begriff der Identität in Erkenntnis, Vol. 6 (1936), pp. 56-64.
** translated as" The Concept of Identity" in Philosophical Papers (1976)
* "De beteekenis van Moritz Schlick voor de wijsbegeerte", Synthese, Vol. 1, No. 12 (1936), pp. 361-370.
** translated as "Moritz Schlick's Significance for Philosophy" in Philosophical Papers (1976)
* "Was ist logische Analyse?", The Journal of Unified Science (Erkenntnis), Vol. 8, No. 5/6 (Apr. 1, 1940), pp. 265-289.
** translated as "What is Logical Analysis?" in Philosophical Papers (1976)
* "Verifiability", Proceedings of the Aristotelian Society, Supplementary Volumes Vol. 19, (1945), pp. 119–150
* "The Many-Level-Structure of Language" Synthese, Vol. 5, No. 5/6 (Sep.-Oct., 1946), pp. 221-229.
* "Logische und Psychologische Aspekte in der Sprachbetrachtung", Synthese, Vol. 6, No. 9/12 (1947/1948), pp. 460-475.
* "Analytic-Synthetic", Analysis, Vol. 10, No. 2 (Dec., 1949), pp. 25-40.
* "Analytic-Synthetic II", Analysis, Vol. 11, No. 2 (Dec., 1950), pp. 25-38.
* "II: Notes on Talks with Wittgenstein", The Philosophical Review, Vol. 74, No. 1 (Jan., 1965), pp. 12-16.