Moritz Schlick

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.

Schlick was born in Berlin to a wealthy Prussian family with deep nationalist and conservative traditions. His father was Ernst Albert Schlick and his mother was Agnes Arndt. At the age of sixteen, he started to read Descartes' Meditations and Schopenhauer's Die beiden Grundprobleme der Ethik. Nietzsche's Also sprach Zarathustra especially impressed him.

He studied physics at the University of Heidelberg, the University of Lausanne, and, ultimately, the University of Berlin under Max Planck. Schlick explained this choice in his autobiography by saying that, despite his love for philosophy, he believed that only mathematical physics could help him obtain actual and exact knowledge. He felt deep distrust towards any metaphysical speculation.

In 1904, he completed his PhD thesis at the University of Berlin under the supervision of Planck. Schlick's thesis was titled Über die Reflexion des Lichts in einer inhomogenen Schicht (On the Reflection of Light in a Non-Homogeneous Medium). After a year as Privatdozent at Göttingen, he turned to the study of philosophy in Zurich. In 1907, he married Blanche Hardy. In 1908, he published Lebensweisheit (The Wisdom of Life), a slim volume about eudaemonism, the theory that happiness results from the pursuit of personal fulfillment as opposed to passing pleasures.

His habilitation thesis at the University of Rostock, Das Wesen der Wahrheit nach der modernen Logik (The Nature of Truth According to Modern Logic), was published in 1910. Several essays about aesthetics followed, whereupon Schlick turned his attention to problems of epistemology, the philosophy of science, and more general questions about science. In this last category, Schlick distinguished himself by publishing a paper in 1915 about Einstein's special theory of relativity, a topic only ten years old. He also published Raum und Zeit in der gegenwärtigen Physik (Space and Time in Contemporary Physics), which extended his earlier results by applying Poincaré's geometric conventionalism to explain Einstein's adoption of a non-Euclidean geometry in the general theory of relativity. Schlick corresponded by letter with Einstein and Einstein praised the book, stating “from the philosophical side nothing has been written about the subject with anything like the same degree of clarity”.

After early appointments at Rostock and Kiel, in 1922, Schlick assumed the chair of Naturphilosophie at the University of Vienna, which had previously been held by Ludwig Boltzmann and Ernst Mach. Schlick displayed an unusual success in organizing talented individuals in the philosophical and scientific spheres. When Schlick arrived in Vienna, he was invited to lead a group of scientists and philosophers who met regularly (on Thursday evenings in the Chemistry Building) to discuss philosophical topics in the sciences. Early members included the mathematician Hans Hahn and, within a few years, they were joined by Rudolf Carnap, Herbert Feigl, Kurt Gödel, Otto Neurath, Friedrich Waismann, and others. They initially called themselves the Ernst Mach Association, but they eventually became best known as the Vienna Circle.

In the years 1925–26, the Thursday night group discussed recent work in the foundations of mathematics by Gottlob Frege, Bertrand Russell, and Ludwig Wittgenstein. Wittgenstein's book, Tractatus Logico-Philosophicus, was a work that advanced, among other things, a logical theory of symbolism and a "picture" or "model" theory of language. Schlick and his group were impressed by the work, devoting considerable time to its study and even when it was no longer the principal focus of their discussion, it was mentioned in discussion.

Eventually, Wittgenstein agreed to meet with Schlick and other Circle members to discuss the Tractatus and other ideas, but he later found it necessary to restrict the visitors to sympathetic interlocutors. Through Schlick's influence, Wittgenstein was encouraged to consider a return to philosophy after some ten years away from the field. Schlick and Waismann's discussions with Wittgenstein continued until the latter felt that germinal ideas had been used without permission in an essay by Carnap, a charge of dubious merit.^{[according to whom?]} But he continued discussions in letters to Schlick after he no longer met with other Circle members.