Rudolf Carnap (May 18, 1891 - September 14, 1970) was a German philosopher.
He was born in Ronsdorf and educated at the Gymnasium of Barmen and the University of Freiburg. At university he studied physics, mathematics and, under Bruno Bauch, philosophy. Initially Carnap's main interest was physics but his intended studies were halted by WW I, during which Carnap served. Post-war Carnap returned to his studies, writing his dissertation, Der Raum, on the theory of space and time under Bauch. Following the acceptance of his thesis in 1922 Carnap continued to work on issues in physics from a philosophical perspective as a logical positivist. Between 1924 and 1925 Carnap also attended seminars held by Edmund Husserl.
He moved to Vienna in 1926 to take up an academic post at the University of Vienna and became involved in the Vienna Circle, a group of intellectuals led by Moritz Schlick and including Hans Hahn, Friedrich Waissman, Otto Neurath, and attended on occasion by Kurt Gödel and Carl Hempel, among others. Carnap and some of the circle's other members also met occasionally with Wittgenstein when the latter was in Vienna. In 1928 Carnap published Der logische Aufbau der Welt, in which he argued for an empiricist reconstruction of scientific knowledge, redefining concepts by phenomentalistic language, based on experience. In 1929 he published a mathematical logic manual, Abriss der Logistik. In 1930 Carnap and Reichenbach founded the philosophy journal Erkenntnis. In 1931 Carnap was appointed Professor of natural philosophy at the University of Prague, he remained in that post until 1935 when he emigrated to the U.S.A. During the early 1930s, W. V. Quine, then on a travelling fellowship, visited him and discussed his philosophy extensively.
He became a professor at the University of Chicago in 1936 and remained there until 1952. At Chicago he became interested in semantics and wrote three books in the 1940s on the subject. He worked briefly at Princeton before becoming a professor at UCLA in 1954. He returned to his work on scientific knowledge, concerned with distinguishing analytic statements from synthetic statements and with the verifiability principle.
Other published works include: Logische Syntax der Sprache (1934), Meaning and Necessity: A Study in Semantics and Modal Logic (1947), Logical Foundations of Probability (1950), The Continuum of Inductive Methods (1952). The autobiographical The Philosophy of Rudolf Carnap, editor P. A. Schlipp was published in 1963.