Philosopher of science and probability theorist. Born in Hamburg, Reichenbach worked in Berlin until 1933, when he left Germany first for Istanbul, and thence to the United States. Although not a member of the Vienna circle he sympathized with the empiricist ideals of logical positivism, but substituting relationships of probability between different strata of scientific theories, in place of the positivist ideal of reduction. Influential works included Philosophie der Raum-Zeit-Lehre (1928, trs. as The Philosophy of Space and Time, 1958), and Experience and Prediction (1938).