and leading light of the Vienna circle (see logical positivism). Born in Berlin, Schlick originally studied physics, eventually under Max Planck. Alongside physics he wrote essays on ethics and aesthetics. In 1922 he became professor of the inductive sciences in Vienna, and formed the association with Hahn, Feigl, Neurath and others that became known as the Vienna circle. His own distinctive contributions include his General Theory of Knowledge written between 1918 and 1925, containing amongst much else his case against synthetic a priori knowledge. Schlick was instrumental in luring Wittgenstein back to philosophy, although the latter’s relation to the Circle remained wary. Schlick was shot by a deranged student on the steps of the university of Vienna; the case became a catalyst for anti-Semitic feeling in the city (although Schlick was not in fact Jewish) and the student was later released, becoming a member of the Nazi party.