Moritz Schlick (1882–1936) is famous for claiming that philosophy was dependent on science, intellectually. He was a philosopher who studied with the physicist Max Planck before arriving in Vienna, Austria, in 1922. His presence was the inspiration for the mathematician Hans Hahn to inaugurate the discussion group of the Vienna Circle, which, in addition to Hahn and Schlick, at first contained Otto Neurath (1882–1945) and the physicist Philip Frank. Rudolf Carnap (1891–1970) joined them in 1926.

Schlick was professor of the philosophy of inductive sciences at the University of Vienna, while he led the Vienna Circle. He believed that empirical knowledge was not about the content of experience, which could not be communicated, but about the form of experience. He maintained that all genuine philosophical problems and questions were either mathematical or logical, or could be solved by scientific investigation.

Schlick believed that this implied that philosophy had no subject matter of its own that was distinct from the sciences. However, unlike other logical positivists, he thought that ethics were practical and that moral goodness was simply whatever is approved by society; moral obligation could be studied as what is generally required by society. His main works include General Theory of Knowledge (second edition, 1925) and Problems of Ethics (translated, 1939).