Logical positivism

Unlike the physicist, the psychologist ... investigates processes that belong to the same order—perception, learning, thinking—as those by which he conducts his investigation.

— Logical positivism

The difference between Hayek’s view and that of the logical positivists was that he moved in an idealist direction and they emphasized verification.

— Logical positivism

:...Vienna is the origin of so many schools of its own which were dominant in the 1920s. And one of the most fundamental and influential, in which we all were partially caught, was logical positivism. In fact, Mises’ brother, Richard von Mises, became one of the leading figures. Now he and I all grew up in this Ernst Mach philosophy that ultimately everything must be rationally justified…

— Logical positivism