 The metaphysical or semantic policing of psychological vocabulary took place at two levels: as a science integrated within the unity of the sciences according to principles of physicalism, and as part of the scientific representation of relevant perception in the form of protocol sentences. As a matter of psychology of perception and language, all events and processes, all perceptual, speech and thought terms involved in the production of empirical data were to be taken physicalistically, e.g., as descriptions of spatio-temporal structures involving behavior or bodily—anatomical and physiological- changes under given observed conditions (Neurath 1931/1983, 55).