 “The exact description of consciousness [Bewusstsein] is the sole aim of experimental psychology” (cited by Titchener 1921b: 164). Wundt identifies “physiological” with “experimental”  psychology.[15]  Thus, for Wundt, experimental psychology is the unmediated study of consciousness, aided by the experimental protocols of the natural sciences. Yet this definition involves two contestable assumptions: first, that “consciousness” is susceptible to experiment (rejected by Kant); second, that psychology, even if conceived as experimental, has for its object consciousness or “the mental” (later rejected by the Behaviorists) (cf. Hearst 1979b: 10). Let us focus on the first assumption, since it is one Wundt addresses.