 In founding the experimental science of psychology, Wundt in effect “triangulated” a media via between the available options: he rejected Fechner’s mysticism while maintaining his experimental approach; at the same time, Wundt went beyond the purely physical interpretation of physiological experiments à la Helmholtz, arguing that at least in humans experimentation could reveal law-like regularities of inner (psychological) reality. Thus, to use the phrase of Ben-David and Collins, he established the “hybrid science” whose dual provenance is expressed in Wundt’s name for it, “physiological psychology” (Ben-David and Collins 1966: 459; Kusch 1995: 122,  ff.).[14]  Wundt’s interest, both to scholars of the history of philosophy and to contemporary philosophers of mind, flows ultimately from the definition, methodology, and “metaphysics” of this physiological psychology. Sections  3  and  4  are devoted to a description of its definition, method, and doctrine, while  Section 5  is concerned with its theoretical underpinnings. The practical and theoretical limits of experimental psychology will be treated in  Section 6,  on Völkerpsychologie.