The author is primarily concerned with the explanation of behavior in regard to (1) the mecanical model, (2) the effects of physical-organic processes on behavior, (3) the lack of understanding between philosophers and psychologists as to sufficient conditions for predicting a behavioral event, (4) conditions leading to expalantions of behavior that could predict behavior exclusive of any antecedent psychological behavior, and (5) variations of the mechanical-model introducing differing sorts of explanation. (staff).