Interbehavioral psychology holds that the fundamental psychological event is people (and other organisms) in interaction with their surroundings. Although all events in the universe involve interactions of two or more things, what is unique about person-environment interactions is that they develop an ever-changing history that becomes a contributing part of those ongoing interactions. Further, these interactions occur not in isolation but in a context. Taking together the person, the object or surroundings the person is in interaction with, the history of those interactions, and the context or setting conditions in which the interaction occurs, these interdependent factors comprise the field of psychological events. Mind- body dualism, biological or environmental reductionism, mental processing, internal representations, external or internal motivation, empty organism, epiphenomenalism, and S-->R mechanisms are all rejected.

The system begins not with such constructs but with the concrete events of orgnism, object, setting, and history in their interdependencies. This field of relationships is organized differently than any of its components and has principles of its own that must be examined at its own level of organization, not at the level of biology, culture, or chemistry. Although biological and environmental conditions contribute to the field and may facilitate or impede the interactions, they do not cause it. Those components are necessary but not sufficient conditions for the psychological field. Causality consists of the total field of interdependent events. Perceiving, learning, knowing, feeling, dreaming, reasoning, believing, imagining, etc. must be observed and analyzed as fields of specific concrete events. In short, interbehavioral psychology replaces ghostly causative constructs with observations of concrete interdependent events, which can be descriptively and systematically classified.