Abstract
It is argued that there are three modes of psychological explanation that are available and in wide use, but that the three are often unwittingly confounded. These are, identity theory, functionalism and intentionality.
Identity theory explains by viewing psychological events as direct products of design, that is, manifestations of brain events. The stance of functionalism is to study psychological events and those past and current stimuli that evoke them. In other words, functionalism studies the way in which psychological events are programmed. Intentionality approaches psychic events as a product of both conscious and unconscious purposes, beliefs, wishes, reasons and meanings, and concludes that it is of considerable worth to treat persons as intentional systems. It is claimed that the demarcation between these explanatory modes is crucial in psychiatric, and especially psychotherapeutic practice and research.