This research examines the mind-body dualism split in the history of psychology. The research will review the philosophical background of dualism and then discuss how the legacy of philosophical dualism informed the emergence of psychological theory and its application in practice over the course of the 20th century.
What must be appreciated about the debate over dualism in psychology and philosophy is that in each of these disciplines, most answers are either partial or always subject to further debate, not only on account of conceptually creative theory but also on account of the accumulation of an increasing body of new, scientifically verifiable knowledge and information about how body and mind function. The dualism debate arose in the ancient period, not solely between Plato and Aristotle but in part because their metaphysics answered questions about the nature of reality and existence differently.
Plato's doctrine of Ideal forms illustrates one view. The nature of reality is a persistent Platonic theme, and the preoccupation with reality of existence per se is bound up with what is real about human experience in particular. For Plato, what is most real about it, i.e., what drives it and gives it meaning, is what cannot be seen but what can be conceptualized. The Ideal Forms are real entities that "our minds may learn to recognize as permanent realities, continually imparting their unchanging form and character to the transient flux of mortality on our earth" (Loomis 11).
The transient flux is material reality. The Republic's discussion of justice is an attribute of conceptualization of the just, which must precede the just material action. Properly conceptualized and internalized as an Ideal Form, justice will perforce be realized (= made real) in the external life of the community. Socrates's summary of the nexus of justice as idea and as practice near the end of Book IV of The Republic has psychological resonance becau...