ABSTRACT
THE CONCEPT of isomorphism originates in mathematics and the natural sciences. In the former discipline it means 'identity of form and of operations between two or more groups'; in the latter, it means 'the property of crystallizing in the same or closely related forms, especially as exhibited by substances of analogous composition'. In psychology, it is a concept invoked to heal the mind/body wound, that chronic split which appears both as subjective events/observable behaviour and as bio-psychological life/anorganic nature. Although the concept is particularly evident in Gestalt psychology, some sort of what we might call isomorphic thinking appears in those areas of psychology where the unity of the organism (organismal view) is stressed and where the problems of the mind/body relationship are understood as two aspects of the same thing or as two languages expressing the same thing. Thus we find it in the Gestalt theory of Koffka:
Subjective feeling and objective observation of behaviour or of physiological symptoms are in the best possible agreement. This is fundamental for our theory of emotions. If there were no such agreement, if we could feel excited . . . when our psychophysical field were . . . calm . . . our theory of emotions, nay our whole psychology would have to be entirely different. Then it certainly would not be isomorphic, whereas the real facts support our isomorphic methodology.
—K. Koffka, Principles of Gestalt Psychology, London, 1935, p. 402. (See also Chapter XI, below.)