2. The Psycho-Physical Apparatus*1: An Introduction to a Physical Interpretation of Psycho-analytic Theory

The psycho-analytic doctrine is divided into two parts which should never be confused; into facts, and into the pictures that represent them. Freud himself has been careful to make this distinction and has repeatedly affirmed that his pictures are not to be mistaken for existences. If, however, we take as pictures something which does exist, and which has an independent correlation with the facts that it is to represent, certain advantages are won. Thus, if we know that there is a correlation between neural and psychic processes, the former, which are more easily visualized, may be used to represent the latter. Such a representation has the advantage over purely fantastic analogy in that it is less likely to deceive, and more likely to suggest undiscovered uniformities. Brain physiology is itself the object of a science. Two sciences known to be correlated advance twice as quickly after the correlation has been observed. Knowledge of both is pooled. Each illustrates points in the other that hitherto remained obscure. Advance in one is immediately transferable to the other. Thus, two geometries that had been studied independently doubled their rate of progress after the discovery that the points of one were correlates of the straight lines of the other.

It is the purpose of this paper to outline the sort of correlation between behaviourism and psychology which I believe will be some day established.