Coming as I do between psyche anatomized and psyche synthesized, I must define my terms that I can bridge the traditional gulf between mind and body and the technical gap between things begotten and things made.
By the term "mind," I mean ideas and purposes. By the term "body," I mean stuff and process. Stuff and process are familiar to every physicist as mass and energy in space and time, but ideas and purposes he keeps only in the realm of discourse and will not postulate them of the phenomena he observes. In this I agree with him, but what he observes is some sort of order or invariance in the flux of events. Every object he detects in the world is some sort of regularity. . .
To detect regularities in the relations of objects and so construct theoretical physics requires the dsciplines of logic and mathematics. In these fundamentally tautological endeavors we invent surprising regularities, complicated transformations which conserve whatever truth may lie in the propositions they transform. . . . It is these regularities, or invariants, which I call ideas, whether they are theorems of great abstraction or qualities simply sensed.
But let us now compel our physicist to account for himself as a part of the physcial world. In all fairness, he must stick to his own rules and show in terms of mass, energy, space, and time how it comes about that he creates theoretical phsyics. He must then become a neurophysiologist. . . , but in so doing he will be compelled to answer whether theoretical physics is something which he can discuss in terms of neurophysiology. . . To answer "no" is to remain a physicist undefiled. To answer "yes" is to become a metaphysician—or so I am told.
Warren S. McCulloch, "Why the Mind is in the Head," 1951