WARREN S. McCULLOCH University of Illinois, College of Medicine, and Illinois Neuropsychiatric Institute
As the industrial revolution concludes in bigger and better bombs, an intellectual revolution opens with bigger and better robots. The former revolution replaced muscles by engines and was limited by the law of the conservation of energy, or of mass-energy. The new revolution threatens us, the thinkers, with technological unemployment, for it will replace brains with machines limited by the law that entropy never decreases. These machines, whose evolution competition will compel us to foster, raise the appropriate practical question: "Why is the mind in the head?"
Coming as I do between psyche anatomized and psyche synthesized, I must so 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. The existence of these objects is the first law of science. To detect regularities in the relations of objects and so construct theoretical physics requires the disciplines 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. This is invariance, many steps removed from simple sensation but not essentially different. It is these regularities, or invariants, which I call ideas, whether they are theorems of great abstraction or qualities simply sensed. The reason for excluding them from physics is that they must not be supposed to be either stuff or process in the causal sequences of any part of the world. They are