VII. Principles of Psychosomatic Physiology

The study of the whole matter has been greatly confused by the separation of the nerves into sensory and motor. Securely anchored as this distinction appears to be in contemporary physiological ideas, it is not supported by unbiased observation. The findings of physiology based on neural sections, or on the pathological elimination of certain nerves, do not prove what the experiment or the case-history is said to show. They prove something quite different. They prove that the supposed distinction between sensory and motor nerves does not exist. On the contrary, both kinds of nerve are essentially alike. The so called motor nerve does not implement movement in the manner that the theory of two kinds of nerve assumes. What happens is that the nerve as carrier of the neural function implements an inner perception of the particular metabolic process that underlies the will—in exactly the same way that the sensory nerve implements perception of what is coming to pass within the sense-organ. Unless and until neurological theory begins to operate in this domain with clear concepts, no satisfactory co-ordination of psychic and somatic life can come about.[^3]