Number and the Human Sciences1 (1951)

An article for Géza Róheim's Festschrift should be about psychoanalysis and anthropology: as I have contributed nothing to either subject and he has contributed much to both it would be prudent to keep off both topics and talk about something else, let us say psychology.

Suppose one of those oft spoken of but seldom met travellers from Mars visited us to satisfy his naive curiosity about psychology; he would find a state of affairs which might at first seem somewhat puzzling. In the write-up of his field work he would report on one-person psychology, two-person psychology, three-person psychology, possibly a four-person psychology, and a multi-person psychology; what would strike him most would of course be the interrelation of these aspects of the subject.

‘The breakup of the whole field of psychology into categories according to the minimum number of persons essential to the study of each branch of the subject is the first thing that strikes the visitor’, he might write in his thesis, adding that distressing confusions sometimes occurred because these simple categories were thought to be irrelevant to the study of detail by the practitioners of each category and the implications so disconcerting that they were generally ignored.

One-Person Psychology concerns itself with what goes on inside one person taken in isolation. It studies the neurological aspect of the mind, sensation, reaction time, learning and forgetting, memory, imagery, hallucinations, introspection, etc.—a very varied field. It is true that in the study of some of these phenomena an experimenter or observer is usually present, but with the present richness of imagination and ingenuity now given to the construction of apparatus of all kinds it would be possible for most of the experiments in this branch of psychology to be carried out, not to be sure designed, by a robot. Where for reasons of economy or of scientific curiosity an observer is used