Vygotsky's Main formulaEvery function in the child's cultural development appears twice: first, on the social level, and, later, on the individual level; first, between people (inter-psychological) and then inside the child (intrapsychological). This applies equally to voluntary attention, to logical memory, and to the formation of concepts. All the higher originate as actual relationships between individuals (Vygotsky, 1960[1]/1983: 145; see also Vygotsky, 1978). This passage from Lev Vygotsky's history of the development of higher mental functions is one of the most often cited from his works. It is his principal formula, and one may find dozens of similar propositions in his other works. For reference I call this proposition his Main Formula. It is not clear what exactly interpsychological means in this formula. The purpose here is to clarify what it could mean.With the help of his Main Formula, Vygotsky tried to accomplish two tasks at once: to describe the parallel processes of (1) the internalization of psychological function and (2) the acquiring of behavior. Is it necessary for both processes to be connected with language?Vygotsky's interest in the sign without meaning (for example, tying a string around one's finger as a reminder) and in children's pointing gestures in his early works shows that the process of behavior acquiring may be connected with nonlinguistic signs. Later his interest shifted. Why? Why did Vygotsky in his texts that were published later interpret interpsychological as a special kind of communication by means of language, as the order to do something? Many examples can be found to confirm this tendency. This is one of them:As a person masters the action of external natural forces, he masters his own behavior using the natural laws of this behavior. At the base of the natural laws of behavior are the laws of stimuli-response, so one cannot master the response while one has not mastered the stimuli. Hence, the child acquires his behavior, but the key to this process is in acquiring the system of stimuli. (Vygotsky, 1960/1983, p. 154)The Main Formula now becomes:Each system I speak about goes through three stages. The first is the interpsychological--I order, you execute; then the extrapsychological stage follows--I begin to order myself; and then the intrapsychological stage comes--two brain elements that are activated by external stimuli show a tendency to perform as a whole system and become an intra-cortical element. (Vygotsky, 1982[2], p. 130)The reference to physiological processes here is absent in the previous version of the Main Formula. And he goes further. It is impossible to understand all aspects of Vygotsky's motivation for writing the following (I tend to think that ideological pressure was one of the causes):Let a psychological process move a brain atom a distance of one micron--and the energy-conservation law is crushed, and we shall have to give up the main principle of natural science, which [our] entire present-day science is based on. So we have to suppose that our acquiring our own behavioral process is in essence like our domination over processes that take place in Nature. A person living in society is always under the influence of other people. Speech, for example, is one such powerful means of affecting another's behavior, and it is natural that a developing child acquires the same means that others use to conduct his behavior. (Vygotsky, 1983, p. 279).The argument about the energy-conservation law shows that Vygotsky in his Main Formula had an interest in solving the body-mind problem in such a manner. It is difficult to agree that the mind can easily move a brain atom by means of a voice order. To give a voice order, one has to move some atoms of the vocal apparatus, and one has to do so, of course, not by means of a voice order to these atoms.So the scheme of acquiring one's behavior by means of a language order does not help us to solve the body-mind problem, but this scheme may be to some extent empirically true. …