Psychohistory

Definition

That branch of mathematics that deals with the overall reactions of large groups of human beings to given stimuli under given conditions In other words, it is supposed to predict social and historical changes.

Hari Seldon modeled his science of psychohistory on the kinetic theory of gases.  Each atom or molecule in a gas moves randomly so that the position or velocity of any one of them cannot be known.  Nevertheless, using statistics, the rules governing their overall behaviour can be worked out with great precision.  In the same way, Seldon intended to work out the overall behaviour of human societies even though the solutions would not apply to the behaviour of individual human beings.