Encyclopedia Galactica

PSYCHOHISTORY -- Gaal Dornick, using nonmathematical concepts, has defined Psychohistory to be that branch of mathematics which deals with the reactions of human conglomerates to fixed social and economic stimuli. Implicit in all these definitions the assumption that the human conglomerate being dealt with s sufficiently large for valid statistical treatment. The necessary size of such a conglomerate may be determined by Seldon's First Theorem which ... a further necessary assumption is that human conglomerate be itself unaware of Psychohistory analysis in order that its reactions be truly random. The basis of all valid Psychohistory lies in the development of the Seldon functions which exhibit properties congruent to those of such social and economic forces as ...

Psychohistory is the main concept around which the plot and events of the Foundation Series revolve around. It is a mathematical sub-discipline, created and developped by Hari Seldon and some others (Yugo Amaryl, Wanda Seldon, etc...). Its purpose it to reduce the social, political, economic, and cultural tendencies of human societies to mathematical equations, thus allowing for certain predictions to be made about the future, and how given actions would change that future. It is described as a statistical science that took more than 35 years to develop into maturity.