Psychohistory, like psychoanalysis, is a science in which the researcher's feelings are as much or even more a part of his research equipment than his eyes or his hands. [...] Weighing of complex motives can only be accomplished by identification with human actors, the usual suppression of all feeling preached and followed by most "science" simply cripples a psychohistorian as badly as it would cripple a biologist to be forbidden the use of a microscope. The emotional development of a psychohistorian is therefore as much a topic for discussion as his or her intellectual development.

Ch. 2, p. 100. - Foundations of Psychohistory (1982)