The early interpretation of insanity was demon possession, which the medicine man or priest might exorcise - though in the face of idiocy he was helpless.

States of ecstasy and trance were sought for prophesy and religious rites. Strange notions originated as of the influence of the moon, perpetuated in the term lunacy. The mentally disordered seemed dehumanized. The humane conception begins with Pinel (1791), who first dared to release the shackles of the maniac and to consider the true sources of disturbed behavior. In the absence of a clue to the vicissitudes of mind, such belated theories could for a time command attention as those of Mesmer, claiming an "animal magnetism" paralleling the physical force, but streaming through his person and by that route inducing and allaying what we plainly recognize as hysterical manifestations. Such a concept as hysteria (retaining in its etymology the false notion of a connection with the uterus) in its modern renaissance compasses a large range of aberrant phenomena. Abnormal psychology has been naturalized into a confederation of disciplines conferring insight into human nature.

How much of this enlightenment is traceable to the Freudian invasion is not easy to determine. What may be termed the clinical phase of psychology was certain to arrive, even if there had been no Freud; it was written in the course of the emergent psychology, whose genetic stages we have been roughly and eclectically following. But the fact remains that the essential Freudian concept had a revitalizing influence similar to that of the Darwinian contribution. Yet this, too, has its antecedents in sporadic points of insight from Galen on: that the sufferings of mind were not only closely related to bodily infirmities and disqualifications, but also reacted upon them - a tenet now formulated as the psychogenic principle. It took on a novel Freudian form when hysterical lameness or blindness - a bodily symptom - was referred to a mental mechanism - a subconscious repression, expressive of a motive to avoid, to shut out, to escape a situation too harrowing to be borne. It was the discovery, or at least the novel formulation, of a new order of mental mechanism.

The concepts of the Freudian system can hardly be reduced to a synopsis. Yet, as a guide to the account that follows, it may be stated that the purpose is to explain the motivation of conduct in all its varieties. The instinctive urges, the sex urge most of all, supply the energy and give set and direction. The urge to power, mastery, regard, is the ego urge. When these meet with opposition, there results conflict, frequently below the conscious level. Such unconscious or suppressed tendencies may come to expression symbolically, in dreams; they may lead to a neurosis or maladjustment. Character traits arise from sublimations and compensations for such frustration. The systems of emotionally tinged ideas become complexes when elaborated, and become fixations when expressed in a personal relation, notably that of child to parent. Childhood influences dominate in the total personality, and the family relation sets its course. Much of it is in sex terms. Psychoanalysis is a method of revealing buried complexes of ideas from which maladjusted individuals suffer. Phobias and obsessions thus take their root and grow. The same processes are at work in the primitive unconscious and are responsible for totem and taboo, for myth and fairy tale, all of which carry a Freudian plot. Social repression in terms of a censorship plays a large part. Upon this outline has arisen an elaborate system of interpretation calling for hypothetical divisions of the ego as the nucleus of the strivings which make the personality and account for its desires and behavior.

The Freudian psychology, a piecemeal structure with slight architectural unity to begin with but growing by irregular additions from clinical experience, offers an inviting opportunity to illustrate how variously a specific advance extends the psychological insight. Beginning with the interpretation of an hysterical symptom (such as an inability to move a limb, yet with no true paralysis; eyes that do not see, yet with no real blindness; ears that hear not, yet without impairment), it was extended to a variety of fundamental neuroses. It was then made a clue to the interpretation of dreams, a subject almost outlawed from recognized psychology and relegated to the pseudo-psychology that continues the folklore products of cruder ways of thought. Still later it was applied to everyday lapses, mishandlings, forgettings, in all of which the same factor of motive gave a new meaning to incidents and reactions seemingly accidental. And finally it was enlarged to a comprehensive formulation of human motives, furnishing an insight into character traits, emotional disturbances, social relations generally. It introduced a new determinism. Still more importantly it projected a psychology from above, complementing that "primitive" reflex psychology, which is a psychology from below. Both are phases of an inclusive neurological concept of the sources of behavior. The question of its validity in principle is not the same as that of the correctness of its details. Its contribution is permanent. We shall never return to a pre-Freudian any more than to a pre-Darwinian outlook. The manner in which Freud, and especially his followers, have elaborated the details of the drama of life, has aroused violent protest within and without the medical profession. It is denounced as unscientific and speculative, as basing large conclusions on slender (and subjective) evidence, using such treacherous devices as symbolism, reading remote meaning into the obvious, ignoring well-established diagnoses. Its reception by psychologists is likewise divided; many are Freudians, but with large reservations. Freudianism has proceeded far more as a cult than as a science, and if it persists in its present temper, its status will continue to be uncertain.