This illustrates that the unconscious mental processes of all persons have much that is held in common, based upon biological promptings that are the common property of mankind. The varied ways in which they manifest themselves are due to the different trends of disposition, mental aptitude, environmental influences, etc.
According to the psychoanalytic hypothesis, the sexual impulse of the psychoneurotic shows all the aberrations of morbid sexual life. This principle may be summarized as follows (after Freud):
(a) In all the neurotics without exception there is evident feelings of inversion in the unconscious psychic life, fixation of libido on persons of the same sex. It is impossible, without a deep and searching discussion, adequately to appreciate the significance of this factor for the formation of the picture of the disease; but it may be safely asserted that the unconscious propensity to inversion is never wanting and is particularly of immense service in explaining male hysteria.
(b) All the inclinations to anatomical transgression can be demonstrated in psychoneurotics in the unconscious and as symptom-creators. Of special frequency and intensity are those which impart to the mouth and the mucous membrane of the anus the role of genitals.
(c) The partial desires which usually appear in contrasting pairs, play a very prominent role among the symptom-creators in psychoneuroses. They are known as carriers of new sexual aims, such as peeping mania, exhibitionism and the actively and passively formed impulses of cruelty. The contribution of the last is indis-
