The transition from the pleasure principle to that of fact is the most important advance in the development of the ego. We already know that the sexual instincts pass through this stage unwillingly and late. We shall presently learn the consequence to man of the fact that his sexuality admits of such a loose relation to the external realities of his life. Yet one more observation belongs here. Since the ego of man has, like the libido, its history of evolution, you will not be surprised to hear that there are "ego-regressions," and you will want to know what role this return of the ego to former phases of development plays in neurotic disease. TWENTY-THIRD LECTURE GENERAL THEORY OF THE NEUROSES _The Development of the Symptoms_ In the layman's eyes the symptom shows the nature of the disease, and cure means removal of symptoms. The physician, however, finds it important to distinguish the symptoms from the disease and recognizes that doing away with the symptoms is not necessarily curing the disease. Of course, the only tangible thing left over after the removal of the symptoms is the capacity to build new symptoms. Accordingly, for the time being, let us accept the layman's viewpoint and consider the understanding of the symptoms as equivalent to the understanding of the sickness. The symptoms,--of course, we are dealing here with psychic (or psychogenic) symptoms, and psychic illness--are acts which are detrimental to life as a whole, or which are at least useless; frequently they are obnoxious to the individual who performs them and are accompanied by distaste and suffering. The principal injury lies in the psychic exertion which they cost, and in the further exertion needed to combat them. The price these efforts exact may, when there is an extensive development of the symptoms, bring about an extraordinary impoverishment of the personality of the patient with respect to his available psychic energy, and consequently cripple him in all the important tasks of life. Since such an outcome is dependent on the amount of energy so utilized, you will readily understand that "being sick" is essentially a practical concept. But if you take a theoretical standpoint and disregard these quantitative relations, you can readily say that we are all sick, or rather neurotic, since the conditions favorable to the development of symptoms are demonstrable also among normal persons.