We must admit that this conception is a very plausible one, because the hypothesis of fixation is based upon the well-known fact, that certain periods of human life, and particularly infancy, do sometimes leave determining traces for ever. The only question is whether this principle is a sufficient explanation or not. If we examine persons who have been neurotic from infancy it seems to be confirmed, for we see the nucleus-complex as a permanent and powerful activity throughout the whole life. But if we take cases which never show any considerable traces of neurosis except at the particular time when they break down, and there are many such, this principle becomes doubtful. If there is such a thing as fixation, it is not permissible to base upon it a new hypothesis, claiming that at times during certain epochs of life the fixation becomes loosened and ineffective, while at others it suddenly becomes strengthened and effective. In such cases we find the nucleus-complex as active and as potent as in those which apparently support the theory of fixation. Here a critical attitude is peculiarly justifiable, when we consider the often-repeated observation that the moment of the outbreak of the disease is by no means indifferent; as a rule it is most critical. It usually occurs _at the moment when a new psychological adjustment, that is, a new adaptation, is demanded_. Such moments facilitate the outbreak of a neurosis, as every experienced neurologist knows. This fact seems to me extremely significant. If the fixation were indeed real we should expect to find its influence constant, _i.e._ a neurosis continuous throughout life. This is obviously not the case. The psychological determination of a neurosis is only partially due to an early infantile predisposition; it is due to a certain actual cause as well. And if we carefully examine the kind of infantile phantasies and events to which the neurotic individual is attached, we shall be obliged to agree that there is nothing in them specific for neurosis. Normal individuals have pretty much the same kind of internal and external experiences, and are attached to them to an even astonishing degree, without developing a neurosis. You will find primitive people, especially, very much bound to their infantility. It now begins to look as if this so-called fixation were a normal phenomenon, and that the importance of infancy for the later mental attitude is natural and prevails everywhere. The fact that the neurotic seems to be markedly influenced by his infantile conflicts, shows that it is less a matter of fixation than of a peculiar use which he makes of his infantile past. It looks as if he exaggerated its importance, and attributed a very great artificial value to it (Adler, a pupil of Freud's, expresses a very similar view). It would be unjust to say that Freud confined himself to the hypothesis of fixation; he also was conscious of the impression I have just discussed. He called this phenomenon of reactivation or secondary exaggeration of infantile reminiscences "regression." But in Freud's conception it appears as if the incestuous desires of the Œdipus-complex were the real cause of the regression to infantile phantasies. If this were the case, we should have to postulate an unexpected intensity of the primary incestuous tendencies. This view led Freud to his recent comparison between the so-called psychological "incest-barrier" in children and the "incest-taboo" in primitive man. He supposes that a real incestuous desire has led the primitive man to the invention of a protective law; while to me it looks as if the incest-taboo is one among numerous taboos of all sorts, and due to the typical superstitious fear of primitive man, a fear existing independently of incest and its interdiction. I am able to attribute as little particular strength to incestuous desires in childhood as in primitive humanity. I do not even seek the reason for regression in primary incestuous or any other sexual desires. I must state that a purely sexual ætiology of neurosis seems to me much too narrow. I base this criticism upon no prejudice against sexuality, but upon an intimate acquaintance with the whole problem.