We can often influence what a man shall dream _about_, but never _what_ he will dream; for the mechanism of the dream-work and the unconscious dream-wish are inaccessible to external influence of any sort. We realized, when we were considering dreams arising out of bodily stimuli, that in the reaction to the bodily or mental stimuli brought to bear upon the dreamer the peculiarity and independence of dream-life is clearly seen. The criticism I have just discussed which tends to cast a doubt upon the objectivity of dream investigation is again an assertion based upon confounding, this time confounding dreams with—their material. I wanted to tell you as much as this about the problems of dreams. You will guess that I have passed over a great deal and will have discovered for yourselves that my treatment of nearly every point has necessarily been incomplete; but this is due to the phenomena of dreams being so closely connected with those of the neuroses. Our plan was to study dreams as an introduction to the study of the neuroses and it was certainly a better one than beginning the other way about; but since dreams prepare us for comprehension of the neuroses, so also can a correctly-formed estimate of dreams be acquired only after some knowledge of neurotic manifestations has been gained. I do not know how you may think about it, but I can assure you that I do not regret having taken up so much of your interest and of the time at our disposal in the consideration of problems connected with dreams. I know no other way by which one can so speedily arrive at conviction of the correctness of those statements by which psycho-analysis stands or falls. It requires strenuous work for many months, and even years, to demonstrate that the symptoms in a case of neurotic illness have a meaning, serve a purpose, and arise from the patient’s experiences in life. On the other hand, a few hours’ effort may be enough to show these things in some dream which at first seemed utterly confused and incomprehensible, and in this way to confirm all the premises upon which psycho-analysis rests—the existence of unconscious mental processes, the special mechanisms which they obey, and the instinctive propelling forces which are expressed by them. And when we remember how far-reaching is the analogy in the structure of dreams to that of neurotic symptoms and, with that, reflect how rapid is the transformation of a dreamer into a wide-awake, reasonable human being, we acquire an assurance that the neuroses too depend only upon an alteration in the balance of the forces at work in mental life. _PART III_ GENERAL THEORY OF THE NEUROSES SIXTEENTH LECTURE PSYCHO-ANALYSIS AND PSYCHIATRY