In explaining matters to you, I will allude to our theory dogmatically, as if it already were an accepted doctrine. Nevertheless, I do not want you to assume that our theory, as I shall presently put it before you, came into being as a fully developed, well-rounded out philosophical system. The development of our theory came about only very gradually, little by little, and was built up through continuous contact with observations. Moreover, our theory, in accordance with these observations, was continually modified until it finally evolved in a manner apparently satisfactory for our purposes. Only so short a time as a few years back, it would have been necessary for me to express this theory in somewhat different terms. And even today, I cannot guarantee that the terms I am using are definitely fixed and will not be modified again. You know very well that scientific truths do not burst upon us with the unexpectedness of a sudden phenomenon. As a rule, any science, long after its early stages, lacks the character of definiteness, unchangeability, and infallibility for which our human way of thinking longs so intensely. However, any science, as it presents itself to contemporaries, is science as its best, so far as contemporaries are able to judge. My introductory remarks, I hope, will assist you in gaining a correct perspective in reference to psychoanalysis, especially when I ask you to bear in mind that our specific science is still very young—hardly as old as our century, as a matter of fact—and deals with about the most difficult matter presenting itself to human research. Let me therefore encourage you to interrupt me unabashedly in my explanations, when you do not grasp the full meaning of my words and require further elucidation. “I am already interrupting you, even before you really start. You say that you are going to acquaint me with a new psychology. But I was always under the impression that psychology as such is no new science. As a matter of fact, it seems to me there always has been enough psychology and enough psychologists. In college, I learned of the great things achieved in this realm of human endeavor.” Far be it from me to deny these achievements. However, scrutinizing them closely, you will find that they rather belong in the category of sensory psychology. A doctrine of soul life never had a chance for development, because its conception was obstructed by one very essential misunderstanding. After all, what does psychology embrace today, as it is taught in colleges? Aside from a few important sensorimotoric perceptions, there are just a number of classifications and definitions referring to certain processes of the soul which, thanks to the fact that these terms have become a part of our living language, are now the common property of all educated people. To all appearances, such limited information does not enable us to clearly grasp our soul life.