Jung, C.J. (1961). Memories, dreams, reflections. New York: Vintage Press, 1965.

In Chapter 5, "Sigmund Freud," Jung tells of his deep fascination, and eventual disillusionment, with Freud and psychoanalysis. Freud was, according to Jung, deeply ambivalent about matters of the "spirit" -- and the psychosexual theory was a compensatory result:

Freud never asked himself why he was compelled to talk continually of sex, why this idea had taken such possession of him. He remained unaware that his '~monotony of interpretation" expressed a flight from himself, or from that other side of him which might perhaps be called mystical. So long as he refused to acknowledge that side, he could never be reconciled with himself. He was blind toward the paradox and ambiguity of the contents of the unconscious, and did not know that everything which arises out of the unconscious has a top and a bottom, an inside and an outside. When we speak of the outside -- and that is what Freud did -- we are considering only half of the whole, with the result that a countereffect arises out of the unconscious. (Jung, 1961/1965, pp. 152-153)

Jung's version of the split between them turns on dream-interpretation:

The trip to the United States which began in Bremen in 1909 lasted for seven weeks. We were together every day, and analyzed each other's dreams. At the time I had a number of important ones, but Freud could make nothing of them. I did not regard that as any reflection upon him, for it sometimes happens to the best analyst that he is unable to unlock the riddle of a dream. It was a human failure, and I would never have wanted to discontinue our dream analyses on that account. On the contrary, they meant a great deal to me, and I found our relationship exceedingly valuable. I regarded Freud as an older, more mature and experienced personality, and felt like a son in that respect. But then something happened which proved to be a severe blow to the whole relationship.

Freud had a dream -- I would not think it right to air the problem it involved. I interpreted it as best I could, but added that a great deal more could be said about it if he would supply me with some additional details from his private life. Freud's response to these words was a curious look -- a look of the utmost suspicion. Then he said, "But I cannot risk my authority!" At that moment he lost it altogether. That sentence burned itself into my memory; and in it the end of our relationship was already foreshadowed. Freud was placing personal authority above truth.

As I have already said, Freud was able to interpret the dreams I was then having only incompletely or not at all. They were dreams with collective contents, containing a great deal of symbolic material. One in particular was important to me, for it led me for the first time to the concept of the "collective unconscious" and thus formed a kind of prelude to my book, Wandlungen und Symbole' der Libido.

This was the dream. I was in a house I did not know, which had two stories. It was "my house." I found myself in the upper story, where there was a kind of salon furnished with fine old pieces in rococo style. On the walls hung a number of precious old paintings. I wondered that this should be my house, and thought, "Not bad." But then it occurred to me that I did not know what the lower floor looked like. Descending the stairs, I reached the ground floor. There everything was much older, and I realized that this part of the house must date from about the fifteenth or sixteenth century. The furnishings were medieval; the floors were of red brick. Everywhere it was rather dark. I went from one room to another, thinking, "Now I really must explore the whole house." I came upon a heavy door, and opened it. Beyond it, I discovered a stone stairway that led down into the cellar. Descending again, I found myself in a beautifully vaulted room which looked exceedingly ancient. Examining the walls, I discovered layers of brick among the ordinary stone blocks, and chips of brick in the mortar. As soon as I saw this I knew that the walls dated from Roman times. My interest by now was intense. I looked more closely at the floor. It was of stone slabs, and in one of these I discovered a ring. When I pulled it, the stone slab lifted, and again I saw a stairway of narrow stone steps leading down into the depths. These, too, I descended, and entered a low cave cut into the rock. Thick dust lay on the floor, and in the dust were scattered bones and broken pottery, like remains of a primitive culture. I discovered two human skulls, obviously very old and half disintegrated. Then I awoke.

What chiefly interested Freud in this dream were the two skulls. He returned to them repeatedly, and urged me to find a wish in connection with them. What did I think about these skulls? And whose were they? I knew perfectly well, of course, what he was driving at: that secret death-wishes were concealed in the dream. "But what does he really expect of me?" I thought to myself. Toward whom would I have death-wishes? I felt violent resistance to any such interpretation. I also had some intimation of what the dream might really mean. But I did not then trust my own judgment, and wanted to hear Freud's opinion. I wanted to learn from him. Therefore I submitted to his intention and said, "My wife and my sister-in-law -- after all, I had to name someone whose death was worth the wishing! I was newly married at the time and knew perfectly well that there was nothing within myself which pointed to such wishes. But I would not have been able to present to Freud my own ideas on an interpretation of the dream without encountering incomprehension and vehement resistance. I did not feel up to quarreling with him, and I also feared that I might lose his friendship if I insisted on my own point of view. On the other hand, I wanted to know what he would make of my answer, and what his reaction would be if I deceived him by saying something that suited his theories. And so I told him a lie.

I was quite aware that my conduct was not above reproach, but à la guerre, comme à la guerre! It would have been impossible for me to afford him any insight into my mental world. The gulf between it and his was too great. In fact Freud seemed greatly relieved by my reply. I saw from this that he was completely helpless in dealing with certain kinds of dreams and had to take refuge in his doctrine. I realized that it was up to me to find out the real meaning of the dream.

It was plain to me that the house represented a kind of image of the psyche-that is to say, of my then state of consciousness, with hitherto unconscious additions. Consciousness was represented by the salon. It had an inhabited atmosphere, in spite of its antiquated style.

The ground floor stood for the first level of the unconscious. The deeper I went, the more alien and the darker the scene became. In the cave, I discovered remains of a primitive culture, that is, the world of the primitive man within myself -- a world which can scarcely be reached or illuminated by consciousness. The primitive psyche of man borders on the life of the animal soul, just as the caves of prehistoric times were usually inhabited by animals before men laid claim to them.

During this period I became aware of how keenly I felt the difference between Freud's intellectual attitude and mine. I had grown up in the intensely historical atmosphere of Basel at the end of the nineteenth century, and had acquired, thanks to reading the old philosophers, some knowledge of the history of psychology. When I thought about dreams and the contents of the unconscious, I never did so without making historical comparisons; in my student days I always used Krug's old dictionary of philosophy. I was especially familiar with the writers of the eighteenth and early nineteenth century. Theirs was the world which had formed the atmosphere of my first-story salon. By contrast, I had the impression that Freud's intellectual history began with Buchner, Moleschott, Du Bois-Reymond, and Darwin.

The dream pointed out that there were further reaches to the state of consciousness I have just described: the long uninhabited ground floor in medieval style, then the Roman cellar, and finally the prehistoric cave. These signified past times and passed stages of consciousness.

Certain questions had been much on my mind during the days preceding this dream. They were: On what premises is Freudian psychology founded? To what category of human thought does it belong? What is the relationship of its almost exclusive personalism to general historical assumptions? My dream was giving me the answer. It obviously pointed to the foundations of cultural history -- a history of successive layers of consciousness. My dream thus constituted a kind of Structural diagram of the human psyche; it postulated something of an altogether impersonal nature underlying that psyche. It "clicked," as the English have it -- and the dream became for me a guiding image which in the days to come was to be corroborated to an extent I could not at first suspect. It was my first inkling of a collective a priori beneath the personal psyche. This I first took to be the traces of earlier modes of functioning. Later, with increasing experience and on the basis of more reliable knowledge, I recognized them as forms of instinct, that is, as archetypes. (Jung, 1961/1965, pp. 158-161)

cf. Davis, D.A. (1997). Jung in the Psychoanalytic movement.