The other element common to all dreams, their peculiarity in mental life, is on the one hand very difficult to grasp and on the other seems to afford no clue for further inquiry. Our experiences in dreams for the most part take the form of visual images. Can these be explained by the stimuli? Is it really the stimulus that we experience? If so, why is the experience visual, when it can only be in the very rarest instance that any stimulus has operated upon our eyesight? Or, can it be shown that when we dream of speech any conversation or sounds resembling conversation reached our ears during sleep? I venture to discard such a possibility without any hesitation whatever. If we cannot get any further with the common characteristics of dreams as a starting-point, let us try beginning with their differences. Dreams are often meaningless, confused, and absurd, yet there are some which are sensible, sober, and reasonable. Let us see whether these latter sensible dreams can help to elucidate those which are meaningless. I will tell you the latest reasonable dream which was told to me, the dream of a young man: “I went for a walk in the Kärntnerstrasse and there I met Mr. X.; after accompanying him for a short time I went into a restaurant. Two ladies and a gentleman came and sat down at my table. At first I was annoyed and refused to look at them, but presently I glanced across at them and found that they were quite nice.” The dreamer’s comment on this was that the evening before he had actually been walking in the Kärntnerstrasse, which is the way he usually goes, and that he had met Mr. X. there. The other part of the dream was not a direct reminiscence, but only bore a certain resemblance to an occurrence of some time previously. Or here we have another prosaic dream, that of a lady. “Her husband says to her: ‘Don’t you think we ought to have the piano tuned?’ and she replies: ‘It is not worth it, for the hammers need fresh leather anyhow.’” This dream repeats a conversation which took place in almost the same words between herself and her husband the day before the dream. What then do we learn from these two prosaic dreams? Merely that there occur in them recollections of daily life or of matters connected with it. Even that would be something if it could be asserted of all dreams without exception. But that is out of the question; this characteristic too belongs only to a minority of dreams. In most dreams we find no connection with the day before, and no light is thrown from this quarter upon meaningless and absurd dreams. All we know is that we have met with a new problem. Not only do we want to know what a dream is saying, but if as in our examples that is quite plain, we want to know further from what cause and to what end we repeat in dreams this which is known to us and has recently happened to us.