This is far from being all that could be said about errors. There is still much to be enquired into and discussed. But I shall be satisfied if you have been shaken somewhat in your previous beliefs by our investigations, so far as they have gone, and if you have gained a certain readiness to accept new ones. For the rest, I must be content to leave you with certain problems still unsolved. We cannot prove all our principles by the study of errors, nor are we indeed by any means solely dependent on this material. The great value of errors for our purpose lies in this, that they are such common occurrences, may easily be observed in oneself, and are not at all contingent upon illness. I should like to mention one more of your unanswered questions before concluding: “If, as we see from so many examples, people come so close to understanding errors and so often act as if they perceived their meaning, how is it possible that they should so generally consider them accidental, senseless, and meaningless, and so energetically oppose the psycho-analytic explanation of them?” You are right: this is indeed striking and requires an explanation. But I will not give it to you; I will rather guide you slowly towards the connections by which the explanation will be forced upon you without any aid from me. _PART II_ DREAMS FIFTH LECTURE DIFFICULTIES AND PRELIMINARY APPROACH TO THE SUBJECT One day the discovery was made that the symptoms of disease in certain nervous patients have meaning.[25] It was upon this discovery that the psycho-analytic method of treatment was based. In this treatment it happened that patients in speaking of their symptoms also mentioned their dreams, whereupon the suspicion arose that these dreams too had meaning. However, we will not pursue this historical path, but will strike off in the opposite direction. Our aim is to demonstrate the meaning of dreams, in preparation for the study of the neuroses. There are good grounds for this reversal of procedure, since the study of dreams is not merely the best preparation for that of the neuroses, but a dream is itself a neurotic symptom and, moreover, one which possesses for us the incalculable advantage of occurring in all healthy people. Indeed, if all human beings were healthy and would only dream, we could gather almost all the knowledge from their dreams which we have gained from studying the neuroses.