Applying these remarks to the considered problem, we can say that the answer to the question of how to explain the variation in the results of analytical therapy, lies in the fact that we are trying to replace unreliable displacement on a reliable ego-syntonic control also does not always achieve our goal of completely or do it's not quite thoroughly. The transformation achieved, but often only partially: fragments of old mechanisms remain untouched by the analysis work. It is difficult to prove that this is indeed the case, since we have no other way to judge what has happened, except for the result, which we are trying to explain. Nevertheless, the experiences that occur during the analysis, do not contradict this assumption; on the contrary, they rather confirm it. But we should not use the clarity of our own understanding to measure beliefs that we have given to the patient. His conviction may not be enough "depth", as one might say; it is always a quantitative factor, which is so easily overlooked. If this is the correct answer to our question, we can say that the analysis by stating that it cures neuroses by strengthening control over the instincts, always right in theory but not always in practice. And so, because it is not always successful in sufficiently strengthen the foundations on which to base control of the instincts. Presence of such failure is easy to detect. In the past, the quantitative factor of instinctual strength opposed the protective efforts of the ego; For this reason, we are calling on the help of analytical work; and now that same factor sets a limit to the effectiveness of this new work. If the force of instincts is excessive, the mature ego, supported by analysis, fails in the same way as the helpless ego before. His control of the instincts is improving but remains imperfect because the transformation of the defense mechanisms is not complete. There is nothing surprising in the fact that, since the power of the tools, which operates the analysis is not unlimited, but limited to, the final outcome always depends on the relative strength of the mental institutions, who are fighting with each other.