In Modern Man in Search of a Soul, C.G. Jung discusses the keys to assimilating the unconscious mind with the conscious mind and achieving the ultimate goal of individuation:
Dreams give information about the secrets of the inner life and reveal to the dreamer hidden factors of his personality. As long as these are undiscovered, they disturb his waking life and betray themselves only in the form of symptoms. This means that we cannot effectively treat the patient from the side of consciousness alone, but must bring about a change in and through the unconscious. As far as present knowledge goes, there is only one way of doing this: there must be a thorough-going, conscious assimilation of unconscious contents. By “assimilation”, I mean a mutual interpenetration of conscious and unconscious contents, and not—as is too commonly thought—a one-sided valuation, interpretation and deformation of unconscious contents by the conscious mind.
As to the value and significance of unconscious contents in general, very mistaken views are abroad. It is well known that the Freudian school presents the unconscious in a thoroughly depreciatory light, just as also it looks on primitive man as little better than a wild beast. Its nursery-tales about the terrible old man of the tribe and its teachings about the “infantile-perverse-criminal” unconscious have led people to make a dangerous monster out of the unconscious, that really very natural thing. As if all that is good, reasonable, beautiful and worth living for had taken up its abode in consciousness! Have the horrors of the World War really not opened our eyes? Are we still unable to see that man’s conscious mind is even more devilish and perverse than the unconscious?
I was recently reproached with the charge that my teaching about the assimilation of the unconscious, were it accepted, would undermine culture and exalt primitivity at the cost of our highest values. Such an opinion can have no foundation other than the erroneous belief that the unconscious is a monster. Such a view arises from fear of nature and of life as it actually is. Freud has invented the idea of sublimation to save us from the imaginary claws of the unconscious. But what actually exists cannot be alchemistically sublimated, and if anything is apparently sublimated, it never was what a false interpretation took it to be.
The unconscious is not a demonic monster, but a thing of nature that is perfectly neutral as far as moral sense, æsthetic taste and intellectual judgement go. It is dangerous only when our conscious attitude towards it becomes hopelessly false. And this danger grows in the measure that we practise repressions. But as soon as the patient begins to assimilate the contents that were previously unconscious, the danger from the side of the unconscious diminishes. As the process of assimilation goes on, it puts an end to the dissociation of the personality and to the anxiety that attends and inspires the separation of the two realms of the psyche. That which my critic feared—I mean the overwhelming of consciousness by the unconscious—is most likely to occur when the unconscious is excluded from life by repressions, or is misunderstood and depreciated.
The way of successive assimilations reaches far beyond the curative results that specifically concern the doctor. It leads in the end to that distant goal (which may perhaps have been the first urge to life), the bringing into reality of the whole human being—that is, individuation.
Excerpt from the Carl Jung ebook, Modern Man in Search of a Soul