If the contents of dreams agree with a sex theory, then we know their essence already, but if they are symbolic we at least know that we do not understand them yet.
A symbol does not disguise, it reveals in time.
It is obvious that dream interpretation will yield one result when you consider the dream to be symbolic, and an entirely different one when you assume that the essential thought is merely disguised but already known in principle.
In the latter case, dream interpretation makes no sense whatever, for you find only what you know already.
Therefore I always advise my pupils: “Learn as much as you can about symbolism and forget it all when you are analysing a dream.”
This advice is so important in practice that I myself have made it a rule to admit that I never understand a dream well enough to interpret it correctly.
I do this in order to check the flow of my own associations and reactions, which might otherwise prevail over my patient’s uncertainties and hesitations.
As it is of the highest therapeutic importance for the analyst to get the message of the dream as accurately as possible, it is essential for him to explore the context of the dream-images with the utmost thoroughness.
I had a dream while I was working with Freud that illustrates this very clearly. ~Carl Jung, CW 18, Para 483