The Swiss psychiatrist, CG Jung (1875 – 1961), was the founder of analytical psychology and is known for his exploration and description of processes of the unconscious and archetypal phenomena.
Jung found that the unconscious spoke to us in our dreams by way of symbols. Convinced that dreams offer practical advice, sent from the unconscious to the conscious self, he felt that self-understanding would lead to a full and productive life. (Blurp from Man and His Symbols)
In CG Jung speaking: Interviews and Encounters, edited by William McGuire and RFC Hull, Jung says:
Together the patient and I address ourselves to the 2,000,000 year old man that is in all of us. In the last analysis, most of our difficulties come from losing contact with our instincts, with the age-old forgotten wisdom stored up in us.