The Practice of Psychotherapy (The Collected Works of C. G. Jung, Volume 16)
Instinct is not an isolated thing, nor can it be isolated in practice.
It always brings in its train archetypal contents of a spiritual nature, which are at once its foundation and its limitation.
In other words, an instinct is always and inevitably coupled with something like a philosophy of life, however archaic, unclear, and hazy this may be. Instinct stimulates thought, and if a man does not think of his own free will, then you get compulsive thinking, for the two poles of the psyche, the physiological and the mental, are indissolubly connected.
For this reason instinct cannot be freed without freeing the mind, just as mind divorced from instinct is condemned to futility.
Not that the tie between mind and instinct is necessarily a harmonious one.
On the contrary it is full of conflict and means suffering.
So they speak soothingly about progress and the greatest possible happiness, forgetting that happiness is itself poisoned if the measure of suffering has not been fulfilled.
Behind a neurosis there is so often concealed all the natural and necessary suffering the patient has been unwilling to bear.
We can see this most clearly from hysterical pains, which are relieved in the course of treatment by the corresponding psychic suffering which the patient sought to avoid.
Life demands for its completion and fulfillment a balance between joy and sorrow.
But because suffering is positively disagreeable, people naturally prefer not to ponder how much fear and sorrow fall to the lot of man. ~Carl Jung, CW 16, Para 185
