Separation from his instinctual nature inevitably plunges civilized man into the conflict between conscious and unconscious, spirit and nature, knowledge and faith, a split that becomes pathological the moment his consciousness is no longer able to neglect or suppress his instinctual side.
Jung identifies estrangement from instinctual nature as the generative cause of the modern psychic split, rendering the suppression of instinct structurally pathogenic for civilization as a whole.
, The Undiscovered Self: With Symbols and the Interpretation of Dreams, 1957thesis