Now in all of us, however constituted, but to a degree the greater in proportion as we are intense and sensitive and subject to diversified temptations, and to the greatest possible degree if we are decidedly psychopathic, does the normal evolution of character chiefly consist in the straightening out and unifying of the inner self. The higher and the lower feelings, the useful and the erring impulses, begin by being a comparative chaos within us — they must end by forming a stable system of functions in right subordination. Unhappiness is apt to characterize the period of order-making and struggle.

Lecture VIII, "The Divided Self, and the Process of its Unification" - The Varieties of Religious Experience (1902)