The mainspring of creativity appears to be the same tendency which we discover so deeply as the curative force in psychotherapy, man's tendency to actualize himself, to become his potentialities. By this I mean the organic and human life, the urge to expand, extend, develop, mature - the tendency to express and activate all the capacities of the organism, or the self.

On Becoming a Person: A Therapist's View of Psychotherapy (ed. Houghton Mifflin Harcourt, 2012) - ISBN: 9780544086661