"A man, therefore, who gets so far as making the supposed unity of the self twofold is already almost a genius, in any case a most exceptional and interesting person. In reality, however, every ego, so far from being a unity is in the highest degree a manifold world, a constellated heaven, a chaos of forms, of stages and stages, of inheritances and potentialities ... not yet a finished creation but rather a challenge of the spirit"
A tribute to the human need to know: the baby's delight in her first amazed discovery of her own hand, or that a parent comes when called, or that an object fallen from her grasp remains much the same when it is regained. Another tribute to the same need to know: scientific theories on all subjects repeatedly capture widespread public attention.
Psychological theories touch a special chord, our natural interest in ourselves and in each other. Different theories, although they may be seen as competing for the best way of integrating psychological knowledge, can also be viewed as reflecting different aspects of this complexity of self and social interest.
Only a few psychologists in our century have approached the status of household word: Freud and his lineal descendant Erikson, Pavlov and his lineal descendant Skinner, and Piaget. To understand Piaget's particular impact, it is useful to reflect a moment on the differences among these points of view. Psychoanalysis focuses its attention on the animal, irrational, unconscious aspects of human experience and conduct. It promises amelioration of human ills through new techniques for establishing healthier relations between the rational, which it does not deny, and the irrational, which it acclaims. Behaviorism challenges the simplistic rationalism of previous centuries from another quarter, denying scientific status to the very idea of consciousness, and promising control of behavior through the management of external stimuli and rewards. Whatever their raisons d'être, or their merits, neither psychoanalysis nor behaviorism dwells on certain essential human characteristics from which we derive our species name homo sapiens: we think, we know, we act knowingly, we strive for greater knowledge and understanding.
Piaget's whole scientific effort addresses itself to this human need to know. When he received the Distinguished Scientist Award from the American Psychological Association in 1969, the citation included this sentence: "He has approached questions up to now exclusively philo-