The foundation of Piaget's theories: mental and physical action

Piaget's late theory of action and action implication was the realization of a long history of development. A review of that history shows the central place of action in all of his theoretical assertions, despite the waxing and waning of other important features of his theories. Action was said to be the primary source of knowledge with perception and language in secondary roles. Action is for the most part not only organized but there is logic in action. Action, which is at first physical, becomes internalized and transformed into mental action and mental representation, largely in the development of the symbolic or semiotic function in the sensorimotor period. A number of alternative theories of cognitive development place primary emphasis on mental representation. Piaget provided it with an important place as well, but subordinated it to mental action in the form of operations. In this, as Russell claims, he paralleled Schopenhauer's distinction between representation and will. Piaget's theory of action was intimately related to the gradual development of intentionality in childhood. Intentions were tied to actions by way of the conscious awareness of goals and the means to achieve them. Mental action, following the sensorimotor period, was limited in its logical form to semilogical or one-way functions. These forms were said by Piaget to lack logical reversibility, which was achieved only in the sixth or seventh year, in concrete operations. Mental action was not to be fully realized until the development of formal operations, with hypothetical reasoning, in adolescence, according to the classical Piagetian formulation. This view of the child's logical development, which relied heavily on truth-table (extensional) logic, underwent a number of changes. First from the addition of other logics: category theory and the theory of functions among them. In his last theory, however, an even more radical change occurred. With the collaboration of R. Garcia, he proposed a logic of meanings that would require a recasting of his earlier truth-table-based operatory logic that he claimed explained the development of logical thought and problem solving. The new logic of meanings, influenced by Anderson and Belnap's (1975) logic of entailment, placed new emphasis on inferential processes in the sensorimotor period, introduced protological forms in the actions of the very young child, and proposed that knowledge has an inferential dimension. The consequence was that the late theory shifted emphasis to intentional (qualitative) logic and meaning from the earlier extensional (quantitative) logic and truth testing. The profound changes in Piaget's late theory requires a serious reevaluation of Piaget's entire corpus of research and theory; a task which is yet to be done. Seen in a new light, the late theory is much closer to intellectual currents associated with hermeneutic and semiotic traditions in their concern with meaning and interpretation and less, if at all, with truth. This, despite Piaget's couching of the new theory in a logical mode. The late theory added significant new elements to the theory of action and action-implication, and suggest that Piaget's, and his collaborator's, new research data, which were interpreted within the new theoretical framework, require corroboration and review. The question as to whether Piaget's assertions are at root metaphorical and lack psychological reality, which has followed his theories from its earliest days, arises as well with the assertions of the late theory. Possibly, even more so, since even a limited historical review of his theories points to a considerable concurrence between changes in the fundamental assumptions of his theories and intellectual currents of the times. In hindsight, Piaget's theories appear as "works in progress," down to his last theory. Yet, even in the end, he charted the direction of possible further progress.