ABSTRACT
Just prior to his death, Piaget was engaged in a study of the relationship between possibility and necessity. This work, originally published in French in two volumes (1981 and 1983), has recently been translated into English (1987a, b) and provides epistemologists with a rich description of the development of the notion of possibilities and the effect of the generation of possibilities on the construction of operational thought. Three types of schemes are distinguished: (a) presentative schemes involving simultaneous characteristics of objects; (b) procedural schemes or means applied toward a goal; and (c) operational schemes that “constitute a synthesis of the two previous ones; they are procedural in that they are performed in real time, but the atemporal structure of the combinatorial laws regulating operations has the characteristic of a higher order presentative scheme” (Piaget, 1987a). Through a study of 23 tasks, Piaget documents the increasing differentiation and reintegration of these three schemes, or cognitive systems. He concluded:
Initially any object or substance in a presentative scheme will first appear to subjects not only as what they are, but also as being that way of necessity, excluding the possibility of variation or change. However, once a possibility gets actualized through the application of procedural schemes, a new presentative scheme is created, thence the complementarity of the two systems. To conceive of new possibilities, it is not enough to think of procedures oriented toward a particular goal, one also needs to compensate for that actual or virtual perturbation that is the resistance of reality to explanation when it is conceived as pseudonecessary. (Piaget, 1987a, pp. 5,6)
