The essential functions of the mind consist in understanding and in inventing, in other words, in building up structures by structuring reality. - Jean Piaget

Every response, whether it be an act directed towards the outside world or an act internalized as thought, takes the form of an adaptation or, better, of a re-adaptation.

As far as the game of marbles is concerned, there is therefore no contradiction between the egocentric practice of games and the mystical respect entertained for rules. This respect is the mark of a mentality fashioned, not by free cooperation between equals, but by adult constraint.

In certain circumstances where he experiments in new types of conduct by cooperating with his equals, the child is already an adult. There is an adult in every child and a child in every adult. … There exist in the child certain attitudes and beliefs which intellectual development will more and more tend to eliminate: there are others which will acquire more and more importance. The later are not derived from the former but are partly antagonistic to them.