"According to Claparède, feelings appoint a goal for behaviour, while intelligence merely provides the means (the "technique"). But there exists an awareness of ends as well as of means, and this continually modifies the goals of action."

- Jean Piaget

"What we see changes what we know. What we know changes what we see."

- Jean Piaget

"A response is thus a particular case of interaction between the external world and the subject, but unlike physiological interactions, which are of a material nature and involve an internal change in the bodies which are present, the responses studied by psychology are of a functional nature and are achieved at greater and greater distances in space (perception, etc.) and in time (memory, etc.) besides following more and more complex paths (reversals, detours, etc.)."

- Jean Piaget

"Every structure is to be thought of as a particular form of equilibrium, more or less stable within its restricted field and losing its stability on reaching the limits of the field."

- Jean Piaget

"We shall simply say then that every action involves an energetic or affective aspect and a structural or cognitive aspect, which, in fact, unites the different points of view already mentioned."

- Jean Piaget