Jean Piaget

“To express the same idea in still another way, I think that human knowledge is essentially active.”

“From this time on, the universe is built up into an aggregate of permanent objects connected by causal relations that are independent of the subject and are placed in objective space and time.”

“Logic and mathematics are nothing but specialised linguistic structures.”

“Egocentrism appears to us as a form of behavior intermediate between purely individual and socialized behavior.”

“The child often sees only what he already knows. He projects the whole of his verbal thought into things. He sees mountains as built by men, rivers as dug out with spades, the sun and moon as following us on our walks.”

“The main functions of intelligence, that of inventing solutions and that of verifying them, do not necessarily involve one another. The first partakes of imagination; the second alone is properly logical.”

“To accustom the infant to get out of its own difficulties or to calm it by rocking it may be to lay the foundations of a good or of a bad disposition.”

“All morality consists in a system of rules, and the essence of all morality is to be sought for in the respect which the individual acquires for these rules.”

“Before playing with his equals, the child is influenced by his parents. He is subjected from his cradle to a multiplicity of regulations, and even before language he becomes conscious of certain obligations.”

“Intelligence is what you use when you don't know what to do: when neither innateness nor learning has prepared you for the particular situation.”

“Every acquisition of accommodation becomes material for assimilation, but assimilation always resists new accommodations.”

“Everyone knows that at the age of 11-12, children have a marked impulse to form themselves into groups and that the respect paid to the rules and regulations of their play constitutes an important feature of this social life.”

“Reflective abstraction, however, is based not on individual actions but on coordinated actions.”

“Knowing reality means constructing systems of transformations that correspond, more or less adequately, to reality.”

“Play is the answer to the question, 'How does anything new come about?'”

“Logical reasoning is an argument which we have with ourselves and which reproduces internally the features of a real argument.”

“The current state of knowledge is a moment in history, changing just as rapidly as the state of knowledge in the past has ever changed and, in many instances, more rapidly.”

“One of the most striking things one finds about the child under 7-8 is his extreme assurance on all subjects.”

“With regard to moral rules, the child submits more or less completely in intention to the rules laid down for him, but these, remaining, as it were, external to the subject's conscience, do not really transform his conduct.”

“Play is the work of childhood.”