Jean Piaget

"Every time one prematurely teaches a child something he could have discovered himself, that child is kept from inventing it and consequently from understanding it completely."

"The Swiss psychologist understood that childhood is not a race to the finish line of adulthood."

"What is pedagogy but the art of transmitting to the young the intellectual and moral heritage of the adult generation?"

"The mind does not come into the world fully formed. It emerges through stages of development."

"Cognitive development is a journey with distinct waypoints, not a smooth incline."

"The child who understands conservation understands that quantity does not change merely because appearance changes."

"Conserving principles allow us to reason about the world with increasing sophistication."

"The ability to reverse operations is crucial to logical thought."

"Decentralization of thought marks the transition from pre-operational to concrete operational thinking."

"Reality is not fixed; it is constructed through our interactions with it."

"Children are natural scientists, constantly formulating hypotheses about how the world works."

"The adult can recover childhood only by making a great effort to think all over again what he has forgotten."

"It is a miracle that curiosity survives formal education."

"The observer must himself participate in the phenomena he observes."

"To teach a child to read is to teach him to recognize the symbols and understand their meaning."

"Assimilation is the process by which new information is incorporated into existing mental schemas."

"Accommodation is when we modify our existing schemas to fit new information."

"Equilibration is the balance we seek between assimilation and accommodation."

"The child progresses through cognitive stages at his own pace, not according to an external timetable."

"Logical necessity is not an external constraint but an internal coherence of thought."

"The essence of thought is to establish relationships."

"If education aims to form free and creative individuals, we must recognize the importance of play."

"Play is the royal road to childhood learning."

"The symbolic function emerges when the child can use one thing to represent another."

"Language is one manifestation of the symbolic function, not its origin."

"The horizontal décalage explains why a child can conserve number before conserving volume."

"Formal operational thinking allows us to reason about propositions, not just concrete objects."

"The adolescent becomes capable of abstract reasoning and systematic hypothesis testing."

"To think formally is to engage in propositional logic and to consider all possible combinations."

"Centration is the tendency of the young child to focus on one aspect of a situation while ignoring others."