Punishment renders autonomy of conscience impossible.

Scientific thought, then, is not momentary; it is not a static instance; it is a process.

Each 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.

Play is the answer to how anything new comes about.

It is with children that we have the best chance of studying the development of logical knowledge, mathematical knowledge, physical knowledge, and so forth.

Logic and mathematics are nothing but specialised linguistic structures.

Every time we teach a child something, we keep him from inventing it himself. On the other hand, that which we allow him to discover for himself will remain with him visible for the rest of his life.