Play is the work of childhood.

How can we, with our adult minds, know what will be interesting? If you follow the child...you can find out something new.

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.

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

I could not think without writing.

When you teach a child something you take away forever his chance of discovering it for himself.

Experience precedes understanding.