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.

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

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.

To understand is to invent.

Intelligence is what you use when you don't know what to do.

The self thus becomes aware of itself, at least in its practical action, and discovers itself as a cause among other causes and as an object subject to the same laws as other objects.

I have always detested any departure from reality, an attitude which I relate to my mother's poor mental health.