There is no learning without remembering.

All that I know is nothing - I'm not even sure of that.

To know, is to know that you know nothing. That is the meaning of true knowledge.

The only good is knowledge and the only evil is ignorance.

You don't know what you don't know.

Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity.