There is nothing more ancient than the truth.
The reading of all good books is like a conversation with the finest minds of past centuries.
In order to improve the mind, we ought less to learn, than to contemplate.
The only thing that I know, is that I know nothing
Mathematics is a more powerful instrument of knowledge than any other that has been bequeathed to us by human agency.
How do we know that anything really exists, that anything is really the way it seems ot us through our senses?