Your joy is your sorrow unmasked. And the self-same well from which your laughter rises was often-times filled with your tears.

If I go for the alternative which is false, then obviously I shall be in error; if I take the other side, then it is by... chance that I arrive at the truth, and I shall still be at fault.... In this incorrect use of free will may be found the privation which constitutes the essence of error.

It is possible that I am dreaming right now and that all of my perceptions are false.

Mathematics is a more powerful instrument of knowledge than any other that has been bequeathed to us by human agency.

It is not enough to have a good mind. The main thing is to use it well.

How do we know that anything really exists, that anything is really the way it seems ot us through our senses?

Conquer yourself rather than the world.