For all good and evil, whether in the body or in human nature, originates ... in the soul, and overflows from thence, as from the head into the eyes.

Knowledge is the rediscovering of our own insight.

My plainness of speech makes people hate me, and what is their hatred but a proof that I am speaking the truth.

Let no one destitute of geometry enter my doors.

To win over your bad self is the grandest and foremost of victories.

It is not noble to return evil for evil, at no time ought we to do an injury to our neighbors.

Mathematics is the language in which the gods talk to people.