Let no one destitute of geometry enter my doors.
Only the dead have seen the end of war.
The ludicrous state of solid geometry made me pass over this branch.
Every serious man in dealing with really serious subjects carefully avoids writing. ... There does not exist, nor will there ever exist, any writing of mine dealing with this subject.
Geometry will draw the soul toward truth and create the spirit of philosophy.
The science [geometry] is pursued for the sake of the knowledge of what eternally exists, and not of what comes for a moment into existence, and then perishes.