Just be indipendent of the external world, so you don't have to fear for what's in it.
Black seems to make a colour cloudy, but darkness doesn't. A ruby could thus keep getting darker without ever becoming cloudy; but if it became blackish red, it would become cloudy.
At the end of reasons comes persuasion.
The object of philosophy is the logical clarification of thought.
The face is the soul of the body.
An honest religious thinker is like a tightrope walker. He almost looks as though he were walking on nothing but air. His support is the slenderest imaginable. And yet it really is possible to walk on it.