The most perfect ape cannot draw an ape; only man can do that; but, likewise, only man regards the ability to do this as a sign of superiority.
Non cogitant, ergo non sunt.
A good metaphor is something even the police should keep an eye on.
It is almost impossible to carry the torch of truth through a crowd without singeing somebody's beard.
Doubt must be no more than vigilance, otherwise it can become dangerous.
We can see nothing whatever of the soul unless it is visible in the expression of the countenance; one might call the faces at a large assembly of people a history of the human soul written in a kind of Chinese ideograms.