The strongest memory is not as strong as the weakest ink.
To think twice is quite enough.
First there must be order and harmony within your own mind.
Be aroused by poetry; structure yourself with propriety, refine yourself with music.
The ideal teacher guides his students but does not pull them along; he urges them to go forward and does not suppress them; he opens the way but does not take them to the place.
The beginning of wisdom is to call things by their proper name.