The truth of things is the chief nutriment of superior intellects.

Learning never exhausts the mind.

Nothing strengthens authority so much as silence.

Knowledge of the past 

and of the places of the earth 

is the ornament and food 

of the mind of man.

All our knowledge has its origins in our perceptions.

Painting is poetry that is seen rather than felt, 

and poetry is painting that is felt rather than seen.

There are three classes of people: 

those who see, 

those who see when they are shown, 

those who do not see.

The noblest pleasure is the joy of understanding.

He who cannot do what he wants,

let him want what he can do.