There are three classes of people: those who see, those who see when they are shown, those who do not see.

Many have made a trade of delusions and false miracles, deceiving the stupid multitudes.

Old age takes in part savoury wisdom for its food - see to that your old age will not lack in nourishment.

The senses are of the earth, the reason stands apart from them in contemplation.

A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements, but not with a corresponding degree of strength, though it is deficient only in the power of maintaining equilibrium. We may therefore say that such an instrument constructed by man is lacking in nothing except the life of the bird, and this life must needs be supplied from that of man.

How painting surpasses all human works by reason of the subtle possibilities which it contains.

To speak well of a base man is much the same as speaking ill of a good man.