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.

The good painter must paint two things: a person and the essence of his soul.

Wherever good fortune enters, envy lays siege to the place and attacks it; and when it departs, sorrow and repentance remain behind.

Art lives from constraints and dies from freedom.

He who wishes to see how the soul inhabits the body should look to see how that body uses its daily surroundings. If the dwelling is dirty and neglected, the body will be kept by its soul in the same condition, dirty and neglected.

Medicine is the restoration of discordant elements; sickness is the discord of the elements infused into the living body.

He turns not back who is bound to a star.