While you are alone you are entirely your own master and if you have one companion you are but half your own, and the less so in proportion to the indiscretion of his behavior.

But to me all sciences seem vain and full of error that are not born of experience, mother of all certainty, and do not terminate in an actual experience.

O painter skilled in anatomy, beware lest the undue prominence of the bones, sinews and muscles cause you to become a wooden painter from the desire to make your nude figures reveal all.

When Fortune comes, seize her in front with a sure hand, because behind she is bald.

Poor is the pupil who does not surpass his master.

Weight is caused by one element being situated in another; and it moves by the shortest line towards its centre, not by its own choice, not because the centre draws it to itself, but because the other intervening element cannot withstand it.

The study of what is excellent is food for the mind and body.