I forget most of what I read, just as I do most of what I have eaten, but I know that both contribute no less to the conservation of my mind and my body on that account.

Most subjects at universities are taught for no other purpose than that they may be re-taught when the students become teachers.

One is rarely an impulsive innovator after the age of sixty, but one can still be a very fine orderly and inventive thinker. One rarely procreates children at that age, but one is all the more skilled at educating those who have already been procreated, and education is procreation of another kind.

It is a great shame; most of our words are misused tools / which often still smell of the mud in which previous owners / desecrated them.

To err is human also in so far as animals seldom or never err, or at least only the cleverest of them do so.

If another Messiah was born he could hardly do so much good as the printing-press.

Be attentive, feel nothing in vain, measure and compare: this is the whole law of philosophy.