The sciences that have not arisen from experiment, the mother of all certainty, are in vain and full of errors.
He who truly knows what he's talking about, finds no reason to raise his voice.
Those who fall in love with practice without theory are like pilots without a rudder or compass, who will never know where they are going.
I have offended God and humanity because my work did not have the quality it should have had.
Truly, man is the king of the animals, for his brutality surpasses theirs.
Just as iron rusts from disuse, so does inactivity destroy the intellect.
While I thought I was learning how to live, I have learned how to die.
If possible, one should make even the dead laugh.
Our greatest foolishness can be very wise.