It should not be hard for you to stop sometimes and look into the stains of walls, or ashes of a fire, or clouds, or mud or like places, in which...you may find really marvellous ideas.

I have offended God and mankind because my work didn't reach the quality it should have.

Learning is the only thing the mind never exhausts, never fears, and never regrets.

The supreme misfortune is when theory outstrips performance

There is no higher or lower knowledge, but one only, flowing out of experimentation.

How many emperors and how many princes have lived and died and no record of them remains, and they only sought to gain dominions and riches in order that their fame might be ever-lasting.

To be a winner you must want to win but must know of the chance of losing and must not fear of it.