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.

If you find from your own experience that something is a fact and it contradicts what some authority has written down, then you must abandon the authority and base your reasoning on your own findings.

Learning is the only thing that never disappoints us.

A man was desired to rise from bed because the sun was already up. He replied: "If I had as far to go and as much to do as he has, I should be up by now; but having but a little way to go, I shall not get up yet."

When taking a selfie, remember the most natural pose is still best

An arch consists of two weaknesses which, leaning one against the other, make a strength.

For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return.