Never look down to test the ground before taking your next step; only he who keeps his eye fixed on the far horizon will find his right road.

Never, 'for the sake of peace and quiet,' deny your own experience or convictions.

Never measure the height of a mountain until you have reached the top. Then you will see how low it was.

Maturity: among other things, the unclouded happiness of the child at play, who takes it for granted that he is at one with his play-mates.