A bird maintains itself in the air by imperceptible balancing, when near to the mountains or lofty ocean crags; it does this by means of the curves of the winds which as they strike against these projections, being forced to preserve their first impetus bend their straight course towards the sky with divers revolutions, at the beginning of which the birds come to a stop with their wings open, receiving underneath themselves the continual buffetings of the reflex courses of the winds.

A clever man without wisdom is like a beautiful flower without fragrance.

Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.

Where the spirit does not work with the hand, there is no art.

He who does not oppose evil......commands it to be done.

Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.

While I thought that I was learning how to live, I have been learning how to die.