Just as eating against one's will is injurious to health, so studying without a liking for it spoils the memory, and it retains nothing it takes in.

once you have tasted the taste of sky, you will forever look up

A wave is never found alone, but is mingled with the other waves.

Why does the eye see a thing more clearly in dreams than the imagination when awake?

The greatest deception men suffer is from their own opinions.

He who is fixed to a star does not change his mind.

There are three classes of people: those who see, those who see when they are shown, those who do not see.

Time stays long enough for anyone who will use it.

Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity.