Do not imagine that these most difficult problems can be thoroughly understood by any one of us.

A truth does not become greater by repetition.

Know that for the human mind there are certain objects of perception which are within the scope of its nature and capacity; on the other hand, there are, amongst things which actually exist, certain objects which the mind can in no way and by no means grasp: the gates of perception are closed against it.

For every force charged by God, may He be exalted, with some business is an angel put in charge.

How individuals of the same species surpass each other in these sensations and in other bodily faculties is universally known, but there is a limit to them, and their power cannot extend to every distance or to every degree.

To sum up: I am the man who when the concern pressed him and his way was straitened and he could find no other device by which to teach a demonstrable truth other than by giving satisfaction to a single virtuous man while displeasing ten thousand ignoramuses - I am he who prefers to address that single man by himself, and I do not heed the blame of those many creatures.

Your purpose...should always be to know...the whole that was intended to be known.