Great men too make mistakes, and many among them do it so often that one is almost tempted to call them little men.

He was always smoothing and polishing himself, and in the end he became blunt before he was sharp.

To err is human also in so far as animals seldom or never err, or at least only the cleverest of them do so.

One has to do something new in order to see something new.

Pain warns us not to exert our limbs to the point of breaking them. How much knowledge would we not need to recognize this by the exercise of mere reason.

We cannot remember too often that when we observe nature, and especially the ordering of nature, it is always ourselves alone we are observing.

It is almost everywhere the case that soon after it is begotten the greater part of human wisdom is laid to rest in repositories.