Most subjects at universities are taught for no other purpose than that they may be re-taught when the students become teachers.

If you are going to build something in the air it is always better to build castles than houses of cards.

Never undertake anything for which you wouldn't have the courage to ask the blessings of heaven.

People who have read a good deal rarely make great discoveries. I do not say this in excuse of laziness, but because invention presupposes an extensive independent contemplation of things.

In the world we live in, one fool makes many fools, but one sage only a few sages.

Some people come by the name of genius in the same way that certain insects come by the name of centipede -- not because they have a hundred feet, but because most people can't count above 14.

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