History warns us that it is the customary fate of new truths to begin as heresies and to end as superstitions.

Only one absolute certainty is possible to man, namely that at any given moment the feeling which he has exists.

Try to learn something about everything and everything about something.

And you very soon find out, if you have not found it out before, that patience and tenacity of purpose are worth more than twice their weight of cleverness.

There is no greater mistake than the hasty conclusion that opinions are worthless because they are badly argued.

I care not what subject is taught, if only it be taught well.

The best men of the best epochs are simply those who make the fewest blunders and commit the fewest sins.