Professors in every branch of the sciences, prefer their own theories to truth: the reason is that their theories are private property, but truth is common stock.

It is a mortifying truth, and ought to teach the wisest of us humility, that many of the most valuable discoveries have been the result of chance rather than of contemplation, and of accident rather than of design.

Men are more readily contented with no intellectual light than with a little; and wherever they have been taught to acquire some knowledge in order to please others, they have most generally gone on to acquire more, to please themselves.

We should have all our communications with men, as in the presence of God; and with God, as in the presence of men.

Women that are the least bashful are often the most modest.

Physical courage, which despises all danger, will make a man brave in one way; and moral courage, which despises all opinion, will make a man brave in another.

The wisest man may be wiser to-day than he was yesterday, and to-morrow than he is to-day. Total freedom from change would imply total freedom from error; but this is the prerogative of Omniscience alone.