Those who know nothing of foreign languages know nothing of their own.

The artist may be well advised to keep his work to himself till it is completed, because no one can readily help him or advise him with it... but the scientist is wiser not to withhold a single finding or a single conjecture from publicity.

Two souls dwell, alas! in my breast.

A stated truth loses its grace, but a repeated error appears insipid and ridiculous.

If a poet would work politically, he must give himself up to a party; and so soon as he does that, he is lost as a poet.

Habit is a man's sole comfort. We dislike doing without even unpleasant things to which we have become accustomed.

The close and thoughtful observer more and more learns to recognize his limitations. He realizes that with the steady growth of knowledge more and more new problems keep on emerging.