Beware of dissipating your powers; strive constantly to concentrate them.

No one knows what he is doing so long as he is acting rightly; but of what is wrong one is always conscious.

All ages have said and repeated that one should strive to know one's self. This is a strange demand which no one up to now has measured up to and, strictly considered, no one should. With all their study and effort, people are directed to what is outside, to the world about them, and they are kept busy coming to know this and to master it to the extent that their purposes require. . . . How can you come to know yourself? Never by thinking, always by doing. Try to do your duty, and you'll know right away what you amount to. And what is your duty? Whatever the day calls for.

Beware of wishing for anything in youth, because you will get it in middle age.

Our senses don't deceive us: our judgment does

The real scholar learns how to evolve the unknown from the known, and draws near the master.

If a man knows where to get good advice, it is as though he could supply it himself.