A maxim is a conclusion upon observation of matters of fact, and is merely speculative; a "principle" carries knowledge within itself, and is prospective.
In other words, a person who is fanatic in matters of religion, and clings to certain ideas about the nature of God and the universe, becomes a person who has no faith at all.
No matter when, at whatever moment, if she were asked what she was thinking about she could reply quite correctly - one thing, her happiness and her unhappiness.
There are women who have an indefinable charm in their faces which makes them beautiful to their intimates, but a cold stranger who tried to reason the matter out and find this beauty would fail.