The first precept was never to accept a thing as true until I knew it as such without a single doubt.
Never esteem anything as of advantage to you that will make you break your word or lose your self-respect.
One of the lessons of history is that nothing is often a good thing to do and always a clever thing to say.
You can have it all. You just can't have it all at once.
My head rang like a gong.
It is nobler to declare oneself wrong than to insist on being right - especially when one is right.
You should not live one way in private, another in public.