Art is science made clear.
Vigorous writing is concise.
We cannot deny the facts of nature, but we should certainly try to improve on them.
Prove all things; hold fast that which is good.
If you refuse to be made straight when you are green, you will not be made straight when you are dry.
What is the use of a house if you haven't got a tolerable planet to put it on?
The aim of life is self-development. To realize one's nature perfectly - that is what each of us is here for.