Hypotheses are only the pieces of scaffolding which are erected round a building during the course of construction, and which are taken away as soon as the edifice is completed.

Well-mannered children could be conceived if the parents were well-mannered.

Someone criticized an elderly man for wooing young women. He replied that that was the only way to rejuvenation, which was, afterall, everybody's wish.

To create something you must be something.

Every solution of a problem is a new problem.

The finished man, you know, is difficult to please; a growing mind will ever show you gratitude. --Faust 1, lines 182-3

Rest not. Life is sweeping by; go and dare before you die. Something mighty and sublime, leave behind to conquer time.