Конституция, която цели най-голямата човешка свобода според закони, които правят така, че свободата на всеки да може да съществува заедно с тази на в… - Immanuel Kant

Chisels and hammers may suffice to work a piece of wood, but for etching we require an etcher's needle. Thus common sense and speculative understanding are both useful, but each in its own way: the former in judgments which apply immediately to experience; the latter when we judge universally from mere concepts, as in metaphysics, where sound common sense, so called in spite of the inappropriateness of the word, has no right to judge at all.

You must, therefore you can. A free will and a will subject to moral laws are one and the same thing.

Since the human race's natural end is to make steady cultural progress, its moral end is to be conceived as progressing toward the better. And this progress may well be occasionally interrupted, but it will never be broken off.