Human freedom is realised in the adoption of humanity as an end in itself, for the one thing that no-one can be compelled to do by another is to adop… - Immanuel Kant

What does it avail, one will say, that this man has so much talent, that he is so active therewith, and that he exerts thereby a useful influence over the community, thus having a great worth both in relation to his own happy condition and to the benefit of others, if he does not possess a good will?

On the other band, if adversity and hopeless sorrow have completely taken away the relish for life; if the unfortunate one, strong in mind, indignant at his fate rather than desponding or dejected, wishes for death, and yet preserves his life without loving it — not from inclination or fear, but from duty — then his maxim has a moral worth.

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.