The Metaphysical Elements of Ethics · Immanuel Kant
I. Exposition of the Conception of Ethics
Now the power and resolved purpose to resist a strong but unjust opponent is called fortitude (fortitudo), and when concerned with the opponent of the moral character within us, it is virtue (virtus, fortitudo moralis). Accordingly, general deontology, in that part which brings not external, but internal, freedom under laws is the doctrine of virtue. {INTRODUCTION ^paragraph 10} Jurisprudence had to do only with the formal condition of external freedom (the condition of consistency with itself, if its maxim became a universal law), that is, with law. Ethics, on the contrary, supplies us with a matter (an object of the free elective will), an end of pure reason which is at the same time conceived as an objectively necessary end, i.e., as duty for all men. For, as the sensible inclinations mislead us to ends (which are the matter of the elective will) that may contradict duty, the legislating reason cannot otherwise guard against their influence than by an opposite moral end, which therefore must be given a priori independently on inclination.
An end is an object of the elective will (of a rational being) by the idea of which this will is determined to an action for the production of this object. Now I may be forced by others to actions which are directed to an end as means, but I cannot be forced to have an end; I can only make something an end to myself. If, however, I am also bound to make something which lies in the notions of practical reason an end to myself, and therefore besides the formal determining principle of the elective will (as contained in law) to have also a material principle, an end which can be opposed to the end derived from sensible impulses; then this gives the notion of an end which is in itself a duty. The doctrine of this cannot belong to jurisprudence, but to ethics, since this alone includes in its conception self-constraint according to moral laws. For this reason, ethics may also be defined as the system of the ends of the pure practical reason. The two parts of moral philosophy are distinguished as treating respectively of ends and of duties of constraint. That ethics contains duties to the observance of which one cannot be (physically) forced by others, is merely the consequence of this, that it is a doctrine of ends, since to be forced to have ends or to set them before one's self is a contradiction.
Text from Project Gutenberg, public domain in the United States.