The Metaphysical Elements of Ethics | Page 4

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.
Now that ethics is a doctrine of virtue (doctrina officiorum virtutis) follows from the definition of virtue given above compared with the obligation, the peculiarity of which has just been shown. There is in fact no other determination of the elective will, except that to an end, which in the very notion of it implies that I cannot even physically be forced to it by the elective will of others. Another may indeed force me to do something which is not my end (but only means to the end of another), but he cannot force me to make it my own end, and yet I can have no end except of my own making. The latter supposition would be a contradiction- an act of freedom which yet at the same time would not be free. But there is no contradiction in setting before one's self an end which is also a duty: for in this case I constrain myself, and this is quite consistent with freedom. * But how is such an end possible? That is now the question. For the possibility of the notion of the thing (viz., that it is not self-contradictory) is not enough to prove the possibility of the thing itself (the objective reality of the notion).

{INTRODUCTION ^paragraph 15}
* The less a man can be physically forced, and the more he can be morally forced (by the mere idea of duty), so much the freer he is. The man, for example, who is of sufficiently firm resolution and strong mind not to give up an enjoyment which he has resolved on, however much loss is shown as resulting therefrom, and who yet desists from his purpose unhesitatingly, though very reluctantly, when he finds that it would cause him to neglect an official duty or a sick father; this man proves his freedom in the highest degree by this very thing, that he cannot resist the voice of duty.

II. Exposition of the Notion of an End which is also a Duty

We can conceive the relation of end to duty in two ways; either starting from the end to find the maxim of the dutiful actions; or conversely, setting out from this to find the end which is also duty. jurisprudence proceeds in the former way. It is left to everyone's free elective will what end he will choose for his action. But its maxim is determined a priori; namely, that the freedom of the agent must be consistent with the freedom of every other according to a universal law.
{INTRODUCTION ^paragraph 20}
Ethics, however, proceeds in the opposite way. It cannot start from the ends which the man may propose to himself, and hence give directions as to the maxims he should adopt, that is, as to his duty; for that would be to take empirical principles of maxims, and these could not give any notion of duty; since this, the categorical ought, has its root in pure reason alone. Indeed, if the maxims were to be adopted in accordance with those ends (which are all selfish), we could not properly speak of the notion of duty at all. Hence in ethics the notion of duty must lead to ends, and must on moral principles give the foundation of maxims with respect to the ends which we ought to propose to ourselves.
Setting aside the question what sort of end that is which is in itself a duty, and how such an end is possible, it is here only necessary to show that a duty of this kind is called a duty