If happiness, then, is in question, which it is to be my duty to promote as my end, it must be the happiness of other men whose (permitted) end I hereby make also mine.  It still remains left to themselves to decide what they shall reckon as belonging to their happiness; only that it is in my power to decline many things which they so reckon, but which I do not so regard, supposing that they have no right to demand it from me as their own.  A plausible objection often advanced against the division of duties above adopted consists in setting over against that end a supposed obligation to study my own (physical) happiness, and thus making this, which is my natural and merely subjective end, my duty (and objective end).  This requires to be cleared up.

Adversity, pain, and want are great temptations to transgression of one’s duty; accordingly it would seem that strength, health, a competence, and welfare generally, which are opposed to that influence, may also be regarded as ends that are also duties; that is, that it is a duty to promote our own happiness not merely to make that of others our end.  But in that case the end is not happiness but the morality of the agent; and happiness is only the means of removing the hindrances to morality; permitted means, since no one has a right to demand from me the sacrifice of my not immoral ends.  It is not directly a duty to seek a competence for one’s self; but indirectly it may be so; namely, in order to guard against poverty which is a great temptation to vice.  But then it is not my happiness but my morality, to maintain which in its integrity is at once my end and my duty.

{Introduction ^paragraph 55}

VI.  Ethics does not supply Laws for Actions (which is done by

Jurisprudence), but only for the Maxims of Action

The notion of duty stands in immediate relation to a law (even though I abstract from every end which is the matter of the law); as is shown by the formal principle of duty in the categorical imperative:  “Act so that the maxims of thy action might become a universal law.”  But in ethics this is conceived as the law of thy own will, not of will in general, which might be that of others; for in the latter case it would give rise to a judicial duty which does not belong to the domain of ethics.  In ethics, maxims are regarded as those subjective laws which merely have the specific character of universal legislation, which is only a negative principle (not to contradict a law in general).  How, then, can there be further a law for the maxims of actions?

{Introduction ^paragraph 60}