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.