something that is relative to a subjective feeling of pleasure or
pain, which determines what we need in order to be satisfied with
our condition. But just because this material principle of
determination can only be empirically known by the subject, it is
impossible to regard this problem as a law; for a law being
objective must contain the very same principle of determination of the
will in all cases and for all rational beings. For, although the
notion of happiness is in every case the foundation of practical
relation of the objects to the desires, yet it is only a general
name for the subjective determining principles, and determines nothing
specifically; whereas this is what alone we are concerned with in this
practical problem, which cannot be solved at all without such specific
determination. For it is every man's own special feeling of pleasure
and pain that decides in what he is to place his happiness, and even
in the same subject this will vary with the difference of his wants
according as this feeling changes, and thus a law which is
subjectively necessary (as a law of nature) is objectively a very
contingent practical principle, which can and must be very different
in different subjects and therefore can never furnish a law; since, in
the desire for happiness it is not the form (of conformity to law)
that is decisive, but simply the matter, namely, whether I am to
expect pleasure in following the law, and how much. Principles of
self-love may, indeed, contain universal precepts of skill (how to
find means to accomplish one's purpose), but in that case they are
merely theoretical principles; * as, for example, how he who would
like to eat bread should contrive a mill; but practical precepts
founded on them can never be universal, for the determining principle
of the desire is based on the feeling pleasure and pain, which can
never be supposed to be universally directed to the same objects.