“The friends whom I love I gladly would serve, but to this inclination
        incites me;
 And so I am forced from virtue to swerve since my act, through affection,
        delights me. 
 The friends whom thou lovest thou must first seek to scorn, for to no
        other way can I guide thee;
 ’Tis alone with disgust thou canst rightly perform the acts to which
        duty would lead thee.”

If we return from this necessary limitation of a groundless inference (that true morality is present only when duty is performed against our inclinations, when it is difficult for us, when a conflict with sensuous motives has preceded), to the development of the fundamental ethical conceptions, we find that important conclusions concerning the origin and content of the moral law result from the principle obtained by the analysis of moral judgment:  this law commands with unconditional authority—­for every rational being and under all circumstances—­what has unconditioned worth—­the disposition which corresponds to it.  The universality and necessity (unconditionalness) of the categorical imperative proves that it springs from no other source than reason itself.  Those who derive the moral law from the will of God subject it to a condition, viz., the immutability of the divine will.  Those who find the source of moral legislation in the pursuit of happiness make rational will dependent on a natural law of the sensibility; it would be folly to enjoin by a moral law that which everyone does of himself, and does superabundantly.  Moreover, the theories of the social inclinations and of moral sense fail of their purpose, since they base morality on the uncertain ground of feeling.  Even the principle of perfection proves insufficient, inasmuch as it limits the individual to himself, and, in the end, like those which have preceded, amounts to a refined self-love.  Theonomic ethics, egoistic ethics, the ethics of sympathy, and the ethics of perfection are all eudemonistic, and hence heteronomic.  The practical reason[1] receives the law neither from the will of God nor from natural impulse, but draws it out of its own depths; it binds itself.

[Footnote 1:  Will and practical reason are identical.  The definition runs:  Will is the faculty of acting in accordance with the representation of laws.]

The grounds which establish the derivation of the moral law from the will or reason itself exclude at the same time every material determination of it.  If the categorical imperative posited definite ends for the will, if it prescribed a direction to definite objects, it could neither be known a priori nor be valid for all rational beings:  its apodictic character forbids the admission of empirical elements of every sort.[1] If we think away all content from the law we retain the form of universal legality,[2] and gain the formula:  “Act so that the maxim of thy will can always at the same time hold good