The universality of this principle of Human and Rational Nature as End-in-self, as also its character of objective end limiting merely subjective ends, prove that its source is in pure Reason.  Objectively, the ground of all practical legislation is Rule and the Form of Universality that enables rule to be Law (of Nature), according to principle first (in its double form); subjectively, it is End, the subject of all ends being every rational being as End-in-self, according to principle second.  Hence follows the third practical principle of the Will, as supreme condition of its agreement with universal practical Reason—­the idea of the Will of every rational being as a Will that legislates universally.  The Will, if subject to law, has first itself imposed it.

This new idea—­of the Will of every rational being as universally legislative—­is what, in the implication of the Categorical Imperative, specifically marks it off from any Hypothetical:  Interest is seen to be quite incompatible with Duty, if Duty is Volition of this kind.  A will merely subject to laws can be bound to them by interest; not so a will itself legislating supremely, for that would imply another law to keep the interest of self-love from trenching upon the validity of the universal law.  Illustration is not needed to prove that a Categorical Imperative, or law for the will of every rational being, if it exist at all, cannot exclude Interest and be unconditional, except as enjoining everything to be done from the maxim of a will that in legislating universally can have itself for object.  This is the point that has been always missed, that the laws of duty shall be at once self-imposed and yet universal.  Subjection to a law not springing from one’s own will implies interest or constraint, and constitutes a certain necessity of action, but never makes Duty.  Be the interest one’s own or another’s, the Imperative is conditional only.  Kant’s principle is the Autonomy of the Will; every other its Heteronomy.

The new point of view opens up the very fruitful conception of an Empire or Realm of Ends.  As a Realm is the systematic union of rational beings by means of common laws, so the ends determined by the laws may, abstractly viewed, be taken to form a systematic whole.  Rational beings, as subject to a law requiring them to treat themselves and others as ends and never merely as means, enter into a systematic union by means of common objective laws, i.e. into an (ideal) Empire or Realm of Ends, from the laws being concerned about the mutual relations of rational beings as Ends and Means.  In this Realm, a rational being is either Head or Member:  Head, if legislating universally and with complete independence; Member, if also universally, but at the same time subject to the laws.  When now the maxim of the will does not by nature accord necessarily with the demand of the objective principle—­that the will through its maxim be able to regard itself