with itself, considering itself as a priori practical. Now this principle of morality, just on account of the universality of the legislation which makes it the formal supreme determining principle of the will, without regard to any subjective differences, is declared by the reason to be a law for all rational beings, in so far as they have a will, that is, a power to determine their causality by the conception of rules; and, therefore, so far as they are capable of acting according to principles, and consequently also according to practical a priori principles (for these alone have the necessity that reason requires in a principle). It is, therefore, not limited to men only, but applies to all finite beings that possess reason and will; nay, it even includes the Infinite Being as the supreme intelligence. In the former case, however, the law has the form of an imperative, because in them, as rational beings, we can suppose a pure will, but being creatures affected with wants and physical motives, not a holy will, that is, one which would be incapable of any maxim conflicting with the moral law. In their case, therefore, the moral law is an imperative, which commands categorically, because the law is unconditioned; the relation of such a will to this law is dependence under the name of obligation, which implies a constraint to an action, though only by reason and its objective law; and this action is called duty, because an elective will, subject to pathological affections (though not determined by them, and, therefore, still free), implies a wish that arises from subjective causes and, therefore, may often be opposed to the pure objective determining principle; whence it requires the moral constraint of a resistance of the practical reason, which may be called an internal, but intellectual, compulsion. In the supreme intelligence the elective will is rightly conceived as incapable of any maxim which could not at the same time be objectively a law; and the notion of holiness, which on that account belongs to it, places it, not indeed above all practical laws, but above all practically restrictive laws, and consequently above obligation and duty. This holiness of will is, however, a practical idea, which must necessarily serve as a type to which finite rational beings can only approximate indefinitely, and which the pure moral law, which is itself on this account called holy, constantly and rightly holds before their eyes. The utmost that finite practical reason can effect is to be certain of this indefinite progress of one's maxims and of their steady disposition to advance. This is virtue, and virtue, at least as a naturally acquired faculty, can never be perfect, because assurance in such a case never becomes apodeictic certainty and, when it only amounts to persuasion, is very dangerous.
VIII. THEOREM IV
The autonomy of the will is the sole principle of all moral laws and of all duties which conform to them; on the other hand, heteronomy of the elective will not only cannot be the basis of any obligation, but is, on the contrary, opposed to the principle thereof and to the morality of the will.
{BOOK_1|CHAPTER_1 ^paragraph 85}
In fact the sole principle of morality consists in the independence on all matter of the law (namely, a desired object), and in the determination of the elective will by the mere universal legislative form of which its maxim must be capable. Now this independence is freedom in the negative sense, and this self-legislation of the pure, and therefore practical, reason is freedom in the positive sense. Thus the moral law expresses nothing else than the autonomy of the pure practical reason; that is, freedom; and this is itself the formal condition of all maxims, and on this condition only can they agree with the supreme practical law. If therefore the matter of the volition, which can be nothing else than the object of a desire that is connected with the law, enters into the practical law, as the condition of its possibility, there results heteronomy of the elective will, namely, dependence on the physical law that we should follow some impulse or inclination. In that case the will does not give itself the law, but only the precept how rationally to follow pathological law; and the maxim which, in such a case, never contains the universally legislative form, not only produces no obligation, but is itself opposed to the principle of a pure practical reason and, therefore, also to the moral disposition, even though the resulting action may be conformable to the law.
Hence a practical precept, which contains a material (and therefore empirical) condition, must never be reckoned a practical law. For the law of the pure will, which is free, brings the will into a sphere quite different from the empirical; and as the necessity involved in the law is not a physical necessity, it can only consist in the formal conditions of the possibility of a law in general. All the matter of practical rules rests on subjective conditions, which give them only a conditional universality (in case I desire this or that, what I must do in order to obtain it), and they all turn on the principle of private happiness. Now, it is indeed undeniable that every volition must have an object, and therefore a matter; but it does not follow that this is the determining principle and the condition of the maxim; for, if it is so, then this cannot be exhibited in a universally legislative form, since in that case the expectation of the existence of the object would be the determining cause of the choice, and the volition must presuppose the dependence of the faculty of desire on the existence of something; but this dependence can only be sought in empirical conditions and, therefore, can never furnish a foundation for a necessary and universal rule. Thus, the happiness of others may be the object of the will of a rational being. But if it were the determining principle of the maxim, we must assume that we find not only a rational satisfaction in the welfare of others, but also a want such as the sympathetic disposition in some men occasions. But I cannot assume the existence of this want in every rational being (not at all in God). The matter, then, of the maxim may remain, but it must not be the condition of it, else the maxim could not be fit for a law. Hence, the mere form of law, which limits the matter, must also be a reason for adding this matter to the will, not for presupposing it. For example, let the matter be my own happiness. This (rule), if I attribute it to everyone (as, in fact, I may, in the case of every finite being), can become an objective practical law only if I include the happiness of others. Therefore, the law that we should promote the happiness of others does not arise from the assumption that this is an object of everyone's choice, but merely from this, that the form of universality which reason requires as the condition of giving to a maxim of self-love the objective validity of a law is the principle that determines the will. Therefore it was not the object (the happiness of others) that determined the pure will, but it was the form of law only, by which I restricted my maxim, founded on inclination, so as to give it the universality of a law, and thus to adapt it to the practical reason; and it is this restriction alone, and not the addition of an external spring, that can give rise to the notion of the obligation to extend the maxim of my self-love to the happiness of others.
{BOOK_1|CHAPTER_1 ^paragraph 90}
The direct opposite of the principle of morality is, when the principle of private happiness is made the determining principle of the will, and with this is to be reckoned, as I have shown above, everything that places the determining principle which is to serve as a law, anywhere but in the legislative form of the maxim. This contradiction, however, is not merely logical, like that which would arise between rules empirically conditioned, if they were raised to the rank of necessary principles of cognition, but is practical, and would ruin morality altogether were not the voice of reason in reference to the will so clear, so irrepressible, so distinctly audible, even to the commonest men. It can only, indeed, be maintained in the perplexing speculations of the schools, which are bold enough to shut their ears against that heavenly voice, in order to support a theory that costs no trouble.
Suppose that an acquaintance whom you otherwise liked were to attempt to justify himself to you for having borne false witness, first by alleging the, in his view, sacred duty of consulting his own happiness; then by enumerating the advantages which he had gained thereby, pointing out the prudence he had shown in securing himself against detection, even by yourself, to whom he now reveals the secret, only in order that he may be able to deny it at any time; and suppose he were then to affirm, in all seriousness, that he has fulfilled a true human duty; you would either laugh in his face, or shrink back from him with disgust; and yet, if a man has regulated his principles of action solely with a view to his own advantage, you would have nothing whatever to object against this mode of proceeding. Or suppose some one recommends you a man as steward, as a man to whom you can blindly trust all your affairs; and, in order to inspire you with confidence, extols him as a prudent man who thoroughly understands his own interest, and is so indefatigably active that he lets slip no opportunity of advancing