II. Critick of the Practical Reason.—With the Critick of the Practical Reason, we enter a wholly different world, where the reason richly recovers that of which it was deprived in the theoretical province. The essential problem of the Critick of the Practical Reason is almost diametrically different from that of the critick of the theoretical reason. The object of investigation in the critick of the speculative reason, was,—how can the pure reason know objects apriori; in the practical reason it is,—how can the pure reason determine apriori the will in respect of objects. The critick of the speculative reason inquired after the cognizableness of objects apriori: the practical reason has nothing to do with the cognizableness of objects, but only with the determination of the will. Hence, in the latter critick, we have an order directly the reverse of that which we find in the former. As the original determinations of our theoretical knowledge are intuitions, so the original determinations of our will are principles and conceptions. The critick of the practical reason must, therefore, start from moral principles, and only after these are firmly fixed, may we inquire concerning the relation in which the practical reason stands to the sensory.
Freedom, says Kant, is given to us apriori as an inner fact, it is a fact of the inner experience. While, therefore, the reason in the theoretical field had only a negative result, because, when it would attain to a true thing in itself it became transcendent, yet now in the practical province it becomes positive through the idea of freedom, because with the fact of freedom we have no need to go out beyond ourselves, but possess a principle immanent to the reason. But why then give a critick of practical reason? In order to determine the relation of freedom to the sensory. Since the free will works through its acts upon the sensory, there must be a point of contact between the two. This is found in the sensuous motives of the will, which exist implanted in it by nature, in the impulses and inclinations which, as the principle of the empiric in opposition to the free or pure will, bear in themselves the character of a want of freedom. Since, then, freedom cannot be touched, a critick of the practical reason can only relate to these empirical motives, in the sense of divesting these from the claim of being exclusively the motives by which the will is determined. While, therefore, in the theoretical reason the empirical element was immanent, and the intelligible transcendent, the reverse is the case in the practical reason, since here the empirical is transcendent, and the intelligible immanent. It is the object of the Analytic to show the relation of these two momenta of the will, and the highest moral principle which springs therefrom, while it belongs to the Dialectic to solve the antinomies which result from the contradiction of the pure and empiric will.
(1.) The Analytic.—Freedom, as the one constituent element which shows itself in the activity of our will, is the simple form of our actions. The universal law binding the will, is that it should determine itself purely from itself, independently of every external incitement. This capacity of self-lawgiving, or self-determining, Kant calls the autonomy of the will. The free autonomic will says to man: thou oughtest! and since this moral ought commands to an unconditioned obedience, the moral imperative is a categorical imperative. What is it now which is categorically commanded by the practical reason? To answer this question, we must first consider the empirical will, i. e. the nature-side of man.
The empirical, as the other constituent element of our will, first produces a definite deed when it has filled the empty form of action with the matter of action. The matter of the will is furnished by the sensory in the desire of pleasure and the dread of pain. Since this second principle of our actions does not find its seat in the freedom of the will as the higher faculty of desire, but in the sensory, as the lower faculty of desire, and a foreign law is thus laid upon the will,—Kant calls it, in opposition to the autonomy of the reason, the heteronomy of the will.
The categorical imperative is the necessary law of freedom binding upon all men, and is distinguished from material motives, in that the latter have no fixed character. For men are at variance in respect of pleasure and pain, since that which is disagreeable to one may seem pleasant to another, and if they ever agree, this is simply accidental. Consequently, these material motives can never act the part of laws binding upon every being, but each subject may find his end in a different motive. Such rules of acting, Kant calls maxims of the will. He also censures those moralists who have exalted such maxims as universal principles of morality.
Nevertheless, these maxims, though not the highest principles of morality, are yet necessary to the autonomy of the will, because they alone furnish for it a content. It is only by uniting the two sides, that we gain the true principle of morality. To this end the maxims of acting must be freed from their limitation, and widened to the form of universal laws of the reason. Only those maxims should be chosen as motives of action which are capable of becoming universal laws of the reason. The highest principle of morality will therefore be this: act so that the maxims of thy will can at the same time be valid as the principle of a universal lawgiving, i.e. that no contradiction shall arise in the attempt to conceive the maxims of thy acting as a law universally obeyed. Through this formal moral principle all material moral principles which can only be of a heteronomic nature, are excluded.
The question next arises—what impels the will to act conformably to this highest moral law? Kant answers: the moral law itself, apprehended and revered, must be the only moving spring of the human will. If an act which in itself might be conformable to the moral law, be done only through some impulse to happiness arising simply from an inclination of the sense, if it be not done purely for the sake of the law, then have we simply legality and not morality. That which is included in every inclination of the sense is self-love and self-conceit, and of these the former is restricted by the moral law, and the latter wholly stricken down. But that which strikes down our self-conceit and humbles us must appear to us in the highest degree worthy of esteem. But this is done by the moral law. Consequently the positive feeling which we shall cherish in respect of the moral law will be reverence. This reverence, though a feeling, is neither sensuous nor pathological, for it stands opposed to these; but is rather an intellectual feeling, since it arises from the notion of the practical law of the reason. On the one side as subordination to law, the reverence includes pain; on the other side, since the coercion can only be exercised through the proper reason, it includes pleasure. Reverence is the single sensation befitting man in reference to the moral law. Man, as creature of sense, cannot rest on any inner inclination to the moral law, for he has ever inclinations within him which resist the law; love to the law can only be considered as something ideal.—Thus the moral purism of Kant, or his effort to separate every impulse of the sense from the motives to action, merges into rigorism, or the dark view that duty can never be done except with resistance. A similar exaggeration belongs to the well-known epigram of Schiller, who answers the following scruple of conscience—
The friends whom I love, I gladly would serve,
But to this inclination incites me;
And so I am forced from virtue to swerve