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Immanuel Kant:
Critique of Practical Reason (excerpts)


On the Principles of Pure Practical Reason

A rational being cannot regard his maxims as practical universal laws, unless he conceives them as principles which determine the will, not by their matter, but by their form only.

By the matter of a practical principle I mean the object of the will. This object is either the determining ground of the will or it is not. In the former case the rule of the will is subjected to an empirical condition (viz., the relation of the determining idea to the feeling of pleasure and pain), consequently it can not be a practical law. Now, when we abstract from a law all matter, i.e., every object of the will (as a determining principle), nothing is left but the mere form of a universal legislation. Therefore, either a rational being cannot conceive his subjective practical principles, that is, his maxims, as being at the same time universal laws, or he must suppose that their mere form, by which they are fitted for universal legislation, is alone what makes them practical laws.

The commonest understanding can distinguish without instruction what form of maxim is adapted for universal legislation, and what is not. Suppose, for example, that I have made it my maxim to increase my fortune by every safe means. Now, I have a deposit in my hands, the owner of which is dead and has left no writing about it. This is just the case for my maxim. I desire then to know whether that maxim can also hold good as a universal practical law. I apply it, therefore, to the present case, and ask whether it could take the form of a law, and consequently whether I can by my maxim at the same time give such a law as this, that everyone may deny a deposit of which no one can produce a proof. I at once become aware that such a principle, viewed as a law, would annihilate itself, because the result would be that there would be no deposits. A practical law which I recognise as such must be qualified for universal legislation; this is an identical proposition and, therefore, self-evident. Now, if I say that my will is subject to a practical law, I cannot adduce my inclination (e.g., in the present case my avarice) as a principle of determination fitted to be a universal practical law; for this is so far from being fitted for a universal legislation that, if put in the form of a universal law, it would destroy itself.

It is, therefore, surprising that intelligent men could have thought of calling the desire of happiness a universal practical law on the ground that the desire is universal, and, therefore, also the maxim by which everyone makes this desire determine his will. For whereas in other cases a universal law of nature makes everything harmonious; here, on the contrary, if we attribute to the maxim the universality of a law, the extreme opposite of harmony will follow, the greatest opposition and the complete destruction of the maxim itself and its purpose. For, in that case, the will of all has not one and the same object, but everyone has his own (his private welfare), which may accidentally accord with the purposes of others which are equally selfish, but it is far from sufficing for a law; because the occasional exceptions which one is permitted to make are endless, and cannot be definitely embraced in one universal rule. In this manner, then, results a harmony like that which a certain satirical poem depicts as existing between a married couple bent on going to ruin, "O, marvellous harmony, what he wishes, she wishes also"; or like what is said of the pledge of Francis I to the Emperor Charles V, "What my brother Charles wishes that I wish also" (viz., Milan). Empirical principles of determination are not fit for any universal external legislation, but just as little for internal; for each man makes his own subject the foundation of his inclination, and in the same subject sometimes one inclination, sometimes another, has the preponderance. To discover a law which would govern them all under this condition, namely, bringing them all into harmony, is quite impossible. ...

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 it; lastly, lest you should be afraid of finding a vulgar selfishness in him, praises the good taste with which he lives; not seeking his pleasure in money-making, or in coarse wantonness, but in the enlargement of his knowledge, in instructive intercourse with a select circle, and even in relieving the needy; while as to the means (which, of course, derive all their value from the end), he is not particular, and is ready to use other people's money for the purpose as if it were his own, provided only he knows that he can do so safely, and without discovery; you would either believe that the recommender was mocking you, or that he had lost his senses. So sharply and clearly marked are the boundaries of morality and self-love that even the commonest eye cannot fail to distinguish whether a thing belongs to the one or the other. The few remarks that follow may appear superfluous where the truth is so plain, but at least they may serve to give a little more distinctness to the judgement of common sense.

The principle of happiness may, indeed, furnish maxims, but never such as would be competent to be laws of the will, even if universal happiness were made the object. For since the knowledge of this rests on mere empirical data, since every man's judgement on it depends very much on his particular point of view, which is itself moreover very variable, it can supply only general rules, not universal; that is, it can give rules which on the average will most frequently fit, but not rules which must hold good always and necessarily; hence, no practical laws can be founded on it. Just because in this case an object of choice is the foundation of the rule and must therefore precede it, the rule can refer to nothing but what is [felt], and therefore it refers to experience and is founded on it, and then the variety of judgement must be endless. This principle, therefore, does not prescribe the same practical rules to all rational beings, although the rules are all included under a common title, namely, that of happiness. The moral law, however, is conceived as objectively necessary, only because it holds for everyone that has reason and will.

The maxim of self-love (prudence) only advises; the law of morality commands. Now there is a great difference between that which we are advised to do and that to which we are obliged.

The commonest intelligence can easily and without hesitation see what, on the principle of autonomy of the will, requires to be done; but on supposition of heteronomy of the will, it is hard and requires knowledge of the world to see what is to be done. That is to say, what duty is, is plain of itself to everyone; but what is to bring true durable advantage, such as will extend to the whole of one's existence, is always veiled in impenetrable obscurity; and much prudence is required to adapt the practical rule founded on it to the ends of life, even tolerably, by making proper exceptions. But the moral law commands the most punctual obedience from everyone; it must, therefore, not be so difficult to judge what it requires to be done, that the commonest unpractised understanding, even without worldly prudence, should fail to apply it rightly.

It is always in everyone's power to satisfy the categorical command of morality; whereas it is seldom possible, and by no means so to everyone, to satisfy the empirically conditioned precept of happiness, even with regard to a single purpose. The reason is that in the former case there is question only of the maxim, which must be genuine and pure; but in the latter case there is question also of one's capacity and physical power to realize a desired object. A command that everyone should try to make himself happy would be foolish, for one never commands anyone to do what he of himself infallibly wishes to do. We must only command the means, or rather supply them, since he cannot do everything that he wishes. But to command morality under the name of duty is quite rational; for, in the first place, not everyone is willing to obey its precepts if they oppose his inclinations; and as to the means of obeying this law, these need not in this case be taught, for in this respect whatever he wishes to do be can do.

He who has lost at play may be vexed at himself and his folly, but if he is conscious of having cheated at play (although he has gained thereby), he must despise himself as soon as he compares himself with the moral law. This must, therefore, be something different from the principle of private happiness. For a man must have a different criterion when he is compelled to say to himself: "I am a worthless fellow, though I have filled my purse"; and when he approves himself, and says: "I am a prudent man, for I have enriched my treasure."

Finally, there is something further in the idea of our practical reason, which accompanies the transgression of a moral law -- namely, its ill desert. Now the notion of punishment, as such, cannot be united with that of becoming a partaker of happiness; for although he who inflicts the punishment may at the same time have the benevolent purpose of directing this punishment to this end, yet it must first be justified in itself as punishment, i.e., as mere harm, so that if it stopped there, and the person punished could get no glimpse of kindness hidden behind this harshness, he must yet admit that justice was done him, and that his reward was perfectly suitable to his conduct. In every punishment, as such, there must first be justice, and this constitutes the essence of the notion. Benevolence may, indeed, be united with it, but the man who has deserved punishment has not the least reason to reckon upon this. Punishment, then, is a physical evil, which, though it be not connected with moral evil as a natural consequence, ought to be connected with it as a consequence by the principles of a moral legislation. Now, if every crime, even without regarding the physical consequence with respect to the actor, is in itself punishable, that is, forfeits happiness (at least partially), it is obviously absurd to say that the crime consisted just in this, that be has drawn punishment on himself, thereby injuring his private happiness (which, on the principle of self-love, must be the proper notion of all crime). According to this view, the punishment would be the reason for calling anything a crime, and justice would, on the contrary, consist in omitting all punishment, and even preventing that which naturally follows; for, if this were done, there would no longer be any evil in the action, since the harm which otherwise followed it, and on account of which alone the action was called evil, would now be prevented. To look, however, on all rewards and punishments as merely the machinery in the hand of a higher power, which is to serve only to set rational creatures striving after their final end (happiness), this is to reduce the will to a mechanism destructive of freedom; this is so evident that it need not detain us.

More refined, though equally false, is the theory of those who suppose a certain special moral sense, which sense and not reason determines the moral law, and in consequence of which the consciousness of virtue is supposed to be directly connected with contentment and pleasure; that of vice, with mental dissatisfaction and pain; thus reducing the whole to the desire of private happiness. Without repeating what has been said above, I will here only remark the fallacy they fall into. In order to imagine the vicious man as tormented with mental dissatisfaction by the consciousness of his transgressions, they must first represent him as in the main basis of his character, at least in some degree, morally good; just as he who is pleased with the consciousness of right conduct must be conceived as already virtuous. The notion of morality and duty must, therefore, have preceded any regard to this satisfaction, and cannot be derived from it. A man must first appreciate the importance of what we call duty, the authority of the moral law, and the immediate dignity which the following of it gives to the person in his own eyes, in order to feel that satisfaction in the consciousness of his conformity to it and the bitter remorse that accompanies the consciousness of its transgression. It is, therefore, impossible to feel this satisfaction or dissatisfaction prior to the knowledge of obligation, or to make it the basis of the latter. A man must be at least half honest in order even to be able to form a conception of these feelings. I do not deny that as the human will is, by virtue of liberty, capable of being immediately determined by the moral law, so frequent practice in accordance with this principle of determination can, at least, produce subjectively a feeling of satisfaction; on the contrary, it is a duty to establish and to cultivate this, which alone deserves to be called properly the moral feeling; but the notion of duty cannot be derived from it, else we should have to suppose a feeling for the law as such, and thus make that an object of sensation which can only be thought by the reason; and this, if it is not to be a flat contradiction, would destroy all notion of duty and put in its place a mere mechanical play of refined inclinations sometimes contending with the coarser. ...


On the Deduction of the Principles of Pure Practical Reason

When the maxim which I am disposed to follow in giving testimony is tested by the practical reason, I always consider what it would be if it were to hold as a universal law of nature. It is manifest that in this view it would oblige everyone to speak the truth. For it cannot hold as a universal law of nature that statements should be allowed to have the force of proof and yet to be purposely untrue. Similarly, the maxim which I adopt with respect to disposing freely of my life is at once determined, when I ask myself what it should be, in order that a system, of which it is the law, should maintain itself. It is obvious that in such a system no one could arbitrarily put an end to his own life, for such an arrangement would not be a permanent order of things. And so in all similar cases. Now, in nature, as it actually is an object of experience, the free will is not of itself determined to maxims which could of themselves be the foundation of a natural system of universal laws, or which could even be adapted to a system so constituted; on the contrary, its maxims are private inclinations which constitute, indeed, a natural whole in conformity with pathological (physical) laws, but could not form part of a system of nature, which would only be possible through our will acting in accordance with pure practical laws. Yet we are, through reason, conscious of a law to which all our maxims are subject, as though a natural order must be originated from our will. This law, therefore, must be the idea of a natural system not given in experience, and yet possible through freedom; a system, therefore, which is supersensible, and to which we give objective reality, at least in a practical point of view, since we look on it as an object of our will as pure rational beings.

Hence the distinction between the laws of a natural system to which the will is subject, and of a natural system which is subject to a will (as far as its relation to its free actions is concerned), rests on this, that in the former the objects must be causes of the ideas which determine the will; whereas in the latter the will is the cause of the objects; so that its causality has its determining principle solely in the pure faculty of reason, which may therefore be called a pure practical reason. ...


On the Incentives of Pure Practical Reason

Respect applies always to persons only -- not to things. The latter may arouse inclination, and if they are animals (e.g., horses, dogs, etc.), even love or fear, like the sea, a volcano, a beast of prey; but never respect. Something that comes nearer to this feeling is admiration, and this, as an affection, astonishment, can apply to things also, e.g., lofty mountains, the magnitude, number, and distance of the heavenly bodies, the strength and swiftness of many animals, etc. But all this is not respect. A man also may be an object to me of love, fear, or admiration, even to astonishment, and yet not be an object of respect. His jocose humour, his courage and strength, his power from the rank be has amongst others, may inspire me with sentiments of this kind, but still inner respect for him is wanting. Fontenelle says, "I bow before a great man, but my spirit does not bow." I would add, before an humble plain man, in whom I perceive uprightness of character in a higher degree than I am conscious of in myself, -- my spirit bows whether I choose it or not, and though I bear my head never so high that he may not forget my superior rank. Why is this? Because his example exhibits to me a law that humbles my self-conceit when I compare it with my conduct: a law, the practicability of obedience to which I see proved by fact before my eyes. Now, I may even be conscious of a like degree of uprightness, and yet the respect remains. For since in man all good is defective, the law made visible by an example still humbles my pride, my standard being furnished by a man whose imperfections, whatever they may be, are not known to me as my own are, and who therefore appears to me in a more favourable light. Respect is a tribute which we cannot refuse to merit, whether we will or not; we may indeed outwardly withhold it, but we cannot help feeling it inwardly.

Respect is so far from being a feeling of pleasure that we only reluctantly give way to it as regards a man. We try to find out something that may lighten the burden of it, some fault to compensate us for the humiliation which such which such an example causes. Even the dead are not always secure from this criticism, especially if their example appears inimitable. Even the moral law itself in its solemn majesty is exposed to this endeavour to save oneself from yielding it respect. Can it be thought that it is for any other reason that we are so ready to reduce it to the level of our familiar inclination, or that it is for any other reason that we all take such trouble to make it out to be the chosen precept of our own interest well understood, but that we want to be free from the deterrent respect which shows us our own unworthiness with such severity? Nevertheless, on the other hand, so little is there pain in it that if once one has laid aside self-conceit and allowed practical influence to that respect, he can never have his fill of contemplating the majesty of this law, and the soul believes itself elevated in proportion as it sees the holy law elevated above it and its frail nature. No doubt great talents and activity proportioned to them may also occasion respect or an analogous feeling. It is very proper to yield it to them, and then it appears as if this sentiment were the same thing as admiration. But if we look closer we shall observe that it is always uncertain how much of the ability is due to native talent, and how much to diligence in cultivating it. Reason represents it to us as probably the fruit of cultivation, and therefore as meritorious, and this notably reduces our self-conceit, and either casts a reproach on us or urges us to follow such an example in the way that is suitable to us. This respect, then, which we show to such a person (properly speaking, to the law that his example exhibits) is not mere admiration; and this is confirmed also by the fact that when the common run of admirers think they have learned from any source the badness of such a man's character (for instance Voltaire's) they give up all respect for him; whereas the true scholar still feels it at least with regard tohis talents, because he is himself engaged in a business and a vocation which make imitation of such a man in some degree a law.

Respect for the moral law is, therefore, the only and the undoubted moral motive, and this feeling is directed to no object, except on the ground of this law. The moral law first determines the will objectively and directly in the judgement of reason; and freedom, whose causality can be determined only by the law, consists just in this, that it restricts all inclinations, and consequently self-esteem, by the condition of obedience to its pure law. This restriction now has an effect on feeling, and produces the impression of displeasure which can be known a priori from the moral law. Since it is so far only a negative effect which, arising from the influence of pure practical reason, checks the activity of the subject, so far as it is determined by inclinations, and hence checks the opinion of his personal worth (which, in the absence of agreement with the moral law, is reduced to nothing); hence, the effect of this law on feeling is merely humiliation. We can, therefore, perceive this a priori, but cannot know by it the force of the pure practical law as a motive, but only the resistance to motives of the sensibility. But since the same law is objectively, that is, in the conception of pure reason, an immediate principle of determination of the will, and consequently this humiliation takes place only relatively to the purity of the law; hence, the lowering of the pretensions of moral self-esteem, that is, humiliation on the sensible side, is an elevation of the moral, i.e., practical, esteem for the law itself on the intellectual side; in a word, it is respect for the law, and therefore, as its cause is intellectual, a positive feeling which can be known a priori. For whatever diminishes the obstacles to an activity furthers this activity itself. Now the recognition of the moral law is the consciousness of an activity of practical reason from objective principles, which only fails to reveal its effect in actions because subjective (pathological) causes hinder it. Respect for the moral law then must be regarded as a positive, though indirect, effect of it on feeling, inasmuch as this respect weakens the impeding influence of inclinations by humiliating selfesteem; and hence also as a subjective principle of activity, that is, as a motive to obedience to the law, and as a principle of the maxims of a life conformable to it. From the notion of a motive arises that of an interest, which can never be attributed to any being unless it possesses reason, and which signifies a motive of the will in so far as it is conceived by the reason. Since in a morally good will the law itself must be the motive, the moral interest is a pure interest of practical reason alone, independent of sense. On the notion of an interest is based that of a maxim. This, therefore, is morally good only in case it rests simply on the interest taken in obedience to the law. All three notions, however, that of a motive, of an interest, and of a maxim, can be applied only to finite beings. For they all suppose a limitation of the nature of the being, in that the subjective character of his choice does not of itself agree with the objective law of a practical reason; they suppose that the being requires to be impelled to action by something, because an internal obstacle opposes itself. Therefore they cannot be applied to the Divine will.

There is something so singular in the unbounded esteem for the pure moral law, apart from all advantage, as it is presented for our obedience by practical reason, the voice of which makes even the boldest sinner tremble and compels him to hide himself from it, that we cannot wonder if we find this influence of a mere intellectual idea on the feelings quite incomprehensible to speculative reason and have to be satisfied with seeing so much of this a priori that such a feeling is inseparably connected with the conception of the moral law in every finite rational being. If this feeling of respect were pathological, and therefore were a feeling of pleasure based on the inner sense, it would be in vain to try to discover a connection of it with any idea a priori. But [it] is a feeling that applies merely to what is practical, and depends on the conception of a law, simply as to its form, not on account of any object, and therefore cannot be reckoned either as pleasure or pain, and yet produces an interest in obedience to the law, which we call the moral interest, just as the capacity of taking such an interest in the law (or respect for the moral law itself) is properly the moral feeling.

The consciousness of a free submission of the will to the law, yet combined with an inevitable constraint put upon all inclinations, though only by our own reason, is respect for the law. The law that demands this respect and inspires it is clearly no other than the moral (for no other precludes all inclinations from exercising any direct influence on the will). An action which is objectively practical according to this law, to the exclusion of every determining principle of inclination, is duty, and this by reason of that exclusion includes in its concept practical obligation, that is, a determination to actions, however reluctantly they may be done. The feeling that arises from the consciousness of this obligation is not pathological, as would be a feeling produced by an object of the senses, but practical only, that is, it is made possible by a preceding (objective) determination of the will and a causality of the reason. As submission to the law, therefore, that is, as a command (announcing constraint for the sensibly affected subject), it contains in it no pleasure, but on the contrary, so far, pain in the action. On the other hand, however, as this constraint is exercised merely by the legislation of our own reason, it also contains something elevating, and this subjective effect on feeling, inasmuch as pure practical reason is the sole cause of it, may be called in this respect self-approbation, since we recognize ourselves as determined thereto solely by the law without any interest, and are now conscious of a quite different interest subjectively produced thereby, and which is purely practical and free; and our taking this interest in an action of duty is not suggested by any inclination, but is commanded and actually brought about by reason through the practical law; whence this feeling obtains a special name, that of respect.

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