To secure one's own happiness is a duty, at least indirectly; for discontent with one's condition, under a pressure of many anxieties and amidst unsatisfied wants, might easily become a great temptation to transgression of duty. But here again, without looking to duty, all men have already the strongest and most intimate inclination to happiness, because it is just in this idea that all inclinations are combined in one total. But the precept of happiness is often of such a sort that it greatly interferes with some inclinations, and yet a man cannot form any definite and certain conception of the sum of satisfaction of all of them which is called happiness. It is not then to be wondered at that a single inclination, definite both as to what it promises and as to the time within which it can be gratified, is often able to overcome such a fluctuating idea, and that a gouty patient, for instance, can choose to enjoy what he likes, and to suffer what he may, since, according to his calculation, on this occasion at least, he has not sacrificed the enjoyment of the present moment to a possibly mistaken expectation of a happiness which is supposed to be found in health. But even in this case, if the general desire for happiness did not influence his will, and supposing that in his particular case health was not a necessary element in this calculation, there yet remains in this, as in all other cases, this law, namely, that he should promote his happiness not from inclination but from duty, and by this would his conduct first acquire true moral worth.

It is in this manner, undoubtedly, that we are to understand those passages of Scripture also in which we are commanded to love our neighbour, even our enemy. For love, as an affection, cannot be commanded, but beneficence for duty's sake may; even though we are not impelled to it by any inclination- nay, are even repelled by a natural and unconquerable aversion. This is practical love and not pathological- a love which is seated in the will, and not in the propensions of sense- in principles of action and not of tender sympathy; and it is this love alone which can be commanded.

The second proposition is: That an action done from duty derives its moral worth, not from the purpose which is to be attained by it, but from the maxim by which it is determined, and therefore does not depend on the realization of the object of the action, but merely on the principle of volition by which the action has taken place, without regard to any object of desire. It is clear from what precedes that the purposes which we may have in view in our actions, or their effects regarded as ends and springs of the will, cannot give to actions any unconditional or moral worth. In what, then, can their worth lie, if it is not to consist in the will and in reference to its expected effect? It cannot lie anywhere but in the principle of the will without regard to the ends which can be attained by the action. For the will stands between its a priori principle, which is formal, and its a posteriori spring, which is material, as between two roads, and as it must be determined by something, it follows that it must be determined by the formal principle of volition when an action is done from duty, in which case every material principle has been withdrawn from it.

The third proposition, which is a consequence of the two preceding, I would express thus: Duty is the necessity of acting from respect for the law. I may have inclination for an object as the effect of my proposed action, but I cannot have respect for it, just for this reason, that it is an effect and not an energy of will. Similarly I cannot have respect for inclination, whether my own or another's; I can at most, if my own, approve it; if another's, sometimes even love it; i.e., look on it as favourable to my own interest. It is only what is connected with my will as a principle, by no means as an effect- what does not subserve my inclination, but overpowers it, or at least in case of choice excludes it from its calculation- in other words, simply the law of itself, which can be an object of respect, and hence a command. Now an action done from duty must wholly exclude the influence of inclination and with it every object of the will, so that nothing remains which can determine the will except objectively the law, and subjectively pure respect for this practical law, and consequently the maxim ¹ that I should follow this law even to the thwarting of all my inclinations.

Thus the moral worth of an action does not lie in the effect expected from it, nor in any principle of action which requires to borrow its motive from this expected effect. For all these effects- agreeableness of one's condition and even the promotion of the happiness of others- could have been also brought about by other causes, so that for this there would have been no need of the will of a rational being; whereas it is in this alone that the supreme and unconditional good can be found. The pre-eminent good which we call moral can therefore consist in nothing else than the conception of law in itself, which certainly is only possible in a rational being, in so far as this conception, and not the expected effect, determines the will. This is a good which is already present in the person who acts accordingly, and we have not to wait for it to appear first in the result. ²

But what sort of law can that be, the conception of which must determine the will, even without paying any regard to the effect expected from it, in order that this will may be called good absolutely and without qualification? As I have deprived the will of every impulse which could arise to it from obedience to any law, there remains nothing but the universal conformity of its actions to law in general, which alone is to serve the will as a principle, i.e., I am never to act otherwise than so that I could also will that my maxim should become a universal law. Here, now, it is the simple conformity to law in general, without assuming any particular law applicable to certain actions, that serves the will as its principle and must so serve it, if duty is not to be a vain delusion and a chimerical notion. The common reason of men in its practical judgements perfectly coincides with this and always has in view the principle here suggested. Let the question be, for example: May I when in distress make a promise with the intention not to keep it? I readily distinguish here between the two significations which the question may have: Whether it is prudent, or whether it is right, to make a false promise? The former may undoubtedly often be the case. I see clearly indeed that it is not enough to extricate myself from a present difficulty by means of this subterfuge, but it must be well considered whether there may not hereafter spring from this lie much greater inconvenience than that from which I now free myself, and as, with all my supposed cunning, the consequences cannot be so easily foreseen but that credit once lost may be much more injurious to me than any mischief which I seek to avoid at present, it should be considered whether it would not be more prudent to act herein according to a universal maxim and to make it a habit to promise nothing except with the intention of keeping it. But it is soon clear to me that such a maxim will still only be based on the fear of consequences. Now it is a wholly different thing to be truthful from duty and to be so from apprehension of injurious consequences. In the first case, the very notion of the action already implies a law for me; in the second case, I must first look about elsewhere to see what results may be combined with it which would affect myself. For to deviate from the principle of duty is beyond all doubt wicked; but to be unfaithful to my maxim of prudence may often be very advantageous to me, although to abide by it is certainly safer. The shortest way, however, and an unerring one, to discover the answer to this question whether a lying promise is consistent with duty, is to ask myself, "Should I be content that my maxim (to extricate myself from difficulty by a false promise) should hold good as a universal law, for myself as well as for others?" and should I be able to say to myself, "Every one may make a deceitful promise when he finds himself in a difficulty from which he cannot otherwise extricate himself?" Then I presently become aware that while I can will the lie, I can by no means will that lying should be a universal law. For with such a law there would be no promises at all, since it would be in vain to allege my intention in regard to my future actions to those who would not believe this allegation, or if they over hastily did so would pay me back in my own coin. Hence my maxim, as soon as it should be made a universal law, would necessarily destroy itself.

I do not, therefore, need any far-reaching penetration to discern what I have to do in order that my will may be morally good. Inexperienced in the course of the world, incapable of being prepared for all its contingencies, I only ask myself: Canst thou also will that thy maxim should be a universal law? If not, then it must be rejected, and that not because of a disadvantage accruing from it to myself or even to others, but because it cannot enter as a principle into a possible universal legislation, and reason extorts from me immediate respect for such legislation. I do not indeed as yet discern on what this respect is based (this the philosopher may inquire), but at least I understand this, that it is an estimation of the worth which far outweighs all worth of what is recommended by inclination, and that the necessity of acting from pure respect for the practical law is what constitutes duty, to which every other motive must give place, because it is the condition of a will being good in itself, and the worth of such a will is above everything.

Thus, then, without quitting the moral knowledge of common human reason, we have arrived at its principle. And although, no doubt, common men do not conceive it in such an abstract and universal form, yet they always have it really before their eyes and use it as the standard of their decision. Here it would be easy to show how, with this compass in hand, men are well able to distinguish, in every case that occurs, what is good, what bad, conformably to duty or inconsistent with it, if, without in the least teaching them anything new, we only, like Socrates, direct their attention to the principle they themselves employ; and that, therefore, we do not need science and philosophy to know what we should do to be honest and good, yea, even wise and virtuous. Indeed we might well have conjectured beforehand that the knowledge of what every man is bound to do, and therefore also to know, would be within the reach of every man, even the commonest. Here we cannot forbear admiration when we see how great an advantage the practical judgement has over the theoretical in the common understanding of men. In the latter, if common reason ventures to depart from the laws of experience and from the perceptions of the senses, it falls into mere inconceivabilities and self-contradictions, at least into a chaos of uncertainty, obscurity, and instability. But in the practical sphere it is just when the common understanding excludes all sensible springs from practical laws that its power of judgement begins to show itself to advantage. It then becomes even subtle, whether it be that it chicanes with its own conscience or with other claims respecting what is to be called right, or whether it desires for its own instruction to determine honestly the worth of actions; and, in the latter case, it may even have as good a hope of hitting the mark as any philosopher whatever can promise himself. Nay, it is almost more sure of doing so, because the philosopher cannot have any other principle, while he may easily perplex his judgement by a multitude of considerations foreign to the matter, and so turn aside from the right way. Would it not therefore be wiser in moral concerns to acquiesce in the judgement of common reason, or at most only to call in philosophy for the purpose of rendering the system of morals more complete and intelligible, and its rules more convenient for use (especially for disputation), but not so as to draw off the common understanding from its happy simplicity, or to bring it by means of philosophy into a new path of inquiry and instruction?

Innocence is indeed a glorious thing; only, on the other hand, it is very sad that it cannot well maintain itself and is easily seduced. On this account even wisdom- which otherwise consists more in conduct than in knowledge- yet has need of science, not in order to learn from it, but to secure for its precepts admission and permanence. Against all the commands of duty which reason represents to man as so deserving of respect, he feels in himself a powerful counterpoise in his wants and inclinations, the entire satisfaction of which he sums up under the name of happiness. Now reason issues its commands unyieldingly, without promising anything to the inclinations, and, as it were, with disregard and contempt for these claims, which are so impetuous, and at the same time so plausible, and which will not allow themselves to be suppressed by any command. Hence there arises a natural dialectic, i.e., a disposition, to argue against these strict laws of duty and to question their validity, or at least their purity and strictness; and, if possible, to make them more accordant with our wishes and inclinations, that is to say, to corrupt them at their very source, and entirely to destroy their worth- a thing which even common practical reason cannot ultimately call good.

Thus is the common reason of man compelled to go out of its sphere, and to take a step into the field of a practical philosophy, not to satisfy any speculative want (which never occurs to it as long as it is content to be mere sound reason), but even on practical grounds, in order to attain in it information and clear instruction respecting the source of its principle, and the correct determination of it in opposition to the maxims which are based on wants and inclinations, so that it may escape from the perplexity of opposite claims and not run the risk of losing all genuine moral principles through the equivocation into which it easily falls. Thus, when practical reason cultivates itself, there insensibly arises in it a dialetic which forces it to seek aid in philosophy, just as happens to it in its theoretic use; and in this case, therefore, as well as in the other, it will find rest nowhere but in a thorough critical examination of our reason.