Immanuel Kant .........................................................................................................................................1

PREFACE ...............................................................................................................................................1

MORALITY TO THE PHILOSOPHICAL .............................................................................................4

METAPHYSIC OF MORALS..............................................................................................................10

CRITIQUE OF PURE PRACTICAL REASON...................................................................................30

FIRST SECTION. Transition from the common rational knowledge of morality to the philosophical.

SECOND SECTION. Transition from popular moral philosophy to the metaphysic of morals.

THIRD SECTION. Final step from the metaphysic of morals to the critique of the pure practical reason

Ancient Greek philosophy was divided into three sciences: physics, ethics, and logic. This division is

perfectly suitable to the nature of the thing; and the only improvement that can be made in it is to add the

principle on which it is based, so that we may both satisfy ourselves of its completeness, and also be able to

All rational knowledge is either material or formal: the former considers some object, the latter is concerned

only with the form of the understanding and of the reason itself, and with the universal laws of thought in

general without distinction of its objects. Formal philosophy is called logic. Material philosophy, however,

has to do with determinate objects and the laws to which they are subject, is again twofold; for these laws are

either laws of nature or of freedom. The science of the former is physics, that of the latter, ethics; they are

Logic cannot have any empirical part; that is, a part in which the universal and necessary laws of thought

should rest on grounds taken from experience; otherwise it would not be logic, i.e., a canon for the

understanding or the reason, valid for all thought, and capable of demonstration. Natural and moral

philosophy, on the contrary, can each have their empirical part, since the former has to determine the laws of

nature as an object of experience; the latter the laws of the human will, so far as it is affected by nature: the

former, however, being laws according to which everything does happen; the latter, laws according to which

everything ought to happen. Ethics, however, must also consider the conditions under which what ought to

We may call all philosophy empirical, so far as it is based on grounds of experience: on the other band, that

which delivers its doctrines from a priori principles alone we may call pure philosophy. When the latter is

merely formal it is logic; if it is restricted to definite objects of the understanding it is metaphysic.

In this way there arises the idea of a twofold metaphysic a metaphysic of nature and a metaphysic of morals.

Physics will thus have an empirical and also a rational part. It is the same with Ethics; but here the empirical

part might have the special name of practical anthropology, the name morality being appropriated to the

All trades, arts, and handiworks have gained by division of labour, namely, when, instead of one man doing

everything, each confines himself to a certain kind of work distinct from others in the treatment it requires, so

as to be able to perform it with greater facility and in the greatest perfection. Where the different kinds of

work are not distinguished and divided, where everyone is a jackofalltrades, there manufactures remain

still in the greatest barbarism. It might deserve to be considered whether pure philosophy in all its parts does

not require a man specially devoted to it, and whether it would not be better for the whole business of science

if those who, to please the tastes of the public, are wont to blend the rational and empirical elements together,

mixed in all sorts of proportions unknown to themselves, and who call themselves independent thinkers,

giving the name of minute philosophers to those who apply themselves to the rational part only if these, I

say, were warned not to carry on two employments together which differ widely in the treatment they

demand, for each of which perhaps a special talent is required, and the combination of which in one person

only produces bunglers. But I only ask here whether the nature of science does not require that we should

always carefully separate the empirical from the rational part, and prefix to Physics proper (or empirical

physics) a metaphysic of nature, and to practical anthropology a metaphysic of morals, which must be

carefully cleared of everything empirical, so that we may know how much can be accomplished by pure

reason in both cases, and from what sources it draws this its a priori teaching, and that whether the latter

inquiry is conducted by all moralists (whose name is legion), or only by some who feel a calling thereto.

As my concern here is with moral philosophy, I limit the question suggested to this: Whether it is not of the

utmost necessity to construct a pure thing which is only empirical and which belongs to anthropology? for

that such a philosophy must be possible is evident from the common idea of duty and of the moral laws.

Everyone must admit that if a law is to have moral force, i.e., to be the basis of an obligation, it must carry

with it absolute necessity; that, for example, the precept, "Thou shalt not lie," is not valid for men alone, as if

other rational beings had no need to observe it; and so with all the other moral laws properly so called; that,

therefore, the basis of obligation must not be sought in the nature of man, or in the circumstances in the world

in which he is placed, but a priori simply in the conception of pure reason; and although any other precept

which is founded on principles of mere experience may be in certain respects universal, yet in as far as it rests

even in the least degree on an empirical basis, perhaps only as to a motive, such a precept, while it may be a

Thus not only are moral laws with their principles essentially distinguished from every other kind of practical

knowledge in which there is anything empirical, but all moral philosophy rests wholly on its pure part. When

applied to man, it does not borrow the least thing from the knowledge of man himself (anthropology), but

gives laws a priori to him as a rational being. No doubt these laws require a judgement sharpened by

experience, in order on the one hand to distinguish in what cases they are applicable, and on the other to

procure for them access to the will of the man and effectual influence on conduct; since man is acted on by so

many inclinations that, though capable of the idea of a practical pure reason, he is not so easily able to make

A metaphysic of morals is therefore indispensably necessary, not merely for speculative reasons, in order to

investigate the sources of the practical principles which are to be found a priori in our reason, but also

because morals themselves are liable to all sorts of corruption, as long as we are without that clue and

supreme canon by which to estimate them correctly. For in order that an action should be morally good, it is

not enough that it conform to the moral law, but it must also be done for the sake of the law, otherwise that

conformity is only very contingent and uncertain; since a principle which is not moral, although it may now

and then produce actions conformable to the law, will also often produce actions which contradict it. Now it

is only a pure philosophy that we can look for the moral law in its purity and genuineness (and, in a practical

matter, this is of the utmost consequence): we must, therefore, begin with pure philosophy (metaphysic), and

without it there cannot be any moral philosophy at all. That which mingles these pure principles with the

empirical does not deserve the name of philosophy (for what distinguishes philosophy from common rational

knowledge is that it treats in separate sciences what the latter only comprehends confusedly); much less does

it deserve that of moral philosophy, since by this confusion it even spoils the purity of morals themselves, and

Let it not be thought, however, that what is here demanded is already extant in the propaedeutic prefixed by

the celebrated Wolf to his moral philosophy, namely, his socalled general practical philosophy, and that,

therefore, we have not to strike into an entirely new field. just because it was to be a general practical

philosophy, it has not taken into consideration a will of any particular kind say one which should be

determined solely from a priori principles without any empirical motives, and which we might call a pure

will, but volition in general, with all the actions and conditions which belong to it in this general

signification. By this it is distinguished from a metaphysic of morals, just as general logic, which treats of the

acts and canons of thought in general, is distinguished from transcendental philosophy, which treats of the

particular acts and canons of pure thought, i.e., that whose cognitions are altogether a priori. For the

metaphysic of morals has to examine the idea and the principles of a possible pure will, and not the acts and

conditions of human volition generally, which for the most part are drawn from psychology. It is true that

moral laws and duty are spoken of in the general moral philosophy (contrary indeed to all fitness). But this is

no objection, for in this respect also the authors of that science remain true to their idea of it; they do not

distinguish the motives which are prescribed as such by reason alone altogether a priori, and which are

properly moral, from the empirical motives which the understanding raises to general conceptions merely by

comparison of experiences; but, without noticing the difference of their sources, and looking on them all as

homogeneous, they consider only their greater or less amount. It is in this way they frame their notion of

obligation, which, though anything but moral, is all that can be attained in a philosophy which passes no

judgement at all on the origin of all possible practical concepts, whether they are a priori, or only a posteriori.

Intending to publish hereafter a metaphysic of morals, I issue in the first instance these fundamental

principles. Indeed there is properly no other foundation for it than the critical examination of a pure practical

Reason; just as that of metaphysics is the critical examination of the pure speculative reason, already

published. But in the first place the former is not so absolutely necessary as the latter, because in moral

concerns human reason can easily be brought to a high degree of correctness and completeness, even in the

commonest understanding, while on the contrary in its theoretic but pure use it is wholly dialectical; and in

the second place if the critique of a pure practical reason is to be complete, it must be possible at the same

time to show its identity with the speculative reason in a common principle, for it can ultimately be only one

and the same reason which has to be distinguished merely in its application. I could not, however, bring it to

such completeness here, without introducing considerations of a wholly different kind, which would be

perplexing to the reader. On this account I have adopted the title of Fundamental Principles of the Metaphysic

of Morals instead of that of a Critical Examination of the pure practical reason.

But in the third place, since a metaphysic of morals, in spite of the discouraging title, is yet capable of being

presented in popular form, and one adapted to the common understanding, I find it useful to separate from it

this preliminary treatise on its fundamental principles, in order that I may not hereafter have need to introduce

The present treatise is, however, nothing more than the investigation and establishment of the supreme

principle of morality, and this alone constitutes a study complete in itself and one which ought to be kept

apart from every other moral investigation. No doubt my conclusions on this weighty question, which has

hitherto been very unsatisfactorily examined, would receive much light from the application of the same

principle to the whole system, and would be greatly confirmed by the adequacy which it exhibits throughout;

but I must forego this advantage, which indeed would be after all more gratifying than useful, since the easy

applicability of a principle and its apparent adequacy give no very certain proof of its soundness, but rather

inspire a certain partiality, which prevents us from examining and estimating it strictly in itself and without

I have adopted in this work the method which I think most suitable, proceeding analytically from common

knowledge to the determination of its ultimate principle, and again descending synthetically from the

examination of this principle and its sources to the common knowledge in which we find it employed. The

1 FIRST SECTION. Transition from the common rational knowledge of morality to the philosophical.

2 SECOND SECTION. Transition from popular moral philosophy to the metaphysic of morals.

3 THIRD SECTION. Final step from the metaphysic of morals to the critique of the pure practical reason.

Nothing can possibly be conceived in the world, or even out of it, which can be called good, without

qualification, except a good will. Intelligence, wit, judgement, and the other talents of the mind, however they

may be named, or courage, resolution, perseverance, as qualities of temperament, are undoubtedly good and

desirable in many respects; but these gifts of nature may also become extremely bad and mischievous if the

will which is to make use of them, and which, therefore, constitutes what is called character, is not good. It is

the same with the gifts of fortune. Power, riches, honour, even health, and the general wellbeing and

contentment with one's condition which is called happiness, inspire pride, and often presumption, if there is

not a good will to correct the influence of these on the mind, and with this also to rectify the whole principle

of acting and adapt it to its end. The sight of a being who is not adorned with a single feature of a pure and

good will, enjoying unbroken prosperity, can never give pleasure to an impartial rational spectator. Thus a

good will appears to constitute the indispensable condition even of being worthy of happiness.

There are even some qualities which are of service to this good will itself and may facilitate its action, yet

which have no intrinsic unconditional value, but always presuppose a good will, and this qualifies the esteem

that we justly have for them and does not permit us to regard them as absolutely good. Moderation in the

affections and passions, selfcontrol, and calm deliberation are not only good in many respects, but even

seem to constitute part of the intrinsic worth of the person; but they are far from deserving to be called good

without qualification, although they have been so unconditionally praised by the ancients. For without the

principles of a good will, they may become extremely bad, and the coolness of a villain not only makes him

far more dangerous, but also directly makes him more abominable in our eyes than he would have been

A good will is good not because of what it performs or effects, not by its aptness for the attainment of some

proposed end, but simply by virtue of the volition; that is, it is good in itself, and considered by itself is to be

esteemed much higher than all that can be brought about by it in favour of any inclination, nay even of the

sum total of all inclinations. Even if it should happen that, owing to special disfavour of fortune, or the

niggardly provision of a stepmotherly nature, this will should wholly lack power to accomplish its purpose,

if with its greatest efforts it should yet achieve nothing, and there should remain only the good will (not, to be

sure, a mere wish, but the summoning of all means in our power), then, like a jewel, it would still shine by its

own light, as a thing which has its whole value in itself. Its usefulness or fruitfulness can neither add nor take

away anything from this value. It would be, as it were, only the setting to enable us to handle it the more

conveniently in common commerce, or to attract to it the attention of those who are not yet connoisseurs, but

There is, however, something so strange in this idea of the absolute value of the mere will, in which no

account is taken of its utility, that notwithstanding the thorough assent of even common reason to the idea,

yet a suspicion must arise that it may perhaps really be the product of mere highflown fancy, and that we

may have misunderstood the purpose of nature in assigning reason as the governor of our will. Therefore we

FIRST SECTION. TRANSITION FROM THE COMMON RATIONAL KNOWLEDGE OF MORALITY TO THE PHILOSOPHICAL 4

In the physical constitution of an organized being, that is, a being adapted suitably to the purposes of life, we

assume it as a fundamental principle that no organ for any purpose will be found but what is also the fittest

and best adapted for that purpose. Now in a being which has reason and a will, if the proper object of nature

were its conservation, its welfare, in a word, its happiness, then nature would have hit upon a very bad

arrangement in selecting the reason of the creature to carry out this purpose. For all the actions which the

creature has to perform with a view to this purpose, and the whole rule of its conduct, would be far more

surely prescribed to it by instinct, and that end would have been attained thereby much more certainly than it

ever can be by reason. Should reason have been communicated to this favoured creature over and above, it

must only have served it to contemplate the happy constitution of its nature, to admire it, to congratulate itself

thereon, and to feel thankful for it to the beneficent cause, but not that it should subject its desires to that

weak and delusive guidance and meddle bunglingly with the purpose of nature. In a word, nature would have

taken care that reason should not break forth into practical exercise, nor have the presumption, with its weak

insight, to think out for itself the plan of happiness, and of the means of attaining it. Nature would not only

have taken on herself the choice of the ends, but also of the means, and with wise foresight would have

And, in fact, we find that the more a cultivated reason applies itself with deliberate purpose to the enjoyment

of life and happiness, so much the more does the man fail of true satisfaction. And from this circumstance

there arises in many, if they are candid enough to confess it, a certain degree of misology, that is, hatred of

reason, especially in the case of those who are most experienced in the use of it, because after calculating all

the advantages they derive, I do not say from the invention of all the arts of common luxury, but even from

the sciences (which seem to them to be after all only a luxury of the understanding), they find that they have,

in fact, only brought more trouble on their shoulders. rather than gained in happiness; and they end by

envying, rather than despising, the more common stamp of men who keep closer to the guidance of mere

instinct and do not allow their reason much influence on their conduct. And this we must admit, that the

judgement of those who would very much lower the lofty eulogies of the advantages which reason gives us in

regard to the happiness and satisfaction of life, or who would even reduce them below zero, is by no means

morose or ungrateful to the goodness with which the world is governed, but that there lies at the root of these

judgements the idea that our existence has a different and far nobler end, for which, and not for happiness,

reason is properly intended, and which must, therefore, be regarded as the supreme condition to which the

For as reason is not competent to guide the will with certainty in regard to its objects and the satisfaction of

all our wants (which it to some extent even multiplies), this being an end to which an implanted instinct

would have led with much greater certainty; and since, nevertheless, reason is imparted to us as a practical

faculty, i.e., as one which is to have influence on the will, therefore, admitting that nature generally in the

distribution of her capacities has adapted the means to the end, its true destination must be to produce a will,

not merely good as a means to something else, but good in itself, for which reason was absolutely necessary.

This will then, though not indeed the sole and complete good, must be the supreme good and the condition of

every other, even of the desire of happiness. Under these circumstances, there is nothing inconsistent with the

wisdom of nature in the fact that the cultivation of the reason, which is requisite for the first and

unconditional purpose, does in many ways interfere, at least in this life, with the attainment of the second,

which is always conditional, namely, happiness. Nay, it may even reduce it to nothing, without nature thereby

failing of her purpose. For reason recognizes the establishment of a good will as its highest practical

destination, and in attaining this purpose is capable only of a satisfaction of its own proper kind, namely that

from the attainment of an end, which end again is determined by reason only, notwithstanding that this may

We have then to develop the notion of a will which deserves to be highly esteemed for itself and is good

without a view to anything further, a notion which exists already in the sound natural understanding,

requiring rather to be cleared up than to be taught, and which in estimating the value of our actions always

FIRST SECTION. TRANSITION FROM THE COMMON RATIONAL KNOWLEDGE OF MORALITY TO THE PHILOSOPHICAL 5

takes the first place and constitutes the condition of all the rest. In order to do this, we will take the notion of

duty, which includes that of a good will, although implying certain subjective restrictions and hindrances.

These, however, far from concealing it, or rendering it unrecognizable, rather bring it out by contrast and

I omit here all actions which are already recognized as inconsistent with duty, although they may be useful

for this or that purpose, for with these the question whether they are done from duty cannot arise at all, since

they even conflict with it. I also set aside those actions which really conform to duty, but to which men have

no direct inclination, performing them because they are impelled thereto by some other inclination. For in this

case we can readily distinguish whether the action which agrees with duty is done from duty, or from a

selfish view. It is much harder to make this distinction when the action accords with duty and the subject has

besides a direct inclination to it. For example, it is always a matter of duty that a dealer should not over

charge an inexperienced purchaser; and wherever there is much commerce the prudent tradesman does not

overcharge, but keeps a fixed price for everyone, so that a child buys of him as well as any other. Men are

thus honestly served; but this is not enough to make us believe that the tradesman has so acted from duty and

from principles of honesty: his own advantage required it; it is out of the question in this case to suppose that

he might besides have a direct inclination in favour of the buyers, so that, as it were, from love he should give

no advantage to one over another. Accordingly the action was done neither from duty nor from direct

On the other hand, it is a duty to maintain one's life; and, in addition, everyone has also a direct inclination to

do so. But on this account the of anxious care which most men take for it has no intrinsic worth, and their

maxim has no moral import. They preserve their life as duty requires, no doubt, but not because duty

requires. On the other band, if adversity and hopeless sorrow have completely taken away the relish for life;

if the unfortunate one, strong in mind, indignant at his fate rather than desponding or dejected, wishes for

death, and yet preserves his life without loving it not from inclination or fear, but from duty then his

To be beneficent when we can is a duty; and besides this, there are many minds so sympathetically

constituted that, without any other motive of vanity or selfinterest, they find a pleasure in spreading joy

around them and can take delight in the satisfaction of others so far as it is their own work. But I maintain

that in such a case an action of this kind, however proper, however amiable it may be, bas nevertheless no

true moral worth, but is on a level with other inclinations, e.g., the inclination to honour, which, if it is

happily directed to that which is in fact of public utility and accordant with duty and consequently

honourable, deserves praise and encouragement, but not esteem. For the maxim lacks the moral import,

namely, that such actions be done from duty, not from inclination. Put the case that the mind of that

philanthropist were clouded by sorrow of his own, extinguishing all sympathy with the lot of others, and that,

while he still has the power to benefit others in distress, he is not touched by their trouble because he is

absorbed with his own; and now suppose that he tears himself out of this dead insensibility, and performs the

action without any inclination to it, but simply from duty, then first has his action its genuine moral worth.

Further still; if nature bas put little sympathy in the heart of this or that man; if he, supposed to be an upright

man, is by temperament cold and indifferent to the sufferings of others, perhaps because in respect of his own

he is provided with the special gift of patience and fortitude and supposes, or even requires, that others should

have the same and such a man would certainly not be the meanest product of nature but if nature had not

specially framed him for a philanthropist, would he not still find in himself a source from whence to give

himself a far higher worth than that of a goodnatured temperament could be? Unquestionably. It is just in

this that the moral worth of the character is brought out which is incomparably the highest of all, namely, that

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

FIRST SECTION. TRANSITION FROM THE COMMON RATIONAL KNOWLEDGE OF MORALITY TO THE PHILOSOPHICAL 6

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, be 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

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;

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 that it must be determined by the formal principle of volition when an action is done from duty,

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* that I should follow this law even to the thwarting of all my

*A maxim is the subjective principle of volition. The objective principle (i.e., that which would also serve

subjectively as a practical principle to all rational beings if reason had full power over the faculty of desire) is

FIRST SECTION. TRANSITION FROM THE COMMON RATIONAL KNOWLEDGE OF MORALITY TO THE PHILOSOPHICAL 7

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 preeminent 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

*It might be here objected to me that I take refuge behind the word respect in an obscure feeling, instead of

giving a distinct solution of the question by a concept of the reason. But although respect is a feeling, it is not

a feeling received through influence, but is selfwrought by a rational concept, and, therefore, is specifically

distinct from all feelings of the former kind, which may be referred either to inclination or fear, What I

recognise immediately as a law for me, I recognise with respect. This merely signifies the consciousness that

my will is subordinate to a law, without the intervention of other influences on my sense. The immediate

determination of the will by the law, and the consciousness of this, is called respect, so that this is regarded as

an effect of the law on the subject, and not as the cause of it. Respect is properly the conception of a worth

which thwarts my selflove. Accordingly it is something which is considered neither as an object of

inclination nor of fear, although it has something analogous to both. The object of respect is the law only, and

that the law which we impose on ourselves and yet recognise as necessary in itself. As a law, we are

subjected too it without consulting selflove; as imposed by us on ourselves, it is a result of our will. In the

former aspect it has an analogy to fear, in the latter to inclination. Respect for a person is properly only

respect for the law (of honesty, etc.) of which he gives us an example. Since we also look on the

improvement of our talents as a duty, we consider that we see in a person of talents, as it were, the example of

a law (viz., to become like him in this by exercise), and this constitutes our respect. All socalled moral

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 of 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

FIRST SECTION. TRANSITION FROM THE COMMON RATIONAL KNOWLEDGE OF MORALITY TO THE PHILOSOPHICAL 8

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

I do not, therefore, need any farreaching 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

selfcontradictions, 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

FIRST SECTION. TRANSITION FROM THE COMMON RATIONAL KNOWLEDGE OF MORALITY TO THE PHILOSOPHICAL 9

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

If we have hitherto drawn our notion of duty from the common use of our practical reason, it is by no means

to be inferred that we have treated it as an empirical notion. On the contrary, if we attend to the experience of

men's conduct, we meet frequent and, as we ourselves allow, just complaints that one cannot find a single

certain example of the disposition to act from pure duty. Although many things are done in conformity with

what duty prescribes, it is nevertheless always doubtful whether they are done strictly from duty, so as to

have a moral worth. Hence there have at all times been philosophers who have altogether denied that this

disposition actually exists at all in human actions, and have ascribed everything to a more or less refined

selflove. Not that they have on that account questioned the soundness of the conception of morality; on the

contrary, they spoke with sincere regret of the frailty and corruption of human nature, which, though noble

enough to take its rule an idea so worthy of respect, is yet weak to follow it and employs reason which ought

to give it the law only for the purpose of providing for the interest of the inclinations, whether singly or at the

In fact, it is absolutely impossible to make out by experience with complete certainty a single case in which

the maxim of an action, however right in itself, rested simply on moral grounds and on the conception of

duty. Sometimes it happens that with the sharpest selfexamination we can find nothing beside the moral

principle of duty which could have been powerful enough to move us to this or that action and to so great a

sacrifice; yet we cannot from this infer with certainty that it was not really some secret impulse of selflove,

under the false appearance of duty, that was the actual determining cause of the will. We like them to flatter

ourselves by falsely taking credit for a more noble motive; whereas in fact we can never, even by the strictest

examination, get completely behind the secret springs of action; since, when the question is of moral worth, it

is not with the actions which we see that we are concerned, but with those inward principles of them which

Moreover, we cannot better serve the wishes of those who ridicule all morality as a mere chimera of human

imagination over stepping itself from vanity, than by conceding to them that notions of duty must be drawn

only from experience (as from indolence, people are ready to think is also the case with all other notions); for

or is to prepare for them a certain triumph. I am willing to admit out of love of humanity that even most of

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 10

our actions are correct, but if we look closer at them we everywhere come upon the dear self which is always

prominent, and it is this they have in view and not the strict command of duty which would often require

selfdenial. Without being an enemy of virtue, a cool observer, one that does not mistake the wish for good,

however lively, for its reality, may sometimes doubt whether true virtue is actually found anywhere in the

world, and this especially as years increase and the judgement is partly made wiser by experience and partly,

also, more acute in observation. This being so, nothing can secure us from falling away altogether from our

ideas of duty, or maintain in the soul a wellgrounded respect for its law, but the clear conviction that

although there should never have been actions which really sprang from such pure sources, yet whether this

or that takes place is not at all the question; but that reason of itself, independent on all experience, ordains

what ought to take place, that accordingly actions of which perhaps the world has hitherto never given an

example, the feasibility even of which might be very much doubted by one who founds everything on

experience, are nevertheless inflexibly commanded by reason; that, e.g., even though there might never yet

have been a sincere friend, yet not a whit the less is pure sincerity in friendship required of every man,

because, prior to all experience, this duty is involved as duty in the idea of a reason determining the will by a

When we add further that, unless we deny that the notion of morality has any truth or reference to any

possible object, we must admit that its law must be valid, not merely for men but for all rational creatures

generally, not merely under certain contingent conditions or with exceptions but with absolute necessity, then

it is clear that no experience could enable us to infer even the possibility of such apodeictic laws. For with

what right could we bring into unbounded respect as a universal precept for every rational nature that which

perhaps holds only under the contingent conditions of humanity? Or how could laws of the determination of

our will be regarded as laws of the determination of the will of rational beings generally, and for us only as

such, if they were merely empirical and did not take their origin wholly a priori from pure but practical

Nor could anything be more fatal to morality than that we should wish to derive it from examples. For every

example of it that is set before me must be first itself tested by principles of morality, whether it is worthy to

serve as an original example, i.e., as a pattern; but by no means can it authoritatively furnish the conception

of morality. Even the Holy One of the Gospels must first be compared with our ideal of moral perfection

before we can recognise Him as such; and so He says of Himself, "Why call ye Me (whom you see) good;

none is good (the model of good) but God only (whom ye do not see)?" But whence have we the conception

of God as the supreme good? Simply from the idea of moral perfection, which reason frames a priori and

connects inseparably with the notion of a free will. Imitation finds no place at all in morality, and examples

serve only for encouragement, i.e., they put beyond doubt the feasibility of what the law commands, they

make visible that which the practical rule expresses more generally, but they can never authorize us to set

aside the true original which lies in reason and to guide ourselves by examples.

If then there is no genuine supreme principle of morality but what must rest simply on pure reason,

independent of all experience, I think it is not necessary even to put the question whether it is good to exhibit

these concepts in their generality (in abstracto) as they are established a priori along with the principles

belonging to them, if our knowledge is to be distinguished from the vulgar and to be called philosophical.

In our times indeed this might perhaps be necessary; for if we collected votes whether pure rational

knowledge separated from everything empirical, that is to say, metaphysic of morals, or whether popular

practical philosophy is to be preferred, it is easy to guess which side would preponderate.

This descending to popular notions is certainly very commendable, if the ascent to the principles of pure

reason has first taken place and been satisfactorily accomplished. This implies that we first found ethics on

metaphysics, and then, when it is firmly established, procure a hearing for it by giving it a popular character.

But it is quite absurd to try to be popular in the first inquiry, on which the soundness of the principles

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 11

depends. It is not only that this proceeding can never lay claim to the very rare merit of a true philosophical

popularity, since there is no art in being intelligible if one renounces all thoroughness of insight; but also it

produces a disgusting medley of compiled observations and halfreasoned principles. Shallow pates enjoy

this because it can be used for everyday chat, but the sagacious find in it only confusion, and being

unsatisfied and unable to help themselves, they turn away their eyes, while philosophers, who see quite well

through this delusion, are little listened to when they call men off for a time from this pretended popularity, in

order that they might be rightfully popular after they have attained a definite insight.

We need only look at the attempts of moralists in that favourite fashion, and we shall find at one time the

special constitution of human nature (including, however, the idea of a rational nature generally), at one time

perfection, at another happiness, here moral sense, there fear of God. a little of this, and a little of that, in

marvellous mixture, without its occurring to them to ask whether the principles of morality are to be sought

in the knowledge of human nature at all (which we can have only from experience); or, if this is not so, if

these principles are to be found altogether a priori, free from everything empirical, in pure rational concepts

only and nowhere else, not even in the smallest degree; then rather to adopt the method of making this a

separate inquiry, as pure practical philosophy, or (if one may use a name so decried) as metaphysic of

morals,* to bring it by itself to completeness, and to require the public, which wishes for popular treatment,

*Just as pure mathematics are distinguished from applied, pure logic from applied, so if we choose we may

also distinguish pure philosophy of morals (metaphysic) from applied (viz., applied to human nature). By this

designation we are also at once reminded that moral principles are not based on properties of human nature,

but must subsist a priori of themselves, while from such principles practical rules must be capable of being

Such a metaphysic of morals, completely isolated, not mixed with any anthropology, theology, physics, or

hyperphysics, and still less with occult qualities (which we might call hypophysical), is not only an

indispensable substratum of all sound theoretical knowledge of duties, but is at the same time a desideratum

of the highest importance to the actual fulfilment of their precepts. For the pure conception of duty, unmixed

with any foreign addition of empirical attractions, and, in a word, the conception of the moral law, exercises

on the human heart, by way of reason alone (which first becomes aware with this that it can of itself be

practical), an influence so much more powerful than all other springs* which may be derived from the field

of experience, that, in the consciousness of its worth, it despises the latter, and can by degrees become their

master; whereas a mixed ethics, compounded partly of motives drawn from feelings and inclinations, and

partly also of conceptions of reason, must make the mind waver between motives which cannot be brought

under any principle, which lead to good only by mere accident and very often also to evil.

*I have a letter from the late excellent Sulzer, in which he asks me what can be the reason that moral

instruction, although containing much that is convincing for the reason, yet accomplishes so little? My

answer was postponed in order that I might make it complete. But it is simply this: that the teachers

themselves have not got their own notions clear, and when they endeavour to make up for this by raking up

motives of moral goodness from every quarter, trying to make their physic right strong, they spoil it. For the

commonest understanding shows that if we imagine, on the one hand, an act of honesty done with steadfast

mind, apart from every view to advantage of any kind in this world or another, and even under the greatest

temptations of necessity or allurement, and, on the other hand, a similar act which was affected, in however

low a degree, by a foreign motive, the former leaves far behind and eclipses the second; it elevates the soul

and inspires the wish to be able to act in like manner oneself. Even moderately young children feel this

From what has been said, it is clear that all moral conceptions have their seat and origin completely a priori in

the reason, and that, moreover, in the commonest reason just as truly as in that which is in the highest degree

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 12

speculative; that they cannot be obtained by abstraction from any empirical, and therefore merely contingent,

knowledge; that it is just this purity of their origin that makes them worthy to serve as our supreme practical

principle, and that just in proportion as we add anything empirical, we detract from their genuine influence

and from the absolute value of actions; that it is not only of the greatest necessity, in a purely speculative

point of view, but is also of the greatest practical importance, to derive these notions and laws from pure

reason, to present them pure and unmixed, and even to determine the compass of this practical or pure

rational knowledge, i.e., to determine the whole faculty of pure practical reason; and, in doing so, we must

not make its principles dependent on the particular nature of human reason, though in speculative philosophy

this may be permitted, or may even at times be necessary; but since moral laws ought to hold good for every

rational creature, we must derive them from the general concept of a rational being. In this way, although for

its application to man morality has need of anthropology, yet, in the first instance, we must treat it

independently as pure philosophy, i.e., as metaphysic, complete in itself (a thing which in such distinct

branches of science is easily done); knowing well that unless we are in possession of this, it would not only

be vain to determine the moral element of duty in right actions for purposes of speculative criticism, but it

would be impossible to base morals on their genuine principles, even for common practical purposes,

especially of moral instruction, so as to produce pure moral dispositions, and to engraft them on men's minds

But in order that in this study we may not merely advance by the natural steps from the common moral

judgement (in this case very worthy of respect) to the philosophical, as has been already done, but also from a

popular philosophy, which goes no further than it can reach by groping with the help of examples, to

metaphysic (which does allow itself to be checked by anything empirical and, as it must measure the whole

extent of this kind of rational knowledge, goes as far as ideal conceptions, where even examples fail us), we

must follow and clearly describe the practical faculty of reason, from the general rules of its determination to

Everything in nature works according to laws. Rational beings alone have the faculty of acting according to

the conception of laws, that is according to principles, i.e., have a will. Since the deduction of actions from

principles requires reason, the will is nothing but practical reason. If reason infallibly determines the will,

then the actions of such a being which are recognised as objectively necessary are subjectively necessary

also, i.e., the will is a faculty to choose that only which reason independent of inclination recognises as

practically necessary, i.e., as good. But if reason of itself does not sufficiently determine the will, if the latter

is subject also to subjective conditions (particular impulses) which do not always coincide with the objective

conditions; in a word, if the will does not in itself completely accord with reason (which is actually the case

with men), then the actions which objectively are recognised as necessary are subjectively contingent, and the

determination of such a will according to objective laws is obligation, that is to say, the relation of the

objective laws to a will that is not thoroughly good is conceived as the determination of the will of a rational

being by principles of reason, but which the will from its nature does not of necessity follow.

The conception of an objective principle, in so far as it is obligatory for a will, is called a command (of

All imperatives are expressed by the word ought [or shall], and thereby indicate the relation of an objective

law of reason to a will, which from its subjective constitution is not necessarily determined by it (an

obligation). They say that something would be good to do or to forbear, but they say it to a will which does

not always do a thing because it is conceived to be good to do it. That is practically good, however, which

determines the will by means of the conceptions of reason, and consequently not from subjective causes, but

objectively, that is on principles which are valid for every rational being as such. It is distinguished from the

pleasant, as that which influences the will only by means of sensation from merely subjective causes, valid

only for the sense of this or that one, and not as a principle of reason, which holds for every one.*

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 13

*The dependence of the desires on sensations is called inclination, and this accordingly always indicates a

want. The dependence of a contingently determinable will on principles of reason is called an interest. This

therefore, is found only in the case of a dependent will which does not always of itself conform to reason; in

the Divine will we cannot conceive any interest. But the human will can also take an interest in a thing

without therefore acting from interest. The former signifies the practical interest in the action, the latter the

pathological in the object of the action. The former indicates only dependence of the will on principles of

reason in themselves; the second, dependence on principles of reason for the sake of inclination, reason

supplying only the practical rules how the requirement of the inclination may be satisfied. In the first case the

action interests me; in the second the object of the action (because it is pleasant to me). We have seen in the

first section that in an action done from duty we must look not to the interest in the object, but only to that in

A perfectly good will would therefore be equally subject to objective laws (viz., laws of good), but could not

be conceived as obliged thereby to act lawfully, because of itself from its subjective constitution it can only

be determined by the conception of good. Therefore no imperatives hold for the Divine will, or in general for

a holy will; ought is here out of place, because the volition is already of itself necessarily in unison with the

law. Therefore imperatives are only formulae to express the relation of objective laws of all volition to the

subjective imperfection of the will of this or that rational being, e.g., the human will.

Now all imperatives command either hypothetically or categorically. The former represent the practical

necessity of a possible action as means to something else that is willed (or at least which one might possibly

will). The categorical imperative would be that which represented an action as necessary of itself without

Since every practical law represents a possible action as good and, on this account, for a subject who is

practically determinable by reason, necessary, all imperatives are formulae determining an action which is

necessary according to the principle of a will good in some respects. If now the action is good only as a

means to something else, then the imperative is hypothetical; if it is conceived as good in itself and

consequently as being necessarily the principle of a will which of itself conforms to reason, then it is

Thus the imperative declares what action possible by me would be good and presents the practical rule in

relation to a will which does not forthwith perform an action simply because it is good, whether because the

subject does not always know that it is good, or because, even if it know this, yet its maxims might be

Accordingly the hypothetical imperative only says that the action is good for some purpose, possible or

actual. In the first case it is a problematical, in the second an assertorial practical principle. The categorical

imperative which declares an action to be objectively necessary in itself without reference to any purpose,

Whatever is possible only by the power of some rational being may also be conceived as a possible purpose

of some will; and therefore the principles of action as regards the means necessary to attain some possible

purpose are in fact infinitely numerous. All sciences have a practical part, consisting of problems expressing

that some end is possible for us and of imperatives directing how it may be attained. These may, therefore, be

called in general imperatives of skill. Here there is no question whether the end is rational and good, but only

what one must do in order to attain it. The precepts for the physician to make his patient thoroughly healthy,

and for a poisoner to ensure certain death, are of equal value in this respect, that each serves to effect its

purpose perfectly. Since in early youth it cannot be known what ends are likely to occur to us in the course of

life, parents seek to have their children taught a great many things, and provide for their skill in the use of

means for all sorts of arbitrary ends, of none of which can they determine whether it may not perhaps

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 14

hereafter be an object to their pupil, but which it is at all events possible that he might aim at; and this anxiety

is so great that they commonly neglect to form and correct their judgement on the value of the things which

There is one end, however, which may be assumed to be actually such to all rational beings (so far as

imperatives apply to them, viz., as dependent beings), and, therefore, one purpose which they not merely may

have, but which we may with certainty assume that they all actually have by a natural necessity, and this is

happiness. The hypothetical imperative which expresses the practical necessity of an action as means to the

advancement of happiness is assertorial. We are not to present it as necessary for an uncertain and merely

possible purpose, but for a purpose which we may presuppose with certainty and a priori in every man,

because it belongs to his being. Now skill in the choice of means to his own greatest wellbeing may be

called prudence,* in the narrowest sense. And thus the imperative which refers to the choice of means to

one's own happiness, i.e., the precept of prudence, is still always hypothetical; the action is not commanded

*The word prudence is taken in two senses: in the one it may bear the name of knowledge of the world, in the

other that of private prudence. The former is a man's ability to influence others so as to use them for his own

purposes. The latter is the sagacity to combine all these purposes for his own lasting benefit. This latter is

properly that to which the value even of the former is reduced, and when a man is prudent in the former

sense, but not in the latter, we might better say of him that he is clever and cunning, but, on the whole,

Finally, there is an imperative which commands a certain conduct immediately, without having as its

condition any other purpose to be attained by it. This imperative is categorical. It concerns not the matter of

the action, or its intended result, but its form and the principle of which it is itself a result; and what is

essentially good in it consists in the mental disposition, let the consequence be what it may. This imperative

There is a marked distinction also between the volitions on these three sorts of principles in the dissimilarity

of the obligation of the will. In order to mark this difference more clearly, I think they would be most suitably

named in their order if we said they are either rules of skill, or counsels of prudence, or commands (laws) of

morality. For it is law only that involves the conception of an unconditional and objective necessity, which is

consequently universally valid; and commands are laws which must be obeyed, that is, must be followed,

even in opposition to inclination. Counsels, indeed, involve necessity, but one which can only hold under a

contingent subjective condition, viz., they depend on whether this or that man reckons this or that as part of

his happiness; the categorical imperative, on the contrary, is not limited by any condition, and as being

absolutely, although practically, necessary, may be quite properly called a command. We might also call the

first kind of imperatives technical (belonging to art), the second pragmatic* (to welfare), the third moral

*It seems to me that the proper signification of the word pragmatic may be most accurately defined in this

way. For sanctions are called pragmatic which flow properly not from the law of the states as necessary

enactments, but from precaution for the general welfare. A history is composed pragmatically when it teaches

prudence, i.e., instructs the world how it can provide for its interests better, or at least as well as, the men of

Now arises the question, how are all these imperatives possible? This question does not seek to know how we

can conceive the accomplishment of the action which the imperative ordains, but merely how we can

conceive the obligation of the will which the imperative expresses. No special explanation is needed to show

how an imperative of skill is possible. Whoever wills the end, wills also (so far as reason decides his conduct)

the means in his power which are indispensably necessary thereto. This proposition is, as regards the volition,

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 15

analytical; for, in willing an object as my effect, there is already thought the causality of myself as an acting

cause, that is to say, the use of the means; and the imperative educes from the conception of volition of an

end the conception of actions necessary to this end. Synthetical propositions must no doubt be employed in

defining the means to a proposed end; but they do not concern the principle, the act of the will, but the object

and its realization. E.g., that in order to bisect a line on an unerring principle I must draw from its extremities

two intersecting arcs; this no doubt is taught by mathematics only in synthetical propositions; but if I know

that it is only by this process that the intended operation can be performed, then to say that, if I fully will the

operation, I also will the action required for it, is an analytical proposition; for it is one and the same thing to

conceive something as an effect which I can produce in a certain way, and to conceive myself as acting in this

If it were only equally easy to give a definite conception of happiness, the imperatives of prudence would

correspond exactly with those of skill, and would likewise be analytical. For in this case as in that, it could be

said: "Whoever wills the end, wills also (according to the dictate of reason necessarily) the indispensable

means thereto which are in his power." But, unfortunately, the notion of happiness is so indefinite that

although every man wishes to at. it, yet he never can say definitely and consistently what it is that he really

wishes and wills. The reason of this is that all the elements which belong to the notion of happiness are

altogether empirical, i.e., they must be borrowed from experience, and nevertheless the idea of happiness

requires an absolute whole, a maximum of welfare in my present and all future circumstances. Now it is

impossible that the most clearsighted and at the same time most powerful being (supposed finite) should

frame to himself a definite conception of what he really wills in this. Does he will riches, how much anxiety,

envy, and snares might he not thereby draw upon his shoulders? Does he will knowledge and discernment,

perhaps it might prove to be only an eye so much the sharper to show him so much the more fearfully the

evils that are now concealed from him, and that cannot be avoided, or to impose more wants on his desires,

which already give him concern enough. Would he have long life? who guarantees to him that it would not be

a long misery? would he at least have health? how often has uneasiness of the body restrained from excesses

into which perfect health would have allowed one to fall? and so on. In short, he is unable, on any principle,

to determine with certainty what would make him truly happy; because to do so he would need to be

omniscient. We cannot therefore act on any definite principles to secure happiness, but only on empirical

counsels, e.g. of regimen, frugality, courtesy, reserve, etc., which experience teaches do, on the average, most

promote wellbeing. Hence it follows that the imperatives of prudence do not, strictly speaking, command at

all, that is, they cannot present actions objectively as practically necessary; that they are rather to be regarded

as counsels (consilia) than precepts precepts of reason, that the problem to determine certainly and

universally what action would promote the happiness of a rational being is completely insoluble, and

consequently no imperative respecting it is possible which should, in the strict sense, command to do what

makes happy; because happiness is not an ideal of reason but of imagination, resting solely on empirical

grounds, and it is vain to expect that these should define an action by which one could attain the totality of a

series of consequences which is really endless. This imperative of prudence would however be an analytical

proposition if we assume that the means to happiness could be certainly assigned; for it is distinguished from

the imperative of skill only by this, that in the latter the end is merely possible, in the former it is given; as

however both only ordain the means to that which we suppose to be willed as an end, it follows that the

imperative which ordains the willing of the means to him who wills the end is in both cases analytical. Thus

there is no difficulty in regard to the possibility of an imperative of this kind either.

On the other hand, the question how the imperative of morality is possible, is undoubtedly one, the only one,

demanding a solution, as this is not at all hypothetical, and the objective necessity which it presents cannot

rest on any hypothesis, as is the case with the hypothetical imperatives. Only here we must never leave out of

consideration that we cannot make out by any example, in other words empirically, whether there is such an

imperative at all, but it is rather to be feared that all those which seem to be categorical may yet be at bottom

hypothetical. For instance, when the precept is: "Thou shalt not promise deceitfully"; and it is assumed that

the necessity of this is not a mere counsel to avoid some other evil, so that it should mean: "Thou shalt not

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 16

make a lying promise, lest if it become known thou shouldst destroy thy credit," but that an action of this kind

must be regarded as evil in itself, so that the imperative of the prohibition is categorical; then we cannot show

with certainty in any example that the will was determined merely by the law, without any other spring of

action, although it may appear to be so. For it is always possible that fear of disgrace, perhaps also obscure

dread of other dangers, may have a secret influence on the will. Who can prove by experience the

nonexistence of a cause when all that experience tells us is that we do not perceive it? But in such a case the

socalled moral imperative, which as such appears to be categorical and unconditional, would in reality be

only a pragmatic precept, drawing our attention to our own interests and merely teaching us to take these into

We shall therefore have to investigate a priori the possibility of a categorical imperative, as we have not in

this case the advantage of its reality being given in experience, so that [the elucidation of] its possibility

should be requisite only for its explanation, not for its establishment. In the meantime it may be discerned

beforehand that the categorical imperative alone has the purport of a practical law; all the rest may indeed be

called principles of the will but not laws, since whatever is only necessary for the attainment of some

arbitrary purpose may be considered as in itself contingent, and we can at any time be free from the precept if

we give up the purpose; on the contrary, the unconditional command leaves the will no liberty to choose the

opposite; consequently it alone carries with it that necessity which we require in a law.

Secondly, in the case of this categorical imperative or law of morality, the difficulty (of discerning its

possibility) is a very profound one. It is an a priori synthetical practical proposition;* and as there is so much

difficulty in discerning the possibility of speculative propositions of this kind, it may readily be supposed that

*I connect the act with the will without presupposing any condition resulting from any inclination, but a

priori, and therefore necessarily (though only objectively, i.e., assuming the idea of a reason possessing full

power over all subjective motives). This is accordingly a practical proposition which does not deduce the

willing of an action by mere analysis from another already presupposed (for we have not such a perfect will),

but connects it immediately with the conception of the will of a rational being, as something not contained in

In this problem we will first inquire whether the mere conception of a categorical imperative may not perhaps

supply us also with the formula of it, containing the proposition which alone can be a categorical imperative;

for even if we know the tenor of such an absolute command, yet how it is possible will require further special

When I conceive a hypothetical imperative, in general I do not know beforehand what it will contain until I

am given the condition. But when I conceive a categorical imperative, I know at once what it contains. For as

the imperative contains besides the law only the necessity that the maxims* shall conform to this law, while

the law contains no conditions restricting it, there remains nothing but the general statement that the maxim

of the action should conform to a universal law, and it is this conformity alone that the imperative properly

*A maxim is a subjective principle of action, and must be distinguished from the objective principle, namely,

practical law. The former contains the practical rule set by reason according to the conditions of the subject

(often its ignorance or its inclinations), so that it is the principle on which the subject acts; but the law is the

objective principle valid for every rational being, and is the principle on which it ought to act that is an

There is therefore but one categorical imperative, namely, this: Act only on that maxim whereby thou canst at

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Now if all imperatives of duty can be deduced from this one imperative as from their principle, then, although

it should remain undecided what is called duty is not merely a vain notion, yet at least we shall be able to

Since the universality of the law according to which effects are produced constitutes what is properly called

nature in the most general sense (as to form), that is the existence of things so far as it is determined by

general laws, the imperative of duty may be expressed thus: Act as if the maxim of thy action were to become

We will now enumerate a few duties, adopting the usual division of them into duties to ourselves and

*It must be noted here that I reserve the division of duties for a future metaphysic of morals; so that I give it

here only as an arbitrary one (in order to arrange my examples). For the rest, I understand by a perfect duty

one that admits no exception in favour of inclination and then I have not merely external but also internal

perfect duties. This is contrary to the use of the word adopted in the schools; but I do not intend to justify

1. A man reduced to despair by a series of misfortunes feels wearied of life, but is still so far in possession of

his reason that he can ask himself whether it would not be contrary to his duty to himself to take his own life.

Now he inquires whether the maxim of his action could become a universal law of nature. His maxim is:

"From selflove I adopt it as a principle to shorten my life when its longer duration is likely to bring more

evil than satisfaction." It is asked then simply whether this principle founded on selflove can become a

universal law of nature. Now we see at once that a system of nature of which it should be a law to destroy life

by means of the very feeling whose special nature it is to impel to the improvement of life would contradict

itself and, therefore, could not exist as a system of nature; hence that maxim cannot possibly exist as a

universal law of nature and, consequently, would be wholly inconsistent with the supreme principle of all

2. Another finds himself forced by necessity to borrow money. He knows that he will not be able to repay it,

but sees also that nothing will be lent to him unless he promises stoutly to repay it in a definite time. He

desires to make this promise, but he has still so much conscience as to ask himself: "Is it not unlawful and

inconsistent with duty to get out of a difficulty in this way?" Suppose however that he resolves to do so: then

the maxim of his action would be expressed thus: "When I think myself in want of money, I will borrow

money and promise to repay it, although I know that I never can do so." Now this principle of selflove or of

one's own advantage may perhaps be consistent with my whole future welfare; but the question now is, "Is it

right?" I change then the suggestion of selflove into a universal law, and state the question thus: "How

would it be if my maxim were a universal law?" Then I see at once that it could never hold as a universal law

of nature, but would necessarily contradict itself. For supposing it to be a universal law that everyone when

he thinks himself in a difficulty should be able to promise whatever he pleases, with the purpose of not

keeping his promise, the promise itself would become impossible, as well as the end that one might have in

view in it, since no one would consider that anything was promised to him, but would ridicule all such

3. A third finds in himself a talent which with the help of some culture might make him a useful man in many

respects. But he finds himself in comfortable circumstances and prefers to indulge in pleasure rather than to

take pains in enlarging and improving his happy natural capacities. He asks, however, whether his maxim of

neglect of his natural gifts, besides agreeing with his inclination to indulgence, agrees also with what is called

duty. He sees then that a system of nature could indeed subsist with such a universal law although men (like

the South Sea islanders) should let their talents rest and resolve to devote their lives merely to idleness,

amusement, and propagation of their species in a word, to enjoyment; but he cannot possibly will that this

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should be a universal law of nature, or be implanted in us as such by a natural instinct. For, as a rational

being, he necessarily wills that his faculties be developed, since they serve him and have been given him, for

4. A fourth, who is in prosperity, while he sees that others have to contend with great wretchedness and that

he could help them, thinks: "What concern is it of mine? Let everyone be as happy as Heaven pleases, or as

be can make himself; I will take nothing from him nor even envy him, only I do not wish to contribute

anything to his welfare or to his assistance in distress!" Now no doubt if such a mode of thinking were a

universal law, the human race might very well subsist and doubtless even better than in a state in which

everyone talks of sympathy and goodwill, or even takes care occasionally to put it into practice, but, on the

other side, also cheats when he can, betrays the rights of men, or otherwise violates them. But although it is

possible that a universal law of nature might exist in accordance with that maxim, it is impossible to will that

such a principle should have the universal validity of a law of nature. For a will which resolved this would

contradict itself, inasmuch as many cases might occur in which one would have need of the love and

sympathy of others, and in which, by such a law of nature, sprung from his own will, he would deprive

These are a few of the many actual duties, or at least what we regard as such, which obviously fall into two

classes on the one principle that we have laid down. We must be able to will that a maxim of our action

should be a universal law. This is the canon of the moral appreciation of the action generally. Some actions

are of such a character that their maxim cannot without contradiction be even conceived as a universal law of

nature, far from it being possible that we should will that it should be so. In others this intrinsic impossibility

is not found, but still it is impossible to will that their maxim should be raised to the universality of a law of

nature, since such a will would contradict itself It is easily seen that the former violate strict or rigorous

(inflexible) duty; the latter only laxer (meritorious) duty. Thus it has been completely shown how all duties

depend as regards the nature of the obligation (not the object of the action) on the same principle.

If now we attend to ourselves on occasion of any transgression of duty, we shall find that we in fact do not

will that our maxim should be a universal law, for that is impossible for us; on the contrary, we will that the

opposite should remain a universal law, only we assume the liberty of making an exception in our own favour

or (just for this time only) in favour of our inclination. Consequently if we considered all cases from one and

the same point of view, namely, that of reason, we should find a contradiction in our own will, namely, that a

certain principle should be objectively necessary as a universal law, and yet subjectively should not be

universal, but admit of exceptions. As however we at one moment regard our action from the point of view of

a will wholly conformed to reason, and then again look at the same action from the point of view of a will

affected by inclination, there is not really any contradiction, but an antagonism of inclination to the precept of

reason, whereby the universality of the principle is changed into a mere generality, so that the practical

principle of reason shall meet the maxim half way. Now, although this cannot be justified in our own

impartial judgement, yet it proves that we do really recognise the validity of the categorical imperative and

(with all respect for it) only allow ourselves a few exceptions, which we think unimportant and forced from

We have thus established at least this much, that if duty is a conception which is to have any import and real

legislative authority for our actions, it can only be expressed in categorical and not at all in hypothetical

imperatives. We have also, which is of great importance, exhibited clearly and definitely for every practical

application the content of the categorical imperative, which must contain the principle of all duty if there is

such a thing at all. We have not yet, however, advanced so far as to prove a priori that there actually is such

an imperative, that there is a practical law which commands absolutely of itself and without any other

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With the view of attaining to this, it is of extreme importance to remember that we must not allow ourselves

to think of deducing the reality of this principle from the particular attributes of human nature. For duty is to

be a practical, unconditional necessity of action; it must therefore hold for all rational beings (to whom an

imperative can apply at all), and for this reason only be also a law for all human wills. On the contrary,

whatever is deduced from the particular natural characteristics of humanity, from certain feelings and

propensions, nay, even, if possible, from any particular tendency proper to human reason, and which need not

necessarily hold for the will of every rational being; this may indeed supply us with a maxim, but not with a

law; with a subjective principle on which we may have a propension and inclination to act, but not with an

objective principle on which we should be enjoined to act, even though all our propensions, inclinations, and

natural dispositions were opposed to it. In fact, the sublimity and intrinsic dignity of the command in duty are

so much the more evident, the less the subjective impulses favour it and the more they oppose it, without

being able in the slightest degree to weaken the obligation of the law or to diminish its validity.

Here then we see philosophy brought to a critical position, since it has to be firmly fixed, notwithstanding

that it has nothing to support it in heaven or earth. Here it must show its purity as absolute director of its own

laws, not the herald of those which are whispered to it by an implanted sense or who knows what tutelary

nature. Although these may be better than nothing, yet they can never afford principles dictated by reason,

which must have their source wholly a priori and thence their commanding authority, expecting everything

from the supremacy of the law and the due respect for it, nothing from inclination, or else condemning the

Thus every empirical element is not only quite incapable of being an aid to the principle of morality, but is

even highly prejudicial to the purity of morals, for the proper and inestimable worth of an absolutely good

will consists just in this, that the principle of action is free from all influence of contingent grounds, which

alone experience can furnish. We cannot too much or too often repeat our warning against this lax and even

mean habit of thought which seeks for its principle amongst empirical motives and laws; for human reason in

its weariness is glad to rest on this pillow, and in a dream of sweet illusions (in which, instead of Juno, it

embraces a cloud) it substitutes for morality a bastard patched up from limbs of various derivation, which

looks like anything one chooses to see in it, only not like virtue to one who has once beheld her in her true

*To behold virtue in her proper form is nothing else but to contemplate morality stripped of all admixture of

sensible things and of every spurious ornament of reward or selflove. How much she then eclipses

everything else that appears charming to the affections, every one may readily perceive with the least exertion

The question then is this: "Is it a necessary law for all rational beings that they should always judge of their

actions by maxims of which they can themselves will that they should serve as universal laws?" If it is so,

then it must be connected (altogether a priori) with the very conception of the will of a rational being

generally. But in order to discover this connexion we must, however reluctantly, take a step into metaphysic,

although into a domain of it which is distinct from speculative philosophy, namely, the metaphysic of morals.

In a practical philosophy, where it is not the reasons of what happens that we have to ascertain, but the laws

of what ought to happen, even although it never does, i.e., objective practical laws, there it is not necessary to

inquire into the reasons why anything pleases or displeases, how the pleasure of mere sensation differs from

taste, and whether the latter is distinct from a general satisfaction of reason; on what the feeling of pleasure or

pain rests, and how from it desires and inclinations arise, and from these again maxims by the cooperation

of reason: for all this belongs to an empirical psychology, which would constitute the second part of physics,

if we regard physics as the philosophy of nature, so far as it is based on empirical laws. But here we are

concerned with objective practical laws and, consequently, with the relation of the will to itself so far as it is

determined by reason alone, in which case whatever has reference to anything empirical is necessarily

excluded; since if reason of itself alone determines the conduct (and it is the possibility of this that we are

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 20

The will is conceived as a faculty of determining oneself to action in accordance with the conception of

certain laws. And such a faculty can be found only in rational beings. Now that which serves the will as the

objective ground of its selfdetermination is the end, and, if this is assigned by reason alone, it must hold for

all rational beings. On the other hand, that which merely contains the ground of possibility of the action of

which the effect is the end, this is called the means. The subjective ground of the desire is the spring, the

objective ground of the volition is the motive; hence the distinction between subjective ends which rest on

springs, and objective ends which depend on motives valid for every rational being. Practical principles are

formal when they abstract from all subjective ends; they are material when they assume these, and therefore

particular springs of action. The ends which a rational being proposes to himself at pleasure as effects of his

actions (material ends) are all only relative, for it is only their relation to the particular desires of the subject

that gives them their worth, which therefore cannot furnish principles universal and necessary for all rational

beings and for every volition, that is to say practical laws. Hence all these relative ends can give rise only to

Supposing, however, that there were something whose existence has in itself an absolute worth, something

which, being an end in itself, could be a source of definite laws; then in this and this alone would lie the

Now I say: man and generally any rational being exists as an end in himself, not merely as a means to be

arbitrarily used by this or that will, but in all his actions, whether they concern himself or other rational

beings, must be always regarded at the same time as an end. All objects of the inclinations have only a

conditional worth, for if the inclinations and the wants founded on them did not exist, then their object would

be without value. But the inclinations, themselves being sources of want, are so far from having an absolute

worth for which they should be desired that on the contrary it must be the universal wish of every rational

being to be wholly free from them. Thus the worth of any object which is to be acquired by our action is

always conditional. Beings whose existence depends not on our will but on nature's, have nevertheless, if

they are irrational beings, only a relative value as means, and are therefore called things; rational beings, on

the contrary, are called persons, because their very nature points them out as ends in themselves, that is as

something which must not be used merely as means, and so far therefore restricts freedom of action (and is an

object of respect). These, therefore, are not merely subjective ends whose existence has a worth for us as an

effect of our action, but objective ends, that is, things whose existence is an end in itself; an end moreover for

which no other can be substituted, which they should subserve merely as means, for otherwise nothing

whatever would possess absolute worth; but if all worth were conditioned and therefore contingent, then there

If then there is a supreme practical principle or, in respect of the human will, a categorical imperative, it must

be one which, being drawn from the conception of that which is necessarily an end for everyone because it is

an end in itself, constitutes an objective principle of will, and can therefore serve as a universal practical law.

The foundation of this principle is: rational nature exists as an end in itself. Man necessarily conceives his

own existence as being so; so far then this is a subjective principle of human actions. But every other rational

being regards its existence similarly, just on the same rational principle that holds for me:* so that it is at the

same time an objective principle, from which as a supreme practical law all laws of the will must be capable

of being deduced. Accordingly the practical imperative will be as follows: So act as to treat humanity,

whether in thine own person or in that of any other, in every case as an end withal, never as means only. We

*This proposition is here stated as a postulate. The ground of it will be found in the concluding section.

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Firstly, under the head of necessary duty to oneself: He who contemplates suicide should ask himself whether

his action can be consistent with the idea of humanity as an end in itself. If he destroys himself in order to

escape from painful circumstances, he uses a person merely as a mean to maintain a tolerable condition up to

the end of life. But a man is not a thing, that is to say, something which can be used merely as means, but

must in all his actions be always considered as an end in himself. I cannot, therefore, dispose in any way of a

man in my own person so as to mutilate him, to damage or kill him. (It belongs to ethics proper to define this

principle more precisely, so as to avoid all misunderstanding, e. g., as to the amputation of the limbs in order

to preserve myself, as to exposing my life to danger with a view to preserve it, etc. This question is therefore

Secondly, as regards necessary duties, or those of strict obligation, towards others: He who is thinking of

making a lying promise to others will see at once that he would be using another man merely as a mean,

without the latter containing at the same time the end in himself. For he whom I propose by such a promise to

use for my own purposes cannot possibly assent to my mode of acting towards him and, therefore, cannot

himself contain the end of this action. This violation of the principle of humanity in other men is more

obvious if we take in examples of attacks on the freedom and property of others. For then it is clear that he

who transgresses the rights of men intends to use the person of others merely as a means, without considering

that as rational beings they ought always to be esteemed also as ends, that is, as beings who must be capable

*Let it not be thought that the common "quod tibi non vis fieri, etc." could serve here as the rule or principle.

For it is only a deduction from the former, though with several limitations; it cannot be a universal law, for it

does not contain the principle of duties to oneself, nor of the duties of benevolence to others (for many a one

would gladly consent that others should not benefit him, provided only that he might be excused from

showing benevolence to them), nor finally that of duties of strict obligation to one another, for on this

principle the criminal might argue against the judge who punishes him, and so on.

Thirdly, as regards contingent (meritorious) duties to oneself: It is not enough that the action does not violate

humanity in our own person as an end in itself, it must also harmonize with it. Now there are in humanity

capacities of greater perfection, which belong to the end that nature has in view in regard to humanity in

ourselves as the subject: to neglect these might perhaps be consistent with the maintenance of humanity as an

Fourthly, as regards meritorious duties towards others: The natural end which all men have is their own

happiness. Now humanity might indeed subsist, although no one should contribute anything to the happiness

of others, provided he did not intentionally withdraw anything from it; but after all this would only harmonize

negatively not positively with humanity as an end in itself, if every one does not also endeavour, as far as in

him lies, to forward the ends of others. For the ends of any subject which is an end in himself ought as far as

possible to be my ends also, if that conception is to have its full effect with me.

This principle, that humanity and generally every rational nature is an end in itself (which is the supreme

limiting condition of every man's freedom of action), is not borrowed from experience, firstly, because it is

universal, applying as it does to all rational beings whatever, and experience is not capable of determining

anything about them; secondly, because it does not present humanity as an end to men (subjectively), that is

as an object which men do of themselves actually adopt as an end; but as an objective end, which must as a

law constitute the supreme limiting condition of all our subjective ends, let them be what we will; it must

therefore spring from pure reason. In fact the objective principle of all practical legislation lies (according to

the first principle) in the rule and its form of universality which makes it capable of being a law (say, e. g., a

law of nature); but the subjective principle is in the end; now by the second principle the subject of all ends is

each rational being, inasmuch as it is an end in itself. Hence follows the third practical principle of the will,

which is the ultimate condition of its harmony with universal practical reason, viz.: the idea of the will of

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On this principle all maxims are rejected which are inconsistent with the will being itself universal legislator.

Thus the will is not subject simply to the law, but so subject that it must be regarded as itself giving the law

and, on this ground only, subject to the law (of which it can regard itself as the author).

In the previous imperatives, namely, that based on the conception of the conformity of actions to general

laws, as in a physical system of nature, and that based on the universal prerogative of rational beings as ends

in themselves these imperatives, just because they were conceived as categorical, excluded from any share

in their authority all admixture of any interest as a spring of action; they were, however, only assumed to be

categorical, because such an assumption was necessary to explain the conception of duty. But we could not

prove independently that there are practical propositions which command categorically, nor can it be proved

in this section; one thing, however, could be done, namely, to indicate in the imperative itself, by some

determinate expression, that in the case of volition from duty all interest is renounced, which is the specific

criterion of categorical as distinguished from hypothetical imperatives. This is done in the present (third)

formula of the principle, namely, in the idea of the will of every rational being as a universally legislating

For although a will which is subject to laws may be attached to this law by means of an interest, yet a will

which is itself a supreme lawgiver so far as it is such cannot possibly depend on any interest, since a will so

dependent would itself still need another law restricting the interest of its selflove by the condition that it

Thus the principle that every human will is a will which in all its maxims gives universal laws,* provided it

be otherwise justified, would be very well adapted to be the categorical imperative, in this respect, namely,

that just because of the idea of universal legislation it is not based on interest, and therefore it alone among all

possible imperatives can be unconditional. Or still better, converting the proposition, if there is a categorical

imperative (i.e., a law for the will of every rational being), it can only command that everything be done from

maxims of one's will regarded as a will which could at the same time will that it should itself give universal

laws, for in that case only the practical principle and the imperative which it obeys are unconditional, since

*I may be excused from adducing examples to elucidate this principle, as those which have already been used

to elucidate the categorical imperative and its formula would all serve for the like purpose here.

Looking back now on all previous attempts to discover the principle of morality, we need not wonder why

they all failed. It was seen that man was bound to laws by duty, but it was not observed that the laws to which

he is subject are only those of his own giving, though at the same time they are universal, and that he is only

bound to act in conformity with his own will; a will, however, which is designed by nature to give universal

laws. For when one has conceived man only as subject to a law (no matter what), then this law required some

interest, either by way of attraction or constraint, since it did not originate as a law from his own will, but this

will was according to a law obliged by something else to act in a certain manner. Now by this necessary

consequence all the labour spent in finding a supreme principle of duty was irrevocably lost. For men never

elicited duty, but only a necessity of acting from a certain interest. Whether this interest was private or

otherwise, in any case the imperative must be conditional and could not by any means be capable of being a

moral command. I will therefore call this the principle of autonomy of the will, in contrast with every other

The conception of the will of every rational being as one which must consider itself as giving in all the

maxims of its will universal laws, so as to judge itself and its actions from this point of view this conception

leads to another which depends on it and is very fruitful, namely that of a kingdom of ends.

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By a kingdom I understand the union of different rational beings in a system by common laws. Now since it

is by laws that ends are determined as regards their universal validity, hence, if we abstract from the personal

differences of rational beings and likewise from all the content of their private ends, we shall be able to

conceive all ends combined in a systematic whole (including both rational beings as ends in themselves, and

also the special ends which each may propose to himself), that is to say, we can conceive a kingdom of ends,

For all rational beings come under the law that each of them must treat itself and all others never merely as

means, but in every case at the same time as ends in themselves. Hence results a systematic union of rational

being by common objective laws, i.e., a kingdom which may be called a kingdom of ends, since what these

laws have in view is just the relation of these beings to one another as ends and means. It is certainly only an

A rational being belongs as a member to the kingdom of ends when, although giving universal laws in it, he

is also himself subject to these laws. He belongs to it as sovereign when, while giving laws, he is not subject

A rational being must always regard himself as giving laws either as member or as sovereign in a kingdom of

ends which is rendered possible by the freedom of will. He cannot, however, maintain the latter position

merely by the maxims of his will, but only in case he is a completely independent being without wants and

Morality consists then in the reference of all action to the legislation which alone can render a kingdom of

ends possible. This legislation must be capable of existing in every rational being and of emanating from his

will, so that the principle of this will is never to act on any maxim which could not without contradiction be

also a universal law and, accordingly, always so to act that the will could at the same time regard itself as

giving in its maxims universal laws. If now the maxims of rational beings are not by their own nature

coincident with this objective principle, then the necessity of acting on it is called practical necessitation, i.e.,

duty. Duty does not apply to the sovereign in the kingdom of ends, but it does to every member of it and to

The practical necessity of acting on this principle, i.e., duty, does not rest at all on feelings, impulses, or

inclinations, but solely on the relation of rational beings to one another, a relation in which the will of a

rational being must always be regarded as legislative, since otherwise it could not be conceived as an end in

itself. Reason then refers every maxim of the will, regarding it as legislating universally, to every other will

and also to every action towards oneself; and this not on account of any other practical motive or any future

advantage, but from the idea of the dignity of a rational being, obeying no law but that which he himself also

In the kingdom of ends everything has either value or dignity. Whatever has a value can be replaced by

something else which is equivalent; whatever, on the other hand, is above all value, and therefore admits of

Whatever has reference to the general inclinations and wants of mankind has a market value; whatever,

without presupposing a want, corresponds to a certain taste, that is to a satisfaction in the mere purposeless

play of our faculties, has a fancy value; but that which constitutes the condition under which alone anything

can be an end in itself, this has not merely a relative worth, i.e., value, but an intrinsic worth, that is, dignity.

Now morality is the condition under which alone a rational being can be an end in himself, since by this alone

is it possible that he should be a legislating member in the kingdom of ends. Thus morality, and humanity as

capable of it, is that which alone has dignity. Skill and diligence in labour have a market value; wit, lively

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 24

imagination, and humour, have fancy value; on the other hand, fidelity to promises, benevolence from

principle (not from instinct), have an intrinsic worth. Neither nature nor art contains anything which in

default of these it could put in their place, for their worth consists not in the effects which spring from them,

not in the use and advantage which they secure, but in the disposition of mind, that is, the maxims of the will

which are ready to manifest themselves in such actions, even though they should not have the desired effect.

These actions also need no recommendation from any subjective taste or sentiment, that they may be looked

on with immediate favour and satisfaction: they need no immediate propension or feeling for them; they

exhibit the will that performs them as an object of an immediate respect, and nothing but reason is required to

impose them on the will; not to flatter it into them, which, in the case of duties, would be a contradiction.

This estimation therefore shows that the worth of such a disposition is dignity, and places it infinitely above

all value, with which it cannot for a moment be brought into comparison or competition without as it were

What then is it which justifies virtue or the morally good disposition, in making such lofty claims? It is

nothing less than the privilege it secures to the rational being of participating in the giving of universal laws,

by which it qualifies him to be a member of a possible kingdom of ends, a privilege to which he was already

destined by his own nature as being an end in himself and, on that account, legislating in the kingdom of

ends; free as regards all laws of physical nature, and obeying those only which he himself gives, and by

which his maxims can belong to a system of universal law, to which at the same time he submits himself. For

nothing has any worth except what the law assigns it. Now the legislation itself which assigns the worth of

everything must for that very reason possess dignity, that is an unconditional incomparable worth; and the

word respect alone supplies a becoming expression for the esteem which a rational being must have for it.

Autonomy then is the basis of the dignity of human and of every rational nature.

The three modes of presenting the principle of morality that have been adduced are at bottom only so many

formulae of the very same law, and each of itself involves the other two. There is, however, a difference in

them, but it is rather subjectively than objectively practical, intended namely to bring an idea of the reason

nearer to intuition (by means of a certain analogy) and thereby nearer to feeling. All maxims, in fact, have:

1. A form, consisting in universality; and in this view the formula of the moral imperative is expressed thus,

that the maxims must be so chosen as if they were to serve as universal laws of nature.

2. A matter, namely, an end, and here the formula says that the rational being, as it is an end by its own nature

and therefore an end in itself, must in every maxim serve as the condition limiting all merely relative and

3. A complete characterization of all maxims by means of that formula, namely, that all maxims ought by

their own legislation to harmonize with a possible kingdom of ends as with a kingdom of nature.* There is a

progress here in the order of the categories of unity of the form of the will (its universality), plurality of the

matter (the objects, i.e., the ends), and totality of the system of these. In forming our moral judgement of

actions, it is better to proceed always on the strict method and start from the general formula of the

categorical imperative: Act according to a maxim which can at the same time make itself a universal law. If,

however, we wish to gain an entrance for the moral law, it is very useful to bring one and the same action

under the three specified conceptions, and thereby as far as possible to bring it nearer to intuition.

*Teleology considers nature as a kingdom of ends; ethics regards a possible kingdom of ends as a kingdom

nature. In the first case, the kingdom of ends is a theoretical idea, adopted to explain what actually is. In the

latter it is a practical idea, adopted to bring about that which is not yet, but which can be realized by our

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 25

We can now end where we started at the beginning, namely, with the conception of a will unconditionally

good. That will is absolutely good which cannot be evil in other words, whose maxim, if made a universal

law, could never contradict itself. This principle, then, is its supreme law: "Act always on such a maxim as

thou canst at the same time will to be a universal law"; this is the sole condition under which a will can never

contradict itself; and such an imperative is categorical. Since the validity of the will as a universal law for

possible actions is analogous to the universal connexion of the existence of things by general laws, which is

the formal notion of nature in general, the categorical imperative can also be expressed thus: Act on maxims

which can at the same time have for their object themselves as universal laws of nature. Such then is the

Rational nature is distinguished from the rest of nature by this, that it sets before itself an end. This end would

be the matter of every good will. But since in the idea of a will that is absolutely good without being limited

by any condition (of attaining this or that end) we must abstract wholly from every end to be effected (since

this would make every will only relatively good), it follows that in this case the end must be conceived, not as

an end to be effected, but as an independently existing end. Consequently it is conceived only negatively, i.e.,

as that which we must never act against and which, therefore, must never be regarded merely as means, but

must in every volition be esteemed as an end likewise. Now this end can be nothing but the subject of all

possible ends, since this is also the subject of a possible absolutely good will; for such a will cannot without

contradiction be postponed to any other object. The principle: "So act in regard to every rational being

(thyself and others), that he may always have place in thy maxim as an end in himself," is accordingly

essentially identical with this other: "Act upon a maxim which, at the same time, involves its own universal

validity for every rational being." For that in using means for every end I should limit my maxim by the

condition of its holding good as a law for every subject, this comes to the same thing as that the fundamental

principle of all maxims of action must be that the subject of all ends, i.e., the rational being himself, be never

employed merely as means, but as the supreme condition restricting the use of all means, that is in every case

It follows incontestably that, to whatever laws any rational being may be subject, he being an end in himself

must be able to regard himself as also legislating universally in respect of these same laws, since it is just this

fitness of his maxims for universal legislation that distinguishes him as an end in himself; also it follows that

this implies his dignity (prerogative) above all mere physical beings, that he must always take his maxims

from the point of view which regards himself and, likewise, every other rational being as lawgiving beings

(on which account they are called persons). In this way a world of rational beings (mundus intelligibilis) is

possible as a kingdom of ends, and this by virtue of the legislation proper to all persons as members.

Therefore every rational being must so act as if he were by his maxims in every case a legislating member in

the universal kingdom of ends. The formal principle of these maxims is: "So act as if thy maxim were to

serve likewise as the universal law (of all rational beings)." A kingdom of ends is thus only possible on the

analogy of a kingdom of nature, the former however only by maxims, that is selfimposed rules, the latter

only by the laws of efficient causes acting under necessitation from without. Nevertheless, although the

system of nature is looked upon as a machine, yet so far as it has reference to rational beings as its ends, it is

given on this account the name of a kingdom of nature. Now such a kingdom of ends would be actually

realized by means of maxims conforming to the canon which the categorical imperative prescribes to all

rational beings, if they were universally followed. But although a rational being, even if he punctually follows

this maxim himself, cannot reckon upon all others being therefore true to the same, nor expect that the

kingdom of nature and its orderly arrangements shall be in harmony with him as a fitting member, so as to

form a kingdom of ends to which he himself contributes, that is to say, that it shall favour his expectation of

happiness, still that law: "Act according to the maxims of a member of a merely possible kingdom of ends

legislating in it universally," remains in its full force, inasmuch as it commands categorically. And it is just in

this that the paradox lies; that the mere dignity of man as a rational creature, without any other end or

advantage to be attained thereby, in other words, respect for a mere idea, should yet serve as an inflexible

precept of the will, and that it is precisely in this independence of the maxim on all such springs of action that

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 26

its sublimity consists; and it is this that makes every rational subject worthy to be a legislative member in the

kingdom of ends: for otherwise he would have to be conceived only as subject to the physical law of his

wants. And although we should suppose the kingdom of nature and the kingdom of ends to be united under

one sovereign, so that the latter kingdom thereby ceased to be a mere idea and acquired true reality, then it

would no doubt gain the accession of a strong spring, but by no means any increase of its intrinsic worth. For

this sole absolute lawgiver must, notwithstanding this, be always conceived as estimating the worth of

rational beings only by their disinterested behaviour, as prescribed to themselves from that idea [the dignity

of man] alone. The essence of things is not altered by their external relations, and that which, abstracting

from these, alone constitutes the absolute worth of man, is also that by which he must be judged, whoever the

judge may be, and even by the Supreme Being. Morality, then, is the relation of actions to the relation of

actions will, that is, to the autonomy of potential universal legislation by its maxims. An action that is

consistent with the autonomy of the will is permitted; one that does not agree therewith is forbidden. A will

whose maxims necessarily coincide with the laws of autonomy is a holy will, good absolutely. The

dependence of a will not absolutely good on the principle of autonomy (moral necessitation) is obligation.

This, then, cannot be applied to a holy being. The objective necessity of actions from obligation is called

From what has just been said, it is easy to see how it happens that, although the conception of duty implies

subjection to the law, we yet ascribe a certain dignity and sublimity to the person who fulfils all his duties.

There is not, indeed, any sublimity in him, so far as he is subject to the moral law; but inasmuch as in regard

to that very law he is likewise a legislator, and on that account alone subject to it, he has sublimity. We have

also shown above that neither fear nor inclination, but simply respect for the law, is the spring which can give

actions a moral worth. Our own will, so far as we suppose it to act only under the condition that its maxims

are potentially universal laws, this ideal will which is possible to us is the proper object of respect; and the

dignity of humanity consists just in this capacity of being universally legislative, though with the condition

Autonomy of the will is that property of it by which it is a law to itself (independently of any property of the

objects of volition). The principle of autonomy then is: "Always so to choose that the same volition shall

comprehend the maxims of our choice as a universal law." We cannot prove that this practical rule is an

imperative, i.e., that the will of every rational being is necessarily bound to it as a condition, by a mere

analysis of the conceptions which occur in it, since it is a synthetical proposition; we must advance beyond

the cognition of the objects to a critical examination of the subject, that is, of the pure practical reason, for

this synthetic proposition which commands apodeictically must be capable of being cognized wholly a priori.

This matter, however, does not belong to the present section. But that the principle of autonomy in question is

the sole principle of morals can be readily shown by mere analysis of the conceptions of morality. For by this

analysis we find that its principle must be a categorical imperative and that what this commands is neither

If the will seeks the law which is to determine it anywhere else than in the fitness of its maxims to be

universal laws of its own dictation, consequently if it goes out of itself and seeks this law in the character of

any of its objects, there always results heteronomy. The will in that case does not give itself the law, but it is

given by the object through its relation to the will. This relation, whether it rests on inclination or on

conceptions of reason, only admits of hypothetical imperatives: "I ought to do something because I wish for

something else." On the contrary, the moral, and therefore categorical, imperative says: "I ought to do so and

so, even though I should not wish for anything else." E.g., the former says: "I ought not to lie, if I would

retain my reputation"; the latter says: "I ought not to lie, although it should not bring me the least discredit."

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 27

The latter therefore must so far abstract from all objects that they shall have no influence on the will, in order

that practical reason (will) may not be restricted to administering an interest not belonging to it, but may

simply show its own commanding authority as the supreme legislation. Thus, e.g., I ought to endeavour to

promote the happiness of others, not as if its realization involved any concern of mine (whether by immediate

inclination or by any satisfaction indirectly gained through reason), but simply because a maxim which

excludes it cannot be comprehended as a universal law in one and the same volition.

Classification of all Principles of Morality which can be founded on the Conception of Heteronomy

Here as elsewhere human reason in its pure use, so long as it was not critically examined, has first tried all

All principles which can be taken from this point of view are either empirical or rational. The former, drawn

from the principle of happiness, are built on physical or moral feelings; the latter, drawn from the principle of

perfection, are built either on the rational conception of perfection as a possible effect, or on that of an

Empirical principles are wholly incapable of serving as a foundation for moral laws. For the universality with

which these should hold for all rational beings without distinction, the unconditional practical necessity

which is thereby imposed on them, is lost when their foundation is taken from the particular constitution of

human nature, or the accidental circumstances in which it is placed. The principle of private happiness,

however, is the most objectionable, not merely because it is false, and experience contradicts the supposition

that prosperity is always proportioned to good conduct, nor yet merely because it contributes nothing to the

establishment of morality since it is quite a different thing to make a prosperous man and a good man, or to

make one prudent and sharpsighted for his own interests and to make him virtuous but because the springs

it provides for morality are such as rather undermine it and destroy its sublimity, since they put the motives to

virtue and to vice in the same class and only teach us to make a better calculation, the specific difference

between virtue and vice being entirely extinguished. On the other hand, as to moral feeling, this supposed

special sense,* the appeal to it is indeed superficial when those who cannot think believe that feeling will

help them out, even in what concerns general laws: and besides, feelings, which naturally differ infinitely in

degree, cannot furnish a uniform standard of good and evil, nor has anyone a right to form judgements for

others by his own feelings: nevertheless this moral feeling is nearer to morality and its dignity in this respect,

that it pays virtue the honour of ascribing to her immediately the satisfaction and esteem we have for her and

does not, as it were, tell her to her face that we are not attached to her by her beauty but by profit.

*I class the principle of moral feeling under that of happiness, because every empirical interest promises to

contribute to our wellbeing by the agreeableness that a thing affords, whether it be immediately and without

a view to profit, or whether profit be regarded. We must likewise, with Hutcheson, class the principle of

Amongst the rational principles of morality, the ontological conception of perfection, notwithstanding its

defects, is better than the theological conception which derives morality from a Divine absolutely perfect

will. The former is, no doubt, empty and indefinite and consequently useless for finding in the boundless field

of possible reality the greatest amount suitable for us; moreover, in attempting to distinguish specifically the

reality of which we are now speaking from every other, it inevitably tends to turn in a circle and cannot avoid

tacitly presupposing the morality which it is to explain; it is nevertheless preferable to the theological view,

first, because we have no intuition of the divine perfection and can only deduce it from our own conceptions,

the most important of which is that of morality, and our explanation would thus be involved in a gross circle;

and, in the next place, if we avoid this, the only notion of the Divine will remaining to us is a conception

made up of the attributes of desire of glory and dominion, combined with the awful conceptions of might and

vengeance, and any system of morals erected on this foundation would be directly opposed to morality.

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 28

However, if I had to choose between the notion of the moral sense and that of perfection in general (two

systems which at least do not weaken morality, although they are totally incapable of serving as its

foundation), then I should decide for the latter, because it at least withdraws the decision of the question from

the sensibility and brings it to the court of pure reason; and although even here it decides nothing, it at all

events preserves the indefinite idea (of a will good in itself free from corruption, until it shall be more

For the rest I think I may be excused here from a detailed refutation of all these doctrines; that would only be

superfluous labour, since it is so easy, and is probably so well seen even by those whose office requires them

to decide for one of these theories (because their hearers would not tolerate suspension of judgement). But

what interests us more here is to know that the prime foundation of morality laid down by all these principles

is nothing but heteronomy of the will, and for this reason they must necessarily miss their aim.

In every case where an object of the will has to be supposed, in order that the rule may be prescribed which is

to determine the will, there the rule is simply heteronomy; the imperative is conditional, namely, if or because

one wishes for this object, one should act so and so: hence it can never command morally, that is,

categorically. Whether the object determines the will by means of inclination, as in the principle of private

happiness, or by means of reason directed to objects of our possible volition generally, as in the principle of

perfection, in either case the will never determines itself immediately by the conception of the action, but

only by the influence which the foreseen effect of the action has on the will; I ought to do something, on this

account, because I wish for something else; and here there must be yet another law assumed in me as its

subject, by which I necessarily will this other thing, and this law again requires an imperative to restrict this

maxim. For the influence which the conception of an object within the reach of our faculties can exercise on

the will of the subject, in consequence of its natural properties, depends on the nature of the subject, either the

sensibility (inclination and taste), or the understanding and reason, the employment of which is by the

peculiar constitution of their nature attended with satisfaction. It follows that the law would be, properly

speaking, given by nature, and, as such, it must be known and proved by experience and would consequently

be contingent and therefore incapable of being an apodeictic practical rule, such as the moral rule must be.

Not only so, but it is inevitably only heteronomy; the will does not give itself the law, but is given by a

foreign impulse by means of a particular natural constitution of the subject adapted to receive it. An

absolutely good will, then, the principle of which must be a categorical imperative, will be indeterminate as

regards all objects and will contain merely the form of volition generally, and that as autonomy, that is to say,

the capability of the maxims of every good will to make themselves a universal law, is itself the only law

which the will of every rational being imposes on itself, without needing to assume any spring or interest as a

How such a synthetical practical a priori proposition is possible, and why it is necessary, is a problem whose

solution does not lie within the bounds of the metaphysic of morals; and we have not here affirmed its truth,

much less professed to have a proof of it in our power. We simply showed by the development of the

universally received notion of morality that an autonomy of the will is inevitably connected with it, or rather

is its foundation. Whoever then holds morality to be anything real, and not a chimerical idea without any

truth, must likewise admit the principle of it that is here assigned. This section then, like the first, was merely

analytical. Now to prove that morality is no creation of the brain, which it cannot be if the categorical

imperative and with it the autonomy of the will is true, and as an a priori principle absolutely necessary, this

supposes the possibility of a synthetic use of pure practical reason, which however we cannot venture on

without first giving a critical examination of this faculty of reason. In the concluding section we shall give the

principal outlines of this critical examination as far as is sufficient for our purpose.

SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS 29

The will is a kind of causality belonging to living beings in so far as they are rational, and freedom would be

this property of such causality that it can be efficient, independently of foreign causes determining it; just as

physical necessity is the property that the causality of all irrational beings has of being determined to activity

The preceding definition of freedom is negative and therefore unfruitful for the discovery of its essence, but it

Since the conception of causality involves that of laws, according to which, by something that we call cause,

something else, namely the effect, must be produced; hence, although freedom is not a property of the will

depending on physical laws, yet it is not for that reason lawless; on the contrary it must be a causality acting

according to immutable laws, but of a peculiar kind; otherwise a free will would be an absurdity. Physical

necessity is a heteronomy of the efficient causes, for every effect is possible only according to this law, that

something else determines the efficient cause to exert its causality. What else then can freedom of the will be

but autonomy, that is, the property of the will to be a law to itself? But the proposition: "The will is in every

action a law to itself," only expresses the principle: "To act on no other maxim than that which can also have

as an object itself as a universal law." Now this is precisely the formula of the categorical imperative and is

the principle of morality, so that a free will and a will subject to moral laws are one and the same.

On the hypothesis, then, of freedom of the will, morality together with its principle follows from it by mere

analysis of the conception. However, the latter is a synthetic proposition; viz., an absolutely good will is that

whose maxim can always include itself regarded as a universal law; for this property of its maxim can never

be discovered by analysing the conception of an absolutely good will. Now such synthetic propositions are

only possible in this way: that the two cognitions are connected together by their union with a third in which

they are both to be found. The positive concept of freedom furnishes this third cognition, which cannot, as

with physical causes, be the nature of the sensible world (in the concept of which we find conjoined the

concept of something in relation as cause to something else as effect). We cannot now at once show what this

third is to which freedom points us and of which we have an idea a priori, nor can we make intelligible how

the concept of freedom is shown to be legitimate from principles of pure practical reason and with it the

possibility of a categorical imperative; but some further preparation is required.

It is not enough to predicate freedom of our own will, from Whatever reason, if we have not sufficient

grounds for predicating the same of all rational beings. For as morality serves as a law for us only because we

are rational beings, it must also hold for all rational beings; and as it must be deduced simply from the

property of freedom, it must be shown that freedom also is a property of all rational beings. It is not enough,

then, to prove it from certain supposed experiences of human nature (which indeed is quite impossible, and it

can only be shown a priori), but we must show that it belongs to the activity of all rational beings endowed

with a will. Now I say every being that cannot act except under the idea of freedom is just for that reason in a

practical point of view really free, that is to say, all laws which are inseparably connected with freedom have

the same force for him as if his will had been shown to be free in itself by a proof theoretically conclusive.*

Now I affirm that we must attribute to every rational being which has a will that it has also the idea of

freedom and acts entirely under this idea. For in such a being we conceive a reason that is practical, that is,

has causality in reference to its objects. Now we cannot possibly conceive a reason consciously receiving a

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 30

bias from any other quarter with respect to its judgements, for then the subject would ascribe the

determination of its judgement not to its own reason, but to an impulse. It must regard itself as the author of

its principles independent of foreign influences. Consequently as practical reason or as the will of a rational

being it must regard itself as free, that is to say, the will of such a being cannot be a will of its own except

under the idea of freedom. This idea must therefore in a practical point of view be ascribed to every rational

*I adopt this method of assuming freedom merely as an idea which rational beings suppose in their actions, in

order to avoid the necessity of proving it in its theoretical aspect also. The former is sufficient for my

purpose; for even though the speculative proof should not be made out, yet a being that cannot act except

with the idea of freedom is bound by the same laws that would oblige a being who was actually free. Thus we

We have finally reduced the definite conception of morality to the idea of freedom. This latter, however, we

could not prove to be actually a property of ourselves or of human nature; only we saw that it must be

presupposed if we would conceive a being as rational and conscious of its causality in respect of its actions,

i.e., as endowed with a will; and so we find that on just the same grounds we must ascribe to every being

endowed with reason and will this attribute of determining itself to action under the idea of its freedom.

Now it resulted also from the presupposition of these ideas that we became aware of a law that the subjective

principles of action, i.e., maxims, must always be so assumed that they can also hold as objective, that is,

universal principles, and so serve as universal laws of our own dictation. But why then should I subject

myself to this principle and that simply as a rational being, thus also subjecting to it all other being endowed

with reason? I will allow that no interest urges me to this, for that would not give a categorical imperative,

but I must take an interest in it and discern how this comes to pass; for this properly an "I ought" is properly

an "I would," valid for every rational being, provided only that reason determined his actions without any

hindrance. But for beings that are in addition affected as we are by springs of a different kind, namely,

sensibility, and in whose case that is not always done which reason alone would do, for these that necessity is

expressed only as an "ought," and the subjective necessity is different from the objective.

It seems then as if the moral law, that is, the principle of autonomy of the will, were properly speaking only

presupposed in the idea of freedom, and as if we could not prove its reality and objective necessity

independently. In that case we should still have gained something considerable by at least determining the

true principle more exactly than had previously been done; but as regards its validity and the practical

necessity of subjecting oneself to it, we should not have advanced a step. For if we were asked why the

universal validity of our maxim as a law must be the condition restricting our actions, and on what we ground

the worth which we assign to this manner of acting a worth so great that there cannot be any higher interest;

and if we were asked further how it happens that it is by this alone a man believes he feels his own personal

worth, in comparison with which that of an agreeable or disagreeable condition is to be regarded as nothing,

We find indeed sometimes that we can take an interest in a personal quality which does not involve any

interest of external condition, provided this quality makes us capable of participating in the condition in case

reason were to effect the allotment; that is to say, the mere being worthy of happiness can interest of itself

even without the motive of participating in this happiness. This judgement, however, is in fact only the effect

of the importance of the moral law which we before presupposed (when by the idea of freedom we detach

ourselves from every empirical interest); but that we ought to detach ourselves from these interests, i.e., to

consider ourselves as free in action and yet as subject to certain laws, so as to find a worth simply in our own

person which can compensate us for the loss of everything that gives worth to our condition; this we are not

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 31

yet able to discern in this way, nor do we see how it is possible so to act in other words, whence the moral

It must be freely admitted that there is a sort of circle here from which it seems impossible to escape. In the

order of efficient causes we assume ourselves free, in order that in the order of ends we may conceive

ourselves as subject to moral laws: and we afterwards conceive ourselves as subject to these laws, because we

have attributed to ourselves freedom of will: for freedom and selflegislation of will are both autonomy and,

therefore, are reciprocal conceptions, and for this very reason one must not be used to explain the other or

give the reason of it, but at most only logical purposes to reduce apparently different notions of the same

object to one single concept (as we reduce different fractions of the same value to the lowest terms).

One resource remains to us, namely, to inquire whether we do not occupy different points of view when by

means of freedom we think ourselves as causes efficient a priori, and when we form our conception of

It is a remark which needs no subtle reflection to make, but which we may assume that even the commonest

understanding can make, although it be after its fashion by an obscure discernment of judgement which it

calls feeling, that all the "ideas" that come to us involuntarily (as those of the senses) do not enable us to

know objects otherwise than as they affect us; so that what they may be in themselves remains unknown to

us, and consequently that as regards "ideas" of this kind even with the closest attention and clearness that the

understanding can apply to them, we can by them only attain to the knowledge of appearances, never to that

of things in themselves. As soon as this distinction has once been made (perhaps merely in consequence of

the difference observed between the ideas given us from without, and in which we are passive, and those that

we produce simply from ourselves, and in which we show our own activity), then it follows of itself that we

must admit and assume behind the appearance something else that is not an appearance, namely, the things in

themselves; although we must admit that as they can never be known to us except as they affect us, we can

come no nearer to them, nor can we ever know what they are in themselves. This must furnish a distinction,

however crude, between a world of sense and the world of understanding, of which the former may be

different according to the difference of the sensuous impressions in various observers, while the second

which is its basis always remains the same, Even as to himself, a man cannot pretend to know what he is in

himself from the knowledge he has by internal sensation. For as he does not as it were create himself, and

does not come by the conception of himself a priori but empirically, it naturally follows that he can obtain his

knowledge even of himself only by the inner sense and, consequently, only through the appearances of his

nature and the way in which his consciousness is affected. At the same time beyond these characteristics of

his own subject, made up of mere appearances, he must necessarily suppose something else as their basis,

namely, his ego, whatever its characteristics in itself may be. Thus in respect to mere perception and

receptivity of sensations he must reckon himself as belonging to the world of sense; but in respect of

whatever there may be of pure activity in him (that which reaches consciousness immediately and not

through affecting the senses), he must reckon himself as belonging to the intellectual world, of which,

however, he has no further knowledge. To such a conclusion the reflecting man must come with respect to all

the things which can be presented to him: it is probably to be met with even in persons of the commonest

understanding, who, as is well known, are very much inclined to suppose behind the objects of the senses

something else invisible and acting of itself. They spoil it, however, by presently sensualizing this invisible

again; that is to say, wanting to make it an object of intuition, so that they do not become a whit the wiser.

Now man really finds in himself a faculty by which he distinguishes himself from everything else, even from

himself as affected by objects, and that is reason. This being pure spontaneity is even elevated above the

understanding. For although the latter is a spontaneity and does not, like sense, merely contain intuitions that

arise when we are affected by things (and are therefore passive), yet it cannot produce from its activity any

other conceptions than those which merely serve to bring the intuitions of sense under rules and, thereby, to

unite them in one consciousness, and without this use of the sensibility it could not think at all; whereas, on

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 32

the contrary, reason shows so pure a spontaneity in the case of what I call ideas [ideal conceptions] that it

thereby far transcends everything that the sensibility can give it, and exhibits its most important function in

distinguishing the world of sense from that of understanding, and thereby prescribing the limits of the

For this reason a rational being must regard himself qua intelligence (not from the side of his lower faculties)

as belonging not to the world of sense, but to that of understanding; hence he has two points of view from

which he can regard himself, and recognise laws of the exercise of his faculties, and consequently of all his

actions: first, so far as he belongs to the world of sense, he finds himself subject to laws of nature

(heteronomy); secondly, as belonging to the intelligible world, under laws which being independent of nature

As a rational being, and consequently belonging to the intelligible world, man can never conceive the

causality of his own will otherwise than on condition of the idea of freedom, for independence of the

determinate causes of the sensible world (an independence which reason must always ascribe to itself) is

freedom. Now the idea of freedom is inseparably connected with the conception of autonomy, and this again

with the universal principle of morality which is ideally the foundation of all actions of rational beings, just

Now the suspicion is removed which we raised above, that there was a latent circle involved in our reasoning

from freedom to autonomy, and from this to the moral law, viz.: that we laid down the idea of freedom

because of the moral law only that we might afterwards in turn infer the latter from freedom, and that

consequently we could assign no reason at all for this law, but could only [present] it as a petitio principii

which well disposed minds would gladly concede to us, but which we could never put forward as a provable

proposition. For now we see that, when we conceive ourselves as free, we transfer ourselves into the world of

understanding as members of it and recognise the autonomy of the will with its consequence, morality;

whereas, if we conceive ourselves as under obligation, we consider ourselves as belonging to the world of

Every rational being reckons himself qua intelligence as belonging to the world of understanding, and it is

simply as an efficient cause belonging to that world that he calls his causality a will. On the other side he is

also conscious of himself as a part of the world of sense in which his actions, which are mere appearances

[phenomena] of that causality, are displayed; we cannot, however, discern how they are possible from this

causality which we do not know; but instead of that, these actions as belonging to the sensible world must be

viewed as determined by other phenomena, namely, desires and inclinations. If therefore I were only a

member of the world of understanding, then all my actions would perfectly conform to the principle of

autonomy of the pure will; if I were only a part of the world of sense, they would necessarily be assumed to

conform wholly to the natural law of desires and inclinations, in other words, to the heteronomy of nature.

(The former would rest on morality as the supreme principle, the latter on happiness.) Since, however, the

world of understanding contains the foundation of the world of sense, and consequently of its laws also, and

accordingly gives the law to my will (which belongs wholly to the world of understanding) directly, and must

be conceived as doing so, it follows that, although on the one side I must regard myself as a being belonging

to the world of sense, yet on the other side I must recognize myself as subject as an intelligence to the law of

the world of understanding, i.e., to reason, which contains this law in the idea of freedom, and therefore as

subject to the autonomy of the will: consequently I must regard the laws of the world of understanding as

And thus what makes categorical imperatives possible is this, that the idea of freedom makes me a member of

an intelligible world, in consequence of which, if I were nothing else, all my actions would always conform

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 33

to the autonomy of the will; but as I at the same time intuite myself as a member of the world of sense, they

ought so to conform, and this categorical "ought" implies a synthetic a priori proposition, inasmuch as

besides my will as affected by sensible desires there is added further the idea of the same will but as

belonging to the world of the understanding, pure and practical of itself, which contains the supreme

condition according to reason of the former will; precisely as to the intuitions of sense there are added

concepts of the understanding which of themselves signify nothing but regular form in general and in this

way synthetic a priori propositions become possible, on which all knowledge of physical nature rests.

The practical use of common human reason confirms this reasoning. There is no one, not even the most

consummate villain, provided only that be is otherwise accustomed to the use of reason, who, when we set

before him examples of honesty of purpose, of steadfastness in following good maxims, of sympathy and

general benevolence (even combined with great sacrifices of advantages and comfort), does not wish that he

might also possess these qualities. Only on account of his inclinations and impulses he cannot attain this in

himself, but at the same time he wishes to be free from such inclinations which are burdensome to himself.

He proves by this that he transfers himself in thought with a will free from the impulses of the sensibility into

an order of things wholly different from that of his desires in the field of the sensibility; since he cannot

expect to obtain by that wish any gratification of his desires, nor any position which would satisfy any of his

actual or supposable inclinations (for this would destroy the preeminence of the very idea which wrests that

wish from him): he can only expect a greater intrinsic worth of his own person. This better person, however,

he imagines himself to be when be transfers himself to the point of view of a member of the world of the

understanding, to which he is involuntarily forced by the idea of freedom, i.e., of independence on

determining causes of the world of sense; and from this point of view he is conscious of a good will, which

by his own confession constitutes the law for the bad will that he possesses as a member of the world of

sense a law whose authority he recognizes while transgressing it. What he morally "ought" is then what he

necessarily "would," as a member of the world of the understanding, and is conceived by him as an "ought"

only inasmuch as he likewise considers himself as a member of the world of sense.

All men attribute to themselves freedom of will. Hence come all judgements upon actions as being such as

ought to have been done, although they have not been done. However, this freedom is not a conception of

experience, nor can it be so, since it still remains, even though experience shows the contrary of what on

supposition of freedom are conceived as its necessary consequences. On the other side it is equally necessary

that everything that takes place should be fixedly determined according to laws of nature. This necessity of

nature is likewise not an empirical conception, just for this reason, that it involves the motion of necessity and

consequently of a priori cognition. But this conception of a system of nature is confirmed by experience; and

it must even be inevitably presupposed if experience itself is to be possible, that is, a connected knowledge of

the objects of sense resting on general laws. Therefore freedom is only an idea of reason, and its objective

reality in itself is doubtful; while nature is a concept of the understanding which proves, and must necessarily

There arises from this a dialectic of reason, since the freedom attributed to the will appears to contradict the

necessity of nature, and placed between these two ways reason for speculative purposes finds the road of

physical necessity much more beaten and more appropriate than that of freedom; yet for practical purposes

the narrow footpath of freedom is the only one on which it is possible to make use of reason in our conduct;

hence it is just as impossible for the subtlest philosophy as for the commonest reason of men to argue away

freedom. Philosophy must then assume that no real contradiction will be found between freedom and physical

necessity of the same human actions, for it cannot give up the conception of nature any more than that of

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 34

Nevertheless, even though we should never be able to comprehend how freedom is possible, we must at least

remove this apparent contradiction in a convincing manner. For if the thought of freedom contradicts either

itself or nature, which is equally necessary, it must in competition with physical necessity be entirely given

It would, however, be impossible to escape this contradiction if the thinking subject, which seems to itself

free, conceived itself in the same sense or in the very same relation when it calls itself free as when in respect

of the same action it assumes itself to be subject to the law of nature. Hence it is an indispensable problem of

speculative philosophy to show that its illusion respecting the contradiction rests on this, that we think of man

in a different sense and relation when we call him free and when we regard him as subject to the laws of

nature as being part and parcel of nature. It must therefore show that not only can both these very well

coexist, but that both must be thought as necessarily united in the same subject, since otherwise no reason

could be given why we should burden reason with an idea which, though it may possibly without

contradiction be reconciled with another that is sufficiently established, yet entangles us in a perplexity which

sorely embarrasses reason in its theoretic employment. This duty, however, belongs only to speculative

philosophy. The philosopher then has no option whether he will remove the apparent contradiction or leave it

untouched; for in the latter case the theory respecting this would be bonum vacans, into the possession of

which the fatalist would have a right to enter and chase all morality out of its supposed domain as occupying

We cannot however as yet say that we are touching the bounds of practical philosophy. For the settlement of

that controversy does not belong to it; it only demands from speculative reason that it should put an end to the

discord in which it entangles itself in theoretical questions, so that practical reason may have rest and security

from external attacks which might make the ground debatable on which it desires to build.

The claims to freedom of will made even by common reason are founded on the consciousness and the

admitted supposition that reason is independent of merely subjectively determined causes which together

constitute what belongs to sensation only and which consequently come under the general designation of

sensibility. Man considering himself in this way as an intelligence places himself thereby in a different order

of things and in a relation to determining grounds of a wholly different kind when on the one hand he thinks

of himself as an intelligence endowed with a will, and consequently with causality, and when on the other he

perceives himself as a phenomenon in the world of sense (as he really is also), and affirms that his causality is

subject to external determination according to laws of nature. Now he soon becomes aware that both can hold

good, nay, must hold good at the same time. For there is not the smallest contradiction in saying that a thing

in appearance (belonging to the world of sense) is subject to certain laws, of which the very same as a thing

or being in itself is independent, and that he must conceive and think of himself in this twofold way, rests as

to the first on the consciousness of himself as an object affected through the senses, and as to the second on

the consciousness of himself as an intelligence, i.e., as independent on sensible impressions in the

employment of his reason (in other words as belonging to the world of understanding).

Hence it comes to pass that man claims the possession of a will which takes no account of anything that

comes under the head of desires and inclinations and, on the contrary, conceives actions as possible to him,

nay, even as necessary which can only be done by disregarding all desires and sensible inclinations. The

causality of such actions lies in him as an intelligence and in the laws of effects and actions [which depend]

on the principles of an intelligible world, of which indeed he knows nothing more than that in it pure reason

alone independent of sensibility gives the law; moreover since it is only in that world, as an intelligence, that

he is his proper self (being as man only the appearance of himself), those laws apply to him directly and

categorically, so that the incitements of inclinations and appetites (in other words the whole nature of the

world of sense) cannot impair the laws of his volition as an intelligence. Nay, he does not even hold himself

responsible for the former or ascribe them to his proper self, i.e., his will: he only ascribes to his will any

indulgence which he might yield them if he allowed them to influence his maxims to the prejudice of the

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 35

When practical reason thinks itself into a world of understanding, it does not thereby transcend its own limits,

as it would if it tried to enter it by intuition or sensation. The former is only a negative thought in respect of

the world of sense, which does not give any laws to reason in determining the will and is positive only in this

single point that this freedom as a negative characteristic is at the same time conjoined with a (positive)

faculty and even with a causality of reason, which we designate a will, namely a faculty of so acting that the

principle of the actions shall conform to the essential character of a rational motive, i.e., the condition that the

maxim have universal validity as a law. But were it to borrow an object of will, that is, a motive, from the

world of understanding, then it would overstep its bounds and pretend to be acquainted with something of

which it knows nothing. The conception of a world of the understanding is then only a point of view which

reason finds itself compelled to take outside the appearances in order to conceive itself as practical, which

would not be possible if the influences of the sensibility had a determining power on man, but which is

necessary unless he is to be denied the consciousness of himself as an intelligence and, consequently, as a

rational cause, energizing by reason, that is, operating freely. This thought certainly involves the idea of an

order and a system of laws different from that of the mechanism of nature which belongs to the sensible

world; and it makes the conception of an intelligible world necessary (that is to say, the whole system of

rational beings as things in themselves). But it does not in the least authorize us to think of it further than as

to its formal condition only, that is, the universality of the maxims of the will as laws, and consequently the

autonomy of the latter, which alone is consistent with its freedom; whereas, on the contrary, all laws that refer

to a definite object give heteronomy, which only belongs to laws of nature and can only apply to the sensible

But reason would overstep all its bounds if it undertook to explain how pure reason can be practical, which

For we can explain nothing but that which we can reduce to laws, the object of which can be given in some

possible experience. But freedom is a mere idea, the objective reality of which can in no wise be shown

according to laws of nature, and consequently not in any possible experience; and for this reason it can never

be comprehended or understood, because we cannot support it by any sort of example or analogy. It holds

good only as a necessary hypothesis of reason in a being that believes itself conscious of a will, that is, of a

faculty distinct from mere desire (namely, a faculty of determining itself to action as an intelligence, in other

words, by laws of reason independently on natural instincts). Now where determination according to laws of

nature ceases, there all explanation ceases also, and nothing remains but defence, i.e., the removal of the

objections of those who pretend to have seen deeper into the nature of things, and thereupon boldly declare

freedom impossible. We can only point out to them that the supposed contradiction that they have discovered

in it arises only from this, that in order to be able to apply the law of nature to human actions, they must

necessarily consider man as an appearance: then when we demand of them that they should also think of him

qua intelligence as a thing in itself, they still persist in considering him in this respect also as an appearance.

In this view it would no doubt be a contradiction to suppose the causality of the same subject (that is, his will)

to be withdrawn from all the natural laws of the sensible world. But this contradiction disappears, if they

would only bethink themselves and admit, as is reasonable, that behind the appearances there must also lie at

their root (although hidden) the things in themselves, and that we cannot expect the laws of these to be the

The subjective impossibility of explaining the freedom of the will is identical with the impossibility of

discovering and explaining an interest* which man can take in the moral law. Nevertheless he does actually

take an interest in it, the basis of which in us we call the moral feeling, which some have falsely assigned as

the standard of our moral judgement, whereas it must rather be viewed as the subjective effect that the law

exercises on the will, the objective principle of which is furnished by reason alone.

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 36

*Interest is that by which reason becomes practical, i.e., a cause determining the will. Hence we say of

rational beings only that they take an interest in a thing; irrational beings only feel sensual appetites. Reason

takes a direct interest in action then only when the universal validity of its maxims is alone sufficient to

determine the will. Such an interest alone is pure. But if it can determine the will only by means of another

object of desire or on the suggestion of a particular feeling of the subject, then reason takes only an indirect

interest in the action, and, as reason by itself without experience cannot discover either objects of the will or a

special feeling actuating it, this latter interest would only be empirical and not a pure rational interest. The

logical interest of reason (namely, to extend its insight) is never direct, but presupposes purposes for which

In order indeed that a rational being who is also affected through the senses should will what reason alone

directs such beings that they ought to will, it is no doubt requisite that reason should have a power to infuse a

feeling of pleasure or satisfaction in the fulfilment of duty, that is to say, that it should have a causality by

which it determines the sensibility according to its own principles. But it is quite impossible to discern, i.e., to

make it intelligible a priori, how a mere thought, which itself contains nothing sensible, can itself produce a

sensation of pleasure or pain; for this is a particular kind of causality of which as of every other causality we

can determine nothing whatever a priori; we must only consult experience about it. But as this cannot supply

us with any relation of cause and effect except between two objects of experience, whereas in this case,

although indeed the effect produced lies within experience, yet the cause is supposed to be pure reason acting

through mere ideas which offer no object to experience, it follows that for us men it is quite impossible to

explain how and why the universality of the maxim as a law, that is, morality, interests. This only is certain,

that it is not because it interests us that it has validity for us (for that would be heteronomy and dependence of

practical reason on sensibility, namely, on a feeling as its principle, in which case it could never give moral

laws), but that it interests us because it is valid for us as men, inasmuch as it had its source in our will as

intelligences, in other words, in our proper self, and what belongs to mere appearance is necessarily

The question then, "How a categorical imperative is possible," can be answered to this extent, that we can

assign the only hypothesis on which it is possible, namely, the idea of freedom; and we can also discern the

necessity of this hypothesis, and this is sufficient for the practical exercise of reason, that is, for the

conviction of the validity of this imperative, and hence of the moral law; but how this hypothesis itself is

possible can never be discerned by any human reason. On the hypothesis, however, that the will of an

intelligence is free, its autonomy, as the essential formal condition of its determination, is a necessary

consequence. Moreover, this freedom of will is not merely quite possible as a hypothesis (not involving any

contradiction to the principle of physical necessity in the connexion of the phenomena of the sensible world)

as speculative philosophy can show: but further, a rational being who is conscious of causality through

reason, that is to say, of a will (distinct from desires), must of necessity make it practically, that is, in idea,

the condition of all his voluntary actions. But to explain how pure reason can be of itself practical without the

aid of any spring of action that could be derived from any other source, i.e., how the mere principle of the

universal validity of all its maxims as laws (which would certainly be the form of a pure practical reason) can

of itself supply a spring, without any matter (object) of the will in which one could antecedently take any

interest; and how it can produce an interest which would be called purely moral; or in other words, how pure

reason can be practical to explain this is beyond the power of human reason, and all the labour and pains of

It is just the same as if I sought to find out how freedom itself is possible as the causality of a will. For then I

quit the ground of philosophical explanation, and I have no other to go upon. I might indeed revel in the

world of intelligences which still remains to me, but although I have an idea of it which is well founded, yet I

have not the least knowledge of it, nor an I ever attain to such knowledge with all the efforts of my natural

faculty of reason. It signifies only a something that remains over when I have eliminated everything

belonging to the world of sense from the actuating principles of my will, serving merely to keep in bounds

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 37

the principle of motives taken from the field of sensibility; fixing its limits and showing that it does not

contain all in all within itself, but that there is more beyond it; but this something more I know no further. Of

pure reason which frames this ideal, there remains after the abstraction of all matter, i.e., knowledge of

objects, nothing but the form, namely, the practical law of the universality of the maxims, and in conformity

with this conception of reason in reference to a pure world of understanding as a possible efficient cause, that

is a cause determining the will. There must here be a total absence of springs; unless this idea of an

intelligible world is itself the spring, or that in which reason primarily takes an interest; but to make this

Here now is the extreme limit of all moral inquiry, and it is of great importance to determine it even on this

account, in order that reason may not on the one band, to the prejudice of morals, seek about in the world of

sense for the supreme motive and an interest comprehensible but empirical; and on the other hand, that it may

not impotently flap its wings without being able to move in the (for it) empty space of transcendent concepts

which we call the intelligible world, and so lose itself amidst chimeras. For the rest, the idea of a pure world

of understanding as a system of all intelligences, and to which we ourselves as rational beings belong

(although we are likewise on the other side members of the sensible world), this remains always a useful and

legitimate idea for the purposes of rational belief, although all knowledge stops at its threshold, useful,

namely, to produce in us a lively interest in the moral law by means of the noble ideal of a universal kingdom

of ends in themselves (rational beings), to which we can belong as members then only when we carefully

conduct ourselves according to the maxims of freedom as if they were laws of nature.

The speculative employment of reason with respect to nature leads to the absolute necessity of some supreme

cause of the world: the practical employment of reason with a view to freedom leads also to absolute

necessity, but only of the laws of the actions of a rational being as such. Now it is an essential principle of

reason, however employed, to push its knowledge to a consciousness of its necessity (without which it would

not be rational knowledge). It is, however, an equally essential restriction of the same reason that it can

neither discern the necessity of what is or what happens, nor of what ought to happen, unless a condition is

supposed on which it is or happens or ought to happen. In this way, however, by the constant inquiry for the

condition, the satisfaction of reason is only further and further postponed. Hence it unceasingly seeks the

unconditionally necessary and finds itself forced to assume it, although without any means of making it

comprehensible to itself, happy enough if only it can discover a conception which agrees with this

assumption. It is therefore no fault in our deduction of the supreme principle of morality, but an objection that

should be made to human reason in general, that it cannot enable us to conceive the absolute necessity of an

unconditional practical law (such as the categorical imperative must be). It cannot be blamed for refusing to

explain this necessity by a condition, that is to say, by means of some interest assumed as a basis, since the

law would then cease to be a supreme law of reason. And thus while we do not comprehend the practical

unconditional necessity of the moral imperative, we yet comprehend its incomprehensibility, and this is all

that can be fairly demanded of a philosophy which strives to carry its principles up to the very limit of human

THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON 38

5. FIRST SECTION. TRANSITION FROM THE COMMON RATIONAL KNOWLEDGE OF MORALITY TO THE PHILOSOPHICAL, page = 7

6. SECOND SECTION. TRANSITION FROM POPULAR MORAL PHILOSOPHY TO THE METAPHYSIC OF MORALS, page = 13

7. THIRD SECTION. TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE PRACTICAL REASON, page = 33