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 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 understanding

itself.

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 have their foundation not in experience but in reason alone.

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 as the law of nature is of all phenomena.

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 sense and at the same time to

the world of understanding.

How is a Categorical Imperative Possible?

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

imperatives for me and the actions which conform to them as duties.

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 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 he 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 pre-eminence 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.

Of the Extreme Limits of all Practical Philosophy.

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 prove, its reality in examples of experience.

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 freedom.

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 up.

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 co-exist, 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

it without title.

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 rational laws of the

will.

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 world.

But reason would overstep all its bounds if it undertook to

explain how pure reason can be practical, which would be exactly the

same problem as to explain how freedom is possible.

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 same as those that govern their appearances.

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.

* 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 reason is employed.

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 subordinated by reason to the nature

of the thing in itself.

Fundamental Principles of the Metaphysic of Morals · 第 6 / 7 段