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 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 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； n