intellectual intuition； to wit； which does not； however； belong to us；
of the very possibility of which we have no notion… and this is a
noumenon in the positive sense。
The doctrine of sensibility is also the doctrine of noumena in the
negative sense； that is； of things which the understanding is
obliged to cogitate apart from any relation to our mode of
intuition； consequently not as mere phenomena； but as things in
themselves。 But the understanding at the same time prehends that it
cannot employ its categories for the consideration of things in
themselves； because these possess significance only in relation to the
unity of intuitions in space and time； and that they are petent
to determine this unity by means of general a priori connecting
conceptions only on account of the pure ideality of space and time。
Where this unity of time is not to be met with； as is the case with
noumena； the whole use； indeed the whole meaning of the categories
is entirely lost； for even the possibility of things to correspond
to the categories is in this case inprehensible。 On this point； I
need only refer the reader to what I have said at the mencement
of the General Remark appended to the foregoing chapter。 Now； the
possibility of a thing can never be proved from the fact that the
conception of it is not self…contradictory； but only by means of an
intuition corresponding to the conception。 If； therefore； we wish to
apply the categories to objects which cannot be regarded as phenomena；
we must have an intuition different from the sensuous； and in this
case the objects would be a noumena in the positive sense of the word。
Now； as such an intuition； that is； an intellectual intuition； is no
part of our faculty of cognition； it is absolutely impossible for
the categories to possess any application beyond the limits of
experience。 It may be true that there are intelligible existences to
which our faculty of sensuous intuition has no relation； and cannot be
applied； but our conceptions of the understanding； as mere forms of
thought for our sensuous intuition； do not extend to these。 What；
therefore； we call noumenon must be understood by us as such in a
negative sense。
If I take away from an empirial intuition all thought （by means of
the categories）； there remains no cognition of any object； for by
means of mere intuition nothing is cogitated； and； from the
existence of such or such an affection of sensibility in me； it does
not follow that this affection or representation has any relation to
an object without me。 But if I take away all intuition； there still
remains the form of thought； that is； the mode of determining an
object for the manifold of a possible intuition。 Thus the categories
do in some measure really extend further than sensuous intuition；
inasmuch as they think objects in general； without regard to the
mode （of sensibility） in which these objects are given。 But they do
not for this reason apply to and determine a wider sphere of
objects； because we cannot assume that such can be given； without
presupposing the possibility of another than the sensuous mode of
intuition； a supposition we are not justified in making。
I call a conception problematical which contains in itself no
contradiction； and which is connected with other cognitions as a
limitation of given conceptions； but whose objective reality cannot be
cognized in any manner。 The conception of a noumenon； that is； of a
thing which must be cogitated not as an object of sense； but as a
thing in itself （solely through the pure understanding）； is not
self…contradictory； for we are not entitled to maintain that
sensibility is the only possible mode of intuition。 Nay； further； this
conception is necessary to restrain sensuous intuition within the
bounds of phenomena； and thus to limit the objective validity of
sensuous cognition； for things in themselves； which lie beyond its
province； are called noumena for the very purpose of indicating that
this cognition does not extend its application to all that the
understanding thinks。 But； after all； the possibility of such
noumena is quite inprehensible； and beyond the sphere of phenomena；
all is for us a mere void； that is to say； we possess an understanding
whose province does problematically extend beyond this sphere； but
we do not possess an intuition； indeed； not even the conception of a
possible intuition； by means of which objects beyond the region of
sensibility could be given us； and in reference to which the
understanding might be employed assertorically。 The conception of a
noumenon is therefore merely a limitative conception and therefore
only of negative use。 But it is not an arbitrary or fictitious notion；
but is connected with the limitation of sensibility； without； however；
being capable of presenting us with any positive datum beyond this
sphere。
The division of objects into phenomena and noumena； and of the world
into a mundus sensibilis and intelligibilis is therefore quite
inadmissible in a positive sense； although conceptions do certainly
admit of such a division； for the class of noumena have no determinate
object corresponding to them； and cannot therefore possess objective
validity。 If we abandon the senses； how can it be made conceivable
that the categories （which are the only conceptions that could serve
as conceptions for noumena） have any sense or meaning at all； inasmuch
as something more than the mere unity of thought； namely； a possible
intuition； is requisite for their application to an object？ The
conception of a noumenon； considered as merely problematical； is；
however； not only admissible； but； as a limitative conception of
sensibility； absolutely necessary。 But； in this case； a noumenon is
not a particular intelligible object for our understanding； on the
contrary； the kind of understanding to which it could belong is itself
a problem； for we cannot form the most distant conception of the
possibility of an understanding which should cognize an object； not
discursively by means of categories； but intuitively in a non…sensuous
intuition。 Our understanding attains in this way a sort of negative
extension。 That is to say； it is not limited by； but rather limits；
sensibility； by giving the name of noumena to things； not considered
as phenomena； but as things in themselves。 But it at the same time
prescribes limits to itself； for it confesses itself unable to cognize
these by means of the categories； and hence is pelled to cogitate
them merely as an unknown something。
I find； however； in the writings of modern authors； an entirely
different use of the expressions； mundus sensibilis and
intelligibilis； which quite departs from the meaning of the
ancients… an acceptation in which； indeed； there is to be found no
difficulty； but which at the same time depends on mere verbal
quibbling。 According to this meaning； some have chosen to call the
plex of phenomena； in so far as it is intuited； mundus
sensibilis； but in so far as the connection thereof is cogitated
according to general laws of thought； mundus intelligibilis。
Astronomy； in so far as we mean by the word the mere observation of
the starry heaven； may represent the former； a system of astronomy；
such as the Copernican or Newtonian； the latter。 But such twisting
of words is a mere sophistical subterfuge； to avoid a difficult
question； by modifying its meaning to suit our own convenience。 To
be sure； understanding and reason are employed in the cognition of
phenomena； but the question is； whether these can be applied when
the object is not a phenomenon and in this sense we regard it if it is
cogitated as given to the understanding alone； and not to the
senses。 The question therefore is whether； over and above the
empirical use of the understanding； a transcendental use is
possible； which applies to the noumenon as an object。 This question we
have answered in the negative。
When therefore we say； the senses represent objects as they
appear； the understanding as they are； the latter statement must not
be understood in a transcendental； but only in an empirical
signification； that is； as they must be represented in the plete
connection of phenomena； and not according to what they may be；
apart from their relation to possible experience； consequently not
as objects of the pure understanding。 For this must ever remain
unknown to us。 Nay； it is also quite unknown to us whether any such
transcendental or extraordinary cognition is possible under any
circumstances； at least； whether it is possible by means of our
categories。 Understanding and sensibility； with us； can determine
objects only in conjunction。 If we separate them； we have intuitions
without conceptions； or conceptions without intuitions； in both cases；
representations； which we cannot apply to any determinate object。
If； after all our inquiries and explanations； any one still
hesitates to abandon the mere transcendental use of the categories；
let him attempt to construct with them a synthetical proposition。 It
would； of course； be unnecessary for this purpose to construct an
analytical proposition； for that does not extend the sphere of the
understanding； but； being concerned only about what is cogitated in
the conception itself； it leaves it quite undecided whether the
conception has any relation to objects； or merely indicates the
unity of thought… plete abstraction being made of the modi in which
an object may be given： in such a proposition； it is sufficient for
the understanding to know what lies in the conception… to what it
applies is to it indifferent。 The attempt must therefore be made
with a synthetical and so…called transcendental principle； for
example： 〃Everything that exists； exists as substance；〃 or；
〃Everything that is contingent exists as an effect of some other
thing； viz。； of its cause。〃 Now I ask； whence can the understanding
draw these synthetical propositions； when the conceptions contained
therein do not relate to possible experience but to things in
themselves （noumena）？ Where is to be found the third term； which is
always requisite PURE site in a synthetical proposition； which may
connect in the same proposition conceptions which