We now e to a conception which was not inserted in the general
list of transcendental conceptions。 and yet must be reckoned with
them； but at the same time without in the least altering； or
indicating a deficiency in that table。 This is the conception； or；
if the term is preferred； the judgement； 〃I think。〃 But it is
readily perceived that this thought is as it were the vehicle of all
conceptions in general； and consequently of transcendental conceptions
also； and that it is therefore regarded as a transcendental
conception； although it can have no peculiar claim to be so ranked；
inasmuch as its only use is to indicate that all thought is
acpanied by consciousness。 At the same time； pure as this
conception is from empirical content （impressions of the senses）； it
enables us to distinguish two different kinds of objects。 〃I；〃 as
thinking； am an object of the internal sense； and am called soul。 That
which is an object of the external senses is called body。 Thus the
expression； 〃I；〃 as a thinking being； designates the object…matter
of psychology； which may be called 〃the rational doctrine of the
soul；〃 inasmuch as in this science I desire to know nothing of the
soul but what； independently of all experience （which determines me in
concreto）； may be concluded from this conception 〃I；〃 in so far as
it appears in all thought。
Now； the rational doctrine of the soul is really an undertaking of
this kind。 For if the smallest empirical element of thought； if any
particular perception of my internal state； were to be introduced
among the grounds of cognition of this science； it would not be a
rational； but an empirical doctrine of the soul。 We have thus before
us a pretended science； raised upon the single proposition； 〃I think；〃
whose foundation or want of foundation we may very properly； and
agreeably with the nature of a transcendental philosophy； here
examine。 It ought not to be objected that in this proposition； which
expresses the perception of one's self； an internal experience is
asserted； and that consequently the rational doctrine of the soul
which is founded upon it； is not pure； but partly founded upon an
empirical principle。 For this internal perception is nothing more than
the mere apperception； 〃I think；〃 which in fact renders all
transcendental conceptions possible； in which we say； 〃I think
substance； cause； etc。〃 For internal experience in general and its
possibility； or perception in general； and its relation to other
perceptions； unless some particular distinction or determination
thereof is empirically given； cannot be regarded as empirical
cognition； but as cognition of the empirical； and belongs to the
investigation of the possibility of every experience； which is
certainly transcendental。 The smallest object of experience （for
example； only pleasure or pain）； that should be included in the
general representation of self…consciousness； would immediately change
the rational into an empirical psychology。
〃I think〃 is therefore the only text of rational psychology； from
which it must develop its whole system。 It is manifest that this
thought； when applied to an object （myself）； can contain nothing but
transcendental predicates thereof； because the least empirical
predicate would destroy the purity of the science and its independence
of all experience。
But we shall have to follow here the guidance of the categories…
only； as in the present case a thing； 〃I；〃 as thinking being； is at
first given； we shall… not indeed change the order of the categories
as it stands in the table… but begin at the category of substance；
by which at the a thing a thing is represented and proceeds
backwards through the series。 The topic of the rational doctrine of
the soul； from which everything else it may contain must be deduced；
is accordingly as follows：
1 2
The Soul is SUBSTANCE As regards its quality
it is SIMPLE
3
As regards the different
times in which it exists；
it is numerically identical；
that is UNITY； not Plurality。
4
It is in relation to possible objects in space*
*The reader； who may not so easily perceive the psychological
sense of these expressions； taken here in their transcendental
abstraction； and cannot guess why the latter attribute of the soul
belongs to the category of existence； will find the expressions
sufficiently explained and justified in the sequel。 I have；
moreover； to apologize for the Latin terms which have been
employed；instead of their German synonyms； contrary to the rules of
correct writing。 But I judged it better to sacrifice elegance to
perspicuity。
From these elements originate all the conceptions of pure
psychology； by bination alone； without the aid of any other
principle。 This substance； merely as an object of the internal
sense； gives the conception of Immateriality； as simple substance；
that of Incorruptibility； its identity； as intellectual substance；
gives the conception of Personality； all these three together；
Spirituality。 Its relation to objects in space gives us the conception
of connection （mercium） with bodies。 Thus it represents thinking
substance as the principle of life in matter； that is； as a soul
（anima）； and as the ground of Animality； and this； limited and
determined by the conception of spirituality； gives us that of
Immortality。
Now to these conceptions relate four paralogisms of a transcendental
psychology； which is falsely held to be a science of pure reason。
touching the nature of our thinking being。 We can； however； lay at the
foundation of this science nothing but the simple and in itself
perfectly contentless representation 〃I which cannot even be called
a conception； but merely a consciousness which acpanies all
conceptions。 By this 〃I；〃 or 〃He；〃 or 〃It；〃 who or which thinks；
nothing more is represented than a transcendental subject of thought =
x； which is cognized only by means of the thoughts that are its
predicates； and of which； apart from these； we cannot form the least
conception。 Hence in a perpetual circle； inasmuch as we must always
employ it； in order to frame any judgement respecting it。 And this
inconvenience we find it impossible to rid ourselves of； because
consciousness in itself is not so much a representation distinguishing
a particular object； as a form of representation in general； in so far
as it may be termed cognition； for in and by cognition alone do I
think anything。
It must； however； appear extraordinary at first sight that the
condition under which I think； and which is consequently a property of
my subject； should be held to be likewise valid for every existence
which thinks； and that we can presume to base upon a seemingly
empirical proposition a judgement which is apodeictic and universal；
to wit； that everything which thinks is constituted as the voice of my
consciousness declares it to be； that is； as a self…conscious being。
The cause of this belief is to be found in the fact that we
necessarily attribute to things a priori all the properties which
constitute conditions under which alone we can cogitate them。 Now I
cannot obtain the least representation of a thinking being by means of
external experience； but solely through self…consciousness。 Such
objects are consequently nothing more than the transference of this
consciousness of mine to other things which can only thus be
represented as thinking beings。 The proposition； 〃I think；〃 is； in the
present case； understood in a problematical sense； not in so far as it
contains a perception of an existence （like the Cartesian 〃Cogito；
ergo sum〃）；* but in regard to its mere possibility… for the purpose of
discovering what properties may be inferred from so simple a
proposition and predicated of the subject of it。
*＇〃I think； therefore I am。〃＇
If at the foundation of our pure rational cognition of thinking
beings there lay more than the mere Cogito… if we could likewise
call in aid observations on the play of our thoughts； and the thence
derived natural laws of the thinking self； there would arise an
empirical psychology which would be a kind of physiology of the
internal sense and might possibly be capable of explaining the
phenomena of that sense。 But it could never be available for
discovering those properties which do not belong to possible
experience （such as the quality of simplicity）； nor could it make
any apodeictic enunciation on the nature of thinking beings： it
would therefore not be a rational psychology。
Now； as the proposition 〃I think〃 （in the problematical sense）
contains the form of every judgement in general and is the constant
acpaniment of all the categories； it is manifest that conclusions
are drawn from it only by a transcendental employment of the
understanding。 This use of the understanding excludes all empirical
elements； and we cannot； as has been shown above； have any
favourable conception beforehand of its procedure。 We shall
therefore follow with a critical eye this proposition through all
the predicaments of pure psychology； but we shall