these transcendental laws of nature； and the peculiar character of
we must make one remark； which will at the same time be important as a
guide in every other attempt to demonstrate the truth of
intellectual and likewise synthetical propositions a priori。 Had we
endeavoured to prove these analogies dogmatically； that is； from
conceptions； that is to say； had we employed this method in attempting
to show that everything which exists； exists only in that which is
permanent… that every thing or event presupposes the existence of
something in a preceding state； upon which it follows in conformity
with a rule… lastly； that in the manifold； which is coexistent； the
states coexist in connection with each other according to a rule…
all our labour would have been utterly in vain。 For more conceptions
of things； analyse them as we may； cannot enable us to conclude from
the existence of one object to the existence of another。 What other
course was left for us to pursue？ This only； to demonstrate the
possibility of experience as a cognition in which at last all
objects must be capable of being presented to us； if the
representation of them is to possess any objective reality。 Now in
this third； this mediating term； the essential form of which
consists in the synthetical unity of the apperception of all
phenomena； we found a priori conditions of the universal and necessary
determination as to time of all existences in the world of
phenomena； without which the empirical determination thereof as to
time would itself be impossible； and we also discovered rules of
synthetical unity a priori； by means of which we could anticipate
experience。 For want of this method； and from the fancy that it was
possible to discover a dogmatical proof of the synthetical
propositions which are requisite in the empirical employment of the
understanding； has it happened that a proof of the principle of
sufficient reason has been so often attempted； and always in vain。 The
other two analogies nobody has ever thought of； although they have
always been silently employed by the mind；* because the guiding thread
furnished by the categories was wanting； the guide which alone can
enable us to discover every hiatus； both in the system of
conceptions and of principles。
*The unity of the universe； in which all phenomena to be
connected； is evidently a mere consequence of the admitted principle
of the munity of all substances which are coexistent。 For were
substances isolated； they could not as parts constitute a whole； and
were their connection （reciprocal action of the manifold） not
necessary from the very fact of coexistence； we could not conclude
from the fact of the latter as a merely ideal relation to the former
as a real one。 We have； however； shown in its place that munity
is the proper ground of the possibility of an empirical cognition of
coexistence； and that we may therefore properly reason from the latter
to the former as its condition。
4。 THE POSTULATES OF EMPIRICAL THOUGHT。
1。 That which agrees with the formal conditions （intuition and
conception） of experience； is possible。
2。 That which coheres with the material conditions of experience
（sensation）； is real。
3。 That whose coherence with the real is determined according to
universal conditions of experience is （exists） necessary。
Explanation。
The categories of modality possess this peculiarity； that they do
not in the least determine the object； or enlarge the conception to
which they are annexed as predicates； but only express its relation to
the faculty of cognition。 Though my conception of a thing is in itself
plete； I am still entitled to ask whether the object of it is
merely possible； or whether it is also real； or； if the latter；
whether it is also necessary。 But hereby the object itself is not more
definitely determined in thought； but the question is only in what
relation it； including all its determinations； stands to the
understanding and its employment in experience； to the empirical
faculty of judgement； and to the reason of its application to
experience。
For this very reason； too； the categories of modality are nothing
more than explanations of the conceptions of possibility； reality； and
necessity； as employed in experience； and at the same time；
restrictions of all the categories to empirical use alone； not
authorizing the transcendental employment of them。 For if they are
to have something more than a merely logical significance； and to be
something more than a mere analytical expression of the form of
thought； and to have a relation to things and their possibility；
reality； or necessity； they must concern possible experience and its
synthetical unity； in which alone objects of cognition can be given。
The postulate of the possibility of things requires also； that the
conception of the things agree with the formal conditions of our
experience in general。 But this； that is to say； the objective form of
experience； contains all the kinds of synthesis which are requisite
for the cognition of objects。 A conception which contains a
synthesis must be regarded as empty and； without reference to an
object； if its synthesis does not belong to experience… either as
borrowed from it； and in this case it is called an empirical
conception； or such as is the ground and a priori condition of
experience （its form）； and in this case it is a pure conception； a
conception which nevertheless belongs to experience； inasmuch as its
object can be found in this alone。 For where shall we find the
criterion or character of the possibility of an object which is
cogitated by means of an a priori synthetical conception； if not in
the synthesis which constitutes the form of empirical cognition of
objects？ That in such a conception no contradiction exists is indeed a
necessary logical condition； but very far from being sufficient to
establish the objective reality of the conception； that is； the
possibility of such an object as is thought in the conception。 Thus；
in the conception of a figure which is contained within two straight
lines； there is no contradiction； for the conceptions of two
straight lines and of their junction contain no negation of a
figure。 The impossibility in such a case does not rest upon the
conception in itself； but upon the construction of it in space； that
is to say； upon the conditions of space and its determinations。 But
these have themselves objective reality； that is； they apply to
possible things； because they contain a priori the form of
experience in general。
And now we shall proceed to point out the extensive utility and
influence of this postulate of possibility。 When I represent to myself
a thing that is permanent； so that everything in it which changes
belongs merely to its state or condition； from such a conception alone
I never can cognize that such a thing is possible。 Or； if I
represent to myself something which is so constituted that； when it is
posited； something else follows always and infallibly； my thought
contains no self…contradiction； but whether such a property as
causality is to be found in any possible thing； my thought alone
affords no means of judging。 Finally； I can represent to myself
different things （substances） which are so constituted that the
state or condition of one causes a change in the state of the other；
and reciprocally； but whether such a relation is a property of
things cannot be perceived from these conceptions； which contain a
merely arbitrary synthesis。 Only from the fact； therefore； that
these conceptions express a priori the relations of perceptions in
every experience； do we know that they possess objective reality； that
is； transcendental truth； and that independent of experience； though
not independent of all relation to form of an experience in general
and its synthetical unity； in which alone objects can be empirically
cognized。
But when we fashion to ourselves new conceptions of substances；
forces； action； and reaction； from the material presented to us by
perception； without following the example of experience in their
connection； we create mere chimeras； of the possibility of which we
cannot discover any criterion； because we have not taken experience
for our instructress； though we have borrowed the conceptions from
her。 Such fictitious conceptions derive their character of possibility
not； like the categories； a priori； as conceptions on which all
experience depends； but only； a posteriori； as conceptions given by
means of experience itself； and their possibility must either be
cognized a posteriori and empirically； or it cannot be cognized at
all。 A substance which is permanently present in space； yet without
filling it （like that tertium quid between matter and the thinking
subject which some have tried to introduce into metaphysics）； or a
peculiar fundamental power of the mind of intuiting the future by
anticipation （instead of merely inferring from past and present
events）； or； finally； a power of the mind to place itself in munity
of thought with other men； however distant they may be… these are
conceptions the possibility of which has no ground to rest upon。 For
they are not based upon experience and its known laws； and； without
experience； they are a merely arbitrary conjunction of thoughts；
which； though containing no internal contradiction； has no claim to
objective reality； neither； consequently； to the possibility of such
an object as is thought in these conceptions。 As far as concerns
reality； it is self…evident that we cannot cogitate such a possibility
in concreto without the aid of experience； because reality is
concerned only with sensation； as the matter of experience； and not
with the form of thought； with which we can no doubt indulge in
shaping fancies。
But I pass by everything which derives its possibility from
reality in experience； and I purpose treating here merely of the
possibility of things by means of a priori conceptions。 I maintain；
then； that the possibility of things is not derived from such
conceptions per se； but only when considered as formal and objective
conditions of an experience in general。
It