analytically to illustrate the conceptions which we form a priori of
things； but we seek to widen the range of our a priori knowledge。
For this purpose； we must avail ourselves of such principles as add
something to the original conception… something not identical with；
nor contained in it； and by means of synthetical judgements a
priori； leave far behind us the limits of experience； for example；
in the proposition； 〃the world must have a beginning；〃 and such
like。 Thus metaphysics； according to the proper aim of the science；
consists merely of synthetical propositions a priori。
VI。 The Universal Problem of Pure Reason。
It is extremely advantageous to be able to bring a number of
investigations under the formula of a single problem。 For in this
manner； we not only facilitate our own labour； inasmuch as we define
it clearly to ourselves； but also render it more easy for others to
decide whether we have done justice to our undertaking。 The proper
problem of pure reason； then； is contained in the question： 〃How are
synthetical judgements a priori possible？〃
That metaphysical science has hitherto remained in so vacillating
a state of uncertainty and contradiction； is only to be attributed
to the fact that this great problem； and perhaps even the difference
between analytical and synthetical judgements； did not sooner
suggest itself to philosophers。 Upon the solution of this problem；
or upon sufficient proof of the impossibility of synthetical knowledge
a priori； depends the existence or downfall of the science of
metaphysics。 Among philosophers； David Hume came the nearest of all to
this problem； yet it never acquired in his mind sufficient
precision； nor did he regard the question in its universality。 On
the contrary； he stopped short at the synthetical proposition of the
connection of an effect with its cause （principium causalitatis）；
insisting that such proposition a priori was impossible。 According
to his conclusions； then； all that we term metaphysical science is a
mere delusion； arising from the fancied insight of reason into that
which is in truth borrowed from experience； and to which habit has
given the appearance of necessity。 Against this assertion； destructive
to all pure philosophy； he would have been guarded； had he had our
problem before his eyes in its universality。 For he would then have
perceived that； according to his own argument； there likewise could
not be any pure mathematical science； which assuredly cannot exist
without synthetical propositions a priori… an absurdity from which his
good understanding must have saved him。
In the solution of the above problem is at the same time
prehended the possibility of the use of pure reason in the
foundation and construction of all sciences which contain
theoretical knowledge a priori of objects； that is to say； the
answer to the following questions：
How is pure mathematical science possible？
How is pure natural science possible？
Respecting these sciences； as they do certainly exist； it may with
propriety be asked； how they are possible？… for that they must be
possible is shown by the fact of their really existing。* But as to
metaphysics； the miserable progress it has hitherto made； and the fact
that of no one system yet brought forward； far as regards its true
aim； can it be said that this science really exists； leaves any one at
liberty to doubt with reason the very possibility of its existence。
*As to the existence of pure natural science； or physics； perhaps
many may still express doubts。 But we have only to look at the
different propositions which are monly treated of at the
mencement of proper （empirical） physical science… those； for
example； relating to the permanence of the same quantity of matter；
the vis inertiae； the equality of action and reaction； etc。… to be
soon convinced that they form a science of pure physics （physica pura；
or rationalis）； which well deserves to be separately exposed as a
special science； in its whole extent； whether that be great or
confined。
Yet； in a certain sense； this kind of knowledge must
unquestionably be looked upon as given； in other words； metaphysics
must be considered as really existing； if not as a science；
nevertheless as a natural disposition of the human mind （metaphysica
naturalis）。 For human reason； without any instigations imputable to
the mere vanity of great knowledge； unceasingly progresses； urged on
by its own feeling of need； towards such questions as cannot be
answered by any empirical application of reason； or principles derived
therefrom； and so there has ever really existed in every man some
system of metaphysics。 It will always exist； so soon as reason
awakes to the exercise of its power of speculation。 And now the
question arises： 〃How is metaphysics； as a natural disposition；
possible？〃 In other words； how； from the nature of universal human
reason； do those questions arise which pure reason proposes to itself；
and which it is impelled by its own feeling of need to answer as
well as it can？
But as in all the attempts hitherto made to answer the questions
which reason is prompted by its very nature to propose to itself；
for example； whether the world had a beginning； or has existed from
eternity； it has always met with unavoidable contradictions； we must
not rest satisfied with the mere natural disposition of the mind to
metaphysics； that is； with the existence of the faculty of pure
reason； whence； indeed； some sort of metaphysical system always
arises； but it must be possible to arrive at certainty in regard to
the question whether we know or do not know the things of which
metaphysics treats。 We must be able to arrive at a decision on the
subjects of its questions； or on the ability or inability of reason to
form any judgement respecting them； and therefore either to extend
with confidence the bounds of our pure reason； or to set strictly
defined and safe limits to its action。 This last question； which
arises out of the above universal problem； would properly run thus：
〃How is metaphysics possible as a science？〃
Thus； the critique of reason leads at last； naturally and
necessarily； to science； and； on the other hand； the dogmatical use of
reason without criticism leads to groundless assertions； against which
others equally specious can always be set； thus ending unavoidably
in scepticism。
Besides； this science cannot be of great and formidable prolixity；
because it has not to do with objects of reason； the variety of
which is inexhaustible； but merely with Reason herself and her
problems； problems which arise out of her own bosom； and are not
proposed to her by the nature of outward things； but by her own
nature。 And when once Reason has previously bee able pletely
to understand her own power in regard to objects which she meets
with in experience； it will be easy to determine securely the extent
and limits of her attempted application to objects beyond the confines
of experience。
We may and must； therefore； regard the attempts hitherto made to
establish metaphysical science dogmatically as non…existent。 For
what of analysis； that is； mere dissection of conceptions； is
contained in one or other； is not the aim of； but only a preparation
for metaphysics proper； which has for its object the extension； by
means of synthesis； of our a priori knowledge。 And for this purpose；
mere analysis is of course useless； because it only shows what is
contained in these conceptions； but not how we arrive； a priori； at
them； and this it is her duty to show； in order to be able
afterwards to determine their valid use in regard to all objects of
experience； to all knowledge in general。 But little self…denial；
indeed； is needed to give up these pretensions； seeing the undeniable；
and in the dogmatic mode of procedure； inevitable contradictions of
Reason with herself； have long since ruined the reputation of every
system of metaphysics that has appeared up to this time。 It will
require more firmness to remain undeterred by difficulty from
within； and opposition from without； from endeavouring； by a method
quite opposed to all those hitherto followed； to further the growth
and fruitfulness of a science indispensable to human reason… a science
from which every branch it has borne may be cut away； but whose
roots remain indestructible。
VII。 Idea and Division of a Particular Science； under the
Name of a Critique of Pure Reason。
From all that has been said； there results the idea of a
particular science； which may be called the Critique of Pure Reason。
For reason is the faculty which furnishes us with the principles of
knowledge a priori。 Hence； pure reason is the faculty which contains
the principles of cognizing anything absolutely a priori。 An organon
of pure reason would be a pendium of those principles according
to which alone all pure cognitions a priori can be obtained。 The
pletely extended application of such an organon would afford us a
system of pure reason。 As this； however； is demanding a great deal；
and it is yet doubtful whether any extension of our knowledge be
here possible； or； if so； in what cases； we can regard a science of
the m