The Critique of Pure Reason | Page 8

enabled to put the justice of this estimate to the test.
For that which of necessity impels us to transcend the limits of
experience and of all phenomena is the unconditioned, which reason
absolutely requires in things as they are in themselves, in order to
complete the series of conditions. Now, if it appears that when, on the
one hand, we assume that our cognition conforms to its objects as
things in themselves, the unconditioned cannot be thought without
contradiction, and that when, on the other hand, we assume that our
representation of things as they are given to us, does not conform to
these things as they are in themselves, but that these objects, as
phenomena, conform to our mode of representation, the contradiction
disappears: we shall then be convinced of the truth of that which we
began by assuming for the sake of experiment; we may look upon it as
established that the unconditioned does not lie in things as we know
them, or as they are given to us, but in things as they are in themselves,
beyond the range of our cognition.*
[*Footnote: This experiment of pure reason has a great similarity to
that of the chemists, which they term the experiment of reduction, or,
more usually, the synthetic process. The analysis of the metaphysician
separates pure cognition a priori into two heterogeneous elements, viz.,
the cognition of things as phenomena, and of things in themselves.
Dialectic combines these again into harmony with the necessary
rational idea of the unconditioned, and finds that this harmony never
results except through the above distinction, which is, therefore,
concluded to be just.]
But, after we have thus denied the power of speculative reason to make
any progress in the sphere of the supersensible, it still remains for our
consideration whether data do not exist in practical cognition which

may enable us to determine the transcendent conception of the
unconditioned, to rise beyond the limits of all possible experience from
a practical point of view, and thus to satisfy the great ends of
metaphysics. Speculative reason has thus, at least, made room for such
an extension of our knowledge: and, if it must leave this space vacant,
still it does not rob us of the liberty to fill it up, if we can, by means of
practical data--nay, it even challenges us to make the attempt.*
[*Footnote: So the central laws of the movements of the heavenly
bodies established the truth of that which Copernicus, first, assumed
only as a hypothesis, and, at the same time, brought to light that
invisible force (Newtonian attraction) which holds the universe
together. The latter would have remained forever undiscovered, if
Copernicus had not ventured on the experiment--contrary to the senses
but still just-- of looking for the observed movements not in the
heavenly bodies, but in the spectator. In this Preface I treat the new
metaphysical method as a hypothesis with the view of rendering
apparent the first attempts at such a change of method, which are
always hypothetical. But in the Critique itself it will be demonstrated,
not hypothetically, but apodeictically, from the nature of our
representations of space and time, and from the elementary conceptions
of the understanding.]
This attempt to introduce a complete revolution in the procedure of
metaphysics, after the example of the geometricians and natural
philosophers, constitutes the aim of the Critique of Pure Speculative
Reason. It is a treatise on the method to be followed, not a system of
the science itself. But, at the same time, it marks out and defines both
the external boundaries and the internal structure of this science. For
pure speculative reason has this peculiarity, that, in choosing the
various objects of thought, it is able to define the limits of its own
faculties, and even to give a complete enumeration of the possible
modes of proposing problems to itself, and thus to sketch out the entire
system of metaphysics. For, on the one hand, in cognition a priori,
nothing must be attributed to the objects but what the thinking subject
derives from itself; and, on the other hand, reason is, in regard to the
principles of cognition, a perfectly distinct, independent unity, in which,

as in an organized body, every member exists for the sake of the others,
and all for the sake of each, so that no principle can be viewed, with
safety, in one relationship, unless it is, at the same time, viewed in
relation to the total use of pure reason. Hence, too, metaphysics has this
singular advantage--an advantage which falls to the lot of no other
science which has to do with objects--that, if once it is conducted into
the sure path of science, by means of this criticism, it can then take in
the whole sphere of its