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OUR knowledge springs from two fundamental sources of the
mind; the first is the capacity of receiving representations
(receptivity for impressions), the second is the power of 
knowing an object through these representations (spontaneity [in
the production] of concepts). Through the first an object is given
to us, through the second the object is thought in relation to
that [given] representation (which is a mere determination of
the mind). Intuition and concepts constitute, therefore, the 
elements of all our knowledge, so that neither concepts without an
intuition in some way corresponding to them, nor intuition 
without concepts, can yield knowledge. Both may be either pure or
empirical. When they contain sensation (which presupposes the
actual presence of the object), they are empirical. When there is
no mingling of sensation with the representation,they are pure.
Sensation may be entitled the material of sensible knowledge.
Pure intuition, therefore, contains only the form under which B75
 something is intuited; the pure concept only the form of the A51
thought of an object in general. Pure intuitions or pure 
concepts alone are possible a priori, empirical intuitions and
empirical concepts only a posteriori.
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If the receptivity of our mind, its power of receiving 
representations in so far as it is in any wise affected, is to be
entitled sensibility, then the mind's power of producing 
representations from itself, the spontaneity of knowledge, should be
called the understanding. Our nature is so constituted that
our intuition can never be other than sensible; that is, it 
contains only the mode in which we are affected by objects. The
faculty, on the other hand, which enables us to think the
object of sensible intuition is the understanding. To neither
of these powers may a preference be given over the other.
Without sensibility no object would be given to us, without
understanding no object would be thought. Thoughts without
content are empty, intuitions without concepts are blind. It
is, therefore, just as necessary to make our concepts sensible,
that is, to add the object to them in intuition, as to make
our intuitions intelligible, that is, to bring them under 
concepts. These two powers or capacities cannot exchange their
functions. The understanding can intuit nothing, the senses
can think nothing. Only through their union can knowledge
arise. But that is no reason for confounding the B76
contribution of either with that of the other; rather is it
a strong reason for carefully separating and distinguishing A52
the one from the other. We therefore distinguish the science
of the rules of sensibility in general, that is, aesthetic, from
the science of the rules of the understanding in general, that
is, logic.
Logic, again, can be treated in a twofold manner, either
as logic of the general or as logic of the special employment
of the understanding. The former contains the absolutely
necessary rules of thought without which there can be no
employment whatsoever of the understanding. It therefore
treats of understanding without any regard to difference in
the objects to which the understanding may be directed. The
logic of the special employment of the understanding contains
the rules of correct thinking as regards a certain kind of
objects. The former may be called the logic of elements, the
latter the organon of this or that science. The latter is 
commonly taught in the schools as a propaedeutic to the sciences,
though, according to the actual procedure of human reason,
it is what is obtained last of all, when the particular science
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under question has been already brought to such completion
that it requires only a few finishing touches to correct and
perfect it. For the objects under consideration must already
be known fairly completely before it can be possible to 
prescribe the rules according to which a science of them is to B77
be obtained.
 General logic is either pure or applied. In the former we
abstract from all empirical conditions under which our understanding A53
is exercised, i.e. from the influence of the senses, the
play of imagination, the laws of memory, the force of habit,
inclination, etc. , and so from all sources of prejudice, indeed
from all causes from which this or that knowledge may arise
or seem to arise. For they concern the understanding only in
so far as it is being employed under certain circumstances,
and to become acquainted with these circumstances experience
is required. Pure general logic has to do, therefore, only
with principles a priori, and is a canon of understanding and
of reason, but only in respect of what is formal in their 
employment, be the content what it may, empirical or transcendental.
General logic is called applied, when it is directed
to the rules of the employment of understanding under the
subjective empirical conditions dealt with by psychology.
Applied logic has therefore empirical principles, although it
is still indeed in so far general that it refers to the employment
of the understanding without regard to difference in the
objects. Consequently it is neither a canon of the understanding
in general nor an organon of special sciences, but B78
merely a cathartic of the common understanding.
In general logic, therefore, that part which is to constitute
the pure doctrine of reason must be entirely separated from
that which constitutes applied (though always still general) A54
logic. The former alone is, properly speaking, a science,
though indeed concise and dry, as the methodical exposition
of a doctrine of the elements of the understanding is bound
to be. There are therefore two rules which logicians must
always bear in mind, in dealing with pure general logic:
1. As general logic, it abstracts from all content of the
knowledge of understanding and from all differences in its
objects, and deals with nothing but the mere form of
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2. As pure logic, it has nothing to do with empirical 
principles, and does not, as has sometimes been supposed, borrow
anything from psychology, which therefore has no influence
whatever on the canon of the understanding. Pure logic is a
body of demonstrated doctrine, and everything in it must be
certain entirely a priori.
What I call applied logic (contrary to the usual meaning
of this title, according to which it should contain certain
exercises for which pure logic gives the rules) is a representation
of the understanding and of the rules of its necessary
employment in concreto, that is, under the accidental 
subjective conditions which may hinder or help its application, B79
and which are all given only empirically. It treats of attention,
its impediments and consequences, of the source of error, of
the state of doubt, hesitation, and conviction, etc. Pure general
logic stands to it in the same relation as pure ethics, which
contains only the necessary moral laws of a free will in general,
stands to the doctrine of the virtues strictly so called -- the
doctrine which considers these laws under the limitations of
the feelings, inclinations, and passions to which men are
more or less subject. Such a doctrine can never furnish a
true and demonstrated science, because, like applied logic,
it depends on empirical and psychological principles.
General logic, as we have shown, abstracts from all content
of knowledge, that is, from all relation of knowledge to
the object, and considers only the logical form in the relation of
any knowledge to other knowledge; that is, it treats of the form
of thought in general. But since, as the Transcendental Aesthetic
has shown, there are pure as well as empirical intuitions,
a distinction might likewise be drawn between pure and empirical
thought of objects. In that case we should have a logic B80
in which we do not abstract from the entire content of knowledge.
This other logic, which should contain solely the rules
of the pure thought of an object, would exclude only those
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modes of knowledge which have empirical content. It would
also treat of the origin of the modes in which we know objects,
in so far as that origin cannot be attributed to the objects. A56
General logic, on the other hand, has nothing to do with the
origin of knowledge, but only considers representations, be
they originally a priori in ourselves or only empirically given,
in so far as that origin cannot be attributed to the objects.
according to the laws which the understanding employs when,
in thinking, it relates them to one another. It deals therefore
only with that form which the understanding is able to impart
to the representations, from whatever source they may have
And here I make a remark which the reader must bear
well in mind, as it extends its influence over all that follows.
Not every kind of knowledge a priori should be called 
transcendental, but that only by which we know that -- and how --
certain representations (intuitions or concepts) can be 
employed or are possible purely a priori. The term 'transcendental',
that is to say, signifies such knowledge as concerns the
a priori possibility of knowledge, or its a priori employment. B81
Neither space nor any a priori geometrical determination of it
is a transcendental representation; what can alone be entitled
transcendental is the knowledge that these representations are
not of empirical origin, and the possibility that they can yet
relate a priori to objects of experience. The application of
space to objects in general would likewise be transcendental,
but, if restricted solely to objects of sense, it is empirical.
The distinction between the transcendental and the empirical A57
belongs therefore only to the critique of knowledge; it does
not concern the relation of that knowledge to its objects.
In the expectation, therefore, that there may perhaps be
concepts which relate a priori to objects, not as pure or sensible
intuitions, but solely as acts of pure thought -- that is, as
concepts which are neither of empirical nor of aesthetic
origin -- we form for ourselves by anticipation the idea of a
science of the knowledge which belongs to pure understanding
and reason, whereby we think objects entirely a priori. Such
a science, which should determine the origin, the scope, and
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the objective validity of such knowledge, would have to be
called transcendental logic, because, unlike general logic, B82
which has to deal with both empirical and pure knowledge of
reason, it concerns itself with the laws of understanding and
of reason solely in so far as they relate a priori to objects.
The question, famed of old, by which logicians were
supposed to be driven into a corner, obliged either to have
recourse to a pitiful sophism, or to confess their ignorance
and consequently the emptiness of their whole art, is the
question: What is truth? The nominal definition of truth,
that it is the agreement of knowledge with its object, is
assumed as granted; the question asked is as to what is
the general and sure criterion of the truth of any and every
To know what questions may reasonably be asked is
already a great and necessary proof of sagacity and insight.
For if a question is absurd in itself and calls for an answer
where none is required, it not only brings shame on the 
propounder of the question, but may betray an incautious listener
into absurd answers, thus presenting, as the ancients said, the B83
ludicrous spectacle of one man milking a he-goat and the
other holding a sieve underneath.
If truth consists in the agreement of knowledge with its
object, that object must thereby be distinguished from other
objects; for knowledge is false, if it does not agree with the
object to which it is related, even although it contains 
something which may be valid of other objects. Now a general
criterion of truth must be such as would be valid in each and
every instance of knowledge, however their objects may vary. It
is obvious, however, that such a criterion [being general] cannot
take account of the [varying] content of knowledge (relation
to its [specific] object). But since truth concerns just this very A59
content, it is quite impossible, and indeed absurd, to ask for a
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general test of the truth of such content. A sufficient and at the
same time general criterion of truth cannot possibly be given.
Since we have already entitled the content of knowledge its
matter, we must be prepared to recognise that of the truth
of knowledge, so far as its matter is concerned, no general
criterion can be demanded. Such a criterion would by its
very nature be self-contradictory.
But, on the other hand, as regards knowledge in respect
of its mere form (leaving aside all content), it is evident that
logic, in so far as it expounds the universal and necessary B84
rules of the understanding, must in these rules furnish criteria
of truth. Whatever contradicts these rules is false. For the
understanding would thereby be made to contradict its own
general rules of thought, and so to contradict itself. These
criteria, however, concern only the form of truth, that is, of
thought in general; and in so far they are quite correct, but
are not by themselves sufficient. For although our knowledge
may be in complete accordance with logical demands, that is,
may not contradict itself, it is still possible that it may be in
contradiction with its object. The purely logical criterion of
truth, namely, the agreement of knowledge with the general
and formal laws of the understanding and reason, is a conditio
sine qua non, and is therefore the negative condition of all
truth. But further than this logic cannot go. It has no  A60
touchstone for the discovery of such error as concerns not the
form but the content.
General logic resolves the whole formal procedure of the
understanding and reason into its elements, and exhibits them
as principles of all logical criticism of our knowledge. This
part of logic, which may therefore be entitled analytic, yields
what is at least the negative touchstone of truth. Its rules
must be applied in the examination and appraising of the
form of all knowledge before we proceed to determine whether
their content contains positive truth in respect to their object. B85
But since the mere form of knowledge, however completely
it may be in agreement with logical laws, is far from being
sufficient to determine the material (objective) truth of 
knowledge, no one can venture with the help of logic alone to
judge regarding objects, or to make any assertion. We must
first, independently of logic, obtain reliable information; only
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then are we in a position to enquire, in accordance with logical
laws, into the use of this information and its connection in a
coherent whole, or rather to test it by these laws. There is,
however, something so tempting in the possession of an art so
specious, through which we give to all our knowledge, however
uninstructed we may be in regard to its content, the form
of understanding, that general logic, which is merely a canon A61
of judgment, has been employed as if it were an organon for
the actual production of at least the semblance of objective
assertions, and has thus been misapplied. General logic, when
thus treated as an organon, is called dialectic.
However various were the significations in which the ancients
used 'dialectic' as the title for a science or art, we can safely
conclude from their actual employment of it that with them
it was never anything else than the logic of illusion. It was a B86
sophistical art of giving to ignorance, and indeed to intentional
sophistries, the appearance of truth, by the device of imitating
the methodical thoroughness which logic prescribes, and
of using its 'topic' to conceal the emptiness of its pretensions.
Now it may be noted as a sure and useful warning, that general
logic, if viewed as an organon, is always a logic of illusion,
that is, dialectical. For logic teaches us nothing whatsoever
regarding the content of knowledge, but lays down only the
formal conditions of agreement with the understanding; and
since these conditions can tell us nothing at all as to the
objects concerned, any attempt to use this logic as an 
instrument (organon) that professes to extend and enlarge our
knowledge can end in nothing but mere talk -- in which, with
a certain plausibility, we maintain, or, if such be our choice, A62
attack, any and every possible assertion.
Such instruction is quite unbecoming the dignity of philosophy.
The title 'dialectic' has therefore come to be otherwise
employed, and has been assigned to logic, as a critique of
dialectical illusion. This is the sense in which it is to be 
understood in this work.
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In a transcendental logic we isolate the understanding --
as above, in the Transcendental Aesthetic, the sensibility --
separating out from our knowledge that part of thought which
has its origin solely in the understanding. The employment of
this pure knowledge depends upon the condition that objects
to which it can be applied be given to us in intuition. In the
absence of intuition all our knowledge is without objects,
and therefore remains entirely empty. That part of transcendental
logic which deals with the elements of the pure knowledge
yielded by understanding, and the principles without
which no object can be thought, is transcendental analytic. It
is a logic of truth. For no knowledge can contradict it without
at once losing all content, that is, all relation to any object, and A63
therefore all truth. But since it is very tempting to use these
pure modes of knowledge of the understanding and these principles
by themselves, and even beyond the limits of experience,
which alone can yield the matter (objects) to which those pure B88
concepts of understanding can be applied, the understanding is
led to incur the risk of making, with a mere show of rationality,
a material use of its pure and merely formal principles, and of
passing judgments upon objects without distinction -- upon
objects which are not given to us, nay, perhaps cannot in any
way be given. Since, properly, this transcendental analytic
should be used only as a canon for passing judgment upon the
empirical employment of the understanding, it is misapplied
if appealed to as an organon of its general and unlimited
application, and if consequently we venture, with the pure
understanding alone, to judge synthetically, to affirm, and to
decide regarding objects in general. The employment of the
pure understanding then becomes dialectical. The second part
of transcendental logic must therefore form a critique of this
dialectical illusion, and is called transcendental dialectic, not
as an art of producing such illusion dogmatically (an art 
unfortunately very commonly practised by metaphysical jugglers),
but as a critique of understanding and reason in respect of
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their hyperphysical employment. It will expose the false, 
illusory character of those groundless pretensions, and in place A64
of the high claims to discover and to extend knowledge merely
by means of transcendental principles, it will substitute what is
no more than a critical treatment of the pure understanding,
for the guarding of it against sophistical illusion.