For the external sense the pure image of all quantities
（quantorum） is space； the pure image of all objects of sense in
general； is time。 But the pure schema of quantity （quantitatis） as a
conception of the understanding； is number； a representation which
prehends the successive addition of one to one （homogeneous
quantities）。 Thus； number is nothing else than the unity of the
synthesis of the manifold in a homogeneous intuition； by means of my
generating time itself in my apprehension of the intuition。
Reality； in the pure conception of the understanding； is that
which corresponds to a sensation in general； that； consequently； the
conception of which indicates a being （in time）。 Negation is that
the conception of which represents a not…being （in time）。 The
opposition of these two consists therefore in the difference of one
and the same time； as a time filled or a time empty。 Now as time is
only the form of intuition； consequently of objects as phenomena； that
which in objects corresponds to sensation is the transcendental matter
of all objects as things in themselves （Sachheit； reality）。 Now
every sensation has a degree or quantity by which it can fill time；
that is to say； the internal sense in respect of the representation of
an object； more or less； until it vanishes into nothing （= 0 =
negatio）。 Thus there is a relation and connection between reality
and negation； or rather a transition from the former to the latter；
which makes every reality representable to us as a quantum； and the
schema of a reality as the quantity of something in so far as it fills
time； is exactly this continuous and uniform generation of the reality
in time； as we descend in time from the sensation which has a
certain degree； down to the vanishing thereof； or gradually ascend
from negation to the quantity thereof。
The schema of substance is the permanence of the real in time；
that is； the representation of it as a substratum of the empirical
determination of time； a substratum which therefore remains； whilst
all else changes。 （Time passes not； but in it passes the existence
of the changeable。 To time； therefore； which is itself unchangeable
and permanent； corresponds that which in the phenomenon is
unchangeable in existence； that is； substance； and it is only by it
that the succession and coexistence of phenomena can be determined
in regard to time。）
The schema of cause and of the causality of a thing is the real
which； when posited； is always followed by something else。 It
consists； therefore； in the succession of the manifold； in so far as
that succession is subjected to a rule。
The schema of munity （reciprocity of action and reaction）； or the
reciprocal causality of substances in respect of their accidents； is
the coexistence of the determinations of the one with those of the
other； according to a general rule。
The schema of possibility is the accordance of the synthesis of
different representations with the conditions of time in general
（as； for example； opposites cannot exist together at the same time
in the same thing； but only after each other）； and is therefore the
determination of the representation of a thing at any time。
The schema of reality is existence in a determined time。
The schema of necessity is the existence of an object in all time。
It is clear； from all this； that the schema of the category of
quantity contains and represents the generation （synthesis） of time
itself； in the successive apprehension of an object； the schema of
quality the synthesis of sensation with the representation of time； or
the filling up of time； the schema of relation the relation of
perceptions to each other in all time （that is； according to a rule of
the determination of time）： and finally； the schema of modality and
its categories； time itself； as the correlative of the determination
of an object… whether it does belong to time； and how。 The schemata；
therefore； are nothing but a priori determinations of time according
to rules； and these； in regard to all possible objects； following
the arrangement of the categories； relate to the series in time； the
content in time； the order in time； and finally； to the plex or
totality in time。
Hence it is apparent that the schematism of the understanding； by
means of the transcendental synthesis of the imagination； amounts to
nothing else than the unity of the manifold of intuition in the
internal sense； and thus indirectly to the unity of apperception； as a
function corresponding to the internal sense （a receptivity）。 Thus；
the schemata of the pure conceptions of the understanding are the true
and only conditions whereby our understanding receives an
application to objects； and consequently significance。 Finally；
therefore； the categories are only capable of empirical use；
inasmuch as they serve merely to subject phenomena to the universal
rules of synthesis； by means of an a priori necessary unity （on
account of the necessary union of all consciousness in one original
apperception）； and so to render them susceptible of a plete
connection in one experience。 But within this whole of possible
experience lie all our cognitions； and in the universal relation to
this experience consists transcendental truth； which antecedes all
empirical truth； and renders the latter possible。
It is； however； evident at first sight； that although the schemata
of sensibility are the sole agents in realizing the categories； they
do； nevertheless； also restrict them； that is； they limit the
categories by conditions which lie beyond the sphere of understanding…
namely； in sensibility。 Hence the schema is properly only the
phenomenon； or the sensuous conception of an object in harmony with
the category。 （Numerus est quantitas phaenomenon… sensatio realitas
phaenomenon； constans et perdurabile rerum substantia phaenomenon…
aeternitas； necessitas； phaenomena； etc。） Now； if we remove a
restrictive condition； we thereby amplify； it appears； the formerly
limited conception。 In this way； the categories in their pure
signification； free from all conditions of sensibility； ought to be
valid of things as they are； and not； as the schemata represent
them； merely as they appear； and consequently the categories must have
a significance far more extended； and wholly independent of all
schemata。 In truth； there does always remain to the pure conceptions
of the understanding； after abstracting every sensuous condition； a
value and significance； which is； however； merely logical。 But in this
case； no object is given them； and therefore they have no meaning
sufficient to afford us a conception of an object。 The notion of
substance； for example； if we leave out the sensuous determination
of permanence； would mean nothing more than a something which can be
cogitated as subject； without the possibility of being a
predicate to anything else。 Of this representation I can make nothing；
inasmuch as it does not indicate to me what determinations the thing
possesses which must thus be valid as premier subject。 Consequently；
the categories； without schemata are merely functions of the
understanding for the production of conceptions； but do not
represent any object。 This significance they derive from
sensibility； which at the same time realizes the understanding and
restricts it。
CHAPTER II。 System of all Principles of the Pure Understanding。
In the foregoing chapter we have merely considered the general
conditions under which alone the transcendental faculty of judgement
is justified in using the pure conceptions of the understanding for
synthetical judgements。 Our duty at present is to exhibit in
systematic connection those judgements which the understanding
really produces a priori。 For this purpose； our table of the
categories will certainly afford us the natural and safe guidance。 For
it is precisely the categories whose application to possible
experience must constitute all pure a priori cognition of the
understanding； and the relation of which to sensibility will； on
that very account； present us with a plete and systematic catalogue
of all the transcendental principles of the use of the understanding。
Principles a priori are so called； not merely because they contain
in themselves the grounds of other judgements； but also because they
themselves are not grounded in higher and more general cognitions。
This peculiarity； however； does not raise them altogether above the
need of a proof。 For although there could be found no higher
cognition； and therefore no objective proof； and although such a
principle rather serves as the foundation for all cognition of the
object； this by no means hinders us from drawing a proof from the
subjective sources of the possibility of the cognition of an object。
Such a proof is necessary； moreover； because without it the
principle might be liable to the imputation of being a mere gratuitous
assertion。
In the second place； we shall limit our investigations to those
principles which relate to the categories。 For as to the principles of
transcendental aesthetic； according to which space and time are the
conditions of the possibility of things as phenomena； as also the
res