receptivity for sensations； no perception； and consequently no
experience is possible； which can prove； either immediately or
mediately； an entire absence of all reality in a phenomenon； in
other words； it is impossible ever to draw from experience a proof
of the existence of empty space or of empty time。 For in the first
place； an entire absence of reality in a sensuous intuition cannot
of course be an object of perception； secondly； such absence cannot be
deduced from the contemplation of any single phenomenon； and the
difference of the degrees in its reality； nor ought it ever to be
admitted in explanation of any phenomenon。 For if even the plete
intuition of a determinate space or time is thoroughly real； that
is； if no part thereof is empty； yet because every reality has its
degree； which； with the extensive quantity of the phenomenon
unchanged； can diminish through endless gradations down to nothing
（the void）； there must be infinitely graduated degrees； with which
space or time is filled； and the intensive quantity in different
phenomena may be smaller or greater； although the extensive quantity
of the intuition remains equal and unaltered。
We shall give an example of this。 Almost all natural philosophers；
remarking a great difference in the quantity of the matter of
different kinds in bodies with the same volume （partly on account of
the momentum of gravity or weight； partly on account of the momentum
of resistance to other bodies in motion）； conclude unanimously that
this volume （extensive quantity of the phenomenon） must be void in all
bodies； although in different proportion。 But who would suspect that
these for the most part mathematical and mechanical inquirers into
nature should ground this conclusion solely on a metaphysical
hypothesis… a sort of hypothesis which they profess to disparage and
avoid？ Yet this they do； in assuming that the real in space （I must
not here call it impenetrability or weight； because these are
empirical conceptions） is always identical； and can only be
distinguished according to its extensive quantity； that is；
multiplicity。 Now to this presupposition； for which they can have no
ground in experience； and which consequently is merely metaphysical； I
oppose a transcendental demonstration； which it is true will not
explain the difference in the filling up of spaces； but which
nevertheless pletely does away with the supposed necessity of the
above…mentioned presupposition that we cannot explain the said
difference otherwise than by the hypothesis of empty spaces。 This
demonstration； moreover； has the merit of setting the understanding at
liberty to conceive this distinction in a different manner； if the
explanation of the fact requires any such hypothesis。 For we
perceive that although two equal spaces may be pletely filled by
matters altogether different； so that in neither of them is there left
a single point wherein matter is not present； nevertheless； every
reality has its degree （of resistance or of weight）； which； without
diminution of the extensive quantity； can bee less and less ad
infinitum； before it passes into nothingness and disappears。 Thus an
expansion which fills a space… for example； caloric； or any other
reality in the phenomenal world… can decrease in its degrees to
infinity； yet without leaving the smallest part of the space empty； on
the contrary； filling it with those lesser degrees as pletely as
another phenomenon could with greater。 My intention here is by no
means to maintain that this is really the case with the difference
of matters； in regard to their specific gravity； I wish only to prove；
from a principle of the pure understanding； that the nature of our
perceptions makes such a mode of explanation possible； and that it
is erroneous to regard the real in a phenomenon as equal quoad its
degree； and different only quoad its aggregation and extensive
quantity； and this； too； on the pretended authority of an a priori
principle of the understanding。
Nevertheless； this principle of the anticipation of perception
must somewhat startle an inquirer whom initiation into
transcendental philosophy has rendered cautious。 We must naturally
entertain some doubt whether or not the understanding can enounce
any such synthetical proposition as that respecting the degree of
all reality in phenomena； and consequently the possibility of the
internal difference of sensation itself… abstraction being made of its
empirical quality。 Thus it is a question not unworthy of solution：
〃How the understanding can pronounce synthetically and a priori
respecting phenomena； and thus anticipate these； even in that which is
peculiarly and merely empirical； that； namely； which concerns
sensation itself？〃
The quality of sensation is in all cases merely empirical； and
cannot be represented a priori （for example； colours； taste； etc。）。
But the real… that which corresponds to sensation… in opposition to
negation = O； only represents something the conception of which in
itself contains a being （ein seyn）； and signifies nothing but the
synthesis in an empirical consciousness。 That is to say； the empirical
consciousness in the internal sense can be raised from 0 to every
higher degree； so that the very same extensive quantity of
intuition； an illuminated surface； for example； excites as great a
sensation as an aggregate of many other surfaces less illuminated。
We can therefore make plete abstraction of the extensive quantity
of a phenomenon； and represent to ourselves in the mere sensation in a
certain momentum； a synthesis of homogeneous ascension from 0 up to
the given empirical consciousness； All sensations therefore as such
are given only a posteriori； but this property thereof； namely； that
they have a degree； can be known a priori。 It is worthy of remark；
that in respect to quantities in general； we can cognize a priori only
a single quality； namely； continuity； but in respect to all quality
（the real in phenomena）； we cannot cognize a priori anything more than
the intensive quantity thereof； namely； that they have a degree。 All
else is left to experience。
3。 ANALOGIES OF EXPERIENCE。
The principle of these is： Experience is possible only
through the representation of a necessary connection
of Perceptions。
PROOF。
Experience is an empirical cognition； that is to say； a cognition
which determines an object by means of perceptions。 It is therefore
a synthesis of perceptions； a synthesis which is not itself
contained in perception； but which contains the synthetical unity of
the manifold of perception in a consciousness； and this unity
constitutes the essential of our cognition of objects of the senses；
that is； of experience （not merely of intuition or sensation）。 Now
in experience our perceptions e together contingently； so that no
character of necessity in their connection appears； or can appear from
the perceptions themselves； because apprehension is only a placing
together of the manifold of empirical intuition； and no representation
of a necessity in the connected existence of the phenomena which
apprehension brings together； is to be discovered therein。 But as
experience is a cognition of objects by means of perceptions； it
follows that the relation of the existence of the existence of the
manifold must be represented in experience not as it is put together
in time； but as it is objectively in time。 And as time itself cannot
be perceived； the determination of the existence of objects in time
can only take place by means of their connection in time in general；
consequently only by means of a priori connecting conceptions。 Now
as these conceptions always possess the character of necessity；
experience is possible only by means of a representation of the
necessary connection of perception。
The three modi of time are permanence； succession； and
coexistence。 Accordingly； there are three rules of all relations of
time in phenomena； according to which the existence of every
phenomenon is determined in respect of the unity of all time； and
these antecede all experience and render it possible。
The general principle of all three analogies rests on the
necessary unity of apperception in relation to all possible
empirical consciousness （perception） at every time； consequently； as
this unity lies a priori at the foundation of all mental operations；
the principle rests on the synthetical unity of all phenomena
according to their relation in time。 For the original apperception
relates to our internal sense （the plex of all representations）；
and indeed relates a priori to its form； that is to say； the
relation of the manifold empirical consciousness in time。 Now this
manifold must be bined in original apperception according to
relations of time… a necessity imposed by the a priori
transcendental unity of apperception； to which is subjected all that
can belong to my （i。e。； my own） cognition； and therefore all that
can bee an object for me。 This synthetical and a priori
determined unity in relation of perceptions in time is therefore the
rule： 〃All empirical determinations of time must be subject to rules
of the general determination of time〃； and the analogies of
experience； of which we are now about to treat； must be rules of
this nature。
These principles have this peculiarity； that they do not concern
phenomena； and the synthesis of the empirical intuition thereof； but
merely the existence of phenomena and their relation to each other
in regard to this existence。 Now the mode in which we apprehend a
thing in a phenomenon can be determined a priori in such a manner that
the rule of its synthesis can give； that is to say； can produce this a
priori intuition in every empirical example。 But the existence of
phenomena cannot be known a priori； and although we could arrive by
this path at a conclusion of the fact of some existence； we could
not cognize that existence determinately； that is to say； we should be
incapable of anticipating in what respect the empirical intuition of
it would be distinguishable from that of others。
The two principles above mentioned； which I called math