subsequent to that in which the former existed。 In like manner； the
second state； as reality （in the phenomenon）； differs from the
first； in which the reality of the second did not exist； as b from
zero。 That is to say； if the state； b； differs from the state； a； only
in respect to quantity； the change is a ing into existence of b …
a； which in the former state did not exist； and in relation to which
that state is = O。
Now the question arises how a thing passes from one state = a；
into another state = b。 Between two moments there is always a
certain time； and between two states existing in these moments there
is always a difference having a certain quantity （for all parts of
phenomena are in their turn quantities）。 Consequently； every
transition from one state into another is always effected in a time
contained between two moments； of which the first determines the state
which leaves； and the second determines the state into the thing
passes。 the thing leaves； and the second determines the state into
which the thing Both moments； then； are limitations of the time of a
change； consequently of the intermediate state between both； and as
such they belong to the total of the change。 Now every change has a
cause； which evidences its causality in the whole time during which
the charge takes place。 The cause； therefore； does not produce the
change all at once or in one moment； but in a time； so that； as the
time gradually increases from the mencing instant； a； to its
pletion at b； in like manner also； the quantity of the reality
（b … a） is generated through the lesser degrees which are contained
between the first and last。 All change is therefore possible only
through a continuous action of the causality； which； in so far as it
is uniform； we call a momentum。 The change does not consist of these
momenta； but is generated or produced by them as their effect。
Such is the law of the continuity of all change； the ground of which
is that neither time itself nor any phenomenon in time consists of
parts which are the smallest possible； but that； notwithstanding；
the state of a thing passes in the process of a change through all
these parts； as elements； to its second state。 There is no smallest
degree of reality in a phenomenon； just as there is no smallest degree
in the quantity of time； and so the new state of reality grows up
out of the former state； through all the infinite degrees thereof； the
differences of which one from another； taken all together； are less
than the difference between o and a。
It is not our business to inquire here into the utility of this
principle in the investigation of nature。 But how such a
proposition； which appears so greatly to extend our knowledge of
nature； is possible pletely a priori； is indeed a question which
deserves investigation； although the first view seems to demonstrate
the truth and reality of the principle； and the question； how it is
possible； may be considered superfluous。 For there are so many
groundless pretensions to the enlargement of our knowledge by pure
reason that we must take it as a general rule to be mistrustful of all
such； and without a thoroughgoing and radical deduction； to believe
nothing of the sort even on the clearest dogmatical evidence。
Every addition to our empirical knowledge； and every advance made in
the exercise of our perception； is nothing more than an extension of
the determination of the internal sense； that is to say； a progression
in time； be objects themselves what they may； phenomena； or pure
intuitions。 This progression in time determines everything； and is
itself determined by nothing else。 That is to say； the parts of the
progression exist only in time； and by means of the synthesis thereof；
and are not given antecedently to it。 For this reason； every
transition in perception to anything which follows upon another in
time； is a determination of time by means of the production of this
perception。 And as this determination of time is； always and in all
its parts； a quantity； the perception produced is to be considered
as a quantity which proceeds through all its degrees… no one of
which is the smallest possible… from zero up to its determined degree。
From this we perceive the possibility of cognizing a priori a law of
changes… a law； however； which concerns their form merely。 We merely
anticipate our own apprehension； the formal condition of which；
inasmuch as it is itself to be found in the mind antecedently to all
given phenomena； must certainly be capable of being cognized a priori。
Thus； as time contains the sensuous condition a priori of the
possibility of a continuous progression of that which exists to that
which follows it； the understanding； by virtue of the unity of
apperception； contains the condition a priori of the possibility of
a continuous determination of the position in time of all phenomena；
and this by means of the series of causes and effects； the former of
which necessitate the sequence of the latter； and thereby render
universally and for all time； and by consequence； objectively； valid
the empirical cognition of the relations of time。
C。 THIRD ANALOGY。
Principle of Coexistence； According to the Law
of Reciprocity or munity。
All substances； in so far as they can be perceived in space
at the same time； exist in a state of plete reciprocity
of action。
PROOF。
Things are coexistent； when in empirical intuition the perception of
the one can follow upon the perception of the other； and vice versa…
which cannot occur in the succession of phenomena； as we have shown in
the explanation of the second principle。 Thus I can perceive the
moon and then the earth； or conversely； first the earth and then the
moon； and for the reason that my perceptions of these objects can
reciprocally follow each other； I say； they exist contemporaneously。
Now coexistence is the existence of the manifold in the same time。 But
time itself is not an object of perception； and therefore we cannot
conclude from the fact that things are placed in the same time； the
other fact； that the perception of these things can follow each
other reciprocally。 The synthesis of the imagination in apprehension
would only present to us each of these perceptions as present in the
subject when the other is not present； and contrariwise； but would not
show that the objects are coexistent； that is to say； that； if the one
exists； the other also exists in the same time； and that this is
necessarily so； in order that the perceptions may be capable of
following each other reciprocally。 It follows that a conception of the
understanding or category of the reciprocal sequence of the
determinations of phenomena （existing； as they do； apart from each
other； and yet contemporaneously）； is requisite to justify us in
saying that the reciprocal succession of perceptions has its
foundation in the object； and to enable us to represent coexistence as
objective。 But that relation of substances in which the one contains
determinations the ground of which is in the other substance； is the
relation of influence。 And； when this influence is reciprocal； it is
the relation of munity or reciprocity。 Consequently the coexistence
of substances in space cannot be cognized in experience otherwise than
under the precondition of their reciprocal action。 This is therefore
the condition of the possibility of things themselves as objects of
experience。
Things are coexistent； in so far as they exist in one and the same
time。 But how can we know that they exist in one and the same time？
Only by observing that the order in the synthesis of apprehension of
the manifold is arbitrary and a matter of indifference； that is to
say； that it can proceed from A； through B； C； D； to E； or
contrariwise from E to A。 For if they were successive in time （and
in the order； let us suppose； which begins with A）； it is quite
impossible for the apprehension in perception to begin with E and go
backwards to A； inasmuch as A belongs to past time and； therefore；
cannot be an object of apprehension。
Let us assume that in a number of substances considered as phenomena
each is pletely isolated； that is； that no one acts upon another。
Then I say that the coexistence of these cannot be an object of
possible perception and that the existence of one cannot； by any
mode of empirical synthesis； lead us to the existence of another。
For we imagine them in this case to be separated by a pletely
void space； and thus perception； which proceeds from the one to the
other in time； would indeed determine their existence by means of a
following perception； but would be quite unable to distinguish whether
the one phenomenon follows objectively upon the first； or is
coexistent with it。
Besides the mere fact of existence； then； there must be something by
means of which A determines the position of B in time and； conversely；
B the position of A； because only under this condition can
substances be empirically represented as existing contemporaneously。
Now that alone determines the position of another thing in time
which is th