Section VIII. Regulative Principle of Pure Reason in relation to the

Cosmological Ideas

The cosmological principle of totality could not give us any certain

knowledge in regard to the maximum in the series of conditions in the

world of sense, considered as a thing in itself. The actual regress in

the series is the only means of approaching this maximum. This

principle of pure reason, therefore, may still be considered as

valid—not as an axiom enabling us to cogitate totality in the object as

actual, but as a problem for the understanding, which requires it to

institute and to continue, in conformity with the idea of totality in

the mind, the regress in the series of the conditions of a given

conditioned. For in the world of sense, that is, in space and time,

every condition which we discover in our investigation of phenomena is

itself conditioned; because sensuous objects are not things in

themselves (in which case an absolutely unconditioned might be reached

in the progress of cognition), but are merely empirical representations

the conditions of which must always be found in intuition. The

principle of reason is therefore properly a mere rule—prescribing a

regress in the series of conditions for given phenomena, and

prohibiting any pause or rest on an absolutely unconditioned. It is,

therefore, not a principle of the possibility of experience or of the

empirical cognition of sensuous objects—consequently not a principle of

the understanding; for every experience is confined within certain

proper limits determined by the given intuition. Still less is it a

constitutive principle of reason authorizing us to extend our

conception of the sensuous world beyond all possible experience. It is

merely a principle for the enlargement and extension of experience as

far as is possible for human faculties. It forbids us to consider any

empirical limits as absolute. It is, hence, a principle of reason,

which, as a rule, dictates how we ought to proceed in our empirical

regress, but is unable to anticipate or indicate prior to the empirical

regress what is given in the object itself. I have termed it for this

reason a regulative principle of reason; while the principle of the

absolute totality of the series of conditions, as existing in itself

and given in the object, is a constitutive cosmological principle. This

distinction will at once demonstrate the falsehood of the constitutive

principle, and prevent us from attributing (by a transcendental

subreptio) objective reality to an idea, which is valid only as a rule.

In order to understand the proper meaning of this rule of pure reason,

we must notice first that it cannot tell us what the object is, but

only how the empirical regress is to be proceeded with in order to

attain to the complete conception of the object. If it gave us any

information in respect to the former statement, it would be a

constitutive principle—a principle impossible from the nature of pure

reason. It will not therefore enable us to establish any such

conclusions as: “The series of conditions for a given conditioned is in

itself finite,” or, “It is infinite.” For, in this case, we should be

cogitating in the mere idea of absolute totality, an object which is

not and cannot be given in experience; inasmuch as we should be

attributing a reality objective and independent of the empirical

synthesis, to a series of phenomena. This idea of reason cannot then be

regarded as valid—except as a rule for the regressive synthesis in the

series of conditions, according to which we must proceed from the

conditioned, through all intermediate and subordinate conditions, up to

the unconditioned; although this goal is unattained and unattainable.

For the absolutely unconditioned cannot be discovered in the sphere of

experience.

We now proceed to determine clearly our notion of a synthesis which can

never be complete. There are two terms commonly employed for this

purpose. These terms are regarded as expressions of different and

distinguishable notions, although the ground of the distinction has

never been clearly exposed. The term employed by the mathematicians is

progressus in infinitum. The philosophers prefer the expression

progressus in indefinitum. Without detaining the reader with an

examination of the reasons for such a distinction, or with remarks on

the right or wrong use of the terms, I shall endeavour clearly to

determine these conceptions, so far as is necessary for the purpose in

this Critique.

We may, with propriety, say of a straight line, that it may be produced

to infinity. In this case the distinction between a progressus in

infinitum and a progressus in indefinitum is a mere piece of subtlety.

For, although when we say, “Produce a straight line,” it is more

correct to say in indefinitum than in infinitum; because the former

means, “Produce it as far as you please,” the second, “You must not

cease to produce it”; the expression in infinitum is, when we are

speaking of the power to do it, perfectly correct, for we can always

make it longer if we please—on to infinity. And this remark holds good

in all cases, when we speak of a progressus, that is, an advancement

from the condition to the conditioned; this possible advancement always

proceeds to infinity. We may proceed from a given pair in the

descending line of generation from father to son, and cogitate a

never-ending line of descendants from it. For in such a case reason

does not demand absolute totality in the series, because it does not

presuppose it as a condition and as given (datum), but merely as

conditioned, and as capable of being given (dabile).

Very different is the case with the problem: “How far the regress,

which ascends from the given conditioned to the conditions, must

extend”; whether I can say: “It is a regress in infinitum,” or only “in

indefinitum”; and whether, for example, setting out from the human

beings at present alive in the world, I may ascend in the series of

their ancestors, in infinitum—or whether all that can be said is, that

so far as I have proceeded, I have discovered no empirical ground for

considering the series limited, so that I am justified, and indeed,

compelled to search for ancestors still further back, although I am not

obliged by the idea of reason to presuppose them.

My answer to this question is: “If the series is given in empirical

intuition as a whole, the regress in the series of its internal

conditions proceeds in infinitum; but, if only one member of the series

is given, from which the regress is to proceed to absolute totality,

the regress is possible only in indefinitum.” For example, the division

of a portion of matter given within certain limits—of a body, that

is—proceeds in infinitum. For, as the condition of this whole is its

part, and the condition of the part a part of the part, and so on, and

as in this regress of decomposition an unconditioned indivisible member

of the series of conditions is not to be found; there are no reasons or

grounds in experience for stopping in the division, but, on the

contrary, the more remote members of the division are actually and

empirically given prior to this division. That is to say, the division

proceeds to infinity. On the other hand, the series of ancestors of any

given human being is not given, in its absolute totality, in any

experience, and yet the regress proceeds from every genealogical member

of this series to one still higher, and does not meet with any

empirical limit presenting an absolutely unconditioned member of the

series. But as the members of such a series are not contained in the

empirical intuition of the whole, prior to the regress, this regress

does not proceed to infinity, but only in indefinitum, that is, we are

called upon to discover other and higher members, which are themselves

always conditioned.

In neither case—the regressus in infinitum, nor the regressus

in indefinitum, is the series of conditions to be considered as

actually infinite in the object itself. This might be true of things

in themselves, but it cannot be asserted of phenomena, which, as

conditions of each other, are only given in the empirical regress

itself. Hence, the question no longer is, “What is the quantity of

this series of conditions in itself—is it finite or infinite?” for

it is nothing in itself; but, “How is the empirical regress to be

commenced, and how far ought we to proceed with it?” And here a signal

distinction in the application of this rule becomes apparent. If the

whole is given empirically, it is possible to recede in the series of

its internal conditions to infinity. But if the whole is not given, and

can only be given by and through the empirical regress, I can only say:

“It is possible to infinity, to proceed to still higher conditions in

the series.” In the first case, I am justified in asserting that more

members are empirically given in the object than I attain to in the

regress (of decomposition). In the second case, I am justified only

in saying, that I can always proceed further in the regress, because

no member of the series is given as absolutely conditioned, and thus

a higher member is possible, and an inquiry with regard to it is

necessary. In the one case it is necessary to find other members of the

series, in the other it is necessary to inquire for others, inasmuch as

experience presents no absolute limitation of the regress. For, either

you do not possess a perception which absolutely limits your empirical

regress, and in this case the regress cannot be regarded as complete;

or, you do possess such a limitative perception, in which case it is

not a part of your series (for that which limits must be distinct from

that which is limited by it), and it is incumbent on you to continue

your regress up to this condition, and so on.

These remarks will be placed in their proper light by their application

in the following section.

The Critique of Pure Reason · 第 8 / 12 章