Chapter XLV: Section VIII

THE REGULATIVE PRINCIPLE OF PURE REASON IN REGARD TO THE COSMOLOGICAL IDEAS[1562]

The principle of pure Reason, correctly formulated, is that when the conditioned is given a regress upon the totality of its conditions is _set as a problem_. As such it is valid,

“...not indeed as an _axiom_ ... but as a _problem_ for the
understanding ..., leading it to undertake and to continue,
according to the completeness in the Idea, the regress in the
series of conditions of any given conditioned.”[1563]

It does not anticipate, prior to the regress, what actually exists as object, but only postulates, in the form of a rule, how the understanding ought to proceed. It does not tell us whether or how the unconditioned exists, but how the empirical regress is to be carried out under the guidance of a mere Idea. Such a rule can be regulative only, and the Idea of totality which it contains must never be invested with objective reality. As the absolutely unconditioned can never be met with in experience, we know, indeed, beforehand that in the process of the regress the unconditioned will never be reached. But the duty of seeking it by way of such regress is none the less prescribed.

Kant proceeds to give a somewhat bewildering account of the familiar distinction between _progressus in infinitum_ and _progressus in indefinitum_, and to draw a very doubtful distinction between the series in division of a given whole and the series in extension of it.[1564] The illustration from the series of human generations is an unfortunate one; the discovery that it began at some one point in the past would not necessarily violate any demand of Reason. Such a series is not comparable with those of space, time, and causality.[1565] The only important result of this digression is the conclusion that whatever demand be made, whether of regress _in infinitum_ or of regress _in indefinitum_, in neither case can the series of conditions be regarded as being given as infinite in the object.

“The question, therefore, is no longer how great this series of
conditions may be in itself, whether finite or infinite, for it is
nothing in itself; but how we are to carry out the empirical
regress, and how far we should continue it.”[1566]

We have already noted[1567] Kant’s ambiguous suggestion in A 499 = B 527, that in the empirical regress there can be no lack of given conditions. The statement, thus interpreted, is illegitimate. The most that he can claim is that, were further sensations not forthcoming, we should still have to conceive those last obtained as being preceded by empty space and time, and as lacking in any experienced cause. Under such circumstances we should experience neither finitude nor unconditionedness, but only incapacity to find a content suitable to the inexhaustible character of the spatial and temporal conditions of experience, or in satisfaction of our demand for causal antecedents. In A 514-15 = B 542-3 Kant shows consciousness of this difficulty, but in dealing with it adopts a half-way position which still lies open to objection. He recognises that, since no member of a series can be empirically given as absolutely unconditioned, a higher member is always _possible_, and that the search for it is therefore prescribed; none the less he asserts that in regard to _given wholes_ we are justified in taking up a very different position, namely, that the regress in the series of their internal conditions does not proceed, as in the above case, _in indefinitum_, but _in infinitum_, _i.e._ that in this case more members _exist and are empirically given_ than we can reach through the regress. In given wholes we are commanded to _find_ more members; in serial extension we are justified only in _inquiring_ for more. This half-way position is a makeshift, and is in no respect tenable. The evidence for the infinite extensibility of space and time is as conclusive as for their infinite divisibility. And when we consider sensuous existence under these forms, it is just as possible that the transcendental object may, beyond a certain point, fail to supply material for further division, as that it may fail to yield data for further expansion. What Kant asserts of the latter, that further advance must always remain as a possibility, and for that Reason must always call for the open mind of further inquiry, without any attempted anticipatory assertion either _pro_ or _contra_, alone represents the true Critical standpoint. The cessation of data may really, however, be due to an increase in the subtlety of the conditioning processes that incapacitates them from acting upon our senses;[1568] by indirect means this disability may be overcome. Reason, in its conception of an unconditioned, prescribes to us a task that is inexhaustible in its demands. We have no right to lay down our intellectual arms before any barrier however baffling, or to despair before any chasm however empty and abrupt.