To demonstrate the existence of a necessary being, I cannot be permitted in this place to employ any other than the cosmological argument, which ascends from the conditioned in phenomena to the unconditioned in conception- the unconditioned being considered the necessary condition of the absolute totality of the series. The proof, from the mere idea of a supreme being, belongs to another principle of reason and requires separate discussion.
The pure cosmological proof demonstrates the existence of a necessary being, but at the same time leaves it quite unsettled, whether this being is the world itself, or quite distinct from it. To establish the truth of the latter view, principles are requisite, which are not cosmological and do not proceed in the series of phenomena. We should require to introduce into our proof conceptions of contingent beings- regarded merely as objects of the understanding, and also a principle which enables us to connect these, by means of mere conceptions, with a necessary being. But the proper place for all such arguments is a transcendent philosophy, which has unhappily not yet been established.
But, if we begin our proof cosmologically, by laying at the foundation of it the series of phenomena, and the regress in it according to empirical laws of causality, we are not at liberty to break off from this mode of demonstration and to pass over to something which is not itself a member of the series. The condition must be taken in exactly the same signification as the relation of the conditioned to its condition in the series has been taken, for the series must conduct us in an unbroken regress to this supreme condition. But if this relation is sensuous, and belongs to the possible empirical employment of understanding, the supreme condition or cause must close the regressive series according to the laws of sensibility and consequently, must belong to the series of time. It follows that this necessary existence must be regarded as the highest member of the cosmical series.
Certain philosophers have, nevertheless, allowed themselves the liberty of making such a saltus (metabasis eis allo gonos). From the changes in the world they have concluded their empirical contingency, that is, their dependence on empirically-determined causes, and they thus admitted an ascending series of empirical conditions: and in this they are quite right. But as they could not find in this series any primal beginning or any highest member, they passed suddenly from the empirical conception of contingency to the pure category, which presents us with a series- not sensuous, but intellectual- whose completeness does certainly rest upon the existence of an absolutely necessary cause. Nay, more, this intellectual series is not tied to any sensuous conditions; and is therefore free from the condition of time, which requires it spontaneously to begin its causality in time. But such a procedure is perfectly inadmissible, as will be made plain from what follows.
In the pure sense of the categories, that is contingent the contradictory opposite of which is possible. Now we cannot reason from empirical contingency to intellectual. The opposite of that which is changed- the opposite of its state- is actual at another time, and is therefore possible. Consequently, it is not the contradictory opposite of the former state. To be that, it is necessary that, in the same time in which the preceding state existed, its opposite could have existed in its place; but such a cognition is not given us in the mere phenomenon of change. A body that was in motion = A, comes into a state of rest = non-A. Now it cannot be concluded from the fact that a state opposite to the state A follows it, that the contradictory opposite of A is possible; and that A is therefore contingent. To prove this, we should require to know that the state of rest could have existed in the very same time in which the motion took place. Now we know nothing more than that the state of rest was actual in the time that followed the state of motion; consequently, that it was also possible. But motion at one time, and rest at another time, are not contradictorily opposed to each other. It follows from what has been said that the succession of opposite determinations, that is, change, does not demonstrate the fact of contingency as represented in the conceptions of the pure understanding; and that it cannot, therefore, conduct us to the fact of the existence of a necessary being. Change proves merely empirical contingency, that is to say, that the new state could not have existed without a cause, which belongs to the preceding time. This cause- even although it is regarded as absolutely necessary- must be presented to us in time, and must belong to the series of phenomena.