The world of sense, as the sum total of all phenomena, contains a series of changes. For, without such a series, the mental representation of the series of time itself, as the condition of the possibility of the sensuous world, could not be presented to us.* But every change stands under its condition, which precedes it in time and renders it necessary. Now the existence of a given condition presupposes a complete series of conditions up to the absolutely unconditioned, which alone is absolutely necessary. It follows that something that is absolutely necessary must exist, if change exists as its consequence. But this necessary thing itself belongs to the sensuous world. For suppose it to exist out of and apart from it, the series of cosmical changes would receive from it a beginning, and yet this necessary cause would not itself belong to the world of sense. But this is impossible. For, as the beginning of a series in time is determined only by that which precedes it in time, the supreme condition of the beginning of a series of changes must exist in the time in which this series itself did not exist; for a beginning supposes a time preceding, in which the thing that begins to be was not in existence. The causality of the necessary cause of changes, and consequently the cause itself, must for these reasons belong to time- and to phenomena, time being possible only as the form of phenomena. Consequently, it cannot be cogitated as separated from the world of sense- the sum total of all phenomena. There is, therefore, contained in the world, something that is absolutely necessary- whether it be the whole cosmical series itself, or only a part of it.
*Objectively, time, as the formal condition of the possibility of change, precedes all changes; but subjectively, and in consciousness, the representation of time, like every other, is given solely by occasion of perception.