62. The transition from not-being to being implies succession: to conceive that something begins, we must conceive that something did not exist. The series
not-A, A,
has no sense if either term is wanting; and these terms, inasmuch as they are contradictory, cannot exist at the same time.
63. Let us imagine absolute nothingness. The first term, not-A, stands alone. All existence is denied: nothing can be affirmed without contradicting the supposition. Then there is no time; for time being only the succession of things, or of being and not-being,[77] cannot exist when there is nothing which can succeed. If we suppose any thing to begin, we establish the series not-A, A; in which case we imagine two different instants M and N, to which the terms of the series respectively correspond in this manner:
not-A .. A.
M .... N.
It may be said with truth: M is not N. What is the meaning of this proposition? Since time and duration in general is not distinct from the things that endure[78], N can only represent the existence of A, in relation to not-A; M in the same manner can represent only not-A, in relation to A. Hence the conception of A, in so far as it begins, contains the relation to not-A, without which it could not be conceived as begun.
64. What we have explained is conceivable on the supposition at least of one intelligence; because this intelligence would refer not-A and A to their proper duration, successively, if this duration were successive like ours; in some other way, if this duration were not successive. But if there is absolutely nothing, the series, not-A ... A, is inconceivable, since the relation of A, in so far as it begins, has no real or conceived term of comparison, unless we imagine a pure time, entirely empty, in which we suppose the terms of the series to be placed.
65. Thus it seems that by the mere fact of thinking A, in so far as begun, we think also a preceding existence, because there is no beginning unless not-A preceded A; and this precedence means nothing unless there is an existence to which it relates, either as to a successive series, or as to an immutable duration.
66. If A must be preceded by an existence B, then nothing can begin independently of a preceding existence, or unless something already exists; or the simple conception of succession implies the necessity of something always existing, in order that something may begin.
67. As duration is nothing distinct from things, the two terms of the series, B, A, of which one precedes the other, cannot be placed in an absolute duration distinct from the things themselves, as in two distinct instants, independently of the things. The relation, then, which exists between B and A is not a relation of one instant to another, since the instants in themselves are nothing, but of one thing to another. Therefore A, inasmuch as it begins, has a necessary relation to B. Therefore B is the necessary condition of the existence of A. Therefore it is demonstrated that every being which begins, depends on an existent being.