 What has existed from eternity can only be either an independent being (one having in itself the reason of its existence) or an infinite series of dependent beings. However, such an infinite series cannot be what has existed from eternity because by hypothesis it can have no external cause, and no internal cause (no dependent being in the series) can cause the whole series. Hence, an independent being exists. A frequent objection to this argument is that the demand for an explanation is satisfied when it is conceded that each being in the series has a cause (Rowe 1971, 56–57). The series is not a new entity to be explained, so there is no reason to appeal to an eternal, independent being. Furthermore, if the series is not dependent, then it is not contingent, and if it is not contingent, then it is necessary. Clarke finds this options unacceptable, as have many since (including Rowe 1973, 57–59, and van Inwagen 2014, 159–182), but Clarke’s appeal to God’s will to maintain the contingency of the created world has been challenged, especially by Leibniz (see 3.2, above).