Abstract

This essay argues that Anselm’s Proslogium II is self-invalidating and that it must be so in order for Proslogium III to be a valid argument. It begins by differentiating between necessary existence, logical possibility, and contingency, establishing that necessary existence can never be treated as a matter of logical possibility. In turn, possibility must always be defined alongside the concept of contingency. It is then further shown that necessity can in no sense be possible, for the possible implies the contingent at some future time. In the context of Anselm’s Proslogium II, this means that the proposition that that-than-which-nothing-greater-can-be-conceived could exist invalidates Anselm’s conclusion that it does exist in reality for it confines Deity to contingent actuality only. Furthermore, it is shown that the conclusion of Proslogium III—that a necessary being is that than which nothing greater can be conceived—rests on the invalidity of the contingent actuality established in Proslogium II, which is shown to be invalid retrospectively as a logical consequence of the validity of III and prospectively as the condition for the validity of III. It is not that III is merely the stronger of the two arguments; it is, if correct, the only valid argument.