 According to the Ontological Argument, it is self-evident from the idea of the most real being that that being exists. Whatever it is that is this most real being, it must include all predicates that contribute to its greatness or reality; and given that actual existence is (allegedly) one such predicate, whatever it is that is the most real being is therefore a being who by definition must exist. Hence, if one were to compare two beings, both equally great in all respects except that one exists and one does not, the one that does not exist, by virtue of its non-existence, is lacking a predicate that contributes to the greatness of the other. The correct conception of that than which nothing greater can be conceived must, therefore, include existence.