The archaic Ontological arguments for the Existence of God were undermined by reliance on the term ‘Exists’ as a
predicate. The more recent modal logic attempts are more thorough.If we assume the modal logic Axiom S5,then:It is
proposed that a being has maximal excellence in a given possible world W if and only if it is omnipotent,
omniscient and wholly good in W; and
It is proposed that a being has maximal greatness if it has maximal excellence in every possible world.
Maximal greatness is possibly exemplified. That is, it is possible that there be a being that has maximal
greatness. (Premise)
Therefore, possibly it is necessarily true that an omniscient, omnipotent and perfectly good being exists.
Therefore, it is necessarily true that an omniscient, omnipotent and perfectly good being exists. (By S5)
Therefore, an omniscient, omnipotent and perfectly good being exists.
(Axiom S5 is :if necessarily possibly p, then possibly p and if possibly necessarily p then necessarily p. The argument succeds or fails by this assumption)