If this is correct, then Anselm's second version of the argument also fails.
The ontological argument is clearly logically valid—that is to say, the conclusion necessarily follows provided that Premises 1 to 5 are true. God exists in the understanding. Hence Even the Fool cannot reasonably deny that that than which no greater can be conceived exists in reality Hence That than which no greater can be conceived exists in reality.
Nor, as Spinoza observed, will it make sense to say that something could prevent Him from existing. Now if I take the subject God with all its predicates omnipotence being oneand say, God is, or There is a God, I add no new predicate to the conception of God, I merely posit or affirm the existence of the subject with all its predicates - I posit the object in relation to my conception.
Therefore, the existence of God is logically necessary. Therefore, a maximally great being that is, God exists in every logically possible world. Also, it has been explained that the perfection of a thing is the thing itself, and not a thing in addition to it.