Full Idea
God's existence is either impossible or necessary. It can be the former only if the concept of such a being is self-contradictory or in some way logically absurd. Assuming that this is not so, it follows that He necessarily exists.
Gist of Idea
God's existence is either necessary or impossible, and no one has shown that the concept of God is contradictory
Source
Norman Malcolm (Anselm's Argument [1959], §2)
Book Reference
'The Existence of God', ed/tr. Hick,John [Macmillan 1964], p.56
A Reaction
The concept of God suggests paradoxes of omniscience, omnipotence and free will, so self-contradiction seems possible. How should we respond if the argument suggests God is necessary, but evidence suggests God is highly unlikely?