Malcolm develops the second form of Anselm's argument (with necessary existence) and puts it into a modern form.
Argument: nothing greater than god can be concived; god cannot begin to exist (would mean there is something causing god, making the definition innacurate).
Argument (2): if god cannot begin to exist he is either impossible or necessary. He is not impossible as it is not logically absurd. He is necessary.
Objection: if we look at why god is not necessary, it is possible to have a world without god.