Of Gods and Unicorns: there must be a mistake with the ontological argument

Argument A: The Ontological Argument for the Existence of God (1) God is a being greater than which none can be conceived (or the Greatest Conceivable Being). (2) The Greatest Conceivable Being does exist in the mind. (3) If the Greatest Conceivable Being were to exist in only the mind, we could conceive of a…