Anselm's Ontological Argument for God's Existence Reconstructed

Anslem's Ontological Argument in Proslogion 2 is one of the most fascinating ontological arguments.  Moreover, I think it is one of the most fascinating arguments, period.  The very short of it is that if you have the idea of God, you're committed to a contradiction if you believe that God only exists in your mind and not in extra-mental reality.  The key to the argument--the most controversial assumption, I think, is that there are two modes of being--being-in-the-mind and being-in-reality.  For Anselm, a property may be had-in-reality or may be had-in-thought.  Pegasus--the winged horse--has-in-thought the property of being a horse.  If Pegasus existed outside of thought, Pegasus would have the property had-in-reality of being a horse.  Alas, Pegasus does not have the latter property.  I said that this modal assumption is controversial, nonetheless, it seems to me plausible.

Below is my reconstruction of Lynne Rudder Baker and Gareth Matthews' very interesting 2010 The Review of Metaphysics article, "Anselm's Argument Reconsidered," explicating and defending Anselm's argument: