Excellence: How great something is when considered with respect to one world.
Greatness: How great something is when considered in relation to all possible worlds.
(25) It is possible that there be a being that has
maximal greatness.
(26) So there is a possible being that in some
world W has maximal greatness.
(27) A being has maximal greatness in a given
world only if it has maximal excellence in every world.
(28) A being has maximal excellence in a given world only if it has omniscience, omnipotence, and moral perfection in that world.
a. So, it is impossible at W that the being fail to exist or fail to have omniscience, omnipotence or moral perfection
b. So, it is impossible actually that the being fail to exist or fail to have omniscience, omnipotence or moral perfection. (By S5)
c. So, the being exists and has omniscience, omnipotence and moral perfection.
1. If a perfect being exists, then it is necessary that a perfect being exists. (Premise)
2. It’s possible that no perfect being exists. (Premise)
3. If it’s possible that no perfect being exists, then no perfect being exists. (By 1)
4. So, no perfect being exists. (By 2 and 3)