Problem of non-God objects
This argument is aimed primarily at Anselmian conceptions of God or Perfect being Theology. Proponents of Perfect Being Theology typically assert that properties like knowledge, power, love etc. are properties contributing to greatness. So if a god exists and is a maximally great being, then it must have the maximum possible amount of these properties.
Christian philosopher J.P. Moreland writes,
"To say that God is perfect means that there is no possible world where he has his attributes to a greater degree... God is not the most loving being that happens to exist, he is the most loving being that could possibly exist so that God’s possessing the attribute of being loving is to a degree such that it is impossible for him to have it to a greater degree."
Earlier, similar arguments
Benedict de Spinoza argued something similar in the appendix to Part 1 of his Ethics:
"Further, this doctrine does away with the perfection of God: for, if God acts for an object, he necessarily desires something which he lacks. Certainly, theologians and metaphysicians draw a distinction between the object of want and the object of assimilation; still they confess that God made all things for the sake of himself, not for the sake of creation. They are unable to point to anything prior to creation, except God himself, as an object for which God should act, and are therefore driven to admit (as they clearly must), that God lacked those things for whose attainment he created means, and further that he desired them."
The Basic Argument
Consider the concept of "GodWorld," a possible world in which God never actually creates anything. If we presume that that God exists, we can assume that GodWorld could exist, since the act of creating the universe (or any non-God object) was a choice that was not borne of necessity.
- Proposition P1: If the Christian God exists, then GodWorld is the unique best possible world.
- Proposition P2: If GodWorld is the unique best possible world, then the Christian God would maintain GodWorld.
- Proposition P3: GodWorld is false because the Universe (or any non-God object) exists.
- Conclusion: Therefore, the Christian God, as so defined, does not exist.
If God exists, he is an ontologically perfect being - meaning he has those great-making properties to their maximal compossible degrees and no such properties to any lesser degree. A world comprised of only the maximally-great being for eternity would be a world comprised of all those great-making properties to their maximal compossible degrees and no such properties to any lesser degree. Unless there is some source of unique Goodness - Goodness that exists outside of and fully independent of God, GodWorld must be the unique best possible world. GodWorld eternally sustains the highest overall ontological purity and, therefore, overall ontological quality to which no other world can compare, therefore it is the unique best possible world.
An omniscient being would be aware of the fact that himself existing alone for eternity as GodWorld is the unique best possible world that could ever exist, and because God is essentially morally perfect, he couldn’t have a motivating reason to intentionally alter the overall maximal purity and, therefore, the quality of the unique best possible world - because any alteration in overall purity by the introduction of a universe or any Non-God object, would, by necessity, be a degradation of overall purity and, therefore, overall quality. God wouldn’t introduce limited entities each with their own unimpressive set of degraded great-making properties like the creation myth of Genesis records. While Adam and Eve clearly do have great-making properties (knowledge, power), they have them to an unimpressive degree and so introducing such beings would result in a degradation of overall ontological purity and, therefore, a degradation of overall ontological quality. To suggest God is in the degrading business is to suggest he wasn’t maximally great in the first place.
P3 is the easiest of the three to justify. It can be justified merely by a simple recognition that you, yourself, are not God.