I use the term conditional theistic monism (CTM) for the view that if god exists, only god exists. I’m not sure I can think of a header image for this one. Here’s the argument.
- What matters in the survival of a person is Relation R (following Parfit) — strong overlapping chains of strong psychological connectedness between mental states by any reliable cause.
- What matters in the survival of a person is all that matters in the existence of a person.
- All that matters in the existence of a person is Relation R. (from 1 & 2)
- Knowledge of what it is like to have any mental state requires possession of that mental state.
- God — an omniscient being — would know what it is like to have all mental states.
- God would possess all mental states. (from 4 & 5)
- Possession of all mental states entails possession of all psychological connections between those states.
- God would be a reliable cause for psychological connectedness between mental states.
- God would sustain all instances of Relation R. (from 6, 7 & 8)
- God’s existence would be a sufficient condition for everything that matters about the existence of all persons. (from 3 & 9)
- All that could matter about the existence of the universe is that it causes persons to exist.
- If God exists, the existence of the universe does not matter. (from 10 & 11)
- God would never act arbitrarily — that is, without good reasons.
- If it doesn’t matter whether the universe exists independently of God, there would be no good reason for God to create the universe.
- God would not create the universe. (from 12, 13 and 14)
- Therefore if God exists, only God exists. (entailed by 15)
This argument won’t convince many classical theists, but I’m still curious to what extent a classical theistic conception of god as omnipotent, omniscient, omnibenevolent, and eternal or everlasting could be consistent with CTM.