Here is an argument on a forum I read. I shall not disclose either for sake of anonymity.
I came with this argument when I was arguing with a friend about the indestructibility of adamantium. Anyway, it goes more or less like this:
1.- All properties of God are assumed to be necessary.
2.- God changed at least one of his properties at one point.
3.- Therefore not all properties of God are necessary.
4.- From (3), and the PSR, at least one of God properties is contingent.
5.- If one of God’s properties are contingent, it is possible to conceive a God with a different set of properties.
6.- Therefore there may be more than one possible God.
1 I think it’s straightfoward. Since God is eternal and has existed since always, then his properties are necessary and uncaused and all that stuff. 2 seems to be the crux of the argument. I think it is true because God was in a timeless state and then turned into a state in time. Necessary properties can’t change by definition so at least the timeless state of God isn’t necessary. This can also be work out with Jesus, as he was once an aspect of God that existed timelessly ( in the trinity, sans creation of the universe ) and then in time ( as a human, 2000 years ago when He died in the cross for us ).
5 follows I guess, if God’s property is contingent, then it’s logical to conceive a God that lacks it, although it also raise the question if God is a MGB even if he has contingent properties or if he lose one, it also raise the issue from where did it came this property ( allowing the PSR, the question is: ¿where did this proeprty came from?). Anyway, I think many arguments can be constructed from this but I’ve not sleep in 2 days so I can’t think straigh enough to make more arguments, ¿what do you think, anyway?
This will serve as a good exercise for looking at arguments. The first thing to do is to see if the argument is logically valid. (1) is a premise so that’s fine. (2) is also a premise. (3) technically doesn’t follow given the verbiage used. Take a necessary property to be a property that if a thing exists, then it has that property in every possible world. Given that, it could be the case that the property is had in every possible world while not being had eternally in this world. Here it might be objected that if the property is not had at one possible time while had at another, then we could make that a possible world. That’s not obvious though and it needs an additional premise to get to the desired conclusion.
As to (4), it follows logically, but the PSR (principle of sufficient reason) has nothing to do with it. Instead, it follows because if it is the case that God has a certain property P, but He that property is not necessary, then it follows that God has P in one world and does not have P in another world. That is to say that P is a contingent property. (5) is a premise and so validity does not come into the matter. (6) doesn’t follow by the premises given since if we use modus ponens on (5) by saying that God has a contingent property (premise (4)), then all that follows is that “ it is possible to conceive a God with a different set of properties.” However, that’s not the conclusion that is given and so the argument does not follow as is. Therefore, this argument is not logically valid at multiple points.
Nonetheless, the basic thought behind the argument is that if God has some properties contingently, then there can be multiple Gods. However, the problem with this is that it simply is not true. There are essential and accidental properties. Essential properties are properties that a thing having those properties cannot not have; accidental properties are properties that the thing can or cannot have and still be that thing. Let this world be world A. Given S5 (a modal logic system), I have the essential property of “existing-at-A” because in every possible world it would be true of me that I exist at A, since I exist at A. However, I also have accidental properties like “having two and one-half inch long hair”. Certainly, I could get my haircut tomorrow and I would still be the same person!
That discussion entails the following: God can have certain properties accidentally (and thus contingently) and still be God. For instance, God has the property of “instantiating A”. However, there is a possible world B where He does not instantiate A (or else it wouldn’t be B) and thus he lacks the property “instantiating A”. Nonetheless, that Being is still God because He hasn’t lost an essential property. Therefore, a simple understanding of the difference between accidental and essential properties is enough to defeat this argument.