Tuesday, February 15, 2011

Omnipotence and necessary existence

A common argument against theism is to argue that some of God's properties are inconsistent. For example, the logical problem of evil is the objection that God's omnipotence is logically incompatible with his benevolence. I want to highlight another potential incompatibility that I have not seen discussed in the literature: between God's omnipotence and necessary existence. (If I've missed it, please let me know.)

Theists generally agree that God is omnipotent and exists necessarily. On the standard semantics for modal logic,  existing necessarily is existing in every possible world. It's important to notice, however, that existing in every possible world does not entail existing at every time in every possible world. Consider a non-theological example. It may be true that, in each possible world, there exists a first event in the history of that possible world. Perhaps for our world this is the first instant of the Big Bang. On a presentist theory of time, for which only the present exists, it will not be the case that in each possible world the first event in the world's history always exists.

I've shown that necessarily existing and necessarily always existing can come apart. This opens up logical space for two kinds of arguments against theism, understood as the thesis that there is one and only one maximally perfect being that exists at all times in all possible worlds.

The first argument:
(1) God necessarily exists. That is, for all possible worlds W, there is at least one time t in W at which God exists.
(2) Necessarily, in virtue of God's omnipotence, God can bring it about that God no longer exists. That is, for all worlds W, there is at least one time t* at which it is possible that God does not exist.
(3) It is not the case that there is at least one maximally perfect being at all times in all possible worlds, i.e. theism is false.

The second argument:
(4) God necessarily exists. That is, for all possible worlds W, there is at least one time t in W at which God exists.
(5) Necessarily, in virtue of God's omnipotence, God can bring it about that another maximally perfect being also exists. That is, for all worlds W, there is at least one time t* at which it is possible that God is not the only maximally perfect being that exists.
(6) It is not the case that there is at most one maximally perfect being at all times in all possible worlds, i.e. theism is false.

What should we think of these two anti-theistic arguments? While I don't think either one is sound, I think they're both interesting insofar as they highlight two ways in which omnipotence and necessary existence can be incompatible. One way is if God is capable of bringing it his own non-existence. Another is if God is capable of bringing about another maximally perfect being. Now, the second possibility might be objected to on the grounds that two maximally perfect beings cannot coexist. If that scenario is a logical impossibility, then it will not fall under God's omnipotence to be able to bring it about. 

The first scenario, that of God bringing about his own non-existence, is perhaps a more interesting case. A theist might object that this scenario is metaphysically impossible, since God exists necessarily. But, because I've shown that necessarily existing and necessarily always existing can come apart, this objection requires further elaboration. 

Another objection that the theist might appeal to is that the non-existence of God is a state of affairs that God would never choose to bring about, even if he were able to. For example, it may be that God's bringing about his own non-existence is incompatible with God's benevolence, since temporal slices of worlds in which God does not exist are far less valuable than slices of those worlds in which God does exist. So, God's non-existence is an inferior option, and a maximally good being would never choose something inferior-- therefore, God would never will his own non-existence, even if he were capable of doing so. I suspect this is the more promising route for the theist to take in responding to the first argument. 

While these arguments are ultimately not sound, they are useful for getting a grip on some interesting ways in which one might try to argue that God's omnipotence and his necessary existence are incompatible.

4 comments:

  1. I think this is an overly broad view of omnipotence. We don't claim that God can do every conceivable thing: http://www.newadvent.org/cathen/11251c.htm

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  2. Gregory, there's much debate among theists about how to define omnipotence. One way of responding to these arguments, as you've suggested, is to say that God is not able to do the things in question.

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  3. could we also say, that since God is the ground of all BEing, that a universe could not BE without God?
    i'm not sure if that makes sense, but I feel many believe in a deist God instead of a God that is intimately involved in His creation at every moment of it's existence.

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  4. Patrick, yes, that's another option for the theist: to claim that a universe in which God does not always exist is a metaphysical impossibility.

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