Friday, July 30, 2010

A Simple Version of the Modal Ontological Argument

Let "God" = a maximally great being (omnipotent, omniscient, and morally perfect in every possible world).

1. God's existence is either necessary or impossible. (Premise)

Implicit in (1) is that God cannot exist contingently. If God were contingent, then He wouldn't be maximally great, since it is greater to be necessary than to be contingent. The very understanding of God, then, requires that God is either a necessarily existent entity, or else impossible.

2. God's existence is not impossible. (Premise)

(2) is the more controversial premise. More on this below.

3. Therefore, God's existence is necessary. (Conclusion)

In short, it follows from (3) that God actually exists.

It remains to be seen whether (2) should be accepted. Intuitively, most of us probably grant that God's existence is at least possible; and obviously, if it is possible, then it is not impossible. However, a skeptic could easily reverse this:

(2'): God's existence is not necessary.

In support of (2'), one might appeal to the intuition that there is a possible world in which God does not exist.

One relevant question, then, is this: is the intuition of (2') as strong as the intuition of (2)? Both premises are question-begging, barring any additional argumentation that would either prove or make it likely that one premise is correct.

Perhaps the theist cannot prove that (2) is correct and that (2') is false, yet still be within her epistemic rights in believing that. This is Alvin Plantinga's position - e.g. the modal ontological argument is rationally acceptable, even if it is not a conclusive proof.

In any event, there have been some notable attempts to prove that God's existence is possible. Clement Dore and Robert Maydole immediately come to mind. Being someone who accepts the actual existence of a maximally great being (God), I'm especially interested in the developments of a proof of the possibility premise.


  1. The biggest problem with this being a modal logic argument is that I can conceive of a non-contradictory world where nothing exists, including God. This would negate #2 completely, in modal logic anyway, since saying something is possible is to say it is necessary. If it is not necessary in any possible world, it is not necessary and therefore not possible in terms of modal logic.

    As for Plantinga's reliance on presuppositional arguments, it goes to show that there is no proof whatsoever.

    When you allow for the presupposition of things that aren't an absolute necessity, such as a properly foundational belief that your eyes are actually seeing the real world, you have no reason to dismiss ideas that are total fabrications.

    If I say that when you lose socks, it is often my coffee pot that steals them, you can't prove me wrong. If you say that my coffee pot never moves, I can say that it has the ability to stop time, and it only moves when time is stopped.

    This has explanatory power in the form of explaining missing socks. It could also have explanatory power in the form of explaining why you have so many extra hangers in your closet if I were to say that my coffee pot magically transforms the socks into hangers.

    If we can accept the idea that any explanation of unknowns is valid as long as it can't be disproved, then we are stuck being required to believe all sorts of silliness like that.

    Anyway, I have dealt with presuppositional apologetics here, and the modal ontological argument problem here.

  2. Hi Godlessons,

    Thank you for your comments. I'm not really a proponent per se of the ontological argument, but I do think it is capable of surviving most (if not all) common criticisms.

    I wouldn't say Plantinga is a presuppositionalist, though he does make use of some transcendental arguments. I also don't think it's possible for nothing to exist. See my treatment of cosmological arguments on the sidebar, for example.

    The difficulty in assessing the ontological argument with the missing socks illustration is that the latter makes use of inherently contingent objects. Just imagining a possible world without God isn't any better than just imagining a possible world with God. Neither conceptualizations actually establish their respective possibilities.

    Socks exist, but we also know through experience that they can not-be.

    I will take a look at your writings. Thanks for stopping by. You're welcome to comment any time. :)

  3. We do not know through experience that socks can "not-be". You make the assumption that all socks are created by men, and that all socks are created of a substance that can be destroyed. You can't know for sure that there isn't some maximally great sock.

    See where this is going? I can imagine all sorts of nonsense, and you can't prove it wrong. I can just move the goalposts like believers do about God. None of this addresses the ontological argument though, so I don't know why you went on about it.

    The reason I brought up the coffee pot is to explain how presuppositional apologetics fails. The point was, it is not properly foundational to believe in God, and because of that, there is no reason to accept the possibility a priori. I wrote about that here.

  4. A maximally great sock, I take it, is an incoherent concept. If it cannot be destroyed, then it isn't really a sock. Moreover, a maximally great anything just seems to replace "God" with another word.

    As for the a priori possibility, I left that open (e.g. in my comment about Dore and Maydole).