Monday, May 13, 2019

A modal ontological argument

1. If something is actual, then it must be possible. But can we reason in reverse? Can the possibility of something ever entail its existence? 

According to modal logic, for something to be possible means it exists in at least one possible world. Likewise, to exist necessarily is to exist in every possible world.

If God is possible, then God exists in one possible world. If, however, God exists in at least one possible world, then he must exist in more than one possible world. Indeed, if God exists in any possible world, then he must exist in every possible world. He must exist necessarily, in which case he actually exists. To disprove this, an atheist must show that God's existence is impossible. 

i) But why, if God exists in at least one possible world, must he exist in more than one possible world? One potential reason might appeal to the modal principle that possibility is invariant across possible worlds.

ii) Here's another reason. Take aseity. Aseity entails actual existence. Indeed, aseity is stronger than actual existence. Aseity entails necessary existence. But if aseity includes the greater claim (necessary existence), then it must include the lesser claim (actual existence). So an a se being cannot fail to exist. 

This shifts the burden of proof onto the atheist. The onus lies on the atheist to demonstrate that an a se being is impossible.

A possible limitation of this argument is that aseity is just one attribute, so that even if successful, the argument doesn't directly prove Christian theism. It is, however, a useful first step. 

There's also the interesting issue, which I won't pursue here, of what other attributes aseity entails. It's not as if an a se being only has the attribute of aseity. 

2. Sometimes parodies of the ontological argument are offered to deflect the ontological argument. You replace "God" with something else, like the greatest conceivab le unicorn or a perfect square circle. 

i) To begin with, even if there's a greatest conceivable unicorn, the greatest conceivable unicorn is not the greatest conceivable being. It's not the greatest kind of thing imaginable, but only the best example of something (that's not the greatest conceivable being). 

ii) There's the additional question of whether there can even be a greatest conceivable unicorn. Do unicorns range along a continuum with an upper limit of excellence? For instance, is there a greatest color for a unicorn to be? Seems arbitrary.  

iii) Moreover, the best unicorn, even if there were such a thing, or such a thing were possible, is still a contingent being by nature. 

iv) My argument isn't based on the greatest conceivable being, but aseity in particular.

v) A square circle isn't parallel to aseity unless both are impossible.


  1. With my weak intellectual powers I've always wondered whether the modal ontological argument engages in equivocation in its use of the word "possible". Is there shifting from logical possibility, to psychological possibility to metaphysical possibility? Who are we, with our finite minds, to posit whether God is possible or not? Our inability to see any internal incoherence doesn't necessitate there isn't one (or aren't any).

    Even the phrase "greatest conceivable being" to me has always sounded strange. Why not call God the greatest possible being since "conceivability" seems to limit what's possible to our ability to conceive of it. But it's likely that I'm just not understanding what is meant by "conceivable". Also if we phrase it as the "greatest possible being", even if we were able to get to the conclusion that it is God, it would still suggest that possibility is more fundamental than the God himself (which seems problematic). Shouldn't God be "back of" (i.e. more fundamental than) possibility?

    Also, it seems to me that a non-theist can consistently posit as a possibility that whatever thing (singular) or things (plural) that do exist might be among those necessary beings. Theists will respond that the world we experience is contingent, and therefore cannot be necessary. Hence crying out for a necessary being that brought it into existence or sustains its existence. But that's based on our experience of the world as changing. But experiences can be deceiving. The non-theist seems to me to be within his rights to posit that maybe Zeno and Parmenides were right in saying change is illusory. In which case, as Parmenides said, "Whatever is, IS" and cannot be otherwise, there is therefore no change, and therefore no basis to infer contingency. All things, or the singular Thing (were monism true) might be necessary, and self-sufficiently independent. And so the world/universe itself might be a se. The scientific "block universe" view would seem to fit with that hypothesis. In which case, we don't need God to explain the world. Why can't the universe be the perfect being itself, or even be God itself (forms of pantheism argue just for this very thing). Theists might respond by saying these things are plausible or viable options. But plausibility/implausibility, possibility/impossibility, probability/improbability are all a function of, and rated by, one's worldview. On account of all these problems, this is why I think a presuppositionalist approach should always be employed (if not always directly and explicitly, then indirectly and implicitly).

    1. typo correction:

      //Theists might respond by saying these things are [NOT] plausible or viable options.//

    2. Your comment is one big fat waste of time.

    3. Annoyed Pinoy

      You might wish to review what the ontological argument is. In addition to Steve's stimulating thoughts on the ontological argument in this very post, William Lane Craig recently offered a version of the ontological argument to Ben Shapiro at approximately 19 mins.