A User's Guide to the Modal Ontological Argument

Does the Modal Ontological Argument prove God's existence? Here's a guide to help you think critically about this question.

OUTLINE

0:00 Intro
4:31 Presentation outline
5:11 Modality
14:24 Possible worlds
16:14 Ontological arguments
17:10 God
18:47 System S5
24:58 The argument
26:47 First problem: God is impossible
36:15 Second problem: Symmetry
38:12 Breaking symmetry
45:05 Pruss’ ontomystical symmetry breaker
47:24 Relocating the symmetry
57:07 Counterexamples
1:03:17 Ramification
1:06:04 Conclusion
1:07:10 Audience Q&A

RESOURCES

[donatist]

I am a theist, still waiting for my Road to Damascus moment where the ontological argument makes any sense.

[ExploringReality]

I had a lot of fun with that Joe. Thanks again for coming on!

[TheRoark]

Couldn’t double inclusion be possible on a trinitarian conception of God? God himself being United to humanity through the divine son could allow for divinity to permeate a human being without that creating an infinite ingress

[calebp]

Epic video! Let’s hope that Alex O’Connor sees this. :)

[whatsinaname]

Have you read Biłat’s 2021 MOA paper? He outlines an ontological argument that doesn’t use modality among other unique versions that all work in T or a lower modality.

[mistermkultra]

Joe Schmid is One of the Best apologist on The internet, but he doesn't know yet

[roderictaylor]

Plantinga’s modal ontological argument defines a MGB and makes assumptions about the nature of possibility so that the proposition “It is impossible a MGB exists” becomes a logical consequence of “No MGB exists.” It then correctly observes that given these assumptions, if it is possible a MGB exists, then a MGB exists.

The problem with Plantinga’s MOA comes when trying to support the first premise of the argument. Given that the argument works in S5, it only makes sense if we are interpreting possibility as metaphysical possibility. Nevertheless, people continue to try to support S5 using epistemic arguments for the possibility of a MGB’s existence, even though we are working in an axiom system where interpreting possibility as epistemic possibility results in nonsense. They will argue that the concept of a MGB appears to be coherent. They will argue that no one has proven no MGB exists. They will argue it is impossible in principle to derive a contradiction from the definition of a MGB. They will argue that there are symmetry breakers, epistemic reasons for believing it is possible a MGB exists that do not have corresponding reasons for believing it is possible no MGB exists. All of this is a waste of time. Even if these assertions are all true, they are all arguments for the epistemic possibility of a MGB existing. They do nothing to support the first premise of the MOA.

We can see this clearly by more carefully analyzing the MOA. Assume for the sake of argument that no MGB exists. The MOA tells us it will then be impossible a MGB exists. Why? Why will it be impossible a MGB exists, if in reality no MGB exists? For exactly three reasons. (A) No MGB exists, (B) We’ve defined a MGB to be a necessary being, and (C) We are working in S5. So, if no MGB exists, it will be metaphysically impossible a MGB exists. Therefore, it follows if it is metaphysically possible a MGB exists, then a MGB exists.

But there is nothing, absolutely nothing in the MOA to suggest that if no MGB exists, it will then be epistemically impossible a MGB exists. For example, there is nothing in the MOA to suggest that if no MOA exists, then the idea of a MGB will somehow become conceptually incoherent, purely as an idea. If no MGB exists, it will be impossible a MGB exists, not because the idea of a MGB will somehow become conceptually incoherent, but purely because no MGB exists and the definitions and axioms we are assuming, and for no other reason. Therefore, even if we grant the idea of a MGB is perfectly conceptually coherent, we cannot use the MOA together with that to conclude a MGB exists.

There is nothing in the MOA to suggest that if no MGB exists, it will then be possible in principle to prove no MGB exists. If no MGB exists, it will be impossible a MGB exists, not because it will become possible in principle to prove no MGB exists, but purely because no MGB exists and the definitions and axioms we are assuming, and for no other reason. Therefore, even if we grant it is impossible even in principle to prove no MGB exists, we cannot use that together with the MOA to show a MGB exists.

There is nothing In the MOA to suggest that if no MGB exists, then there will fail to be epistemic symmetry breakers that favor the epistemic possibility of a MGB existing over the epistemic possibility of no MGB existing. If no MGB exists, it will be impossible a MGB exists, purely because no MGB exists and the definitions and axioms we are assuming, and for no other reason. Therefore, even if there are epistemic symmetry breakers in favor of the possibility of a MGB existing, we cannot use that together with the MOA to conclude a MGB exists.

Any attempt to justify the first premise of the MOA using epistemic arguments is a waste of time, because there is nothing in the MOA to suggest that if no MGB exists it will then be epistemically impossible a MGB exists. If no MGB exists, it will be metaphysically impossible a MGB purely because no MGB exists, because of the definitions and axiom system we have chosen, and for no other reason.

[erTalhaKhan]

Great video Joe. Thanks!
I would request you to connect with thought adventure podcast YT guys(I have requested them as well to reach out to you, hope they will see the request) and engage in a discussion. They are also deep into philosophy of religion specifically Islam. Would like you to understand the Islamic perspective as well and have a fruitful conversation.

[doggoslayer]

1:08:00 hehe it was fun watching, ontological arguments are cringe.

[cultofscriabin]

This argument just begs the question in P1.

Affirming that "There is a possible world in which there is an entity which possesses maximal greatness." is just to affirm that God exists in our world.

Nobody that is not already convinced that God exists in our world should be convinced by this argument.

I have honestly no idea how this argument is making it this far in academia.

[rand]

the whole idea of a "maximally great God" is just that...an idea.
a concept.

God is as far away from an idea and a concept as you and I are. This is what Paul was saying when he said Gods ways are past finding out.

St Theresa can write endless books describing her experiences with God but all those words fall short of the actual experiences...as far as the east is from the west.

only God can make Himself known. Thats how great He is. And He does so through Christ alone--in us and with us...
if we let Him.

God proves Himself. We do not prove God. this is how great He is.

[theresalotofthingsilove]

In all seriousness, many theists have created different ontological arguments for God's existence, but now that I'm thinking about it, there is nothing stopping atheists from doing the same. If you create a definition of God and prove that definition to be inconsistent/illogical with reality, then you prove God, or at least that definition of God, to be fake; this shouldn't be too hard since if there is at least one other metaphysically possible explanation in a theistic paradigm, then God doesn't exist. Idk mabye i'm asking too much.

[SalemK-tyti]

Great, using logic it is impossible for the Christian god to exist. See according to Christians the god they believe in is all just all loving and all forgiving. But also according to Christians if one doesn’t believe they are condemned to eternal torture but if someone just believes all their evil and wicked deeds are forgiven . That’s not a just god. A god who punishes people just because they don’t believe and for goes justice and doesn’t punish people just because they believe. Therefore Christian god can’t logically exist as described by its followers.

[alanrosenthal]

Salute to the presenter for the best drscription of the OA that i have ever heard. But now i am even more convinced that OA is perhaps the worst of all the pholosophical arguments. The symmetry problem, imho, kills the argument

[geraldharrison]

The problem with the argument is that being maximally great does not involve existing of necessity. On the contrary, a maximally great being would exist contingently. Why? Because a maximally great being would be omnipotent. However, someone who exists of necessity lacks the ability to cease existing and is therefore not omnipotent. Thus, an omnipotent person exists contingently. Indeed, if an omnipotent person exists, there are no necessary existences or necessary truths, as the omnipotent person has the ability to take anything and everything out of existence and to falsify any true proposition. Thus, if God exists, God exists contingently and so does everything else.

[mileskeller]

I disagree with the premise / assertion god is neccessary. This is simply a presupposition. You could make a contigent argument if you want. One cannot make the claim IF something exists then it is necessary. If something by definition is necessary then it is true by definition and would not be a matter of "IF".

[erTalhaKhan]

One question Joe on your rebuttal to pruss's SP using the atheistic experiences of evil & concluding that they are positive experiences of intrinsic impermissibility of anyone allowing such evils.
But the problem here is that you are already assuming that a particular event is evil that gives you such experiences. On an atheistic view defining evil itself is not possible. And what if someone gets a good experience of the supposed 'evil' event?

Could you explain?

[petery]

That thumbnail belongs in the "Philosopher's thug life picture hall of fame"

[John-lfxf]

The argument if taken to actually entail its conclusion and have that mean something in the real world will never not be simply defining God into existence while proxying this effective claim through as sentences formulated purely in modal logical terms. The argument from its logical form reduces to accepting P1 and hence is equivalent to the weight of whatever independent justifications can be given for P1. Since “possibility” (of actuality in the real world) is a synthetic notion, justifying P1 is equivalent to showing that the words which P1 is formulated in terms of, actually have semantic references (as opposed to being vacuous). So really, the argument’s strength is equivalent to DEFINING P1 semantically. Otherwise, without defining the terms in P1 semantically, the entire argument is semantically vacuous as presented. It is not expressing any semantic meaning unless and until P1 is given some meaning by whoever is propounding this argument. But giving P1 meaning is no easier or harder than the initial problem, proving the existence of God. So the MOA is trivial.

[meekerdb]

I've long been aware metaphysical possibility, but I've always known it as nomological possibility, i.e. consistent with the laws of nature.