The Modal Ontological Argument

[CatholicSoxFan]

In this thread, I’ll explain the Modal Ontological Argument. You can’t edit the OP, a d I might want to edit my main post, so I’ll reserve a second one.
EDIT: Oh wait, I can. Oopsies.

 

[CatholicSoxFan]

The Modal Ontological argument is one of the best arguments for the existence of God, but few use it, because they don’t understand it.
The argument uses the concept of possible worlds; a possible world is basically a set of things that could have been true; they are logically coherent and don’t violate any necessary truths, like a law of logic. The actual world is a possible world in which all of these entities and truths are Plantinga’s original argument can seem like he’s making a lot of leaps, so I’ll use another form of it (that I made up) to illustrate how it isn’t a logical leap:
P1: An entity with the property of necessity cannot exist contingently, because that would be a contradiction in terms
Basically, there are three “modalities” (why this is called the Modal Ontological Argument), that can modify the logical possibility of something existing or not existing:
Impossible: An entity that exists in no possible worlds (like a square circle; it is a contradiction in terms, and is thus logically coherent, and can’t exist in any possible worlds)
Contingent: An entity that exists in some possible worlds, but not others (like us;
To be continued

 

[Linusthe2nd]

The Modal Ontological argument is one of the best arguments for the existence of God, but few use it, because they don’t understand it.
The argument uses the concept of possible worlds; a possible world is basically a set of things that could have been true; they are logically coherent and don’t violate any necessary truths, like a law of logic. The actual world is a possible world in which all of these entities and truths are Plantinga’s original argument can seem like he’s making a lot of leaps, so I’ll use another form of it (that I made up) to illustrate how it isn’t a logical leap:
P1: An entity with the property of necessity cannot exist contingently, because that would be a contradiction in terms
Basically, there are three “modalities” (why this is called the Modal Ontological Argument), that can modify the logical possibility of something existing or not existing:
Impossible: An entity that exists in no possible worlds (like a square circle; it is a contradiction in terms, and is thus logically coherent, and can’t exist in any possible worlds)
Contingent: An entity that exists in some possible worlds, but not others (like us;
To be continued

So far you haven’t said anything. You might begin by explaining what a " modal argument " is - for those of us who haven’t been in school for awhile and who are Thomists.

Linus2nd

 

[CatholicSoxFan]

(continued; I didn’t know you couldn’t edit 20 minutes after the post. Oopsies.)
Contingent: An entity that exists in some possible worlds, but not others (like us; there’s nothing incoherent about our existence, nor is our existence necessary)
Necessary: An entity that exists in all possible worlds (like the laws of logic; there is no logically possible world in which logic itself doesn’t exist)
So, an entity that has the property of existing in all possible world can’t exist in only some.
P2: A maximally great being is a necessary entity.
First, we need to define what a maximally great being is; a maximally great being (or MGB) is an entity which possesses every property that is better to have, to an infinite extent. So, since it is better to know things than not to know things, an MGB would be omniscient. And since it is better to be a necessary truth/entity than not, an MGB would be necessary, and so on.
C1: Therefore, an MGB could not be contingent.
P3: The existence of an MGB is not impossible.
This is supposed to be the controversial premise. Another thing about it, though, is that many atheists accept it; they don’t think that the concept of God is incoherent, and they don’t think that His existence violates any necessary truths; their most popular argument against His existence is, “Well, there’s no evidence.”, a claim that is refuted by this argument. Now, we do have a reason that supports the idea that an MGB’s existence does not violate any necessary truths, and that is the Modal Perfection Argument devised by Robert Maydole. Now, in order to understand this argument, you have to understand that when an entity or statement is impossible, everything entails its negation, including the statement itself. As an example to prove that it is possible to have something entail its negation, take the statement, “Every statement that cannot be demonstrated true by direct observation is false.” If this statement were true, it would entail that it was false, since the statement cannot be demonstrated true by direct observation. So, a version of the argument (from this video) goes like this:
P1: If a property is a great-making property (a fancy word for a property which is better to have), its negation is a lesser-making property (a fancy word for a property which is worse to have)
P2: Great-making properties do not entail lesser-making properties. (if one did, it wouldn’t be a great-making property after all)
P3: Maximal greatness is the greatest great-making property.
C1: Therefore, maximal greatness cannot entail its negation of non-maximal greatness
C2: Therefore, maximal greatness is possible.

C2: Therefore, the existence of an MGB is necessary.
Premise 1 proves that the existence of an MGB isn’t contingent, and Premise 3 proves that the existence of an MGB isn’t impossible. The only other option is that the existence of an MGB is necessary.
C3: Therefore, an MGB exists.
Now, I’m sure you still don’t completely understand it, but I’m sure you will eventually when reading over this a few times. And when you properly understand it… the atheists better watch out!
If you want to learn more about this argument, watch the following YouTube videos (I got most of the content of these two posts from the first one)
youtube.com/watch?v=RQPRqHZRP68
youtube.com/watch?v=ixqsZP7QP_o
youtube.com/watch?v=vGVYXog8NUg
youtube.com/watch?v=azHzZ2ADJkA
The next post will talk about some popular objections to the argument, and why they don’t work in debunking it.

 

[CatholicSoxFan]

The first two posts made a more complex version of the argument that proved that there weren’t any logical leaps like it would seem to be the case if one was presented with a simpler version of it, but when you understand the logic behind it, there are really only two premises, as defined in Peter S. Williams’ version of it;
P1: If it is possible for God to exist, then God exists.
P2: It is possible for God to exist.
C: Therefore, God exists.

So let’s go over some common objections to the argument that I’ve heard:

Just because you can define an entity as necessary, doesn’t mean the entity exists. (this is sometimes given with a counterexample, like in this video: youtube.com/watch?v=13puH63HxmQ)
This is a caricature of the argument that emphasizes the first premise of the argument; the definition of God isn’t the only reason why we believe He exists; it’s the definition, combined with the coherence of His existence.

Just because you can conceive of something, doesn’t mean it exists.
Again, this is a caricature of the argument, only this time it emphasizes the second premise.

This doesn’t prove your God.
The argument proves that a maximally great being, which means that there is a being who possesses all properties which are better to have, to an infinite extent. And as you start thinking about what would qualify as a great-making property, it’s pretty obvious that we’re talking about the God that Christianity believes in. And further, if you think about what it means to be all-loving, if an MGB was just one person, who would the one person be loving for all eternity? Different worldviews involving classical theism could answer this question in different ways (like another eternal being), but the best answer, if you think about it, would be that the MGB is multipersonal, because it solves the above problem, and doesn’t involve another entity that had to exist eternally. Specifically, the lover-beloved-love between them explanation of the Trinity makes a lot of sense in the light of that problem.

This doesn’t prove Christianity.
Yes, this is true; this argument doesn’t prove that Jesus Christ was who He claimed to be, but please note that that doesn’t mean you get to fall back to atheism. That would be an argument from ignorance, and also doesn’t take into account that theistic arguments aren’t independent of each other, although most of them prove things which wouldn’t be accepted by an atheist, unless you start to really stretch the definition of atheism. Theistic arguments tend to refute objections to each other. So, the principal argument for Christianity in particular, the argument from the Resurrection of Jesus Christ, is supported by this argument. Many of the objections to the Resurrection rely on naturalistic principles, at least to some extent. And since this argument proves that there is an omnipotent, omnibenevolent necessary being, the argument from the Resurrection, as well as the authenticity of the New Testament, are greatly supported, because many of their objections rely on naturalistic principles.

There is no empirical evidence for the existence of God.
This is an attempt to change the subject; don’t bite. Don’t even mention to them the absurdity of trying to disprove the existence of an entity that exists outside of space-time by the fact that there is no direct evidence for His existence from in space-time. Take them back to the fact that they need to refute one of the premises of this argument in order to refute it, not make an irrelevant claim.

I deny modal logic.
When an atheist sees the logic of the argument, and don’t want to accept the conclusion, a surprising number of them end up just biting the bullet and denying modal logic itself. Once an atheist does this, any claims of the atheist that Christianity is illogical, or any attempts to ridicule it (which, let’s face it, is about half the content of these atheist arguemnts, specifically on YouTube) become farcical.

The most common arguments that try to prove that maximal greatness is impossible, as well as some parodies of the argument, are debunked in these videos:
youtube.com/watch?v=ixqsZP7QP_o
youtube.com/watch?v=_JRsHIN5ATY

If you have another objection to the argument, please provide one.

 

[tabycat]

 

[CatholicSoxFan]

It’s okay, that’s also how I reacted to it

 

[empther]

From wikipdia, about Plantinga’s “publish something or perish sometime” humbug:

en.wikipedia.org/wiki/Ontological_argument#Alvin_Plantinga

The conclusion relies on a form of modal axiom S5, which states that if something is possibly true, then its possibility is necessary (it is possibly true in all worlds). Plantinga’s S5 also states that if something is possibly necessarily true, then it is necessarily true (it is true in all worlds).[32] In other words: If something is not inherently contradictory (i.e. it is possibly true), then it is possibly true in all worlds (including the actual world).
A version of his argument is as follows:[4]
A being has maximal excellence in a given possible world W if and only if it is omnipotent, omniscient and wholly good in W; and
A being has maximal greatness if it has maximal excellence in every possible world.
It is possible that there is a being that has maximal greatness. (Premise)
Therefore, possibly, it is necessarily true that an omniscient, omnipotent, and perfectly good being exists.
Therefore, (by axiom S5) it is necessarily true that an omniscient, omnipotent and perfectly good being exists. :bigyikes:
Therefore, an omniscient, omnipotent and perfectly good being exists.

Why hasn’t the Pope caught on to this?

All versions of the ontological argument have logical truth,
but nevertheless,
they don’t prove God exists…

Hint why not below.





Ontological arguments have no evidence.

 

[CatholicSoxFan]

From wikipdia, about Plantinga’s “publish something or perish sometime” humbug:

en.wikipedia.org/wiki/Ontological_argument#Alvin_Plantinga

Why hasn’t the Pope caught on to this?

All versions of the ontological argument have logical truth,
but nevertheless,
they don’t prove God exists…

Hint why not below.





Ontological arguments have no evidence.

Omniscience, omnipotence, and perfect goodness are just three great-making properties, they’re just the ones that we bring up the most when we talking about God. Necessity, for example, would be another one. At some point, you have to wonder if a non-classical theist is just calling God by a different name when they start accepting these properties.

 

[polytropos]

P1: If a property is a great-making property (a fancy word for a property which is better to have), its negation is a lesser-making property (a fancy word for a property which is worse to have)
P2: Great-making properties do not entail lesser-making properties. (if one did, it wouldn’t be a great-making property after all)
P3: Maximal greatness is the greatest great-making property.
C1: Therefore, maximal greatness cannot entail its negation of non-maximal greatness
C2: Therefore, maximal greatness is possible.

C2: Therefore, the existence of an MGB is necessary.
Premise 1 proves that the existence of an MGB isn’t contingent, and Premise 3 proves that the existence of an MGB isn’t impossible. The only other option is that the existence of an MGB is necessary.
C3: Therefore, an MGB exists.

I am not sure about C1. “Maximal greatness cannot entail its negation of non-maximal greatness.” In other terms, “Necessarily, it is not the case that maximal greatness entails non-maximal greatness.”

I cannot make sense of this. You are going on to claim in C2 that maximal greatness is possible, so evidently you cannot be using the fact that it is possible to get to C1, or else the argument would be circular. But it is fine for us to admit that maximal greatness cannot entail non-maximal greatness if there is not, in fact, any maximal greatness.

The other thing I cannot make sense of is that you are using “maximal greatness”, which is a predicate, in an entailment relation. What do you mean by this? Do you mean that a thing being maximally great cannot entail that it is not not maximally great? But that seems to be analytic and trivial, and does not itself imply the possibility of maximal greatness.

Looking over the argument, you seem to be using the first three premises for this point, but they likewise suffer from this point. I don’t see what is special about great-making properties that they can’t entail their negations. It is true for any property P that Pv does not entail ~Pv.

 

[CatholicSoxFan]

I am not sure about C1. “Maximal greatness cannot entail its negation of non-maximal greatness.” In other terms, “Necessarily, it is not the case that maximal greatness entails non-maximal greatness.”

I cannot make sense of this. You are going on to claim in C2 that maximal greatness is possible, so evidently you cannot be using the fact that it is possible to get to C1, or else the argument would be circular. But it is fine for us to admit that maximal greatness cannot entail non-maximal greatness if there is not, in fact, any maximal greatness. (The other thing I cannot make sense of is that you are using “maximal greatness”, which is a predicate, in an entailment relation. What do you mean by this? Do you mean that a thing being maximally great cannot entail that it is not not maximally great? But that seems to be analytic and trivial, and does not itself imply the possibility of maximal greatness.)

P2 is supported by the fact that a property can’t actually be a great-making property if it entails a lesser-making property (for example, if goodness entailed evil, would it really be goodness?), not the fact that maximal greatness is possible. C1 is supported by P2.

 

[polytropos]

P2 is supported by the fact that a property can’t actually be a great-making property if it entails a lesser-making property (for example, if goodness entailed evil, would it really be goodness?), not the fact that maximal greatness is possible. C1 is supported by P2.

Sorry, I added this since you posted:

Looking over the argument, you seem to be using the first three premises for this point, but they likewise suffer from this point. I don’t see what is special about great-making properties that they can’t entail their negations. It is true for any property P that Pv does not entail ~Pv.

I agree that a great-making property cannot entail a lesser-making property if lesser-making properties are taken to be the negation of great-making properties.

But I don’t see how C1 then gets you to C2, the possibility of maximal greatness.

 

[CatholicSoxFan]

Sorry, I added this since you posted:

I agree that a great-making property cannot entail a lesser-making property if lesser-making properties are taken to be the negation of great-making properties.

But I don’t see how C1 then gets you to C2, the possibility of maximal greatness.

The negation of maximal greatness would be non-maximal greatness, a lesser-making property.

 

[polytropos]

The first two posts made a more complex version of the argument that proved that there weren’t any logical leaps like it would seem to be the case if one was presented with a simpler version of it, but when you understand the logic behind it, there are really only two premises, as defined in Peter S. Williams’ version of it;
P1: If it is possible for God to exist, then God exists.
P2: It is possible for God to exist.
C: Therefore, God exists.
…]
Just because you can conceive of something, doesn’t mean it exists.
Again, this is a caricature of the argument, only this time it emphasizes the second premise.
…]
If you have another objection to the argument, please provide one.

Can you clarify what exactly is the support for P2, if not the premise that consistent conceivability implies real possibility (possibly with some qualifications/restrictions, as with any conceivability premise)?

Here is another objection: If we are allowing axiom S5 and define some p to be necessary, then the the premise “Possibly p,” given the logical system we are using, is logically equivalent to “p”. As such, the argument is necessarily epistemically circular to anyone who is familiar with modal logic; my accepting P2 is equivalent to my accepting C.

 

[polytropos]

The negation of maximal greatness would be non-maximal greatness, a lesser-making property.

Yes, I accept that. But “p entails q” does not get us anywhere if “p” is not true. We don’t know that “p” (say, that maximal greatness is instantiated) is true.

This is the problem with the fact that you are saying that a predicate does not entail another predicate. It is hard to tell what this means. I think we can accept that if a being is P, then that being necessarily is not ~P. But that doesn’t show us that some being is P, or that it is possible that some being is P (which seems to be what you’re saying in C2).

 

[CatholicSoxFan]

Can you clarify what exactly is the support for P2, if not the premise that consistent conceivability implies real possibility (possibly with some qualifications/restrictions, as with any conceivability premise)?

Here is another objection: If we are allowing axiom S5 and define some p to be necessary, then the the premise “Possibly p,” given the logical system we are using, is logically equivalent to “p”. As such, the argument is necessarily epistemically circular to anyone who is familiar with modal logic; my accepting P2 is equivalent to my accepting C.

P2 is supported by the Modal Perfection Argument, as well as the lack of any atheistic arguments for His impossibility that hold up to scrutiny.

The Ontological Argument is essentially saying that the statements, “It is possible for God to exist” and “God exists” are equivalent, which thus shifts the argument to whether the former is true, which is why I substantiate P2 with another argument. Watch this video for further explanation of this.

 

[CatholicSoxFan]

Yes, I accept that. But “p entails q” does not get us anywhere if “p” is not true. We don’t know that “p” (say, that maximal greatness is instantiated) is true.

This is the problem with the fact that you are saying that a predicate does not entail another predicate. It is hard to tell what this means. I think we can accept that if a being is P, then that being necessarily is not ~P. But that doesn’t show us that some being is P, or that it is possible that some being is P (which seems to be what you’re saying in C2).

It seems like you’re making a caricature of the MPA which emphasizes P2 above the other two premises,

 

[empther]

From post 9

Omniscience, omnipotence, and perfect goodness are just three great-making properties, they’re just the ones that we bring up the most when we talking about God. Necessity, for example, would be another one. At some point, you have to wonder if a non-classical theist is just calling God by a different name when they start accepting these properties.

Aquinas demonstrated God’s existence from the evidence of the universe’s existence.
After doing that,
he shows that this universe-creating God must have omniscience, omnipotence and all the rest.

But ontological arguments can’t get to square one. They have no evidence for God’s existence and can’t go on to omniscience, omnipotence and all the rest. They just make assumptions for which there is no evidence.
I assume that in a universe containing more stars than the grains of sand on all the world’s beaches we can’t be the only intelligent beings. It’s absurb. Yet, it doesn’t prove there are other intelligent beings.

 

[CatholicSoxFan]

From post 9

Aquinas demonstrated God’s existence from the evidence of the universe’s existence.
After doing that,
he shows that this universe-creating God must have omniscience, omnipotence and all the rest.

But ontological arguments can’t get to square one. They have no evidence for God’s existence and can’t go on to omniscience, omnipotence and all the rest. They just make assumptions for which there is no evidence.
I assume that in a universe containing more stars than the grains of sand on all the world’s beaches we can’t be the only intelligent beings. It’s absurb. Yet, it doesn’t prove there are other intelligent beings.

So, you have to have evidence of something before you define it? But, wouldn’t you have to have the definition to give evidence for it? It doesn’t make any sense.

 

[Prodigal_Son]

P1: If it is possible for God to exist, then God exists.
P2: It is possible for God to exist.
C: Therefore, God exists.

This argument clearly equivocates on “possible.” For the argument to be valid, “possible” must indicate an ontological state of the world. In other words, consider the contrapositive of “If it is possible that God exists, then God necessarily exists.” This is:

A. If God does not necessarily exist, then it is not possible that God exists.

What non-question-begging reason do we have to believe that the antecedent to A is false? None at all. For all we know, God does not necessarily exist. To deny God’s necessary existence is equivalent to denying God’s existence tout court, and the skeptic does this. So the above argument is completely unconvincing to the skeptic.

In what sense is God’s existence clearly possible? Not a metaphysical sense, but an epistemological sense. No one can deny that, for all we know, God exists. But then again, for all we know, gravity is a manifestation of a deep magnetism in the universe. That does not even mean that it is even (ontologically) possible that gravity is a manifestation of deep magnetism. Possibility, in an epistemological sense, is merely a measure of our ignorance.

All this is to say that S5 could only possibly work if we use “possibility” in a strict metaphysical sense. But if we use “possibility” that strictly, it becomes very difficult to see why “It is possible that God exists” is a plausible premise.