The Modal Ontological Argument Is Sound

Greetings,

Welcome to the debate on the modal ontological argument:

1. It is possible that a maximally great being exists.

2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.

3. If a maximally great being exists in some possible world, then it exists in every possible world.

4. If a maximally great being exists in every possible world, then it exists in the actual world.

5. If a maximally great being exists in the actual world, then a maximally great being exists.

6. Therefore, a maximally great being exists.

We will be discussing whether or not this argument is sound.

Round 1

1 of 2

LancelotDuLac

Con #1

According to Christian theologian William Craig, there is no clear definition of what defines a maximally great being, as it is subjective.: Whether it is better to be timeless or omni-temporal.

For a being to objectively be considered maximally great, it must satisfy three characteristics.:

Omnipotent
Omniscient
Omnibenevolent

Falling short in either of these categories nullifies the resolution.

Furthermore, the Modal Ontological Argument is self-refuting in the fact that its conclusion contradicts its first premise.:

Conclusion: 6. Therefore, a maximally great being exists.
exists.
Premise: 1. It is possible that a maximally great being exists.

I agree with Premise 1. Premise 1 is saying that a maximally great being could exist, in theory. That is what it means by possibility. If the accuracy of a claim is possible, then it is also possible that a claim could be inaccurate. Possibility denies certainty as a factor and allows room for doubt.

The conclusion on the other hand asserts complete certainty on preceding factors which do not logically connect.

"In deductive reasoning, a sound argument is an argument that is valid and all of its premises are true (and as a consequence its conclusion is true as well)."

Soundness - Wikipedia

If I refute even one of the premises, then it stands that the resolution is not true.

"2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.

"3. If a maximally great being exists in some possible world, then it exists in every possible world."

If it is possible that a maximally great being exists, then it is also possible that a maximally great being doesn't exist. And if it is possible that a maximally great being doesn't exist, then a maximally great being exists doesn't exist any hypothetical world.

Rhetorically, fallacies can be countered by reverse-fallacies.

Kohai Administrator

Pro #2

Thank you for this debate.

Framework

My opponent properly defines a sound argument as a deductive an argument that is valid and all of its premises are true. If I can prove the MOA meets this argument then the argument is sound and a vote for pro is warranted. Conversely if I fail to prove that both criteria are met then a vote for con is warranted.

A Primer on S5 Modal Logic

The MOA is built upon S5 modal logic. Modal logic helps us to determine the deductive behavior of the expressions "it is possible that x" and "it is necessary that." In modal logic we use possible world semantics to help map out what is possible, impossible, and necessary.

A possible world is defined as a potential state of affairs that could possibly arise. S5 is a strong system that assumes that all possible worlds are accessible and can "see" each other. The consequence of this is that is if something is possible in a world then it is possible in all worlds, if it is impossible in one world then it is impossible in all worlds, and if something is necessary in some world then it is necessary in all worlds.

Similarly we can identify several types of beings:

Necessary - A being that necessarily exists in all possible worlds
Impossible - A being that cannot exist in any possible world (i.e. a married bachelor)
Contingent - A being that can exist in some possible worlds but not in others.

This is one of the most misunderstood aspects of the MOA. It is important to have a strong understanding of the mechanisms of the argument before it is attacked.

The MOA

It is possible that a maximally great being (MGB) exists
If it is possible that a maximally great being exists, then a maximally great being exists in some possible world
If a maximally great being exists in some possible world, then it exists in every possible world.
If a maximally great being exists in every possible world, then it exists in the actual world.
If a maximally great being exists in the actual world, then a maximally great being exists.
Therefore, a maximally great being exists.

This argument follows all the rules of S5 logic. We begin with asking whether or not something is possible. The first premise can be restated "For all we know an MGB could exist in some possible state of affairs." The rest of the argument maps out what is the logical consequence of an MGB existing in some possible state of affairs. S5 logic concludes that such a being must exist necessarily in every possible world including the actual world.

My opponent already conceded the first premise. This is fatal to pro's case because premise 1 is the only premise that can be attacked. My opponent argues that the conclusion contradicts its first premise; however, this shows a gross misunderstanding of S5 logic. What S5 logic is telling us is that the statement it is possible that an MGB exists is equivalent to stating that a maximally great being necessarily exists. My opponent's argument is a strawman.

The Reverse MOA

My opponent's next line of attack it to mirror this argument. My opponent knowingly or unknowingly is bringing up what is well-known as the reverse modal ontological argument. Does this argument work? Let's restate this in the same S5 logical system.

It is possible that a maximally great being (MGB) does not exists
If it is possible that a maximally great being does not exists, then a maximally great being does not exists in any possible world
If a maximally great being does not exist in some possible world, then it does not exist in every possible world.
If a maximally great being does not exists in every possible world, then it does not exist in the actual world.
If a maximally great being does not exists in the actual world, then a maximally great being does not exist.
Therefore, a maximally great being does not exist.

Both arguments are valid and follow the rules of S5 logic and on first glance both premises seem to be reasonable. If my opponent wants to argue this then he needs to prove the first premise. My opponent is essentially stating that a MGB is impossible and cannot exist anywhere. This is nearly an impossible burden to meet because to meet this burden my opponent will need to show some contradiction within an MGB which does not permit it to exist. However, my opponent already conceded the possibility of an MGB existing so this entire argument is thus refuted.

Conclusion

My opponent attempts two lines of attacks on the MOA: The first is that the first premise and the conclusion premise contradict one another. This is refuted as the S5 logic reveals that they are equivalent. The second line of attack is that it is also possible that an MGB does not exist. This fails because to mirror this argument my opponent is forced to argue that an MGB is impossible - a burden my opponent fails to meet.

As such a vote for pro is warranted.

Round 2

2 of 2

LancelotDuLac

Con #3

FORFEITED

Kohai Administrator

Pro #4

I remain the undefeated champion of S5. Please vote pro

Kohai Administrator

--> @Savant, @whiteflame

Easy one. Two more votes

fauxlaw Global Moderator

Another factor that could have been mentioned in my vote is that Con's sole supporting citation of scholastic evidence for his R1 [and only round] argument is Wikipedia. I will note that Wiki says of itself that it is not accurate, "...admitting vandalism, bias, and factual errors [that] can occur due to its open, collaborative model," because it allows editing by anyone, which dismisses scholastic assurance.

Kohai Administrator

--> @fauxlaw

Please vote

LancelotDuLac

--> @SomeDebatePerson

Accurate. He's going bonkers

SomeDebatePerson

--> @LancelotDuLac

I wouldn’t use William Lane Craig as my support. He’s going off the rails.

Savant Administrator

Criterion	Con	Tie	Pro
Winner

Reason:

Con forfeits after R1 and thus drops all of Pro's responses to their case, this means Pro's arguments are basically unrefuted. I think Pro's conclusion basically summarizes this: "My opponent attempts two lines of attacks on the MOA: The first is that the first premise and the conclusion premise contradict one another. This is refuted as the S5 logic reveals that they are equivalent. The second line of attack is that it is also possible that an MGB does not exist. This fails because to mirror this argument my opponent is forced to argue that an MGB is impossible - a burden my opponent fails to meet." Given that this is enough to nullify Pro's arguments, if true, the debate is basically decided by them not coming back to challenge these conclusions.

whiteflame Global Moderator

Criterion	Con	Tie	Pro
Winner

Reason:

The forfeit pretty much makes this a slam dunk for Pro.

Con only has one argument, but that point is attempting to take apart the MOA and respond to a piece of it rather than meaningfully address its underlying assumption, which is that an MGB is possible. As Pro points out, so long as that being is possible, the rest of the MOA follows from it as showcasing that necessary existence. It's possible to argue against other points in the MOA while leaving that one on the table, but Con conceding it and then just saying that the reverse is possible later isn't enough. It doesn't sufficiently challenge Pro's position, and since Con doesn't respond to Pro's R1 argument, he doesn't get the opportunity to expand on his point. That leaves Pro with the only fully articulated argument, and Con with a lot of ink covering his only pre-response.

fauxlaw Global Moderator

Criterion	Con	Tie	Pro
Winner

Reason:

I am going to ignore that Con forfeited the 2nd round, which could, on its own lose the debate for Con.

Con's argument completely ignores Pro's R1 statement, which is absolute truth: "The MOA [Modal Ontological Argument] is built upon S5 modal logic." Con does not ever mention or acknowledge "S5 modal logic," which leads Con to ignore two essential facts of the MOA: [1] Argument 1 and argument 6 do NOT oppose each other as Con claims, and [2] Con ignores the three factors of a being, including a maximally great being [MGB]: Necessary, Impossible, Contingent. The denial of these two facts completely destroys Con's R1 argument. Lacking any other argument, Pro wins this debate.

Round 1

Round 2

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