(June 18, 2016 at 3:26 pm)Veritas_Vincit Wrote: Premise 1: It's possible that a 'maximally great being' exists.
Premise 2: If it's possible that a maximally great being exists, then a maximally great being exists in some possible world.
Premise 3: If a maximally great being exists in some possible world, then it exists in every possible world.
Premise 4: If a maximally great being exists in every possible world, then it exists in the actual world.
Premise 5: Therefore a maximally great being exists in the actual world.
Premise 6: Therefore a maximally great being exists
Conclusion: Therefore God exists.
We know that there's something wrong with that logic because it can "prove" that gods do not exist just as easily as it "proves" that they do:
Premise 1: It's possible that a 'maximally great being'
does not exist.
Premise 2: If it's possible that a maximally great being
does not exist, then a maximally great being
does not exist in some possible world.
Premise 3: If a maximally great being
does not exist in some possible world, then it
does not exist in every possible world.
Premise 4: If a maximally great being
does not exist in every possible world, then it
does not exist in the actual world.
Premise 5: Therefore a maximally great being
does not exist in the actual world.
Premise 6: Therefore a maximally great being
does not exist.
Conclusion: Therefore God
does not exist.
This second version is exactly as strong as the first version, yet it proves the exact opposite. Any argument that proves both X and not-X is worthless. In the scales of persuasion, its weight is zero.
We know, therefore, that the MOA (modal ontological argument) is worthless, absolutely refuted.
Some of us, however, will wish to know specifically where the flaw lies.
The form is arguably valid. That is, you could point out that P1 is ambiguous, that some people will concede that MGBs are "possible" because they don't know whether MGBs exist, not because they know that MGBs exist in at least one possible world; but if you make that move, a clever theist will thank you for clearing that up, and stipulate that the meaning of "possible" in P1 is intended to be the same as it's meaning in the rest of the proof.
It's a good point to make, but you should be brief, since you won't get a lot of traction.
The conclusion equivocates between MGBs and gods, but you do not want to get into an argument about whether MGBs are really gods. The theists would, for good reason, call that a victory. "His last ditch defense was to pretend that he didn't understand that a maximally great being is a god. From that, you can infer how lame his whole performance was."
So, stipulate: "The argument equivocates between MGBs and gods, but that's not what I want to focus on today. So, for the sake of argument, I'm going to stipulate that MGBs and gods are the same thing." This calls brief attention to the fallacy, and quickly moves beyond it to things more profitable.
P3 can be challenged, but I think it's faster and cleaner just to stipulate that P3 is true. Why dispute whether "great making properties" is a vague and subjective term when you can just point out that
if P3 is true,
then P1 is false.
Again, then, stipulate: "I believe P3 is indefensible, but Let us stipulate, for the sake of argument, that P3 is true: MGBs, gods, are
necessary. That is, if they exist in any possible world, then they exist in all possible worlds. And the corollary is that
unless they exist in all possible worlds, they don't exist in any of them.
Which brings us to P1.
We're talking about necessary gods, gods that don't exist at all unless they exist in all possible worlds. Can a god like that exist in some possible worlds?
No. Certainly not.
We know that some possible worlds are godless. We know this because of the definition of "possible world." A possible world is any world without contradictions. If a world doesn't have square circles or married bachelors, or anything other logical contradiction, then it is a possible world.
There's nothing contradictory about godless worlds, so they are by definition possible.
But a god existing in a godless world would be a contradiction, an impossibility. Therefore, no god can exist in all possible worlds.
Since P3 establishes that the god we are discussing, the god of the modal ontological argument, does not exist in any possible world unless it exists in all of them, it follows that this god does not exist in any possible world.
Therefore, P1 is false.
Therefore, the MOA fails.
We have shown that the MOA fails in two different ways, each dispositive, compelling.
First, we have shown that the logic of the MOA is exactly as good as proving that gods do not exist as that they do exist.
Second, we have shown that the MOA is based on false premises. Specifically, since P1 and P3 cannot both be true, at least one of them is false. Therefore, even if we stipulated that the MOA was valid, it would still be unsound.
For that matter, since this is a matter of logical contradiction, we know that the MOA is unsound in every possible world.
