The modal ontological argument for God

[Disagreeable]

Couldn't you list out a whole bunch of different necessary beings and attempt to prove that they ALL exist using this argument? Lol.

[The Grand Nudger]

Is the unicorn a necessary being?  Then the argument works the same way.  Is it not?  Then the s5 theory of modal logic does not apply.

Yes, sorry that was my point, if we accept that X is possible then the argument works, no matter what X is.

-and again, no.  For this type of inference to work "whatever x" has to be "possibly necessary".  Cant just be "whatever x" because that's not how the modal operator works.  

This of course then requires that first step, that someone believe X is possible, which explains why apologists so often are amazed when I don't accept the conclusion of the argument, it's because I would first need to believe a deity is possible. 

-in some possible world.  It's actually pretty difficult to logically reject that one out of hand - if only because possible world semantics are expansive.  

I'll go out on a limb here and suggest that what you reject is not that an x could be possible in some possible world..but that you don't think or don't believe that gods exist (or are possible) in the actual world - this world.  We could make a more neutral statement and say that you aren't convinced that gods are possible or exist in the actual world.  Thus the request for a demonstration...but the modal argument is an a priori argument..so...  Don't get me wrong, I wholeheartedly agree.  I'm not an agnostic - I personally take it as a settled fact that gods do not exist and are not even possible.    

My interest in the argument has nothing to do with gods.  What I do think is interesting is that a person can logically believe that it is impossible for a unicorn to exist in the actual world -and- grant that unicorns may be possible or possibly necessary in some possible world.  This sets up a logical paradox in the context of modal logic as it prunes qualifiers.  

They shouldn't, but I have encountered people who do seem genuinely surprised I remain unconvinced a deity exists.

Sure....but to be fair....it's not surprising that a successful argument fails to convince a human being, lol.  We could repeat the exercize with the mt/mp switch and we will find that even though we accept it as a "rule of logic" it will yield conclusions that assault our intuitions and may not reflect reality.

[The Grand Nudger]

Couldn't you list out a whole bunch of different necessary beings and attempt to prove that they ALL exist using this argument? Lol.

You can make all sorts of statements about possibility and necessity with this type of logic - that's it's main practical use.  Creating if-then cases for uncertain fields.

[Fake Messiah]

P1. If a god is possible it exists in every possible world
P2. If a god exists in every possible world then it would exist in this world as this world is possible

What does "every possible world" even mean? I only know of one world (universe).

Or are we also taking into account the imaginary worlds? Like if god exists in a novel or a video game this also means that he exists in the real world as well?

[Disagreeable]

For there to be different possible worlds seems to assume that indeterminism is true.

[The Grand Nudger]

P1. If a god is possible it exists in every possible world
P2. If a god exists in every possible world then it would exist in this world as this world is possible

What does "every possible world" even mean? I only know of one world (universe).

Or are we also taking into account the imaginary worlds? Like if god exists in a novel or a video game this also means that he exists in the real world as well?

Most people believe that things as a whole needn't be just the way they are.  All other ways things could be or could have been are possible worlds.

There is a possible world where I filled my cup with beer instead of gatorade - for example.

Gods existing as characters in novels or video games is a possible world, technically..our world - but in general the term is used to refer to other possible worlds. OFC, it's not a necessity of any possible world that they do...so, we couldn't go from characters to beings with modal logic that way. That would actually set up some comments on the neccessity of some kind of being in any world with video games and characters, though.

We could say that creators of novels are necessary in all possible worlds with characters in novels. Like this one..in which we conveniently do exist..and so the statement "humans exist" is true in all possible worlds - even those worlds in which humans do not exist. It would be completely rational for a being in such a possible world to believe that we didn't exist. The evidentiary case in their world would strongly back up that belief...but, nevertheless, that belief would be false.

[Mister Agenda]

You not accepting a premise doesn't make the next premise a fallacy.  It just means that you don't accept a premise.  In this case, the premises you've decided to reject and consider circular are a bare bones statement of the s5 theory of modal logic.  

I don't think it's accurate to say that any arbitrary definition would work - because it's really just the one thing or quality or attribute or x that the argument works -on-.  Necessity.  You could do away with omnipotence, omniscience, and moral perfection..for example....and it would not impact the argument - though it would certainly disappoint some christians.  Frankly, you could discard those things for an existent god and it would still be a christian problem - not a god problem or a logical problem.

Why is it possible that a God is necessary? My philosophy skills never rose above undergraduate electives.

[brewer]

And so the question remains: is God possible?

I haven't heard of an impossible concept yet.

[Nay_Sayer]

My standard rebuttal:

P1. If FSM is possible it exists in every possible world
P2. If FSM exists in every possible world then it would exist in this world as this world is possible
C. FSM exists

Weirdly they don't feel compelled to join Pastafarianism afterwards.

[The Grand Nudger]

Well..traditionally, christians don't think it's just possible that god is a necessary being - it's considered tautologically true that god is a necessary being. What the moa asks is not whether god is a necessary being, but whether a rational person could accept that a necessary being might exist in a possible world. Whether a rational person could accept that a most-of-the-whatevers existed in a possible world (as we've seen, the omnis don't exactly mean all...just, you know, more than anything else - apparently). Whether a person thinks it is possible for there to be a possible world that contains a possible being that possibly cannot fail to exist.

The logic employed trims qualifiers..so possibly necessary is necessary, possibly necessarily existent is necessarily existent. It really isn't any more complicated than that.