Terrible Atheist Argument #1

[MindForgedManacle]

Sure:

P1) If metaphysical naturalism is possibly true, then God does not exist.

P2) Metaphysical naturalism is possibly true. (axiom S5)

C) Therefore God does not exist.

Remember, this argument is not to be taken seriously. It's just to show that if I use the axiom S5 and assume it to be metaphysical possibility, then it just becomes absurd because contradictory conclusions are inevitable.

[Vincenzo Vinny G.]

I'm taking it as a reductio ad absurdum, which is your intention, right MFM? But like I suspected, your P2 is not a proper application of S5 in the same way as the ontological argument.

To make it explicit, given S5,
possibly necessary -> necessary.
So "Possibly Necessary God" -> "Necessary God"

But your argument does not argue that metaphysical naturalism is possibly necessarily true. In fact no claim of necessity is made anywhere in your argument, right?

Mere possibility does not carry the MOA.

[MindForgedManacle]

It's basically a reductio, yes.

Ah, I was careless to some extent. I wasn't really using the S5 axiom in that argument exactly like Plantinga did. Plantinga uses 'possibly necessary' (i.e possibly necessarily true), while I'm simply using 'possibly' (i.e not necessarily necessary, but at least true in one possible world).

However, the argument can be reformulated:

P1) If naturalism is possibly necessarily true, then it is actually true.

P2) Naturalism is possibly necessarily true.

C) Therefore, naturalism is true.

Regardless, both still undermine Plantinga's argument, due to reasons already specified, namely that competing arguments are equally sound, even taking into consideration sometimes different used axioms.

[Vincenzo Vinny G.]

Okay, this rewording makes more sense.

Now your P2, once reworded says "Necessary Metaphysical Naturalism is possibly true" vs "A necessary being possibly exists"

This raises some questions for me:
1) What does necessary metaphysical naturalism entail? That nMN is true in all possible worlds? This is answered for God in the context of the MOA.
2) How do we establish the property of necessity applies to MN? This is argued for in the MOA by saying a MGB cannot be contingent.

[MindForgedManacle]

Those are the objections that came to my mind when making that argument, hence why I prefer the one that does not go the Plantinga route, because it does not have to be true in all possible worlds.

However, I earlier mentioned (a few pages back) one possible reason why even that reformulated argument might work (though I don't prefer it), namely that metaphysical truths would seem to necessarily be trans-possible world true. What sense would it make to say that mathematical Platonism is not true in all possible worlds, for example? Given the transcendent nature, it would seem their truth in any state of affairs necessarily entails.

But, I guess an on-the-spot supporting argument could be:

P1) If a possibly necessary truth is metaphysical in scope, then it is necessarily true (i.e true in all possible worlds).

P2) Naturalism is a possibly necessary truth which is metaphysical in scope.

C) Therefore, if naturalism is possibly necessarily true, then it is actually true.

Of course, I could just misunderstand metaphysics, which would put me in great company with like everyone ever. :p

[Vincenzo Vinny G.]

Those are the objections that came to my mind when making that argument, hence why I prefer the one that does not go the Plantinga route, because it does not have to be true in all possible worlds.

However, I earlier mentioned (a few pages back) one possible reason why even that reformulated argument might work (though I don't prefer it), namely that metaphysical truths would seem to necessarily be trans-possible world true. What sense would it make to say that mathematical Platonism is not true in all possible worlds, for example? Given the transcendent nature, it would seem their truth in any state of affairs necessarily entails.

But, I guess an on-the-spot supporting argument could be:

P1) If a possibly necessary truth is metaphysical in scope, then it is necessarily true (i.e true in all possible worlds).

P2) Naturalism is a possibly necessary truth which is metaphysical in scope.

C) Therefore, if naturalism is possibly necessarily true, then it is actually true.

Of course, I could just misunderstand metaphysics, which would put me in great company with like everyone ever. :p

Do you mean to say metaphysical truths are necessary in all possible worlds? I can understand why mathematical Platonism might seem like a good candidate for your claim, because the consistency of mathematics across all possible worlds seems intuitively true. But what if we used a simpler, less obvious example: Say, solipsism. Isn't that possible in some worlds but not others? Or is that not a metaphysical claim?

[MindForgedManacle]

Well, there's epistemic and metaphysical solipsisms. The former is about what can and can't be known, while the latter is a position about reality itself. The latter is of concern here.

Eh, I'll have to get back later, it's passed 1am here! *sleep time*

Edit: Screw it, I'll finish up some.


If metaphysical solipsism is true, then only you exist. However, you don't know the nature of this 'you' that necessarily exists. If only you exist and ever existed, could it have been otherwise? I'm not so sure, especially wehn the position can't really be assessed for truth necessarily.

[Vincenzo Vinny G.]

I think the question is "Is (metaphysical) solipsism necessarily true in all possible worlds if it is true in one possible world?"

To me the answer seems to be no, because although one PW could include p-zombies and 1 person, that doesn't mean all worlds do. So I'm not so sure that metaphysical possibilities are trans-world necessary.

[MindForgedManacle]

You're confusing epistemological solipsism with metaphysical solipsism. If metaphysical solipsism is true, you are the only mind that exists, while the epistemic version is about doubting that you can ascertain the truth of whether or not other minds exist. Hence, if metaphysical solipsism is true then I'm not sure postulating possible worlds where there are other minds or p-zombies really helps, because then isn't it by definition necessarily the case? Or at best, you could slide to the epistemological version, which means the question of whether or not possible metaphysical truths are necessarily true becomes a non sequitur.


Regardless, I guess I could parse metaphysical truths into 2 camps: necessary metaphysical truths (NMTs) and unnecessary metaphysical truths (UMTs). The former refers to possibly necessary metaphysical truths that, if coherent, have to be true, while the latter refers to metaphysical truths that only happen to be true, but didn't have to be. Thus, my argument would seem to hold, since metaphysical naturalism is self-evidently a NMT (as is God), which would rule out God if you accept modal ontological arguments as valid operating methods.

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But really, the above is all problematic. From what I understand, Immanuel Kant essentially destroyed metaphysics - or certainly dealt it a near KO - so even trying to make metaphysical arguments like Plantinga's MOA (and my own) are non-starters without an amazing metaphysical grounding and defense, which no one has really managed to do. That's why - from what I think I understand and from what I've heard - contemporary philosophy has abandoned metaphysics.

[Vincenzo Vinny G.]

You're confusing epistemological solipsism with metaphysical solipsism. If metaphysical solipsism is true, you are the only mind that exists, while the epistemic version is about doubting that you can ascertain the truth of whether or not other minds exist. Hence, if metaphysical solipsism is true then I'm not sure postulating possible worlds where there are other minds or p-zombies really helps, because then isn't it by definition necessarily the case? Or at best, you could slide to the epistemological version, which means the question of whether or not possible metaphysical truths are necessarily true becomes a non sequitur.


Regardless, I guess I could parse metaphysical truths into 2 camps: necessary metaphysical truths (NMTs) and unnecessary metaphysical truths (UMTs). The former refers to possibly necessary metaphysical truths that, if coherent, have to be true, while the latter refers to metaphysical truths that only happen to be true, but didn't have to be. Thus, my argument would seem to hold, since metaphysical naturalism is self-evidently a NMT (as is God), which would rule out God if you accept modal ontological arguments as valid operating methods.

---

But really, the above is all problematic. From what I understand, Immanuel Kant essentially destroyed metaphysics - or certainly dealt it a near KO - so even trying to make metaphysical arguments like Plantinga's MOA (and my own) are non-starters without an amazing metaphysical grounding and defense, which no one has really managed to do. That's why - from what I think I understand and from what I've heard - contemporary philosophy has abandoned metaphysics.

I have to apologize that I misunderstood what you were trying to say here (http://atheistforums.org/thread-21858-po...#pid554139)

It sounded like you were trying to say that metaphysical claims were somehow ontologically special in modal logic, and I couldn't understand why.

But now I see you were just rephrasing the argument to avoid postulating "necessary metaphysical naturalism." Am I understanding you right here?