Agnosticism is logically incoherent (St. Anselm and Alvin Plantinga)

[warpspeedpetey]

This is his actual wording when he restates the argument:

• There is a possible world in which maximal greatness is instantiated.
• Necessarily, a being is maximally great only if it has maximal excellence in every world.
• Necessarily, a being has maximal excellence in every world only if it has omniscience, omnipotence, and moral perfection in every world.

I paraphrased it because I thought it needed to be fleshed out in accordance with what he says in the piece leading up to this point. (I also didn’t realize that there are trained philosophers on this forum – where have you guys been hiding? )

not trained, so much as experienced, we spend alot more time on these arguments than most people. now lets use platingas actual argument and see who bites

 

[warpspeedpetey]

It’s not defined as such in Kripke semantics.

…ummmmm…thats not kripke semantics, thats possible world semantics, i might be mistaken, but to my understanding they are different non-classical modal systems.

en.wikipedia.org/wiki/Possible_world_semantics

The term “possible worlds semantics” is often used as a synonym for Kripke semantics, but this is widely regarded as a mistake: Kripke semantics can be used to analyse modes other than alethic modes (that is, it can be used in logics concerned not with truth per se; in generally in intensional logic, for one example, in deontic logic, which is the logic of obligation and permission); and Kripke semantics does not presuppose modal realism, which the language of possible worlds arguably presupposes.

en.wikipedia.org/wiki/Kripke_semantics

Kripke semantics (also known as relational semantics or frame semantics, **and often confused with possible world semantics) **is a formal semantics for non-classical logic systems created in the late 1950s and early 1960s by Saul Kripke, beginning when he was a teenager.

 

[MindOverMatter]

…ummmmm…thats not kripke semantics, thats possible world semantics, i might be mistaken, but to my understanding they are different non-classical modal systems.

en.wikipedia.org/wiki/Possible_world_semantics

The term “possible worlds semantics” is often used as a synonym for Kripke semantics, but this is widely regarded as a mistake: Kripke semantics can be used to analyse modes other than alethic modes (that is, it can be used in logics concerned not with truth per se; in generally in intensional logic, for one example, in deontic logic, which is the logic of obligation and permission); and Kripke semantics does not presuppose modal realism, which the language of possible worlds arguably presupposes.

en.wikipedia.org/wiki/Kripke_semantics

Kripke semantics (also known as relational semantics or frame semantics, **and often confused with possible world semantics) **is a formal semantics for non-classical logic systems created in the late 1950s and early 1960s by Saul Kripke, beginning when he was a teenager.

I hate confusion. I love understanding.

 

[hatsoff]

…ummmmm…thats not kripke semantics, thats possible world semantics, i might be mistaken, but to my understanding they are different non-classical modal systems.

en.wikipedia.org/wiki/Possible_world_semantics

The term “possible worlds semantics” is often used as a synonym for Kripke semantics, but this is widely regarded as a mistake: Kripke semantics can be used to analyse modes other than alethic modes (that is, it can be used in logics concerned not with truth per se; in generally in intensional logic, for one example, in deontic logic, which is the logic of obligation and permission); and Kripke semantics does not presuppose modal realism, which the language of possible worlds arguably presupposes.

en.wikipedia.org/wiki/Kripke_semantics

Kripke semantics (also known as relational semantics or frame semantics, **and often confused with possible world semantics) **is a formal semantics for non-classical logic systems created in the late 1950s and early 1960s by Saul Kripke, beginning when he was a teenager.

Yes, I should probably be more exact in my language. Sorry for any confusion.

 

[warpspeedpetey]

I hate confusion. I love understanding.

i thought you might, brother.

 

[warpspeedpetey]

Yes, I should probably be more exact in my language. Sorry for any confusion.

its ok. i make plenty of slip ups myself, liquidpele had to rescue me from myself last night.

 

[hatsoff]

its ok. i make plenty of slip ups myself, liquidpele had to rescue me from myself last night.

Well, in my defense, some logicians do use the terms interchangeably. However, it’s probably best to distinguish between them, as wikipedia suggests. I thank you for the reminder.

 

[warpspeedpetey]

ok, back on track, lets explore the OPs post of platingas modal argument here. to me it seems almost like working backwards from Aquinas’ actus purus, or my attempt at a modal restatement, “maximal state of being.”

Originally Posted by Langdell
This is his actual wording when he restates the argument:

• There is a possible world in which maximal greatness is instantiated.

• Necessarily, a being is maximally great only if it has maximal excellence in every world.

• Necessarily, a being has maximal excellence in every world only if it has omniscience, omnipotence, and moral perfection in every world.

does any one have a refutation of this argument to discuss?

 

[warpspeedpetey]

Well, in my defense, some logicians do use the terms interchangeably. However, it’s probably best to distinguish between them, as wikipedia suggests. I thank you for the reminder.

i do that too sometimes with other arguements from contingency and first cause. no harm no foul, lets move on to the actual argument platinga makes as posted by the OP.

 

[hatsoff]

ok, back on track, lets explore the OPs post of platingas modal argument here. to me it seems almost like working backwards from Aquinas’ actus purus, or my attempt at a modal restatement, “maximal state of being.”

does any one have a refutation of this argument to discuss?

I’m don’t think the argument can be salvaged by re-wording it. In this particular case, we have reason to doubt all three of the claims. It is by no means obvious that a being is “maximally excellent” only if it is metaphysically necessary. And if we are to say that such a being is necessary, then that gives us reason to doubt that there is a possible world where it exists. And of course since “maximal excellence” is inherently subjective, we do not get to immediately assume it entails things like moral perfection (which is also subjective), omniscience, etc.

 

[warpspeedpetey]

I’m don’t think the argument can be salvaged by re-wording it. In this particular case, we have reason to doubt all three of the claims. It is by no means obvious that a being is “maximally excellent” only if it is metaphysically necessary. And if we are to say that such a being is necessary, then that gives us reason to doubt that there is a possible world where it exists. And of course since “maximal excellence” is inherently subjective, we do not get to immediately assume it entails things like moral perfection (which is also subjective), omniscience, etc.

i dont think platinga means “metaphysically necessary”, i believe he means the formal definition below of “necessary”, in possible world semantics given below.

en.wikipedia.org/wiki/Possible_world

Necessarily true propositions (usually simply called necessary propositions) are those that are true in all possible worlds (for example: “2 + 2 = 4”; “all bachelors are unmarried”)

to the specific premises

• There is a possible world in which maximal greatness is instantiated.

is there a reason that this is impossible in some possible world? i mean to say, what reason is there to doubt that this is possible?

• Necessarily, a being is maximally great only if it has maximal excellence in every world.

perfection, or maximal greatness, infers that there is no lack in the substance of that perfection, so a being maximally great or perfect can lack nothing, not being maximal in all worlds then would be imperfect and therefore not maximally great.

• Necessarily, a being has maximal excellence in every world only if it has omniscience, omnipotence, and moral perfection in every world

this too goes to the idea of maximal greatness, or perfection, lacking any of these qualities would then contradict that perfection.

that said, i dont care for his wording, it assumes a certain knowledge of Thomism that most people dont have. which is why it looks like he is working backwards into the maximal state of being.

i can be a little slow, when you respond could you attack the direct premise, the language here is confusing in general. it will help me sort out which premise to defend, thanks

 

[hatsoff]

i dont think platinga means “metaphysically necessary”, i believe he means the formal definition below of “necessary”, in possible world semantics given below.

en.wikipedia.org/wiki/Possible_world

Necessarily true propositions (usually simply called necessary propositions) are those that are true in all possible worlds (for example: “2 + 2 = 4”; “all bachelors are unmarried”)

to the specific premises

Yes, I know. And we beg the question if we assume that God is possibly necessary, because that’s just another way to say, among other things, that God exists.

is there a reason that this is impossible in some possible world? i mean to say, what reason is there to doubt that this is possible?

Of course–and it’s the same reason as above. If we say that maximal greatness is “possible,” then we are saying that maximal greatness exists. But we don’t get to say that until we have good evidence (or some other warrant) to do so!

Imagine if I were to run the argument in reverse: It is possible that maximal greatness doesn’t exist. If Plantinga’s right about maximal greatness existing in all possible worlds or none, then that means maximal greatness is impossible in our Kripke frame.

Plantinga seems to want us to choose between a Kripke frame where God necessarily exists or necessarily does not exist. Nothing else will do, he tells us. Okay, fine. But then this merely prevents us from choosing a Kripke frame until we have more information.

perfection, or maximal greatness, infers that there is no lack in the substance of that perfection, so a being maximally great or perfect can lack nothing, not being maximal in all worlds then would be imperfect and therefore not maximally great.

Maximal excellence is highly subjective. You say a maximally great being can’t lack anything. Perhaps I could say that a maximally great being must lack any hint of evil. I could say that a maximally excellent deity would never create a world with suffering. I could say a lot of things, and I would just be making ad hoc assumptions.

“Maximally excellent” is a decidedly unhelpful term which a maximally excellent being would never employ!

this too goes to the idea of maximal greatness, or perfection, lacking any of these qualities would then contradict that perfection.

that said, i dont care for his wording, it assumes a certain knowledge of Thomism that most people dont have. which is why it looks like he is working backwards into the maximal state of being.

i can be a little slow, when you respond could you attack the direct premise, the language here is confusing in general. it will help me sort out which premise to defend, thanks

Yes, I don’t subscribe to Thomism at all, sorry.

 

[Langdell]

Thanks for the continuing analysis, guys. It’s fascinating.

To the extent it helps, here is Plantinga’s claim regarding the argument:

What shall we say of this argument? It is certainly valid; given its premise, the conclusion follows. The only question of interest, it seems to me, is whether its main premise – that maximal greatness is possibly instantiated – is true. I think it is true; hence I think this version of the ontological argument is sound.

But here we must be careful; we must ask whether this argument is a successful piece of natural theology, whether it proves the existence of God. And the answer must be, I think, that it does not. An argument for God’s existence may be sound, after all, without in any useful sense proving God’s existence. … Still, it is evident, I think, that there is nothing contrary to reason or irrational in accepting this premise . What I claim for this argument, therefore, is that it establishes, not the truth of theism, but its rational acceptability.

 

[hatsoff]

Thanks for the continuing analysis, guys. It’s fascinating.

To the extent it helps, here is Plantinga’s claim regarding the argument:

Plantinga is wrong, there. God-belief is not made rational by the existence of a hypothetical model in which God exists.

 

[warpspeedpetey]

Yes, I know. And we beg the question if we assume that God is possibly necessary, because that’s just another way to say, among other things, that God exists.

to say that it is not necessarily possible, is the equivalent to saying it is impossible. i guess im specifically asking why it would be impossible?

Of course–and it’s the same reason as above. If we say that maximal greatness is “possible,” then we are saying that maximal greatness exists. But we don’t get to say that until we have good evidence (or some other warrant) to do so!

 

[warpspeedpetey]

Plantinga is wrong, there. God-belief is not made rational by the existence of a hypothetical model in which God exists.

i have to disagree, i think that there is a possible model in which G-d exists does lead to a position that can rationally accept this possibility, admittedly im biased, i think its rational purely on the basis of contingnecy, first cause, and other arguments

 

[Langdell]

Plantinga is wrong, there. God-belief is not made rational by the existence of a hypothetical model in which God exists.

Do you say he’s wrong because you don’t accept that the existence of a maximally great being is possible, or because the proposition is too mushy to be meaningfully discussed, or for some other reason?

.

 

[hatsoff]

Do you say he’s wrong because you don’t accept that the existence of a maximally great being is possible, or because the proposition is too mushy to be meaningfully discussed, or for some other reason?

Well, the idea of a “maximally excellent” being, and especially one which requires existence in all possible worlds, indeed strikes me as highly problematic. But the most obvious problem with his argument is that we have absolutely no good reason whatsoever to believe that a necessary God is possible–i.e., that God exists. Since that’s one of his premises, it means that his ontological argument is an exercise in question begging.

 

[Langdell]

Gotcha, thanks.

.

 

[warpspeedpetey]

Well, the idea of a “maximally excellent” being, and especially one which requires existence in all possible worlds, indeed strikes me as highly problematic. But the most obvious problem with his argument is that we have absolutely no good reason whatsoever to believe that a necessary God is possible–i.e., that God exists. Since that’s one of his premises, it means that his ontological argument is an exercise in question begging.

it comes from contingency, contingent beings might not have been and require a necessary being to exist. i dont like the possible worlds angle myself because all possible worlds suffer from this defect, they too require a necessary being in order to exist.