Alvin Plantinga’s Modal Ontological Argument

[Peter_Plato]

They’re not my arguments, they’re from the article I linked.

It appears that you have reformulated most of the parodies in a way to make them your arguments. They weren’t verbatim (at least most of them) and some had key premises altered or left out in such a way as to alter them substantively from the originals. In effect, you made them your arguments.

In addition, you presented them as if they served to refute Plantinga’s argument. They don’t.

Even Oppy says about Gasking’s parody (a more elaborate version of the first one you outlined and truncated and made even more “inferior” in the process,) that this “… parody—at least in its current state—seems to me to be inferior to other parodies in the literature, including the early parodies of Gaunilo and Caterus.”

Are you content with retreating to the position that parodies to Plantingas argument have been presented by philosophers but those parodies aren’t defensible?

Why bring them into the discussion in the first place if you didn’t think they worked?

 

[Peter_Plato]

Look at the antecedent of premise 2. And then premise 6. The argument quite literally reduces to A->A. Which is definitely a tautology. The rest are logical links in the chain to get from the implication to the ergo. And then premise 1 is tacked onto avoid the tautology problem. Which you already gave the bingo for.

It would appear that you think all deductive proofs are tautologies, then, because inherent in the idea of deduction is that what is deduced (or “deducted”) was already contained in the proposed truth and is merely “lifted” out of it. Any deductive proof or argument “quite literally reduces to A->A.”

Take, for example, the classic…

All men are mortal.
Socrates is a man.
Socrates is mortal.

The second premise and conclusion simply “reduce” to the first because Socrates, being a man, must be mortal is precisely what the first premise has already stated. How do you avoid that “tautology problem?”

Arithmetical statements such as 1+1=2 and mathematical proofs are also mere tautologies and would appear to present a “tautological problem” for you in the same way that Plantinga’s argument does. Would you categorize that as a “fair” statement of what follows from your claim?

If not, could explain why it doesn’t?

 

[inocente]

It appears that you have reformulated most of the parodies in a way to make them your arguments. They weren’t verbatim (at least most of them) and some had key premises altered or left out in such a way as to alter them substantively from the originals. In effect, you made them your arguments.

In addition, you presented them as if they served to refute Plantinga’s argument. They don’t.

Even Oppy says about Gasking’s parody (a more elaborate version of the first one you outlined and truncated and made even more “inferior” in the process,) that this “… parody—at least in its current state—seems to me to be inferior to other parodies in the literature, including the early parodies of Gaunilo and Caterus.”

Are you content with retreating to the position that parodies to Plantingas argument have been presented by philosophers but those parodies aren’t defensible?

Why bring them into the discussion in the first place if you didn’t think they worked?

The reverse argument is straight from the article, as are two of the parodies, except with “God” changed to “MGB” in line with the OP. As you noticed, I shortened the other, for comedic effect. So sue me.

Now you’ve finally found the link you’ll see I quoted the reverse argument from section 7, which is where you’ll find Plantinga stating that none of his wordings of the argument prove or establish their conclusion.

Oppy agrees with him on that, and as they’re both professional PhD philosophers and experts in this field, I’m content for you to discuss with them which is least convincing - the parodies, Plantinga’s argument or the reverse argument.

 

[Peter_Plato]

Look at the antecedent of premise 2. And then premise 6. The argument quite literally reduces to A->A. Which is definitely a tautology. The rest are logical links in the chain to get from the implication to the ergo.

To put it more concisely, his argument doesn’t reduce to 'If A, then A," because it takes the “If” completely off the table in a logical sense by showing that A is either necessarily true or a logical impossibility. That places the burden on naysayers to show the logical impossibility of A or they are stuck with A being necessarily true. That doesn’t “reduce” to a tautology because “if A” is removed completely as an option – no fence to sit on exists any longer.

 

[Charlemagne_III]

“Even among critics, there’s still no consensus as to exactly where the flaw lies in Anselm’s reasoning….the ontological argument, though many regard it as a mere philosophical gimmick, seems the most difficult to refute.” (Yujin Nagasawa, The Existence of God.)

yujinnagasawa.co.uk/

Bertrand Russell in his early period accepted Anselm’s argument, but later asserted, “The argument does not, to a modern mind, seem very convincing, but it is easier to feel convinced that it must be fallacious than it is to find out precisely where the fallacy lies.”

Plantinga’s argument seems to suffer the same fate.

 

[TheCuriousCat]

To put it more concisely, his argument doesn’t reduce to 'If A, then A," because it takes the “If” completely off the table in a logical sense by showing that A is either necessarily true or a logical impossibility. That places the burden on naysayers to show the logical impossibility of A or they are stuck with A being necessarily true. That doesn’t “reduce” to a tautology because “if A” is removed completely as an option – no fence to sit on exists any longer.

1. If it is possible for something to not exist in any possible world, then it is impossible for it to be necessary.
2. It is possible for a world to exist in which there is no God.
3. Therefore it is impossible for God to be necessary.

Presto! That was incredibly easy. I’m going to take a wild guess you don’t don’t accept premise #2, just like I don’t accept the premise that God is necessary.

 

[Peter_Plato]

1. If it is possible for something to not exist in any possible world, then it is impossible for it to be necessary.
2. It is possible for a world to exist in which there is no God.
3. Therefore it is impossible for God to be necessary.

Presto! That was incredibly easy. I’m going to take a wild guess you don’t don’t accept premise #2, just like I don’t accept the premise that God is necessary.

The problem is is that you don’t know for certain whether it is possible for a world to exist in which there is no God. You don’t know what it takes for a world to exist in the first place. You may have opinions on that but you don’t KNOW for certain.

Ergo not as “incredibly easy” as you suppose.

In fact, if Aquinas’ cosmological argument is correct that the existence of contingent things requires a self-explanatory and non-contingent (or self-existent) Ipsum Esse Subsistens, then your “incredibly easy” begins to look just a little contrived.

Yes, of course, we can assume or assert many things, but that is quite a different story from demonstrating them with certainty – which, I hate to break it to you, you haven’t done.

 

[TheCuriousCat]

The problem is is that you don’t know for certain whether it is possible for a world to exist in which there is no God. You don’t know what it takes for a world to exist in the first place. You may have opinions on that but you don’t KNOW for certain.

Ergo not as “incredibly easy” as you suppose.

Au contraire. I am a writer. I imagine worlds all the time. I can conceive of a world without a God. I can’t conceive of a world without premises, or in which triangles have more than or less than three angles, or in which effects don’t have causes. If a god were necessary, I shouldn’t be able to imagine a world without one.

In fact, if Aquinas’ cosmological argument is correct that the existence of contingent things requires a self-explanatory and non-contingent (or self-existent) Ipsum Esse Subsistens, then your “incredibly easy” begins to look just a little contrived.

And if he is wrong, it doesn’t. What’s your point?

Yes, of course, we can assume or assert many things, but that is quite a different story from demonstrating them with certainty – which, I hate to break it to you, you haven’t done.

Well, he hasn’t demonstrated anything either, so we’re even. Plantinga freely admits that he hasn’t come to his first premise rationally, and that it doesn’t prove the existence of a MGB. According to him it only shows that it is a rational thing to believe.

My argument is valid. Whether the premises are true is a matter of debate. His argument is valid, whether the premises are true is a matter of debate.

 

[Expatreprocedit]

It looks to me like a rehash of Anselm’s Ontological Argument. Brilliant, but not very convincing.

 

[Peter_Plato]

Au contraire. I am a writer. I imagine worlds all the time. I can conceive of a world without a God. I can’t conceive of a world without premises, or in which triangles have more than or less than three angles, or in which effects don’t have causes. If a god were necessary, I shouldn’t be able to imagine a world without one.

Let’s point out, first of all, that your interchangeable use of “imagine” and “conceive of” as if these two words mean the same thing is playing fast and loose with words. It is possible to imagine many things which are not factually possible given the way the world works. And since we don’t have a complete understanding of how the world came to be the way it is, it is a bit premature to claim that that world could have come about without God. Big Bang cosmology is actually showing us that such a notion just might be very very wrong.

So it may be possible to imagine a world without God, but to conceive or conceptualize such a thing means we need a full and explicit accounting for how things are the way they are that derives FROM the way things are.

Imagining things are what good writers may be good at, but unless those same writers can give not just plausible but explanatorily sufficient and explicit accounts for the way they “conceive” things, imagining something is a far cry from properly conceiving it.

And if he is wrong, it doesn’t. What’s your point?

You left out the part where you have to show that he is wrong, not merely imagine that he is.

Well, he hasn’t demonstrated anything either, so we’re even. Plantinga freely admits that he hasn’t come to his first premise rationally, and that it doesn’t prove the existence of a MGB.

Actually, as I pointed out, he has shown that MGB is either self-contradictory or necessary. To hold that necessary is merely possible is inherently contradictory. So you are correct that it doesn’t “prove” the existence of MGB, but it sets the burden on the skeptic to prove that the existence of the MGB is inherently and logically flawed.

I don’t see much in that vein coming from you, though.

According to him it only shows that it is a rational thing to believe.

Correct, so you are free to imagine all kinds of things, but that doesn’t make it rational to believe in them. If the question of what it is rational to believe matters, then his conclusion ought to be taken seriously. It won’t do to use cheap tricks like equivocating on words like imagine and conceive as if just to imagine or unimagine something is all it takes to make it exist or not.

My argument is valid. Whether the premises are true is a matter of debate.

You haven’t given an argument, you made a few assertions, and they have been dealt with.

His argument is valid, whether the premises are true is a matter of debate.

I suppose you can debate the validity of self-contradictory ideas like square circles if you want, just as you can debate whether necessary things are merely possible – relying, I suppose, on using the words imagine and conceive as if they were identical – but logical debate requires an adherence to logic and reason, not merely to what is imaginable.

 

[TheCuriousCat]

Let’s point out, first of all, that your interchangeable use of “imagine” and “conceive of” as if these two words mean the same thing is playing fast and loose with words. It is possible to imagine many things which are not factually possible given the way the world works. And since we don’t have a complete understanding of how the world came to be the way it is, it is a bit premature to claim that that world could have come about without God. Big Bang cosmology is actually showing us that such a notion just might be very very wrong.

So it may be possible to imagine a world without God, but to conceive or conceptualize such a thing means we need a full and explicit accounting for how things are the way they are that derives FROM the way things are.

Imagining things are what good writers may be good at, but unless those same writers can give not just plausible but explanatorily sufficient and explicit accounts for the way they “conceive” things, imagining something is a far cry from properly conceiving it.

You left out the part where you have to show that he is wrong, not merely imagine that he is.

Actually, as I pointed out, he has shown that MGB is either self-contradictory or necessary. To hold that necessary is merely possible is inherently contradictory. So you are correct that it doesn’t “prove” the existence of MGB, but it sets the burden on the skeptic to prove that the existence of the MGB is inherently and logically flawed.

I don’t see much in that vein coming from you, though.

Correct, so you are free to imagine all kinds of things, but that doesn’t make it rational to believe in them. If the question of what it is rational to believe matters, then his conclusion ought to be taken seriously. It won’t do to use cheap tricks like equivocating on words like imagine and conceive as if just to imagine or unimagine something is all it takes to make it exist or not.

You haven’t given an argument, you made a few assertions, and they have been dealt with.

I suppose you can debate the validity of self-contradictory ideas like square circles if you want, just as you can debate whether necessary things are merely possible – relying, I suppose, on using the words imagine and conceive as if they were identical – but logical debate requires an adherence to logic and reason, not merely to what is imaginable.

Okay, it’s pretty clear to me that you are misunderstanding some fundamental terms for us to have a meaningful conversation.

Worlds: In logic, worlds aren’t planets, solar systems, or universes. Worlds are a global set of premises that are logically consistent.

Necessary: Must exist in all logical worlds.

When someone says that God is logically necessary in all possible worlds, they aren’t saying that this universe couldn’t exist without Gods, they are saying that there are no set that could be logically consistent without also accepting the premise that God exists.

Considering the following premise: There is a world that is two dimensional. It doesn’t matter whether there actually is a world that is only two dimensional, we can still determine whether other premises would be consistent in that world. For instance, cubes would not be possible. People couldn’t exist. However triangles would still be necessarily composed of three angles. The world would still has premises. The additive principle would still apply, and effects would still have causes. These things are logically necessary. They are true given any other set of premises.

If there existed a static universe without a beginning, would God be necessary? If you or I can present any set of logically consistent premises that wouldn’t require there to be a God, then it is impossible for God to be necessary, and… I just did. His argument isn’t sound.

 

[STT]

Alvin Plantinga’s Modal Ontological Argument

1. It’s possible that a Maximally Great Being (MGB) exists.
2. If it is possible that a MGB being exists, then a MGB exists in some possible world.
3. If a MGB exists in some possible world, then it exists in all possible worlds.
4. If a MGB exists in every possible world, then it exists in the actual world.
5. If a MGB exists in the actual world, then a MGB exists.
6. Therefore, a MGB exists.

Definitions:

Possible World – a hypothetical situation used by philosophers to test an idea to see if it’s logical by asking whether it could exist in a world like our own

Maximally Great Being – a being that possesses all qualities that are better to have (love, wisdom, omnipotence, omniscience) but no negative properties (imperfection, corruption). Specifically, a MGB must have the property of necessity since being necessary is better than the alternatives.

Impossible Being – an entity that exists in no possible worlds (a square circle, a married bachelor)
Contingent Being – an entity that exists in some possible worlds and depends on something else for its existence (children exist because their parents existed)
Necessary Being – an entity that cannot be false or incoherent or fail to exist in any possible world (numbers, shape definitions)

God is not a contingent being; He is a Maximally Great Being whose existence is necessary in all possible worlds including the actual world in which we live.

I have problem with (2) and after. Why MGB should be somewhere in order to exist?

 

[TheCuriousCat]

I have problem with (2) and after. Why MGB should be somewhere in order to exist?

A world isn’t a place in logic. It is a set of premises

 

[STT]

A world isn’t a place in logic. It is a set of premises

Then what does “exists in some possible world” means?

 

[TheCuriousCat]

Then what does “exists in some possible world” means?

It is roughly like saying, “There are a set of rules in which this is the case.”

For instance, in plane geometry all triangles are 180°. In that world, triangles with more or fewer than 180° don’t exist. But in a different world, like on the surface of sphere, you can draw a 270° triangle. In that world, triangles over 180° exist.

If something is “necessary” in one world, it is widely believed to be necessary in all worlds. Just like if it is impossible in one world it is impossible for all.

 

[STT]

It is roughly like saying, “There are a set of rules in which this is the case.”

For instance, in plane geometry all triangles are 180°. In that world, triangles with more or fewer than 180° don’t exist. But in a different world, like on the surface of sphere, you can draw a 270° triangle. In that world, triangles over 180° exist.

If something is “necessary” in one world, it is widely believed to be necessary in all worlds. Just like if it is impossible in one world it is impossible for all.

Thank you.

 

[TheCuriousCat]

Thank you.

No problem.

 

[Peter_Plato]

Okay, it’s pretty clear to me that you are misunderstanding some fundamental terms for us to have a meaningful conversation.

Yes, of course, I am “misunderstanding some fundamental terms,” when you define logical reality as…

Worlds: In logic, worlds aren’t planets, solar systems, or universes. Worlds are a global set of premises that are logically consistent.

No, it isn’t true that “In logic, … [w]orlds are a global set of premises that are logically consistent.”

Perhaps in something like modal logic what you say might be proposed, but that doesn’t mean in logic generally that worlds “…are a global set of premises that are logically consistent.”

Collapsing or conflating logic, as a whole, into your preconceptions about modal logic is where you seem to fall apart without realizing it.

You seem to claim that actuality has nothing to do with logical consistency, reality or necessity, but that would seem to undermine your whole case because even though you state that determining whether some premises are consistent with a two-dimensional world doesn’t rely upon the actual existence of that two-dimensional world, you necessarily have to grant that whether any premises are consistent with a proposed world does rely upon the actual existence of logical consistency, which means logical necessity of some kind must be presumed to exist even in worlds which rely purely upon consistency, not least of all because logical consistency implies logical necessity wrapped in that consistency.

What needs to be explained by you is the foundation for “consistency” if not within that which must be true, i.e., that which must be or exist necessarily. Ergo, even in your possible 2-D world, the consistency of that world requires the existence of logical necessity, or you couldn’t even make your case.

Upon what does logical necessity, itself, stand if not upon being or existence itself, which must be necessary? Ergo, MGB must have some connection to that necessity which underwrites logical consistency itself, i.e., provides the framework or structure for all that logically could or possibly exist.

 

[inocente]

Perhaps in something like modal logic what you say might be proposed, but that doesn’t mean in logic generally that worlds “…are a global set of premises that are logically consistent.”

TheCuriousCat is correct.Google is your friend, to find Plantinga’s definition just search for “plantinga possible worlds”:

andrewmbailey.com/ap/Actualism_Possible_Worlds.pdf
plato.stanford.edu/entries/actualism/possible-worlds.html

Modal means relating to modes, in this case two modes of being - possible existence and actual existence.

"Upon what does logical necessity, itself, stand if not upon being or existence itself, which must be necessary? Ergo, MGB must have some connection to that necessity which underwrites logical consistency itself, i.e., provides the framework or structure for all that logically could or possibly exist.

If you’re proposing “Logic exists; therefore MGB” then that isn’t Plantinga’s argument, and is the mother and father of all circular arguments.

 

[Peter_Plato]

TheCuriousCat is correct.Google is your friend, to find Plantinga’s definition just search for “plantinga possible worlds”:

andrewmbailey.com/ap/Actualism_Possible_Worlds.pdf
plato.stanford.edu/entries/actualism/possible-worlds.html

Modal means relating to modes, in this case two modes of being - possible existence and actual existence.

No TheCuriousCat claimed that “Worlds: In logic, worlds aren’t planets, solar systems, or universes. Worlds are a global set of premises that are logically consistent,” which is NOT correct. I merely pointed out that “In modal logic…” would have been a more accurate qualifier for the statement.

So what is your point here? Are you arguing that the Cat’s statement is true in all forms of logic? Then, perhaps YOU need to look up “propositional logic” or “classical truth-functional propositional logic” on your friend Google.

If you are trying to point that the Cat’s point IS possibly true in modal logic, then how is that different from what I wrote?

If you’re proposing “Logic exists; therefore MGB” then that isn’t Plantinga’s argument, and is the mother and father of all circular arguments.

Actually, what I claimed was that the Cat’s use of the word “consistency,” that is presumed to underlie or ground logical truth, requires that necessity also be the case. So yes, logic exists iff necessity holds in all possible worlds. The Cat’s original claim was that s/he could imagine a logical world where necessity did not exist. I am merely pointing out that such a claim is untrue because any “logically consistent” world can only be “logically consistent” if that consistency is a necessary logical aspect.

Ergo, necessity must be the case in all possible worlds, even in those conceived in the realm of modal logic. Or, to use other words, the Cat’s claim regarding worlds in modal logic assumes necessity and can only be considered true if it is necessarily true. I.e., “It is necessarily true that in modal logic, worlds are a global set of premises that are logically consistent.”

The question then becomes, “In what actuality or reality is that necessity grounded?”

Cat’s original claim was that s/he had refuted Plantinga’s argument because s/he could conceive of a possible world where necessity (MGB) wasn’t necessary.

To wit:

If there existed a static universe without a beginning, would God be necessary? If you or I can present any set of logically consistent premises that wouldn’t require there to be a God, then it is impossible for God to be necessary, and… I just did. His argument isn’t sound.

My larger point, then, is to point out that logical consistency requires necessity, therefore all possible worlds, even those in modal logic require and presume necessity for the world to hold as logically “consistent” in that world. In what is that consistency to be grounded? Perhaps in some kind of existential necessity (AKA MGB) which makes logic itself binding and true necessarily even in the form of modal logic?

The Cat needs to answer this little issue. Relying on would-be friends to obfuscate the matter just won’t do.