Alvin Plantinga’s Modal Ontological Argument

[Peter_Plato]

Shhh, he doesn’t know this thread is a behavioral experiment.

And all along I was under the impression that this was a philosophical discussion.

:tiphat: Thanks for disabusing me of that notion before I got led astray by my high expectations.

 

[Peter_Plato]

Long ago, I linked Plantinga’s definition. All I’ve been doing is following his definition, since the OP is about his argument, not yours.

He answers your question with: “Possible worlds themselves are typically ‘taken as primitive’, as the saying goes: but by way of informal explanation it may be said that a possible world is a way things could have been-a total way.” - andrewmbailey.com/ap/Actualism_Possible_Worlds.pdf

Those are his italics btw. He seems very clear “a possible world is a way things could have been”. What is it you don’t understand?

So what is it that is required to make a possible world a “could have been” as opposed to a couldn’t have been?

Obviously Plantinga isn’t here to clarify that distinction, and yet, that distinction does seem to be one that needs to be made.

My contention is that what “could have been,” logically speaking, depends entirely upon what is. We have no other resort because we cannot produce from whole cloth what is or is not “logically possible.”

Our entire concept of logically possible depends entirely upon its consistency with that which we know to exist – some actualizing principle or other. In this case, what we know to exist leads us to speculate about other things which, therefore, might possibly exist.

However, we have nada to say with respect to pure “possibility” without some reference or other to actuality.

As I said, the only reason we know this world we currently reside in is, indeed, possible is because it exists. Absent that we have no grounds to make claims about what is or what is not possible.

You can refute that claim quite easily. Provide some logical grounds for what is or is not possible without any reference whatsoever to what exists.

Now you might claim any world that is logically coherent is one that is possible.

Well, okay, then it is up to you to give an example of logical coherency that makes no reference to and obtains no warrant from things that actually do exist or some actualizing principle found therein.

My second line of argument is that any and all existent things – which form all the grounds we have for determining what is possible or not – positively require the following actualizing principle: that which has existence itself as its essence, i.e., Aquinas’ Ipsum Esse Subsistens or that which exists a se.

Without that, no world or entity is possible whatsoever because contingent things – even an infinite chain of them cannot bootstrap themselves into existence. Necessary being (that which has existence as its very essence) is a requirement for the existence of any possible being – that is what I refer to as the “actualizing principle” behind every possible world if it is indeed to be possible.

That is also the argument to be made from the modal version, as I discussed in post #50 which neither of you have properly addressed.

Let’s go back to this counter argument to Plantinga’s, shall we?

I don’t think Plantinga need accept your 2. precisely because he would claim that the very definition of MGB precludes that possibility.

His point would be that for a MGB to exist in any possible world, it would necessarily have the trait of being necessary in every possible world. That means for a MGB to be maximally great in any possible world, it would, by definition, have to be maximally great in every possible. One of the conditions for being “maximally great” would be to have necessary existence and for necessary existence to logically be ‘necessary’ it must imply, in a logical sense – even in modal logic – that it be not merely possible in every possible world, but, indeed, NECESSARY in every possible world, otherwise you aren’t logically speaking of the MGB, but something else entirely.

Again, the point being that the MGB either must exist in every possible world or be logically self-contradictory and impossible in every possible world.

 

[inocente]

So what is it that is required to make a possible world a “could have been” as opposed to a couldn’t have been?

Obviously Plantinga isn’t here to clarify that distinction, and yet, that distinction does seem to be one that needs to be made.

My contention is that what “could have been,” logically speaking, depends entirely upon what is. We have no other resort because we cannot produce from whole cloth what is or is not “logically possible.”

Our entire concept of logically possible depends entirely upon its consistency with that which we know to exist – some actualizing principle or other. In this case, what we know to exist leads us to speculate about other things which, therefore, might possibly exist.

However, we have nada to say with respect to pure “possibility” without some reference or other to actuality.

As I said, the only reason we know this world we currently reside in is, indeed, possible is because it exists. Absent that we have no grounds to make claims about what is or what is not possible.

You can refute that claim quite easily. Provide some logical grounds for what is or is not possible without any reference whatsoever to what exists.

Now you might claim any world that is logically coherent is one that is possible.

Well, okay, then it is up to you to give an example of logical coherency that makes no reference to and obtains no warrant from things that actually do exist or some actualizing principle found therein.

My second line of argument is that any and all existent things – which form all the grounds we have for determining what is possible or not – positively require the following actualizing principle: that which has existence itself as its essence, i.e., Aquinas’ Ipsum Esse Subsistens or that which exists a se.

Without that, no world or entity is possible whatsoever because contingent things – even an infinite chain of them cannot bootstrap themselves into existence. Necessary being (that which has existence as its very essence) is a requirement for the existence of any possible being – that is what I refer to as the “actualizing principle” behind every possible world if it is indeed to be possible.

That is also the argument to be made from the modal version, as I discussed in post #50 which neither of you have properly addressed.

On your last two points, you don’t need to hypothesize what Plantinga might say as it’s the third premise in his argument, and the thread is about his MGB, not Thomas’ concept of God.

On your first point, you say “Provide some logical grounds for what is or is not possible without any reference whatsoever to what exists”. Do you mean as in starting a new system of math by inventing a set of axioms? Or as in the motivation many scientists give, to be the first person to discover something new?

But that’s for another thread, it’s off-topic here. If you read the Plantinga paper I linked, you’ll see that your worries (about what can be concrete?) aren’t relevant.

Plantinga uses possible world to mean something which is “taken as primitive”, i.e. undefined, and which contains a set of objects, which he calls its domain. He isn’t concerned what the objects are, he instead looks at what happens when operations are done on the sets. For instance he says “If we think of propositions as sets of worlds, then a proposition is true in a given world W if W is a member of it. Necessary propositions are then the propositions true in every world; possible propositions are true in at least one world; impossible propositions are not true in any.”

Plantinga never goes near your concerns as he’s dealing with sets of abstractions. Meanwhile, back at the OP …

 

[Peter_Plato]

On your last two points, you don’t need to hypothesize what Plantinga might say as it’s the third premise in his argument, and the thread is about his MGB, not Thomas’ concept of God.

But that’s for another thread, it’s off-topic here. If you read the Plantinga paper I linked, you’ll see that your worries (about what can be concrete?) aren’t relevant.

Plantinga uses possible world to mean something which is “taken as primitive”, i.e. undefined, and which contains a set of objects, which he calls its domain. He isn’t concerned what the objects are, he instead looks at what happens when operations are done on the sets. For instance he says “If we think of propositions as sets of worlds, then a proposition is true in a given world W if W is a member of it. Necessary propositions are then the propositions true in every world; possible propositions are true in at least one world; impossible propositions are not true in any.”

Plantinga never goes near your concerns as he’s dealing with sets of abstractions. Meanwhile, back at the OP …

I suspect you didn’t even read Plantinga’s paper except to glean from it points that appear to support your view.

In fact, the paper is about the shortcomings of modal logic and how, what Plantinga calls the ‘canonical conception’ creates more confusion that anything. He calls himself an ‘actualist’ and insists that “I believe there neither are nor could have been things that do not exist.” A claim which totally shreds the idea that “possible worlds” or possible entities can even exist in any sense at all.

Here are the relevant parts. The rest of his paper fleshes out the argument for his conclusion (included below in red and bold) in gory detail.

In one respect, however, the idea of possible worlds may seem to have contributed less to clarity than to confusion; for if we take this idea seriously, we may find ourselves committed to the dubious notion that there are or could have been things that do not exist…

**The canonical conception of possible worlds, therefore, is committed to the idea that there are or could have been nonexistent objects. **

I said that the canonical conception of possible worlds produces confusion with respect to the notion of nonexistent objects. **I said this because I believe there neither are nor could have been things that do not exist; the very idea of a nonexistent object is a confusion, or at best a notion, like that of a square circIe, whose exemplification is impossible. **

**Suppose we follow Robert Adams ([l], p. 211) in using the name ‘Actualism’ to designate the view that there neither are nor could be any nonexistent objects.
**
…
Among the properties essential to all objects is existence. Some philosophers have argued that existence is not a property; these arguments, however, even when they are coherent, seem to show at most that existence is a special kind of property. And indeed it is special; like self-identity, existence is essential to each object, and necessarily so. For clearly enough, every object has existence in each world in which it exists. That is not to say, however, that every object is a necessary being. A necessary being is one that exists in every possible world; and only some objects – numbers, properties, pure sets, propositions, states of affairs, God – have this distinction. Many philosophers have thought there couldn’t be a necessary being, that in no possible world is there a being that exists in every possible world. But from the present point of view this is a whopping error; surely there are as many necessary as contingent beings…

On the Boethian conception, an essence of Plato is a property he has essentially; it is, furthermore, “incommunicable to any other” in that there is no possible world in which there exists something distinct from him that has it. It is, we might say, essential to him and essentially unique to him…

As actualists, therefore, we may state the matter thus: (35) although there could have been some things that don’t in fact exist there are no things that don’t exist but could have.

These, then, are the essentials of the actualist conception of possible worlds. It has the virtues but not the vices of the Canonical Conception; we may thus achieve the insights provided by the idea of possible worlds without supposing that there are or could have been things that don’t exist.

So, there you go, in Plantinga’s own words from the article you, yourself, cited.

 

[inocente]

I suspect you didn’t even read Plantinga’s paper except to glean from it points that appear to support your view.

In fact, the paper is about the shortcomings of modal logic and how, what Plantinga calls the ‘canonical conception’ creates more confusion that anything. He calls himself an ‘actualist’ and insists that “I believe there neither are nor could have been things that do not exist.” A claim which totally shreds the idea that “possible worlds” or possible entities can even exist in any sense at all.

Here are the relevant parts. The rest of his paper fleshes out the argument for his conclusion (included below in red and bold) in gory detail.

So, there you go, in Plantinga’s own words from the article you, yourself, cited.

Really? You decided Plantinga hates the idea of possible worlds so much that just for a laugh he satirizes modal logic by using it for his ontological argument, thus disproving it before it even got off the ground?

Come off it. Here is a review of the paper published at Plantinga’s university, Notre Dame:

In “Actualism and Possible Worlds”, Plantinga claims that the more or less standard possible worlds semantics of modal logic developed by Kripke engenders confusions because “it suggests that there are things that do not exist” (p. 105). This fifth essay in the collection aims at producing an account of possible worlds that allows us to retain the insights and understanding achieved by the Kripkean “Canonical Conception of possible worlds”, while clearly retaining the actualistic position. This essay presents most of the modal concepts of his theory in essentially the form developed in the earlier essays, but now the concepts are presented in a more systematic and perspicuous manner. - ndpr.nd.edu/news/23656-essays-in-the-metaphysics-of-modality/

So on one side there’s the professor who wrote that, who says Plantinga developed his modal logic over 30 years, on the other there’s you claiming that he was dissing it all along.

I’d have thought anyone would see that Plantinga’s paper intends to put possible worlds on a more robust platform, but there you go. Perhaps you should read the paper again, this time neutrally and without any preconceptions, letting Plantinga speak to you rather than imposing your opinions on him.

 

[Peter_Plato]

Really? You decided Plantinga hates the idea of possible worlds so much that just for a laugh he satirizes modal logic by using it for his ontological argument, thus disproving it before it even got off the ground?

Come off it. Here is a review of the paper published at Plantinga’s university, Notre Dame:

In “Actualism and Possible Worlds”, Plantinga claims that the more or less standard possible worlds semantics of modal logic developed by Kripke engenders confusions because “it suggests that there are things that do not exist” (p. 105). This fifth essay in the collection aims at producing an account of possible worlds that allows us to retain the insights and understanding achieved by the Kripkean “Canonical Conception of possible worlds”, while clearly retaining the actualistic position. This essay presents most of the modal concepts of his theory in essentially the form developed in the earlier essays, but now the concepts are presented in a more systematic and perspicuous manner. - ndpr.nd.edu/news/23656-essays-in-the-metaphysics-of-modality/

So on one side there’s the professor who wrote that, who says Plantinga developed his modal logic over 30 years, on the other there’s you claiming that he was dissing it all along.

I’d have thought anyone would see that Plantinga’s paper intends to put possible worlds on a more robust platform, but there you go. Perhaps you should read the paper again, this time neutrally and without any preconceptions, letting Plantinga speak to you rather than imposing your opinions on him.

Sure, Plantinga is attempting to put modal logic on a more solid footing by demonstrating that possible worlds are only possible given they are premised upon actuality – which was my point if you recall.

Why don’t you let the fact that Plantinga calls himself an “actualist” and concluded this: “As actualists, therefore, we may state the matter thus: (35) although there could have been some things that don’t in fact exist there are no things that don’t exist but could have.”

What do you suppose “there are no things that don’t exist but could have” means?

The only way to read “there are no things that don’t exist but could have” is that “possible” things and possible worlds (things that don’t exist but could have) are not, in fact, possible.

Why don’t you argue the point – rather than deflect from it by raising a tangential point?

Sure he is attempting to put modal logic on a more substantial footing - actuality rather than imaginary or sheer empty speculation.

The entire article is Plantinga arguing that possible worlds are only meaningful given the presumption that actuality stands at the very core of what is possible and that actuality is a logical requirement for modal logic and at the heart of what “possibility” means. That is why he calls himself an “actualist.”

How else is he attempting to put modal logic on a “more solid footing,” in your estimation? By claiming it is a flight of fancy into whatever anyone wants to believe about anything whatsoever? Yeah, that would be a real “solid” footing.

The other point you seem to be missing completely is that Plantinga has to place modal logic on a more solid footing – actuality and necessity – in order to use it convincingly as a platform for proving the ontological necessity of God.

Logically speaking, he can’t move from “possibility” to “exists necessarily” without demonstrating that the notion of possibility itself rests upon actuality. Again, that has been my point all along. It appears you are not seeing the forest for the trees.

Where did that curious cat disappear to? Here kitty kitty! Apparently CC has lost interest. Not so “curious” after all.

 

[inocente]

Sure, Plantinga is attempting to put modal logic on a more solid footing by demonstrating that possible worlds are only possible given they are premised upon actuality – which was my point if you recall.

Why don’t you let the fact that Plantinga calls himself an “actualist” and concluded this: “As actualists, therefore, we may state the matter thus: (35) although there could have been some things that don’t in fact exist there are no things that don’t exist but could have.”

What do you suppose “there are no things that don’t exist but could have” means?

The only way to read “there are no things that don’t exist but could have” is that “possible” things and possible worlds (things that don’t exist but could have) are not, in fact, possible.

Why don’t you argue the point – rather than deflect from it by raising a tangential point?

Sure he is attempting to put modal logic on a more substantial footing - actuality rather than imaginary or sheer empty speculation.

The entire article is Plantinga arguing that possible worlds are only meaningful given the presumption that actuality stands at the very core of what is possible and that actuality is a logical requirement for modal logic and at the heart of what “possibility” means. That is why he calls himself an “actualist.”

How else is he attempting to put modal logic on a “more solid footing,” in your estimation? By claiming it is a flight of fancy into whatever anyone wants to believe about anything whatsoever? Yeah, that would be a real “solid” footing.

The other point you seem to be missing completely is that Plantinga has to place modal logic on a more solid footing – actuality and necessity – in order to use it convincingly as a platform for proving the ontological necessity of God.

Logically speaking, he can’t move from “possibility” to “exists necessarily” without demonstrating that the notion of possibility itself rests upon actuality. Again, that has been my point all along. It appears you are not seeing the forest for the trees.

Yikes. You seem to have made up you own definition of actualism now, and rambled off to Oz again.

Back in Kansas, actualism is about a difference of view on how to treat non-existence. The way I understand it is that possibilists claim there are things which don’t exist, in other words that existence is a property of a thing, while actualists say no, a thing exists or it’s no thing.

But don’t take my word for it, here’s a philosophy professor at Plantinga’s university, Notre Dame:

"*The fundamental thesis of actualism is:

A: Everything there is exists, or is actual.

Or, equivalently:

A: There is nothing that is not actual.

Possibilism denies thesis A. More specifically, according to the possibilist, there are things that do not, in fact, exist but which could have existed — things like possible Aliens (in the sense above), possible people that were never born, and so on. Note that this is not merely to say that there could have been Aliens, or that there could have been people other than those who actually exist. Nearly everyone believes that. Rather, it is to say that there really are, quite literally, things that do not actually exist but which could have." - plato.stanford.edu/entries/actualism/*

It’s easy to look up information, compare sources and check facts these days, and although you say research is only for us riffraff, your own theories appear to keep changing, including but not limited to “bootstrapping” existence, “actualizing principle”, “trickle down actualizing effect”, “background metaphysical radiation”, etc.

It wears me out, and there doesn’t seem much chance anymore of discussing the OP. Plantinga’s modal ontological argument is still, imho, unconvincing.

 

[Peter_Plato]

Yikes. You seem to have made up you own definition of actualism now, and rambled off to Oz again.

Back in Kansas, actualism is about a difference of view on how to treat non-existence. The way I understand it is that possibilists claim there are things which don’t exist, in other words that existence is a property of a thing, while actualists say no, a thing exists or it’s no thing.

Yes, yes. The way that you understand it is the key qualifier.

It might even be convincing, except for the fact that Plantinga himself (a self-declared actualist) claims that existence IS a property of a thing, while you are claiming actualists deny this.

From the aforementioned paper:

"Among the properties essential to all objects is existence. Some philosophers have argued that existence is not a property; these arguments, however, even when they are coherent, seem to show at most that existence is a special kind of property.”

Who is in Oz imagining the possibility that he is in Kansas?

 

[inocente]

Yes, yes. The way that you understand it is the key qualifier.

It might even be convincing, except for the fact that Plantinga himself (a self-declared actualist) claims that existence IS a property of a thing, while you are claiming actualists deny this.

From the aforementioned paper:

"Among the properties essential to all objects is existence. Some philosophers have argued that existence is not a property; these arguments, however, even when they are coherent, seem to show at most that existence is a special kind of property.”

Who is in Oz imagining the possibility that he is in Kansas?

By all means think of existence as a property where possibilists claim it can be true or false while actualists say it can only be true. In terms of sets, which is what we’re dealing with, if two possible worlds A and B both contain all the same objects except that x only exists in B, the difference is in how many sets and how they’re populated. As he says if you read on, existence is essential.

This isn’t new to me, understand it how you like, but as I said I joined the thread to discuss the OP which isn’t going to happen. Have the last word, see you around.

 

[Peter_Plato]

By all means think of existence as a property where possibilists claim it can be true or false while actualists say it can only be true. In terms of sets, which is what we’re dealing with, if two possible worlds A and B both contain all the same objects except that x only exists in B, an actualist will say you have to have two separate sets. As he says if you read on, existence is essential.

This isn’t new to me, understand it how you like, but as I say I joined the thread to discuss the OP which isn’t going to happen.

It seems to me that it is impossible to discuss Plantinga’s version of the modal argument in the OP without understanding his perspective on what modal logic can or cannot entail.

That would just seem to be a function of being thorough about the question.

Have the last word, see you around.

:tiphat: