If a person like me, in this concrete world can describe another concrete world, then I must have some access to it, and it cannot be absolutely separate. — Metaphysician Undercover

You are not describing this other concrete world, you are describing what this other world could be like as a concrete world.
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The spatial temporal conditions of one must be similar to the spatial temporal conditions of the other, implying that there is a connection between them. — Metaphysician Undercover

In the same way that between the fictional world of Middle Earth there is no causal, spatial or temporal connection to our world other than in our mind.

Kripke showed how give truth conditions for modal claims using Tarski's semantics. — Banno

The concrete approach is one interpretation among many. — Banno

Ambiguity is not evidence of truth, therefore I think the conclusion you make about kripke is false.

Kripke produced what appears to some people, as truth conditions for modal claims. But when philosophers have tried to substantiate this supposed truth, they've had to interpret it in many different ways, none of those ways produces anything acceptable. Clearly that's because Kripke did not do what you claim that he did.

As I've shown, it is impossible to do what you claim that Kripke has done. Possibility and truth are fundamentally incompatible. And that's why the mathematically based semantics which uses probability rather than truth is proving to be a much more effective tool for modeling modal statements.

You are not describing this other concrete world, you are describing what this other world could be like as a concrete world. — RussellA

Not according to concretism as described by the SEP. The possible world is as described, and each possible world is concrete. Therefore the description is of what the concrete possible world is like, not of what it could be like.

Call this the concretist intuition, as possible worlds are understood to be concrete physical situations of a special sort. — SEP

Notice, the physical situation is concrete. It's not a possible situation in a concrete world.

In the same way that between the fictional world of Middle Earth there is no causal, spatial or temporal connection to our world other than in our mind. — RussellA

That's a very significant connection. Don't you think so?

A name is not like a tag, though a tag is, in some ways, very like a name. — Ludwig V

As I understand Kripke’s theory of naming, my knowledge of Aristotle is not directly tied to the reality of Aristotle in 350 BCE, but is tied to where I learnt about Aristotle, which could have been a TV program five years ago. The producers of this TV program in turn could have got their knowledge about Aristotle from Jonathan Barnes’ book “Aristotle”. Jonathan Barnes also got his knowledge from somewhere. There is a chain going back in time from my knowledge of Aristotle to the reality of Aristotle in 350 BCE.

Therefore
1 - For me, the name Aristotle is a tag to what I learnt about Aristotle.
2 - For me, I don’t know the reality of Aristotle in 350 BCE, all I know is what I have learnt about Aristotle.
3 - There is a reality to Aristotle in 350 BCE, even though I may not know what it is.
4 - I agree that we only know what we know.

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I find that remark almost impossible to understand. Such understanding as I have of it rests on my knowledge of who and what Aristotle is. — Ludwig V

Yes, you only know what you know about Aristotle.

I think that there is common agreement that Aristotle was around in 350 BCE, even if no one knows exactly what he was doing at the time.
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I've puzzled about this a great deal. Can you explain the difference to me? — Ludwig V

De re and de dicto
A de re proposition could be “Paul's favourite number 11 is necessarily prime. A de dicto proposition could be “it is necessary that Paul's favourite number 11 is prime”.

There is a difference between saying i) “your favourite drink is necessarily a hot drink” and ii) “it is necessary that your favourite drink is a hot drink”

Modal Logic K Distribution axiom
□(p→q)→(□p→□q).
If "p implies q" is true, then if p is necessarily true, q is also necessarily true

The given example

i) “Your favourite drink is possibly a hot drink” presupposes you have a favourite drink
ii) “It is possible that your favourite drink is a hot drink” does not presuppose you have a favourite drink

iii) “There are possible concrete worlds other than ours” presupposes that there are other concrete worlds
iv) “Possibly there are concrete worlds other than ours” does not presuppose that there are other concrete worlds

Therefore the description is of what the concrete possible world is like, not of what it could be like. — Metaphysician Undercover

At the end of the day, It would be logically impossible to describe something that has no causal, spatial or temporal connection to us.

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That's a very significant connection. Don't you think so? — Metaphysician Undercover

Yes, the mind is central.

There is a causal, spatial and temporal connection to the fictional world of Middle Earth, through books, films, etc.

But there is no causal, spatial or temporal connection to an actual world of Middle Earth, as we have no knowledge about it having any mind-independent existence.

Yes, the mind is central.

There is a causal, spatial and temporal connection to the fictional world of Middle Earth, through books, films, etc.

But there is no causal, spatial or temporal connection to an actual world of Middle Earth, as we have no knowledge about it having any mind-independent existence. — RussellA

That, I believe is why concretism is unacceptable. We produce a fictional idea, a possibility, then to make it fit within the possible worlds semantics, we assign concrete existence to it. This is unacceptable, to arbitrarily, or for that stated purpose, assign concrete existence to something completely imaginary. It demonstrates quite clearly the deficiency of possible worlds semantics. To conform we must accept what is unacceptable.

We produce a fictional idea, a possibility, then to make it fit within the possible worlds semantics, we assign concrete existence to it. — Metaphysician Undercover

I have never been to Chicago, but I imagine what it could be like, and I imagine it as an actual concrete place. I can imagine that the inhabitants of Chicago think of themselves as actual and concrete as I think of myself as concrete and actual.

There is no logical problem with imagining something as being actual and concrete.

For example, if you plan on a holiday to somewhere you have never been before, you presuppose that where you are going is an actual and concrete place. As with David Lewis, in this instance, you are also a Modal Realist, a Concretist.

One last word on intensionality for Abstractionism, concerning that paragraph about methodology.

We saw earlier how speaking roughly, the intension of π is the rule that tells you what π’s truth-value would be in every possible world. At issue now is, which is to be master?

The concretist starts with worlds as given (from AW1) and treats intensions as derivative: once we have worlds, an intension is just a way of tracking truth across them.

The abstractionist reverses the order. Intensionality, understood as truth-at-a-world, is taken as basic, and possible worlds are introduced as whatever is needed to make sense of modal variation.

My own intuition is that the disagreement is not about whether worlds or intensions exist; it’s about which we take as explanatorily primary. Seen this way, the two positions, concrete and abstract, are complementary rather than contradictory: they are different “perspectives” on the same metaphysical landscape. That it's more a difference about how we say it than about what is being said. — Banno

Is the difference between declaring what's true versus learning what's true? Maybe both sides of that are wrapped up in an if/then statement.

If Nixon lost the election, then what?

Answer: He might have continued practicing law in the private sector.

I declare a world where he lost, then ponder and learn the results. Or it could go the other way:

What do we have to do to change the tire?

Answer: in the possible worlds where we change the tire, we might have retrieved a lug wrench.

Is that what you mean?

The truth of a possibility in language can only be established using a coherence theory...

Therefore, if we can coherently talk about the possibility of Hobbits, Trolls and Orcs, which we can, then this is sufficient to ensure the truth or falsity of our statements. — RussellA

Thanks for the clarification, but it provides a good reason for many of us to reject it - since it depends on coherence theory of truth. Obvious objections:

"May not a paranoid's delusions of persecution be frighteningly coherent? May not a patient's faith that a mere placebo is a wonder drug be therapeutically useful? Russell was quick to claim in opposition to Joachim that multiple systems of beliefs may be internally consistent, though incompatible with each other. Nietzsche had already suggested well before James that false beliefs may be not merely useful but indispensable for life. "
--Truth -PRINCETON FOUNDATIONS OF CONTEMPORARY PHILOSOPHY ; Burgess & Burgess, pg 3

Kripke had a more nuanced theory, but it strikes me as a move to rationalize possible world analysis.

At any rate, anyone who chooses to take possible world analysis seriously ought to understand the dependency on coherence theory of truth.

Another way to ask this: what is it that establishes the truth of the statement, "there is a possible world in which Hobbits, Trolls and Orcs exist"
— Relativist
Why isn't a copy of the book(s) enough? — Ludwig V

The book establishes a fiction. We could examine this fictional world for coherence, and draw valid inferences if (and only if) it is, but the inferences are all qualified by, "within Tolkien's fictional world...". But no unqualified objective truths can be inferred.

And critically- nothing here establishes the hobbit world (in toto) as anything more than a fiction, so calling it a "possible world" is misleading.

That, I believe is why concretism is unacceptable. We produce a fictional idea, a possibility, then to make it fit within the possible worlds semantics, we assign concrete existence to it. This is unacceptable, to arbitrarily, or for that stated purpose, assign concrete existence to something completely imaginary. It demonstrates quite clearly the deficiency of possible worlds semantics. To conform we must accept what is unacceptable. — Metaphysician Undercover

There's a lot you and I disagree about, but I 100% agree on what you said here.

1 - For me, the name Aristotle is a tag to what I learnt about Aristotle.
3 - There is a reality to Aristotle in 350 BCE, even though I may not know what it is. — RussellA

1. What you learnt about Aristotle enables you to refer to Aristotle - to use the tag. (Remember - what preserves the causal chain is people using the tag.)
3. Yes. It is that reality that enables Kripke to pass off "rigid designation" as a real thing. It is what enables other people to think of Aristotle even when a parrot or speaking machine says Aristotle. Nonetheless, the link is established by the continuous use of the name by people who understand it.

iii) “There are possible concrete worlds other than ours” presupposes that there are other concrete worlds
iv) “Possibly there are concrete worlds other than ours” does not presuppose that there are other concrete worlds — RussellA

That's perfectly clear. Thank you.

We produce a fictional idea, a possibility, then to make it fit within the possible worlds semantics, we assign concrete existence to it. This is unacceptable, to arbitrarily, or for that stated purpose, assign concrete existence to something completely imaginary. — Metaphysician Undercover

No, we don't have to assign existence to it. All we have to do is to imagine or suppose that it exists.

There is no logical problem with imagining something as being actual and concrete. — RussellA

Quite so.

"May not a paranoid's delusions of persecution be frighteningly coherent? May not a patient's faith that a mere placebo is a wonder drug be therapeutically useful? Russell was quick to claim in opposition to Joachim that multiple systems of beliefs may be internally consistent, though incompatible with each other. Nietzsche had already suggested well before James that false beliefs may be not merely useful but indispensable for life. "
--Truth -PRINCETON FOUNDATIONS OF CONTEMPORARY PHILOSOPHY ; Burgess & Burgess, pg 3 — Relativist

I wouldn't disagree with any of that or with the familiar point that none of those uses or benefits is a substitute for truth.

The book establishes a fiction. We could examine this fictional world for coherence, and draw valid inferences if (and only if) it is, but the inferences are all qualified by, "within Tolkien's fictional world...". But no unqualified objective truths can be inferred. — Relativist

That's true so far as it goes. But the existence of the book does establish that there is a fictional world in which.....

And critically- nothing here establishes the hobbit world (in toto) as anything more than a fiction, so calling it a "possible world" is misleading. — Relativist

I agree that there is this difference between a fictional world and a possible world, that the possible world might or might not exist - become actual, if you will, but we know that the events in LOTR could not possibly take place. On the other hand, many stories seem entirely possible - and there are docudramas. Characterizing the verisimilitude that is required to persuade us to suspend our disbelief is not easy. Aristotle, if I remember right, uses a word that is translated as "plausible". Is that better?

the existence of the book does establish that there is a fictional world — Ludwig V

Yes, but the same could be said for any so-called "possible" world one entertains with the semantics. If I had my way, we'd distinguish between fictional and possible worlds.

I agree that there is this difference between a fictional world and a possible world, that the possible world might or might not exist - become actual, if you will... — Ludwig V

Only if it pertains to the future, and is consistent with the history of the world up to the present, and everything else we know about the world.

However, when entertaining counterfactuals about the past or present, the implication is that this counterfactual world could possibly have happened. But could it? This is analyzable and debatable. It's a very different debate if we're simply examining the coherency of a fictional world.

Regarding plausibility: that just seems an epistemically weaker form of possible, and could apply to either fictional and (truly) possible worlds. Perhaps it's equivalent to epistemic possibility: as far as I know (implicitly based on my internalized beliefs), it is possible.

But that gives w₀ a special status that differentiates it from all the other possible worlds. I suppose, though, that one could point out that for someone in that different possible world in which he is called Barry would make the same claim, with the names reversed. So who a name refers to depends on what world one posits as the world of origin. My question is, whether the system can work without positing some world as the world of origin. — Ludwig V

That's the role of w₀. You answered your own question, I think.

The idea that there may not be One True Account of reference seems very plausible to me. — Ludwig V

I've again got "A nice derangement of epitaphs" in the back of my mind here. A reference is successful if the enterprise in which it is involved is a success.

I am assuming that each possible world will have a similar recursion and therefore be capable as functioning as a world of origin. Yes? — Ludwig V

Yes.

If Determinism is true, there can only be one actual world, meaning that there cannot be possible worlds. — RussellA

This rather depends on how one understands "determinism".

Determinism is a thesis about law-governed evolution within a world, not about the space of logically or metaphysically possible worlds. Even a perfectly deterministic world can be one among many possible worlds, perhaps differing in their initial conditions. Determinism only blocks alternative futures for this world, not alternative worlds altogether.

As I've shown... — Metaphysician Undercover

You pretend your already repudiated arguments were adequate. They are not.

I don't think so, but I'm not sure...

The idea is somewhat ill-formed, but it's related to the idea that some differences make no difference. I need to think on it some more.

the inferences are all qualified by, "within Tolkien's fictional world...". — Relativist

Yep - treating it as a possible world, and truth as true-in-a-world.

The book establishes a fiction. We could examine this fictional world for coherence, and draw valid inferences if (and only if) it is, but the inferences are all qualified by, "within Tolkien's fictional world...". But no unqualified objective truths can be inferred. — Relativist

"unqualified" is problematic; we can take this world, the one we are in, to be w₀ and then define truth simpliciter as true-in-w₀. And note thatin w₀ it is true that in Tolkien's world Frodo is a hobbit...

And critically- nothing here establishes the hobbit world (in toto) as anything more than a fiction, so calling it a "possible world" is misleading. — Relativist

Yes. This is a different point, further complicating the issue; that since in the actual world Tolkien developed Frodo as a fictional character, we might decide that Frodo is necessarily a fiction - a fiction in any possible world in which he occurred. What this would mean is that were we to come across a small hairy man with nine fingers who was a friend to the elves and wizards, that would not be Frodo, because he is actual and Frodo is a fiction.

Fun, isn't it?

1. What you learnt about Aristotle enables you to refer to Aristotle - to use the tag. — Ludwig V

No!

What you learned is irrelevant. You heard someone use the word Aristotle, and you started to use the word; and crucially, you would be talking about Aristotle even if what you think you know about him were completely wrong.

(Remember - what preserves the causal chain is people using the tag.) — Ludwig V

Yes! And that alone!

If you overheard the bloke on the TV say that Aristotle Taught Alexander, and assumed he meant that Aristotle taught Alexander Graham Bell, and that was all you knew about Aristotle, you would be mistaken, and importantly, you would be mistaken about Aristotle. The reference works despite all you know about Aristotle being wrong.

So its not "What you learnt about Aristotle enables you to refer to Aristotle"!

Yes, but the same could be said for any so-called "possible" world one entertains with the semantics. If I had my way, we'd distinguish between fictional and possible worlds. — Relativist

I don't disagree. I made the connection because I thought the analogy/similarity between fictional worlds and possible worlds made it easier to understand the latter. I underestimated the difference.

I agree that there is this difference between a fictional world and a possible world, that the possible world might or might not exist - become actual, if you will...
— Ludwig V
Only if it pertains to the future, and is consistent with the history of the world up to the present, and everything else we know about the world. — Relativist

Well, "it is possible" does pertain to the future, because it is in the future that the possibility resolves. If it is possible that I win the race, I win or lose the race in the future. Past possibilities - "it was possible" - are, by implication resolved and I have already won or lost. I do think that, like probabilities, the future is part of the concept.

However, when entertaining counterfactuals about the past or present, the implication is that this counterfactual world could possibly have happened. But could it? This is analyzable and debatable. It's a very different debate if we're simply examining the coherency of a fictional world. — Relativist

It is tempting to agree that counter-factual is a possibility. But the game of alternative history suggests that a counterfactual does not contemplate a possibility, but an event, whether it is possible or not. "How would things be now if Hitler had won the war?" Since he did not, it is not possible that he did. Yet somehow we can contemplate that eventuality and build a coherent story from it.

That's the role of w₀. You answered your own question, I think. — Banno

I'm glad you agree with my answer. It gives me confidence that I'm not thinking rubbish.

I've again got "A nice derangement of epitaphs" in the back of my mind here. A reference is successful if the enterprise in which it is involved is a success. — Banno

I wouldn't quarrel with that. I wish I could get hold of the article, but the only source I found wants £55 for a copy.

I am assuming that each possible world will have a similar recursion and therefore be capable as functioning as a world of origin. Yes?
— Ludwig V
Yes. — Banno

So each world serves as the origin of its transworld identifications. Which world is the origin depends on which world we are in. Each world is the actual world in that world.

This is a different point, further complicating the issue; that since in the actual world Tolkien developed Frodo as a fictional character, we might decide that Frodo is necessarily a fiction - a fiction in any possible world in which he occurred. What this would mean is that were we to come across a small hairy man with nine fingers who was a friend to the elves and wizards, that would not be Frodo, because he is actual and Frodo is a fiction. — Banno

I think that works for this case. But fictions are a varied bunch, so a story about a real or possible person in our world might well count as a possibility and what you say here wouldn't apply. What about stories that mix real and fictional characters and/or places?

What you learned is irrelevant. You heard someone use the word Aristotle, and you started to use the word; and crucially, you would be talking about Aristotle even if what you think you know about him were completely wrong. — Banno

H'm. I'm working this out as I go. You have a point. But I'm inclined to say that other people would take me to be talking about Aristotle. I, on the other hand, don't know what I'm talking about. But there is an objectivity here. The interpretation of people in general determines what is the case, so it is not wrong to say my deviant use is wrong.

(Remember - what preserves the causal chain is people using the tag.)
— Ludwig V
Yes! And that alone! — Banno

But surely the causal chain is a chain of people learning to use Aristotle in that way. I agree that one person does not determine anything.

If you overheard the bloke on the TV say that Aristotle Taught Alexander, and assumed he meant that Aristotle taught Alexander Graham Bell, and that was all you knew about Aristotle, you would be mistaken, and importantly, you would be mistaken about Aristotle. The reference works despite all you know about Aristotle being wrong. — Banno

Yes. But the causal chain is a chain of people learning to refer to Aristotle correctly. Isn't it? What else could it be?