So....treating it as a possible world, even though it's not possible. — Relativist

What, exactly, is not possible?

Doing what you suggest is inconsistent with correspondence theory of truth - the Frodo statement is not "true" under this theory. — Relativist

Have you an argument to go along with that? And what of it - we are using Tarski's semantics, not correspondence.

I probably should not have mentioned the fiction argument at present. It works by rejecting maximal consistency, which has it's own consequences. They may be treated as partial, consistent worlds. Poor pedagogy on my part. But it's were we might go....

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

Yep, and we need not be referring anybody or anything at all for it to be meaningful, as Wittgenstein said we must not confound the meaning of a name with the bearer of the name. — Richard B

The word "learning" is problematic. It'd be better to say "the causal chain is a chain of people using the name to refer to Aristotle correctly.

“Learning” smuggles in a representational picture: as if what is transmitted along the chain is a mental grasp of an object. That’s exactly the picture Wittgenstein is trying to loosen. On his later view, what is transmitted is not knowledge of a bearer but participation in a practice. Hence my suggestion.

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. — Ludwig V

Yep.

...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. — Ludwig V

Yes, I think so. The point - lost on some - is that the logic is much the same.

What about stories that mix real and fictional characters and/or places? — Ludwig V

That'd just make yet another possible world, with some characters in common with our own...?

I, on the other hand, don't know what I'm talking about. — Ludwig V

That you do not have at hand a definite description of Aristotle does not make your reference fail. The person you are mistaken about is Aristotle... the reference still works, even in near-complete ignorance. Indeed, there are examples in the literature of reference working in complete ignorance.

Maybe have a read of section X of Donnellan's Proper Names and Identifying Descriptions - the Thales example.

Yep.

Jamal was very generous with giving Bob enough rope. The result was inevitable.

While what you say is mostly correct, his views were in the end small and nasty.

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"!

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?

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.

As I've shown... — Metaphysician Undercover

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

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.

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.

We have never, in over 20 years (i've not been here the entire time) required one for any disabled person. — AmadeusD

Given that one in six folk have a disability, your organisation might do well to reconsider it's clientele and hiring strategy. Or is your accessible toilet at the top of the stairs?

But here's the reason your contributions are unproductive: they express personal opinions and anecdotes.

The three most common impairment types New Zealanders experienced were mobility (13 percent), hearing (9 percent) and agility (7 percent). — Appendix: disabled people population and life outcome statistics

While what you say might be so, it remains that the common thread in Bob's justification of racism, homophobia and transphobia was a form essentialism that he took to derive from Aristotle and Aquinas. None of that rescues Bob’s position, because the problem is not essentialism simpliciter, it is the specific way essentialism is being used.

His essentialism was unfalsifiable by design. Counterexamples were dismissed as “pathological,” “deformed,” or “non-natural,” while conformity were treated as confirmation. That is not an epistemology; it is an immunisation strategy. An essence that cannot be contradicted by any actual instance is doing no explanatory work.

His appeal to Aristotle and Aquinas was selective and anachronistic. Neither thinker held that every natural tendency grounds a fixed social role, nor that deviation implies defect in a moral sense. Aquinas in particular is careful to separate natural inclination from law and from virtue. Bob reads later ideological commitments back into scholastic metaphysics.

Tim is correct that racism is not wrong because race is unreal, and that essentialism alone is not the issue. But it remains true that Bob’s justifications for racism, homophobia, and transphobia rely on a misguided essentialism that illegitimately converts descriptive generalisations into normative constraints while insulating itself from criticism.

As you wish.

"there is a possible world in which Hobbits, Trolls and Orcs exist" — Relativist

A thing exists if it is in the domain of a world. That is, if it can be used in an existential quantification. Existence is what the existential quantifier expresses. Things can exist in one world and not in another. One point of difference between Lewis and Kripke is that for Lewis things exist only within a world, while for Kripke the very same thing can exist in multiple worlds. — Banno

On the account given here we make sense of existence within worlds. Frodo is a Hobbit - h(a). By existential generalisation there is something that is a hobbit - ∃(x)(h(x) - which can be read as "something is a hobbit" or as "hobbits exist".

There is a world w whose domain contains at least one object satisfying each of the predicates hobbit, troll, and orc.

The claim that “there is a possible world in which hobbits exist” amounts to nothing more than the claim that the predicate hobbit is satisfied by at least one object in the domain of some world. No commitment follows to hobbits existing outside that domain, nor to their being actual, concrete, or real in any further sense.

The question I have then is about the scope of possible worlds, and what exactly their metaphysical claim is to reality. — QuixoticAgnostic

The logic itself is (almost) metaphysically neutral. The concrete approach is one interpretation among many. And the answers to your questions will depend on what approach is adopted. Alien Properties are intriguing, but the response will very much depend on what else one accepts. It's not difficult so much as complex.

Impossible worlds. Have a look, but we might here stick to the present article.

You are babbling. Kripke showed how give truth conditions for modal claims using Tarski's semantics.

See the Island Universe for a related reflection.

Yep.

This thread reeks of Americans being surprised that their values are not universal.

All I mean by "meta-world" is, basically, some world where all possible worlds exists. Based on the definitions given wrt AW1, that seems impossible, because possible worlds exist maximally, and a "meta-world" would connect possible worlds, hence not maximal, hence a contradiction. — QuixoticAgnostic

Yep. Nice.

And does that not introduce a conflict with how we describe existence? — QuixoticAgnostic

It's a neat point to put pressure on. The simple answer is that the possible worlds are in w₀, the actual world. But all this means is that it is we, in this world, who are talking about them and quantifying them, and they are in our domain of discourse.

What looks a bit paradoxical is actually a recursion. That recursion enters when we describe all possible worlds from the standpoint of a particular world — that’s the “loop” that looks tricky, but it isn’t a real contradiction.

An interesting point, though.

@frank

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.

@frank, it's clear and got lost somewhere. I'm not going back for Meta, who will double down and object to whatever is suggested. Relativist might catch up.

So I think we move on?

but how are they absolutely separate? — Metaphysician Undercover

Again, that's explained in AW1.

But you claim to have read and understood that... :roll:

How can you expect to be taken seriously?

What would make such a world POSSIBLE? IOW, how do you account for its existence? — Relativist

AW1 w is a possible world =def w is a maximal connected object. — SEP

I'd sugest you go back and read that section.

I think you're alluding to modal logic as a formal system. — Relativist

No allusion. I was quite specific.

One can utilize the formal system to go through the mechanics of the logic, without committing to possibilism/actualism much less necessitarianism/contingentarianism. — Relativist

Yep. I've pointed this out, several times. see for example

Filling out that last point, Kripke and Lewis give different ontological readings of the same formal machinery. Their logic is the same, but the metaphysical story differs.

Kripke (Naming and Necessity):
Proper names refer rigidly to the same individual across worlds.
Necessity is primitive and tied to rigid designation.
Modality is not reduced to something non-modal; it is taken as metaphysically basic.


Lewis (Modal Realism / counterpart theory):
Worlds are concrete; individuals do not literally exist in more than one world.
Identity across worlds is determined via counterpart relations.
Modality is reduced to quantification over concrete worlds.

Shared Logic / Semantics
Possible worlds semantics: Both use worlds as the basis for evaluating modal statements.
Quantified modal logic: Both accept first-order quantification over individuals.
Transworld reference: Both presuppose a way to interpret identity or counterparts across worlds.
Truth-at-a-world: Both define modal truth in terms of what holds at particular worlds.
Accessibility relations: Both can accommodate structured relations between worlds (for temporal or metaphysical distinctions).
Formal rigour: Both agree that modal claims can be modelled systematically, independent of metaphysical interpretation.

Summarised by ChatGPT — Banno

Yep.

This cannot be correct. If each possible world is separate from every other, in an absolute sense, then there would be no point to considering them, as they'd be completely irrelevant. — Metaphysician Undercover

You'd think the penny had dropped... but:

So, it's kind of clear that you aren't reading along. Can you remedy that? — frank

Yep. And

If there is no causal connection sometime in history, in what sense are they possible? — Relativist

Fucksake.

How does Kripke get around a name being a rigid designator when it is not known that in a causal chain one event necessarily follows another. For example, being a rigid designator would require there was a necessary connection between two events. — RussellA

Kripke did not fill out his theory of reference. Never did.

It was offered only as an example of how references might be fixed apart from a definite description. At the time his audience would have bee somewhat incredulous; this kid (he was a teenager when he published the first few articles) saying that Russell's logic was wrong.

So he suggested a possible (!) alternative, more as a rhetorical tool than a tight bit piece of argument.

I hope we might leave the theory of reference to one side - we have enough distractions. But I might just suggest that there does not appear to be any reason to think there must be One True Account of reference - there may be many ways in which we can use a proper name. What is salient is that Kripke and Donnellan showed that proper names do not always and only refer in virtue of an attached definite description.

It appears like Banno is trying to hijack the thread to enforce his own brand of modal sophistry when the SEP clear indicates three distinct types: — Metaphysician Undercover

Yep. Guilty as charged. I'm trying to discuss Possible World Semantics, and the three interpretations of it that are listed in the SEP article.

But again, it's not My brand of modal sophistry. It's the standard, accepted logic of modality.

The nature of possibility is such that it is impossible to give "precise truth-conditions for modal claims". That's the fundamental reality of what is referred to by "possibility", it violates the basic truth conditions of the law of non-contradiction, or the law of excluded middle. This was demonstrated by Aristotle with examples like the possible sea battle. — Metaphysician Undercover

And yet, here it is.

If that is what Aristotle claimed — and that reading is itself highly questionable — then Aristotle was wrong. He lacked the resources to do better. You do not.

n a sense, this baptism is the same as JL Austin’s performative utterance. — RussellA

That was the topic of my Honours thesis.

Your statement is incomplete as it needs to add “for whom”. — RussellA

Yep. Spot on. It needs to specify w₀.

So, if there exists possible worlds, are they all existing together as a collection in some world that contains them all? — QuixoticAgnostic

Since @Ludwig V quotes this, I might address it.

In Lewis' system, each world is spaciotemporally distinct - that is how they are defined. SO there is no "place" in which they hang out together.

But for my part, the idea of a world occupying a space appears to be a category error. What space is the Universe in? I don't think that question can be made to work.

Don't we need to mark a distinction between that world and any world we choose to treat as actual for purposes of logical analysis? j — Ludwig V

Not within the logic. We might do that when we give the edifice an interpretation.

Is it really impossible that Aristotle could not have had some other name, if he was born at the right time of the right parents and did all the right things? — Ludwig V

Yep. Have a look at your question. See how it is about Aristotle? there is a possible world in which Aristotle was given a different name. Who was given the different name? Aristotle.

In w₀ there is an individual named Aristotle. In w₁ that individual is named Barry. w₁ is accessible from w₀. Therefore, in w₀, ◇(Aristotle was named Barry)

Something that I'd like to draw your attention to, Ludwig, is the size of the argument here. It's worth mentioning that the argument does not include anything outside of what is needed in order to shoe the point. It's quite discreet. To a Wittgensteinian ear, that might be important. The grand theories we are discussing from the article - counterpart theory and so on - work on a somewhat different scale to the actual arguments philosophers usually use.

Anyway, note that the name of that individual in w₀ - Aristotle - is used as a rigid designator in order to stipulate the very same individual in a different possible world in which he is called Barry. See how the designation w₀ functions in this game? It's the from where that the rigid designation is fixed.

By your definition of existence... — QuixoticAgnostic

Not mine. Standard definitions for modal logic.

"Meta-worlds" sounds like virtual reality? Not too familiar with it. The question of 'where"possible worlds exist is answered differently by different folk. Given that we are talking about possible worlds, they are in the domain of discourse and so we can quantify over them and they exist in that sense.

Might not be a bad idea to go over the terms being used, since it seems there is some confusion.

Exists
A thing exists if it is in the domain of a world. That is, if it can be used in an existential quantification. Existence is what the existential quantifier expresses. Things can exist in one world and not in another. One point of difference between Lewis and Kripke is that for Lewis things exist only within a world, while for Kripke the very same thing can exist in multiple worlds.

A thing that exists is also possible.

In Kripke a thing can exist and not be actual or concrete.
In Lewis if a thing exists then it is concrete, and actual in some world.

Possible
It's possible if it's “true in at least one accessible world”.

Something might be possible and yet not exist - by not existing in w₀ but in some other possible world

Simialrly, a sentence is possible if it is true in some accessible world.

Actual
Actual is indexical. It works like here, or like now. We designate a world as the actual world, w₀, and then the things that exist in that world are actual.

In modal logic being actual is a label. In metaphysics being actual is usually a special ontological state. Lewis rejects this, since everything is actual in some world.

Contingent
A modal variability across worlds, something is contingent if it exists in some, but not all, possible worlds. And similarly, sentences are contingent if ◇P ^ ◇~P. If it exists in all possible worlds it is necessary. If it doesn't exist in any world, it is impossible.

Contingency is assessed modally, not temporally. So an event can occur and still modally contingent.
The fact that it happened does not make it necessary.

Concrete
This one is less clear. If something is physical, spatiotemporal, or causal it might be considered concrete.

In Lewis' system everything is concrete, in a world that is spatiotemporally separate and distinct from every other possible world.

In actualist accounts, only the things in the actual world are concrete. The other stuff is abstract.


Real
A claim of Metaphysical status. In Lewis something is real if it exists. In actualist accounts it is real if it both exists and is actual.


What fun.

I offered an alternative theory. — Metaphysician Undercover

Well, no. What you have offered, a set of assertions, isn’t a theory on a par with possible-worlds semantics. It doesn't provide a formal semantics. Possible-worlds semantics gives precise truth-conditions for modal claims, compositional rules for complex sentences, and a mathematically explicit structure (models, accessibility relations, evaluation clauses). Your proposal is a taxonomic distinction, a mere set of metaphysical labels separating ontology, epistemology, and counterfactual talk, without rules that determine when modal statements are true or false, or how they interact logically. It replaces a working semantic framework with intuitive metaphysical assertions, so it cannot do the same explanatory or inferential work.

The rest is layered confusion on your part.

ok.

Well, I do't see an argument that has as it's comnclusion:

The notion that "actual" is indexical is not consistent with the terminology in the SEP article, The Possibilism-Actualism Debate: — Relativist

So we agree that for Possibilists reality includes possibilia, things that could exist but do not actually exist, that there’s a broader realm beyond the concrete world. And that Actualists suppose only what actually exists counts as real. There’s no domain of merely possible entities. And that Lewis treates "actual" as indexical. To show inconsistency, one would have to demonstrate that the SEP article’s definitions cannot accommodate an indexical sense of “actual”, or that indexical “actual” violates SEP’s logic. I don't see that here.

But as noted, I'm more interested in the main article here than in this side issue. Once we have an agreed view on what the possibilities are for possible worlds, then we might better treat the possible and the actual.

Small steps.

, that quote doesn't seem to do what you think it does.

But, fine, carry on.

See my post

Oh, very good. — Ludwig V

Pleased someone notes the drollery! :grin:

a) that the actual world is the one in which we are constructing the possible worlds and the point of view from which we are surveying them and identifying which world we wish to treat as actual — Ludwig V

Yep. Hence the sometime definition of truth simpliciter as "true in w₀"... All of our modal logic is "true in w₀"!

b) that we do not choose that world - we are lumbered with it - even thrown into it. — Ludwig V

Pretty much.

What we don't have here is any inconsistency...

Leastwise, none I can see.


I was thinking about the "books" analog the other day, but can't now recall what it was I thunked. I think something like that is going on in the article, with the tree differing accounts of what possible worlds are; and I think it is somehow off-centre. But I haven't yet worked out quite how.

Part of the problem is that the books analogy and the three accounts picture the world as complete.