So the whole practice of referring becomes pointless. — Ludwig V

I do not see the problem; could you say it in another way?

No, that's not what contingent means. — Relativist

"Contingent" has varied meaning, it's quite ambiguous. I dismiss determinism, fatalism, and necessitarianism as fundamentally incompatible with our experience.

I perceive that the sun is shining. In my actual world the sun is shining.

I imagine a possible world in which the sun is not shining. It is possible that there is an actual world where the sun is not shining.

Actual worlds may exist or possibly exist. — RussellA

As I explained, that renders "actual" as meaningless. By "meaningless" I mean you could give it any meaning you want, but you haven't so it has no meaning. The world you perceive is "actual". The world you imagine is "actual". You could imagine anything, and that could be said to be "actual". What does "actual" mean? It doesn't mean to be imagined, because what you perceive is actual as well. It isn't that someone, not necessarily, you is perceiving it, because the imaginary ones are actual.

What meaning does "actual" have here? You could remove it from your example without changing the meaning of anything. "I perceive that the sun is shining. In my world the sun is shining." "I imagine a possible world in which the sun is not shining. It is possible that there is a world where the sun is not shining." See, "actual" does absolutely nothing in your usage.

In standard modal logic there is exactly one actual world. — Banno

This states very clearly and precisely, in a nutshell, the significant and substantial problem with possible worlds semantics. We must deny what you yourself acknowledged as the very real and important difference, between the "actual world" of ontology, and the "actual world" of modal logic. To avoid the fallacy of equivocation, there must be "exactly one actual world". The glaring problem though, is that "actual world" is assigned to the modal model, not the ontological world, plunging modal logic deep into Idealism.

(ii) its designated “actual world” is in fact the actual world, — SEP

Just a note, I've bowed out of the above discussion, but when Banno is ready to move on, I'm all in.

Well, you/Kripke have your reasons for saying that, I suppose. But it is clear that whatever "water" means is not based on that information. — Ludwig V

What does “water” mean? "Water" means different things to different people. To a scientist, "water" is necessarily H2O. To me, "water" is necessarily wet, in that if not wet it cannot be water. To a linguist, “water” is necessarily a noun. There is no one meaning of “water”, though each meaning is necessary within its own context.
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Again, perhaps so. But it follows that, whoever is called Aristotle is not necessarily the philosopher that we know and love. — Ludwig V

You love Aristotle for his philosophy. But instead of being born in Stagira, he could have been born in Athens and grown up to be a carpenter. So do you love Aristotle because of who he was or what he did?

What meaning does "actual" have here? You could remove it from your example without changing the meaning of anything. — Metaphysician Undercover

The words actual and possible are still needed.

In conversation, I might say “the sun might not be shining”, but would be confusing to a listener as it lacks context. It would be better to say “it is possible that the sun might not be shining”, as this does infer a context.

Similarly, my saying “the sun is shining” lacks context. It would be better to say “the sun is actually shining”.

The words "possible" and "actual" add context.

I do not think "air" is a rigid designator, and so I am happy to not designate any of the components, whether a majority component or not, as the necessary referent of the term "air." — NotAristotle

Wow, quite an admission. I guess you are saying that when it comes to these general, vague terms like "water" or "air", we have either two choices, one, say possible worlds semantics/rigid designators don't apply, or we can just remove the vagueness and just say "water" means "H2O".

when it so refers it will be the case that necessarily water is H2O as a result of the identity between the stuff and what is referred to by the term in that context. — NotAristotle

If you are indicating that these terms are interchangeable, this is wrong. You would think that if one is saying water is identical to H2O that they would be interchangeable. But that is not the case. For example, can you say that if you had one molecule of water you had one water? No, the term "water" when used in science refers to a collection of H2O molecules that under particular temperature and pressure conditions exhibit the macroscopic properties we typically call a "liquid." But guess what, under others conditions this collection of H2O molecule would not be called "water" anymore, but "steam" or "vapor", and under other conditions you would call it "ice".

So, what is all of this logic posturing by saying "water is H2O"is a posteriori necessary truth to achieve in the realm of science? To make prescriptive linguistic corrections like "Hey scientist, you forgot what Kripke said about "water is H2O", when you call that collection of H2O molecules "steam" you are wrong, please correct yourself and call it "water".

But you said that the possible worlds are actual, so you have no use for actual, regardless of context. The world you perceive is actual, and the possible worlds you imagine are all actual. "Actual" is meaningless. There is an implied difference between the perceived world and the imaginary worlds, but both those categories are actual, so "actual" serves no purpose.

just say "water" means "H2O" — Richard B

Why is that controversial?

the term "water" when used in science refers to a collection of H2O molecules that under particular temperature and pressure conditions exhibit the macroscopic properties we typically call a "liquid." — Richard B

Okay then, "water" is interchangeable with...

a collection of H2O molecules that under particular temperature and pressure conditions exhibit the macroscopic properties we typically call a "liquid." — Richard B

The words actual and possible are still needed.

In conversation, I might say “the sun might not be shining”, but would be confusing to a listener as it lacks context. It would be better to say “it is possible that the sun might not be shining”, as this does infer a context.

Similarly, my saying “the sun is shining” lacks context. It would be better to say “the sun is actually shining”.

The words "possible" and "actual" add context. — RussellA

The modality is equally relevant. Your modality is epistemic: given the facts available to you, it is (epistemically) possible the sun is shining.

But if the sun is actually shining, then although you don't know this fact, it is physically, metaphysically, and logically impossible for the sun to not be shining at that point of time. (Law of noncontradiction).

Yet another issue: is the sun shining at that point of time a contingent fact, or a necessary fact?

There is an implied difference between the perceived world and the imaginary worlds, but both those categories are actual, so "actual" serves no purpose. — Metaphysician Undercover

I can imagine a possible world where aliens live. This imagined possible world may in fact be an actual world.

I agree that if my perceived world was “actual” and all imagined possible worlds were “actual”, then the word “actual “ would be redundant.

However, if my perceived world was “actual” and some imagined possible worlds were “actual”, then the word "actual “ would not be redundant (because some imagined possible worlds would not in fact be “actual”.)

The difference is in the quantifiers all and some.

This imagined possible world may in fact be an actual world. — RussellA

The point, though was that all the possible worlds are actual worlds. If we say "possible" that means "may" be. But Lewis' interpretation appears to be that each possible world "is" an actual world. That's what we were discussing, all the possible worlds are actual worlds.

but in most modern discussions of logic) to have got to a situation where what logic one uses is just a function of what project one is pursuing. — Ludwig V

Logical pluralism rather than pragmatism. The challenge is to use formal grammar to exhibit the incoherences and inconsistencies in our philosophical meanderings. It's not picking a logic that gives the answer we want, but looking at what we have to say using formal tools that set out clearly the problems.

See, for a small example how

What this shows is that Meta's way of talking is incompatible with the formal account. Meta is helping himself to the expressive resources of possible-worlds semantics (modal operators, actuality, evaluation) while rejecting the background grammar that makes those resources coherent. He's not offering an alternative theory. He is attempting to take something he expresses in informal talk, and express it in our best formal language. And in doing so we find that it becomes incoherent. This is precisely where formalisation earns its keep; not by settling metaphysical conundrums, but in exhibiting ways of speaking that cannot be regimented without contradiction. Once that’s shown, the choice is stark: revise the talk, or abandon the framework. You don’t get to keep both - unless you are Meta, and simply double down on your errors.

The point, though was that all the possible worlds are actual worlds. If we say "possible" that means "may" be. But Lewis' interpretation appears to be that each possible world "is" an actual world. That's what we were discussing, all the possible worlds are actual worlds. — Metaphysician Undercover

Lewis does believe that all possible worlds are actual worlds, but that's not a common view. Lots of philosophers disagree about that, but still use possible world semantics to discuss counterfactuals. Whether or not those counterfactual worlds are possible is debatable - but "possible" can apply to past, present, and future.

Contingent" has varied meaning, it's quite ambiguous. — Metaphysician Undercover

In everyday discourse it's ambiguous, but it appears to me that among philosophers, there's no ambiguity about what it means. There are controversies, but not about the basic definition.

For Kripke, that an object, an individual such as Aristotle, is the same object in all possible worlds, is a Rigid Designator, is a consequence of his Theory of Naming. — RussellA

Yours is a good account. That's why I have come back to it - it's close enough to what I understand that I can use it in these explanations.

However I think the quote is around the wrong way.

We have a formal account that talks of things in possible worlds. We want to take that back to our natural language. We have so far two ways of doing this. the first is Lewis' idea that the possible worlds are all concrete, and we look for and match the most similar individuals in each. The second is Kripke's idea that we simply refer to the same individuals with the same name in any possible world in which they exist.

What Kripke expresses that view in natural languages, the result is that proper names are used to refer to the very same individual in every world in which they exist.

So, it's not that rigid designation is a consequence of his theory of meaning, but that his account of modal logic has as a consequence that proper names rigidly designate, and his theory of naming tries to account for that.

That is, the "a"'s and "b"'s in formal logic are most simply understood as cognates of proper name sin English. So since those "a"'s and "b"'s refer to the same thing in different possible worlds, then it seems we might do well to presume that the proper names of English do likewise.

You are right that what Kripke calls an "essence" are those properties that belong to an individual in every possible world.

He uses the example of Queen Elizabeth; we might think the following is an innocent question: "What if Queen Elizabeth had different parents?" It might have been that the babes were swapped at birth, for instance, or some such muck up. But then the person who, in the actual world, is Queen Elizabeth, would, in that other possible world in which the babies were swapped, not have gone on to become queen - perhaps she ran a fish and chip shop in Bristol instead - and the baby for whom she was swapped went on to become the Queen.

Now look carefully at what just happened. We asked the innocent question, "What if Queen Elizabeth had different parents?", and it turned out that this could not have happened! The person who, in the actual world, became Queen Elizabeth, could not have had different parents.

What might have happened is that some other baby, with different parents, could have become the queen.

That's a very different situation.

In parsing the English sentence "What if Queen Elizabeth had different parents?" into our modal logic, we find that what looks to be a question about Queen Elizabeth is better considered as a question about two different people.

So being the child of King George VI and Elizabeth Bowes-Lyon is true of Queen Elizabeth in every possible world, and in those worlds in which the apparent Queen of England is not the daughter of King George VI and Elizabeth Bowes-Lyon, we are talking about some other individual becoming the Queen...

Think on it a bit. Certain characteristics belong with an individual in every possible world in which it exists. This account of essence is quite different to scholastic notions, but has many advantages, not the least being a clear definition.

:grin: IE, it is wrong to say that there are actual possible worlds. — RussellA

Or, any possible world might have been actual, but only the actual world is actually actual... :wink:

I agree, as this seems to follow what Banno wrote: — RussellA

Yep.