:up: Too subtle for me, it seems. Can you explain why Davidson is being inconsistent in dismissing the view that Clark Kent cannot fly?

Read the exchange with I just had with Banno. You do need to understand the issue of Supervenience though in relation to Mental States/Identity.

I think I'll just write a paper on it and send to a Journal. Looks like no one else has written about it yet.

Quine's contribution was to put the problem in terms of substitution, and hence in terms of extensionality, and so presenting it as a puzzle of logical form as opposed to a physiological issue. — Banno

"Physiological" is an odd term to use here. Did you mean something more like "Psychological"? But I take the point. But it seems to have turned out that the logic used to state the problem can't resolve it.

In this last we can see the whole in a single context. The problem - so far as there is one - only arises when the contexts are muddled together. That's what Quine pointed out. — Banno

I believe that "Lois believes that Superman is Clark Kent and Superman can fly, so Clark Kent can fly" represents things better. Whether, post Davidson, "Superman is Clark Kent and Superman can fly, so Clark Kent can fly. Lois believes that." is better, I wouldn't care to say. What I'm after is that it's not enough that she believe three separate sentences. She has to put them together, and that's what it is hard to represent in language. Perhaps what I'm trying to say is that there something like a Gestalt at work here, which it is hard to represent with atomic sentences/propositions. I'm thinking of something like Quine's web of belief.

I suspect that you, Ludwig V, are familiar with all this. — Banno

There are many things that I ought to know and do not know. I did not know that Quine has an actual diagnosis and a solution.
Like all good philosophy, it is obvious when you see it. So thanks for that.
I was not asking in the spirit that some philosophers ask questions to which they believe they know the answer in order to lodge an objection - though I have to admit that I have been known to do that.

However, there are many cases when a form of language is misleading, such as reification. But there are others where it is not, such as a categorial distinction. I'm not sure which kind the intensional/extensional distinction is.

When Macbeth sees Macduff's sword when Macduff comes to kill him, we are all clear the Macbeth sees Macduff's sword. There is a real sword, so it's an extensional context. When Macbeth sees a dagger before him, does Macbeth see an intensional dagger - i.e. a hallucination? What kind of object is that? I want to say that he does not see a dagger and that a hallucination is not an object. You can, I assume, see the implications.

Consider the wholly nomological context of:

Steam is H2O
Ice is H2O
Therefore, steam is ice

This is obviously incorrect. So too:

Ice is H20
Fog is H20
Ice can be walked upon and makes for a good bridge.
Therefore, fog can be walked upon and makes for a good bridge.

Or another false argument can be based on the fact that ice becomes water when heated, yet steam does not.

And yet:

This water is water.
This water has become steam.
Therefore this steam is that water.

Seems fine. These are pretty easy to explain in terms of water. The interesting thing is rather the general form. With the last one, while it seems clear that my cup of water is the same water when it has frozen, consider:

These frogs are frogs.
These frogs have been digested and become a turtle.
Those frogs are this turtle.

...does not seem to work, although we might agree that in some sense the composition of the turtle bears a similar relation to the frogs as the ice to the water.

You aren't using the identity elimination schema there.

That's a nice and thought-provoking collection of examples.

You aren't using the identity elimination schema there. — frank

I'm afraid I don't know or can't recall exactly what the identity elimination schema. Do you mind just outlining what it is?

Read the exchange with I just had with Banno. You do need to understand the issue of Supervenience though in relation to Mental States/Identity. — I like sushi

I'm afraid I'm not competent to express an opinion about what you are trying to say. I don't understand it.

Sure, but you could easily make one that fits the form you were using. The difficulty there is that, in a simple three premise form, you end up with the questionable premise that "ice is steam." Well, that's true in a sense, but the whole point is that it is false in another. But you could do it in terms of a = c and b = c, which implies that a = b E.g.,

Ice and steam are H2O
Ice makes for a good bridge.
Therefore, steam makes for a good bridge.

You could also do it with the less questionable "ice is water."

Ice is water.
Ice makes for a good bridge.
Therefore water makes for a good bridge.

The problem here is an equivocation on "water" as chemical identity versus as a particular phase of that substance.

Now the error in the first is obvious in that H2O is sometimes treated as a sort of identity, chemical identity, (or a rigid designator) and yet the properties of its phases are distinct, and "ice" and "steam/fog" refer to particular phases. But I imagine a clever person could come up with less obvious examples.

I'm afraid I don't know or can't recall exactly what the identity elimination schema. Do you mind just outlining what it is? — Ludwig V

This is from the IEP article. (Beware, I've found incorrect info in the IEP before).

A little more formally, the rule of inference =E can be stated as:

Identity Elimination Schema

Major: t1 = t2

Minor: ϕ(t1)

Conclusion: ϕ(t2)

Here t1 and t2 are expressions which refer to entities (for example, proper names of people or cities). ϕ(t1) is a sentence containing at least one occurrence of t1, and ϕ(t2) is a sentence that results from replacing at least one occurrence of t1 in ϕ(t1) with an occurrence of t2, eliminating the “=” of t1 = t2. Recurring ti presumes that ti is univocal throughout, and recurring ϕ presumes that the sentential context ϕ is not altered, syntactically or semantically, by the replacement. If these uniformity conditions are not met, then the inference scheme is being misapplied, and it is no wonder that false conclusions are derivable. For example, in the inference “The man behind Fred = the man in front of Bill; the man behind Fred saw him leave; therefore, the man in front of Bill saw him leave,” the context “saw him leave” is not uniform, since substitution of “the man behind Fred” by “the man in front of Bill” changes the reference of “him” (Fine 1989:222–3; Linsky 1967:104).

In discussing the problem with apparent substitution-failure by using =E, many examples will be drawn from the fictional story of Superman, treated as if it were true. In the story, a child from the planet Krypton, Kal-El, is sent to Earth, where physical conditions cause him to acquire superpowers. Wearing specific clothing (red cape, blue jumpsuit), Kal-El prevents disasters, rescues endangered innocents, and foils would-be perpetrators of crimes, such as Lex Luthor. People call Kal-El “Superman” when talking about Kal-El’s actions of this kind.

But Kal-El also takes a day job as a reporter, using the name “Clark Kent.” A coworker, Lois Lane, treats him with indifference in the office, but has a pronounced crush on, as she would put it, Superman, unaware they are the same individual.

The problematic examples discussed below involve ascriptions of mental states to Lois (or occasionally Lex), arrived at by applying the rule =E to the major premise “Superman is Clark” and a carefully chosen minor premise. Lois has a crush on Superman (minor premise), so, by =E, Lois has a crush on Clark. But this latter seems false, and would certainly be rejected by Lois herself. Also, Lois believes that Superman can fly, but does not seem to believe that Clark can; she hopes to see Superman again soon, but seems not much to care when she next sees Clark; she would like a date with Superman, but apparently has no interest in one with Clark; and so on — IEP

So after explaining the Superman substitution failure, the IEP sort of asks if this might be a misapplication of the schema. It goes through some misapplications, which I looked at

a. Istanbul is Constantinople.
b. “Istanbul” has eight letters.
c. ∴ “Constantinople” has eight letters.
— IEP

In this case, the problem is coming from the use of Tarskian quotation, which means the quoted part is a word, not a city.
-----------------------------------------
a. Giorgione is Barbarelli.
b. Giorgione is so-called because of his size.
c. ∴ Barbarelli is so-called because of his size.
— IEP

The flaw here is equivocation. The "so-called because of his size" can't skip from one name to the next.
--------------------------------------------

a. The number of planets = 3 squared
b. It is contingent that the number of planets = 9
c. ∴ It is contingent that 3 squared = 9.
— IEP — frank

We end up concluding that this isn't a case of misapplication, but we still have a substitution failure. Are you familiar with de re vs de dicto?

Fine. I don't think you're really looking for my input here. :smile:

Are you familiar with de re vs de dicto? — frank

Yes, but don't see how it applies in the planets case.

Sure, if you have something to add. I was just thinking of similar cases that don't involve belief. Another equivocation with proper names would be the provocative:

Israel is Palestine
Israel is a Jewish state
Therefore, Palestine is a Jewish state.

Which seems false, whereas:

Israel is Palestine.
Israel is considered to be the Holy Land.
Therefore, Palestine is considered to be the Holy Land.

Seems fine. I was thinking this is just old-fashioned equivocation between Israel and Palestine as names for geographic regions versus as names of political entities (you could do it with Tibet or East Turkestan "being Chinese" as well). You could disambiguate with "the state of Israel/Palestine." Wouldn't "Constantinople" / Istanbul just be a sort of special case of equivocation?

Edit: with Superman we could also avoid belief and still get an apparent error with "Clark Kent appears on the Daily Planet payroll." This might be considered the same sort of equivocation as "Constantinople"/Constantinople. It's not as immediately obvious though. One could say it is true in one sense and not in another that Superman appears on the payroll.

The fault likely more with me here. I guess I was trying to say something that appears quite tangental to this thread and I am still far from the level of competence I would like to reach when it comes to philosphical writing (that sentence is a good example!).

Yes, but don't see how it applies in the planets case. — Ludwig V

The planet case is a misapplication because the number of planets isn't a proper noun. Both t1 and t2 have to be rigid designators.

The planet case is a misapplication because the number of planets isn't a proper noun. Both t1 and t2 have to be rigid designators. — frank

Do you mean something like a blank space to be filled in with a number - hopefully the correct number?
Or perhaps more like a question "How many planets are there?" I get that. Thanks.

BTW. What is "9" the rigid designator of?

I think the number of planets is a singular definite description. It's not the same in all possible worlds.

9 is an abstract object.

Let's just share the blame.

I get the point about "the number of planets".

Sorry, but I don't really get the relevance of being an abstract object to rigid designation.

Sorry, but I don't really get the relevance of being an abstract object to rigid designation. — Ludwig V

9 is the same abstract object in all possible worlds, so it's a rigid designator.

Oh, I see. I would have expressed that by saying that the number is the same in all possible worlds, so the numeral "9" designates the same number in all possible worlds. I should have worked that out. Sorry.

the de re reading, contrasting with the more common de dicto reading, [...] relational, contrasting with notional; transparent, contrasting with opaque; and wide scope, contrasting with narrow scope.
— IEP

Also reference, contrasting with sense? (I wonder.) — bongo fury

Also objective, contrasting with subjective, according to Davidson.

Also semantics, contrasting with syntax, according to Searle in his Chinese Room.

Also rigid, contrasting with flaccid.

Also real, contrasting with pretend, according to any five year old.

Or real, contrasting with suppose, from about 10 years.

Let's take care not to confuse the two, as @Banno says. Sure. But let's maybe see the possibility or likelihood of confusion (and the struggles to avert it) as a condition of "rationality", as Davidson says?

@frank's objection is to making it a sufficient as opposed to merely necessary condition of rationality? A machine doesn't achieve beliefs just by getting in a logical tangle over sentences?

Just trying to over-simplify. Carry on.

Too much caffeine will do that.

Too right.

I'm sympathetic to most of what you have been saying. But this contradiction can easily be resolved. "Superman" and "Clark Kent" are both names for the same person - but each name is assigned to a different persona. This is not particularly strange - pen names, professional names, character names (Barry Humphries, for example), regal names, baptismal names, adoptive names, married names, aliases of all sorts. — Ludwig V

Well, if the personas have different properties then you have solved the "puzzle."

Edit: with Superman we could also avoid belief and still get an apparent error with "Clark Kent appears on the Daily Planet payroll." — Count Timothy von Icarus

Right, or:

On your reasoning, we can disprove the thesis simply by noting that Superman wears a cape whereas Kent does not. — Leontiskos

Well, if the personas have different properties then you have solved the "puzzle." — Leontiskos

I don't know I would go that far. That "if" tells me that you have reservations. I suspect there will still be issues to discuss, but it might be a change from going through that argument over and over again.

Oh, Tim.

Referential opacity is to do with individuals, not natural kinds.

In first-order logic a,b,c... are variables picking out individuals. Identity elimination is the rule that if a=b than for any formula that contains a we can write another formula replacing every instance of a with b and this formula will have the exact same truth value. That's pretty much the definition of "=".

That's why we use the individuals Superman and Kent.

Your examples use kinds, not individuals.

Steam is H2O
Ice is H2O
Therefore, steam is ice — Count Timothy von Icarus

would be parsed as

U(x)(x is steam ⊃ x is H₂O)
U(x)(x is ice ⊃ x is H₂O)
Therefore
U(x)(x is steam ⊃x is ice)

It's the same as "All cats are mammals, all dogs are mammals, therefore all cats are dogs".

That's a nice and thought-provoking collection of examples. — Ludwig V

I don't agree.

That's a nice and thought-provoking collection of examples.
— Ludwig V
I don't agree. — Banno

Fair enough.

You aren't using the identity elimination schema there. — frank

Yep.

The schema says that if we have a true formula containing an individual variable a, and if we have a=b, then we can replace a in with b, and the formula will remain true.

Do you recall this?

The problem here is an equivocation on "water" as chemical identity versus as a particular phase of that substance. — Count Timothy von Icarus

No. The problem is that you have moved from individuals to natural kinds.

Referential opacity is to do with individuals, not natural kinds.

Sure, but the issue is similar, as evidenced by the Israel/Palestine geographic area versus state equivocation.

I am not sure how the move to natural kinds explains the issue. If x is y natural kind and z is y natural kind, then in theory they have the same essential properties. If "water" is taken to be equivalent to H2O, i.e., chemical identity, then what is true of H2O is true for water. But water refers to both a chemical identity and a specific phase, which is what allows for equivocation, just as Israel can refer to a certain section of the Levant or the modern state of Israel, or the ancient Northern Kingdom.

But I'd argue that with the person/persona distinction similar sorts of equivocation can occur. Spiderman is the main character of a Marvel franchise. Peter Parker? Well, in the newer versions there is only Miles Morales from what I understand.