Twin Earth conflates meaning and reference.

Twin Earth fails because it does not distinguish meaning and referent.

Same meaning in each case, but different referent. Hence, the argument goes, the meaning of "water" is not its chemical composition.

Let W 1 and W 2 be two possible worlds in which I exist and in which
this glass exists and in which I am giving a meaning explanation by
pointing to this glass and saying "this is water." (We do not assume
that the liquid in the glass is the same in both worlds.) Let us suppose
that in W 1 the glass is full of H20 and in W2 the glass is full of XYZ.
We shall also suppose that W 1 is the actual world and that XYZ is the
stuff typically called "water" in the world W 2 (so that the relation between English speakers in W 1 and English speakers in W 2 is exactly
the same as the relation between English speakers on Earth and English
speakers on Twin Earth). Then there are two theories one might have
concerning the meaning of "water."
( 1) One might hold that "water" was world-relative but constant in
meaning (i.e., the word has a constant relative meaning). On this
theory, "water" means the same in W 1 and W 2; it's just that water is
H20 in W 1 and water is XYZ in Wz.
(2) One might hold that water is H20 in all worlds (the stuff called
"water" in W 2 isn't water), but "water" doesn't have the same meaning
in W1 and Wz.
[b]If what was said before about the Twin Earth case was correct, then
( 2) is clearly the correct theory.[/b]

And yet, despite our clear understanding of S, we have no idea what the referent is. What water is cold? The relevant context is unknown. S has no clear referent and yet is perfectly understandable. This can only be the case if meaning and referent are different: only then can we make sense of understanding the one without knowing the other.

So reference is to some particular item (e.g. glass of liquid), whereas meaning is reference to a wider class or extension (e.g. of water)?

Please explain where I go wrong. :chin:

Simply, we English speakers all know what S means. It is basic English. But we don't know to what it refers.

Therefore, meaning and reference are distinct concepts, and must not be conflated.

I suggest they're interchangeable. We all know that your sentence S refers to water in general, and cold things in general. We just don't know which bit of water you mean.

If you prefer. The point being that it clearly distinguishes meaning and reference, in contrast to your title.

I suggest they're interchangeable.

that S refers to a specific bit of water, not water in general.

In your case, your mental states are different when you are using the same terms, and they are referring to different things.

(II) That the meaning of a term (in the sense of "intension") determines its extension (in the sense that sameness of intension entails sameness of extension).

...

Let A and B be any two terms which differ in extension. By assumption (II) they must differ in meaning (in the sense of "intension").

I guess I should reread the paper.

Nonetheless, when earthlings and twin earthlings say "water", they mean the exact same thing, for them.

n other words, there's no such thing as what I mean by the word "water", there is only what the word "water" means.

Let A and B be any two terms which differ in extension. By assumption (II) they must differ in meaning (in the sense of "intension").

I was confusing contextualized meaning and referent.

Imagine you were killed and replaced by an evil doppelganger. Your friend George, unaware of this, says "Hi Michael". George doesn't mean the doppelganger, he means to greet Good Michael. Only for those who learned of substitution would "Michael" mean the doppelganger.

The context free part, the part you understand just by knowing the language, is only part of the meaning. The other part of the meaning is the part gotten from context. This contextual meaning may include referent(s), though the actual, physical (or mental) referent is of course not a meaning.

That's a proper name. "Michael" doesn't really mean anything, it's just an identifier.

What is a proper name if not a word that means a particular thing?

As well as having a range of entities to which it applies, the common noun “bachelor” has a meaning; it means man who has never been married. What about names? “Socrates” certainly applies to things. It applies, most obviously, to the founder of Western philosophy. Understood as a generic name (see Section 1), “Socrates” applies to several individuals: to a first approximation, all those who are called “Socrates”. But does “Socrates” also possess a meaning?

Some names have meanings in a sense. I have heard “Merlot” used to summon a child, and once knew of a married couple whose respective names were “Sunshine” and “Moonlight”. These names, we would say, have meanings. “Moonlight”, for instance, means light from the Moon. Something similar goes on when we say that “Theodore” means gift of god, or interpret a Mohawk name as a verb phrase. But this sense of meaning turns out not to be the one we are after.

Consider that for “bachelor” the meaning—man who has never been married—is also what determines the noun’s range of application. When the noun “bachelor” applies to someone, it’s because they are a man who has never been married. And when it fails to apply to someone, it’s because they are not. By contrast, the kind of meaning just canvassed for the names “Merlot” or “Moonlight” places no direct constraint on what they apply to. One may be named “Merlot”, and so fall within the name’s range of application, no matter what relationship one bears to the wine grape variety, Merlot (Mill 1843: 34). Moreover, one’s particular relationship to the grape is not the reason the name applies.

In this long tail of the article on semantics, we will confine ourselves to the question of whether names have a meaning in the sense in which “bachelor” does. Do they have a meaning that determines, or at least restricts, their extension (i.e., either range of application or reference)?

The same example can be made without using a proper name. Suppose all the world's water was suddenly replaced with twin water. Until I learned of this replacement, I would still mean water when I said "water". Only when I learned would I mean twin water. While still acknowledging that the people who were naïve to the change still mean water.

And in such a scenario if you were to say "this is a glass of water" you would be wrong because it isn't a glass of water, it's a glass of twin-water.

the term "the President" refers to Joe Biden.

Arent we condemned to a world of ideas?

See the SEP article on names

Let A and B be any two terms which differ in extension. By assumption (II) they must differ in meaning (in the sense of "intension").

Yes, this is why I disagree with Putnam. Putnam believes that differences in the thing in itself, differences which we have no access to, can impose change on our meaning. These differences can only impose changes in the absolute facticity of our claims

Would we all be wrong who say "Joe Biden is president?"

cheerleading different linguistic conventions that emphasize different semantics for different purposes.

To think otherwise is to grant linguists powers of omniscient authority.