Yes, sorry, I did misquote, but still don't think it's a category error. It doesn't seem to me impossible to assess the hardness of a molecule in the same way it would be impossible to assess whether a molecule was 'odd' or 'even', which was the point.

not at all. Of course, they are not properly "names" for the correspondence theory I'm thinking of so not technically empty in the first place, but I think it can easily deal with the fact that they nonetheless have meaning.

1) I guess I didn't find @andrewk 's post really clarified much. On the contrary, far from being a category mistake, meanings are exactly the kinds of thing you ask about in connection with words. And I also don't think asking whether salt is hard is a category error. It might not ultimately be a scientifically helpful avenue of inquiry, but it's not a category error. Now, asking whether salt is even or odd, on the other hand, would imply a category error as I understand that fallacy.

2) I wasn't ultimately addressing the larger issue of empty names, only how the example of @Dawnstorm was not necessarily analogous to that of "Pegasus", "santa claus" or whatever. A correspondence theorist might agree those latter names are empty, but deny that either of the "Joe Smiths" in @Dawnstorm 's example were.

3) In terms of the larger issue of empty names, the original question merely asked how supposed empty names can have meanings. One possible way they can have meanings is under a correspondence theory of truth, according to which, strictly speaking, the truth value of any such name will always be false because there is no such actual thing in the world like "Pegasus" or "santa claus". (I take it generally that a consequence of any correspondence theory is that there are really only two possible meanings for any proposition: true or false)

Yes, I'm assuming a correspondence theory. I'm not sure how it side steps any questions though.

It might be helpful to treat the 2d definition as essentially analytic. In other words, what a "substance" is in the context of defining an "element" is just "one type of atom." However, the definition you quote uses the plural which I think is a little sloppy on its author's part, since it could be that he was generally defining "element" to cover all the various elements and slipped into the plural. Alternatively, It could be the case that the plural was meant to capture the fact that an "element" is any composition of two or more of the same type of atom. The composite of the atoms being what the term "substance" refers to. The 2d possible interpretation also has the attraction of bring the 2d definition more in line with the 1st definition. The definition would then go like: element = substance; substance = two or more of the same type of atom. I don't think the 2d definition you cite excludes that account, but it doesn't exactly where it on its sleeve either, which it should do as a good scientific definition.

Generally I don't have an issue with your claims about how syntax can operate with proper names, and even think the type/token distinction could be useful for explaining the non-definite use of the proper name vs. the definite. I took my claim about the "lexical entity 'john smith'" to be basically consistent with that. However, my concern is exactly with what the actual context of the situation is here and the intentional state of the postal carrier. The package carrier not standing at the door wanting to give the package to anyone who happens to be named John Smith so he can happily walk off feeling like he did his job competently. Rather, he wants to give the package to the John Smith to whom the person who sent it addressed it to, he just doesn't know who that is. In other words, s/he isn't just looking for "a" John Smith, he's looking for "the" John Smith the package is addressed to. So, I just don't see that the syntactic distinctions you bring up - while legitimate in and of themselves - apply to this particular situation here since, in fact, given the context, it does not seem to me that either of the names are empty in the example given.

It looks like you're trying to prove a substitution lemma, or something involving the substitution lemma (I'm assuming I understand the notation you're using). If I recall correctly, the proof proceeds by induction on the structure of the WFF. So, you will assume the truth of the antecedent, i.e. that for each p ∈ At(A), that v(p) = v'(p), then show the truth for each case of the WFF given the assumed truth of the antecedent and the rules for substitution....I think. Happy to be corrected if wrong.

You're right that we can't be certain about anything, that includes our own existence and, a fortiori, any meaning that attaches to it. The reason for this uncertainty is because the universe at its essence is chaos. The human predicament boils down to the inevitably futile attempt to impose order on that chaos, whether in the form of religion, logic, science, language, social customs, law, or whatever. Your anxiety no doubt stems from an attachment to this hopeless project. In other words, there is a part of you that is clinging to the hope or to the ungrounded belief that somehow we will be able to make sense out of what I take to be innately senseless. Let it go. Embrace non-being and chaos, and "you" will be stronger. You will be stronger because you will achieve exactly what it is that you take to be the ideal of the failed human project: some kind of correspondence between your beliefs about the world and the way the world happens to be. The rejection of the structural project and the acceptance of the limitless chaotic nature of "your" own being will be identical to that-which-is(n't).

I realize, of course, the paradoxical nature of even making these claims, but rather than seeing that as problematic, I take their paradoxicality as a testimony to their truth. Also, while I additionally recognize the advice is reminiscent of the teaching of some eastern religions, that is not the point of view that motivates them. Rather, I think probably like yourself, it is from the repeated failure of trying to arrive at even a half-acceptable account of experience and coming to the conclusion that the reason why no such account is forthcoming is because none is possible.

two points:

1) the gist of naming and necessity is that Kripke argues that you can have analytic a posteriori truths. His famous example is the claim that 'water is H2O', which can't be known a priori but is analytic in the sense that what we mean by the conventional term "water" - what water is - is just the material identified scientifically as H20 and not any of the numerous possible descriptions of water (such as being "wet" or "clear" etc.)

2) Don't major in philosophy. it's a waste of an education. You can pursue it just fine as a hobby. If you're going to drop big bucks on an education study something useful to society and the economy. I'd recommend engineering, bio sciences, comp sci, or business...unless of course you have a trust fund, in which case do whatever you want.

I'm not sure the example gets to the difference between type/token and proper names. It seems to me that both speakers there are using proper names. the only possible type/token implication is that one could see the lexical entity 'john smith' as a type for the two token names "John Smith [1]" and "John Smith [2]" given the name is a homonym. I think the more nature description though would just be say there's any ambiguity in the name: they just sound alike but in fact reference two different things, like a river 'bank' vs. a financial 'bank'.

1) Doesn't the description for Frege just unpack into the referents? That's the whole point of the "morning star" example, isn't it? So in the case of

"the difference between A and B does not subsist" — EmaFort

references the fact that A=B is true. In other words, it's essentially just the negation of the claim that ~(A=B), i.e. ~~(A=B).

2) If you use structured predicates the way Russell did to "resolve" the liar paradox, then you have to contend with incompleteness issues a la Godel...although Russell would have agreed you can solve it that way.

The claim that

the truth table is the conjunction of the premises implying in the conclusion — Nicholas Ferreira

does not seem correct. There is nothing inherent in the definition or concept of a truth table that identifies it as being anything other than a tabular representation of the possible binary values assigned to some variable. Consider the simplest truth table:

A | A
_____
T | T
F | F

Which just says the variable "A" has the values assigned to it. There is nothing here about "conjunction" or "implication". Truth tables can further be used to define what certain operators like conjunction and implication mean by showing how the values assigned to variables change when the operator is applied to them. At this point truth tables are used to introduce the notions of conjunction or implication or whatever, but they don't purport to prove anything about these operators. Once you have defined what the operators are, you can construct tautologies that are the functional equivalent of the rules of inference that show that the rules preserve the truth values of the variables they're applied to because they are, well, obviously true as tautologies. The rules of inference then are just short hand ways of constructing these tautologies that are more convenient to work with.

Ferreira is generally correct. The problem with your "proof" is in line 1. There is no rule of replacement or inference that allows the move from (D ->A) ->T to D->(A->T). in fact, "exposition" is not even a term used in prop logic. If you meant "exportation," that is different rule from the one you use. Since Ferreira has provided a value assignment showing invalidity, there should be no way to manipulate the rules of inference to produce a valid argument from the premises you cite.

Consider it on a more intuitive level: "If it is the case that if the moon is blue, then cats bark, then roger is happy" creates much different conditions from "if the moon is blue, then it is the case that if cats bark, roger is happy".

More formally you can see the transformation you use does not preserve truth value under the following value assignments:

A D T | (A→D)→T | A→(D→T)
F F F F T

A rule of inference must preserve truth value regardless of truth assignment, so "exposition" can not be a rule of inference.