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Londoner wrote:To be precise I'd say that synthetic propositions are true both by virtue of the meaning of terms used and by their reference to something other than those words.

The sentence "Vixens are female foxes" is an analytic truth, but it refers to vixens rather than to the noun "vixen" or the concept <vixen>. So it is not the case that all analytic truths lack translinguistic or transconceptual reference.

-- Updated May 12th, 2014, 7:28 pm to add the following --

Fafner88 wrote:Do you accept the common view that analytic propositions are true by virtue of the meaning of the terms?

Not all analytic truths are true by virtue of the meanings of their constituent terms. Conceptual truths such as "Bachelors are unmarried" are, whereas logical truths such as "(p & q) –> p" are not. The latter are true by virtue of their logical form. (The meaning of the logical constants is relevant too.)

An analytic proposition in Frege's sense is a proposition which is synonymous with a logical truth (tautology). It follows trivially that logical truths are analytic, since they are synonymous with themselves. And conceptual truths are implicit (instances of) logical truths, which are transformable into explicit (instances of) logical truths.

If mathematical truths are or are transformable into logical truths, then they are analytic.
See: Logicism and Neologicism

"Before receiving the famous letter from Bertrand Russell informing him of the inconsistency in his system, Frege thought that he had shown that arithmetic is reducible to the analytic truths of logic (i.e., statements which are true solely in virtue of the meanings of the logical words appearing in those statements). It is recognized today, however, that at best Frege showed that arithmetic is reducible to second-order logic extended only by Hume's Principle. Some philosophers think Hume's Principle is analytically true (i.e., true in virtue of the very meanings of its words), while others resist the claim, and there is an interesting debate on this issue in the literature."

http://plato.stanford.edu/entries/frege/

Consul wrote:

The sentence "Vixens are female foxes" is an analytic truth, but it refers to vixens rather than to the noun "vixen" or the concept <vixen>. So it is not the case that all analytic truths lack translinguistic or transconceptual reference.

True, the proposition "Vixens are female foxes" refers to real vixens and not to lexical constraints or mental concepts.

The proposition also refers, by implication it is true, to intersubjective acceptance of modern classifications. According to received classification it is incorrect to propose that vixens are immature rabbits but without the accepted nomenclature "Vixens are immature rabbits" would be as true or as false as "Vixens are female foxes".

A priori truths are not knowledge, but skills. Knowledge is never absolute except, arguably, mystical knowledge.

Me: To be precise I'd say that synthetic propositions are true both by virtue of the meaning of terms used and by their reference to something other than those words.

The sentence "Vixens are female foxes" is an analytic truth, but it refers to vixens rather than to the noun "vixen" or the concept <vixen>. So it is not the case that all analytic truths lack translinguistic or transconceptual reference*.

I disagree. If the concept that goes with the words 'a vixen' and that which goes with 'a female fox' are identical then that proposition is true. In this case, part of that concept is that they both refer to a sort of animal, particular examples of which we believe exist, but that need not be the case; 'Centaurs are men with horse's legs', or 'Beauty is Truth'.

I think your example may be misleading because it contains the word 'are'; this can imply 'exist', which would be an extra claim. We decide claims about existence empirically. But in analytic claims the 'are' applies to the words, so it is short for something like 'has the same meaning as'.

But again, we have the problem of using normal language to describe a problem that is partly about logic. You say 'analytic truths'. So are we discussing; 'Is X an analytic proposition'? Or; 'Is X true?' They are different questions. 'Beauty is Truth' is an analytic proposition as good in logic as the one about foxes, but it doesn't follow that its truth is indisputable.

At this point, the dispute is no longer about how we categorise the proposition but about what sort of things the terms in the proposition refer to, hence the broader question of what we understand by 'truth'. Going that way, we really need to be careful to distinguish whether we are talking about logic or objects, since the same words (valid, fact, proposition etc.) have different meanings. All interesting stuff (some would claim!), but remember in my posts I was addressing Fafner's particular example, so note that I am trying to tease out what he meant, using his terms.

* p.s. I don't think I understand your phrase 'transconceptual reference'.

Londoner wrote:They are components in the sense that you can arrange them in different sentences (e.g. P&Q, P<->Q, ~Q->P etc.). It seems to me pretty obvious that sentences are made of components, you can have the same words but put them in different ways etc.

This may be the key to your misunderstanding. The lines of a proof are not like sentences. Logic is like maths; a 'formal science'.

With sentences, the meaning of the words is important. But 'all women have beards' is just as valid in logic as 'grass is green'. Both will be symbolised by a letter, so both can create 'valid' proofs ('valid' also having a special meaning). It is like 2 + 3 = 5; it is not saying the same as 'I have two apples then three more apples, now I have five'. The first is necessarily correct; the second may be false.

I wasn't talking about proofs, and "grass is green" is not an argument and therefore there's no sense of saying that it's "valid in logic".

This means the symbol; '->' etc. is not really the equivalent of a word like 'then'.

Maybe it's not always an exact equivalent, but in the examples I gave it plainly is, and nobody seriously disputes this among philosophers and logicians.

If we say 'If it rains then we get wet' then this doesn't imply that getting wet can only be the result of rain,

Nobody says it implies that, you are confusing conditionals with biconditionals (-> vs <->).

nor does it imply that it can't be negated (by having an umbrella).

Fine, but then the conditional "If it rains then we get wet" is simply false. But do you have a counterexample in which a 6 meter man is not taller then a 5 meter man? If you don't, then it must mean that the conditional "if there is a 5 and a 6 meter tall men, then the 6 meter tall man must be taller then the other one" is true.

But in the logical P -> Q, which has nothing to do with empirical facts, the relationship is much more strict. It is saying that wetness must follow rain; and does not follow from anything else.

"wetness must follow rain; and does not follow from anything else" means "if and only if", but that's not what "if it's raining then it will get wet" means. "if P then Q" is weaker then "P if and only if Q", it doesn't say also "if Q then P".

But even the 'follow' in my attempt to use words to explain it is misleading, since no cause-effect relationship is implied.

Maybe, but so what?

The relationship is more like 'If you are a bachelor then you will be unmarried' - it is saying the conditions that would make P true are identical to the conditions that would make Q true. Well it's a difficult question what

This is simply not true, at least not in the examples that I used.

So how can you substitute words for letters in P->Q? If those words denoted different things, then P -> Q isn't true. (If Q denoted something different to P, then the line should be P (+ something else) -> Q).

How does it even follow that the conditional isn't true? Again, just look at the truth table of "->" and you'll see that it is true in all cases except when the antecedent is true and the consequent is false, this is basic logic and it's extremely unreasonable to deny this.

Like maths, superficially logic seems to match up with 'common sense' and the practical ways in which we deal with the world of objects, but this is misleading. Logic is not about 'things' and the words which denote them - and this becomes clear when you examine it closely.

Fine, maybe logic doesn't reflect exactly natural language, but it still captures very accurately many aspects of the ways we talk and think.

Of course logic as a subject is not about things, it's about logic, but it does reflect the way we talk about the world, and this is something which is overwhelmingly obvious to anybody who studied the subject seriously (and again, if you don't agree then you must give an argument).

For example, what is the meaning of your word 'person'? In normal speech, that word denotes something that exists now, so we need to find out what you might mean by it.

And is this sentence to be understood as an empirical claim? (...will be a girl) Or a tautology? (...will be human). Since you don't finish it, we cannot guess.

"a person" isn't an empirical claim or claim about existence, it's a concept, how this questions are even relevant?

Is it true or not that there might live people in the future who are not yet born? What part about this sentence you don't understand? Just stop doing philosophy for a moment and think how utterly absurd it is to deny the truth of this claim, I can't believe that I have to argue for this.

1. P (A) (A meaning we assume)

2. P -> Q (A)

3. Q Modus ponens (1,2) (meaning it rests on the assumptions of lines 1 and 2)

How this is relevant to my point?

Note; you can't leave out line 1, even though P also appears in line 2. On its own, P -> Q cannot be used to prove Q.

Where did I try to prove Q?

'A 6 meter man' is an object. '6 meters' is not an object, but nor is it a fact. A fact can be true or false; '6 meters' isn't either.

"6 meters tall" is a predicate, and obviously predicates can be true about their subjects ("green" is not an object but it has nothing to do with the truth of "the grass is green").

You want to borrow the object-ness of 'man' to turn that '6 meters' into a fact, but then deny the sentence concerns objects.

No I'm not, I'm just saying that there are facts about possible objects.

That is not what it is about. Russell is about logic. The problem here is the logic of the 'excluded middle'; it appears logically necessary that the statement 'the present king of France is bald' must either be true or false. But both seem to involve the necessity for there to be a King of France. But (crudely) Russell says the logical meaning of 'is' when talking of identity, prediction and existence are different. By changing the focus of our negation we can say 'It is not the case that there exists a King of France (who is bald)'.

Which, of course, seems obvious. But it seems obvious to us because it corresponds to an empirical fact, but again I make the point that the rules of logic are not about empirical facts. That this negation is true is irrelevant. Russell's object is to prove that such a negation is 'valid'.

(Another way of looking at it is what terms like 'the present king of France' describe. Because if we substitute a proper name then the logic works differently. The 'King of France..' stuff is discussed as an aspect of Russell's 'Theory of Definite Descriptions'.)

You completely missed the point of the example, never mind.

Fafner

Maybe it's not always an exact equivalent, but in the examples I gave it plainly is, and nobody seriously disputes this among philosophers and logicians....

Fine, maybe logic doesn't reflect exactly natural language, but it still captures very accurately many aspects of the ways we talk and think.

Of course logic as a subject is not about things, it's about logic, but it does reflect the way we talk about the world, and this is something which is overwhelmingly obvious to anybody who studied the subject seriously (and again, if you don't agree then you must give an argument).

Would you agree that philosophers who have seriously studied the subject include Russell and Wittgenstein? Then have a look at 'Tractatus Logico-Philosophicus', or rather the introduction. I'm not asking you to absorb it all and comment on it; it is just to give an idea of the character of such discussions.

Honestly, I'm not making all this stuff up, off the top of my head!

Is it true or not that there might live people in the future who are not yet born? What part about this sentence you don't understand? Just stop doing philosophy for a moment and think how utterly absurd it is to deny the truth of this claim, I can't believe that I have to argue for this.

But that wasn't what you wrote.

What you wrote was: When I say "the first person to be born in the year 2017 will be ..." (Unfinished, just like that)

Even in 'natural language' that is not the same.

No I'm not, I'm just saying that there are facts about possible objects.

What relationship have 'possible objects' to 'real objects'? Is there any limit to what might be a 'possible object'? Or a 'possible world'? Because even if we accept that there are such things as 'possible objects', that will just shift the problem to that of what 'facts' might mean in that context.

Londoner wrote:Would you agree that philosophers who have seriously studied the subject include Russell and Wittgenstein? Then have a look at 'Tractatus Logico-Philosophicus', or rather the introduction. I'm not asking you to absorb it all and comment on it; it is just to give an idea of the character of such discussions.

Honestly, I'm not making all this stuff up, off the top of my head!

Did Wittgenstein and Russell disputed that "if it rains then it gets wet" has the logical form of "P->Q"?

I'm not asking the general question of the relation between logic and language, I'm just saying that it's very plausible to assume that many "if, then" sentences in natural language are accurately described as "P->Q", and thus have the same truth table. It's not a controversial claim.

By the way, Wittgenstein was the one who introduced truth tables... (and for "P->Q")

But that wasn't what you wrote.

What you wrote was: When I say "the first person to be born in the year 2017 will be ..." (Unfinished, just like that)

Even in 'natural language' that is not the same.

Yes, it's a different examples but they make the same point: there are facts about possible objects.

What relationship have 'possible objects' to 'real objects'? Is there any limit to what might be a 'possible object'? Or a 'possible world'? Because even if we accept that there are such things as 'possible objects', that will just shift the problem to that of what 'facts' might mean in that context.

I don't know, but these are different questions, and it's not a reason to dispute the claim there are facts about non actual objects, whatever you think about their explanetion (as I said, if you discover a new phenomenon in science which you can't explain, you don't say that it doesn't exist because you can't explain it, why it should be different in philosophy?). And besides it's not the main topic and I don't have to answer all the questions in philosophy to make a particular point about a priori knowledge. All of this has started when you disputed that physical laws can describe reality, quote:

I disagree. I do not see how you can assert a physical law without also asserting 'and this exists in the world'. Not in itself; obviously 'gravity' is not an object. But unless there existed objects being affected by gravity, then what would the term signify? How could gravity be 'true'?

But given the examples I gave, simple conditionals about non actual states of affairs are plainly true about reality, and yet they don't refer to any particular object "there exists an x such that ...", so it's not an objection against the truth of scientific laws because there are many truths of this kind in other non controversial domains. A physical law is really just a universal generalization about all possible objects or states of affairs of a certain kind (such as "f=ma" which talks in general about all the possible moving bodies in our world, in the past present and future), and thus it's very similar to "if there's a 6 meter tall man...".

Londoner wrote:

Consul wrote:The sentence "Vixens are female foxes" is an analytic truth, but it refers to vixens rather than to the noun "vixen" or the concept <vixen>. So it is not the case that all analytic truths lack translinguistic or transconceptual reference*.

I disagree. If the concept that goes with the words 'a vixen' and that which goes with 'a female fox' are identical then that proposition is true. In this case, part of that concept is that they both refer to a sort of animal, particular examples of which we believe exist, but that need not be the case; 'Centaurs are men with horse's legs', or 'Beauty is Truth'.

It depends on whether you think that reference is existence-entailing, such that if x refers to y, both x and y exist. Anyway, my point is that the subject matter of "Vixens are female foxes" are vixens rather than linguistic or mental representations of vixens. And the subject matter of "Centaurs are men with horse's legs" are centaurs rather than linguistic or mental representations of centaurs. That vixens exist and centaurs don't doesn't make any difference.

Londoner wrote:I think your example may be misleading because it contains the word 'are'; this can imply 'exist', which would be an extra claim. We decide claims about existence empirically. But in analytic claims the 'are' applies to the words, so it is short for something like 'has the same meaning as'.

Is "Vixens are female foxes" synonymous with "'Vixen' means 'female fox'"? I don't think so. Is the former logically equivalent to the latter? The latter implies the former, but does the former imply the latter? I'm not sure.

General statements of the form "Xs are Ys" (or "An X is a Y") are logically interpreted as universally quantified conditional statements: "For all z, if z is X, then z is Y." And such statements lack existential import. "Vixens are female foxes" is synonymous with "For all x, if x is a vixen, then x is a female fox", which statement doesn't imply the existence of vixens.

And, again, the subject matters of "Vixens are female foxes" and "'Vixen' means 'female fox'" are different: a statement about vixens is not a (metalinguistic) statement about "vixen".

"[A]nalytic truths are not supposed to be always about words or concepts, even if words or concepts are supposed to play a special role in explaining their truth. The sentence 'Vixens are female foxes' is in no useful sense about the word 'vixen' or any other words; it is about vixens, if anything. Its meaning is not to be confused with that of the metalinguistic sentence ''Vixens are female foxes' is true'. Similarly, the thought vixens are female foxes is not about the concept <vixen> or any other concepts; it too is about vixens, if anything. It is not to be confused with the metaconceptual thought the thought VIXENS ARE FEMALE FOXES is true.
How can a sentence which comes as close as 'Vixens are female foxes' does to being a definition of 'vixen' be about vixens rather than about the word 'vixen'? Uttering it in response to the question 'What does ‘vixen’ mean?' normally enables the questioner to work out the answer to the question, by pragmatic reasoning, even though the literal meaning of the sentence does not directly answer the question, just as does uttering 'That is a gnu' while pointing at one in answer to the question 'What does ‘gnu’ mean?'. If core philosophical truths are analytic, they may exhibit significant features of words or concepts without describing them."

(Williamson, Timothy. The Philosophy of Philosophy. Oxford: Blackwell, 2007. pp. 48-9)

"Analytic statements are a species of necessary truth. A traditional view, which has many supporters, is that such truths are true solely in virtue of the meanings of the terms in which they are expressed. At the same time, it is, surely rightly, denied that analytic truths are truths about words. <A father is a male parent> is true solely in virtue of the meaning of these terms, in particular ‘father’ and ‘male parent’. But the truth is a truth about fathers, not about ‘father’. There is always a certain uneasiness about this solution, a half-feeling that if the statement is true in virtue of words, then it ought to be about words. I suggest that truthmaker theory is in a position to dispel this uneasiness. The phrase ‘in virtue of ’ inevitably suggests truthmakers, at least to those attracted to truthmaker theory. So try this. The statement is about fathers. But this particular truth about fathers has as its truthmakers nothing but the meanings of the words in which it is expressed. In particular ‘father’ and ‘male parent’ have the very same meaning. Provided that we do not accept Quinean scepticism about the notion of meaning and sameness of meaning, and for myself I do reject such scepticism, then uneasiness ought to be considerably allayed. Reference is one thing, truthmaking another. The words in which an analytic truth is expressed do not, save per accidens, refer to meanings. But the meanings may still be truthmakers for the truth. A useful thought here is that given all the meanings, all the analytic truths are fixed. There is supervenience of analytic truth (and indeed analytic falsity) upon meanings. (We can, and should, bracket here the difficult question what meanings are, though I would hope for a naturalistic account of meanings.)"

(Armstrong, D. M. Truth and Truthmakers. Cambridge: Cambridge University Press, 2004. p. 109)

So one could say that analytic truths supervene on meaning (and/or form) and synthetic truths supervene on being.

Londoner wrote:But again, we have the problem of using normal language to describe a problem that is partly about logic. You say 'analytic truths'. So are we discussing; 'Is X an analytic proposition'? Or; 'Is X true?' They are different questions. 'Beauty is Truth' is an analytic proposition as good in logic as the one about foxes, but it doesn't follow that its truth is indisputable.

You're right insofar as if there are analytically true propositions, there are also analytically false propositions. An analytically false proposition/analytic falsehood is a proposition which is or implies the negation of an analytically true proposition/analytic truth.

Londoner wrote:* p.s. I don't think I understand your phrase 'transconceptual reference'.

I mean "object-linguistic reference" rather than "meta-linguistic reference".

Fafner

I'm not asking the general question of the relation between logic and language, I'm just saying that it's very plausible to assume that many "if, then" sentences in natural language are accurately described as "P->Q", and thus have the same truth table. It's not a controversial claim.

By the way, Wittgenstein was the one who introduced truth tables... (and for "P->Q")

I think we have to think about language when we think about logic; ordinary language isn't necessarily logical. Truth tables are fine when dealing with Ps and Qs, but supposing those letters represent a proposition that is more complex, or maybe self-contradicting?

After all, if it was just a matter of putting together words into propositions and processing them using a truth-table, what are all those philosophy books about?

I don't know, (about the relationship of 'possible objects to 'real' objects etc.) but these are different questions, and it's not a reason to dispute the claim there are facts about non actual objects, whatever you think about their explanetion (as I said, if you discover a new phenomenon in science which you can't explain, you don't say that it doesn't exist because you can't explain it, why it should be different in philosophy?).

But in this case, 'possible object' isn't a new phenomenon in the scientific sense - it isn't like an unexplained observation.

Suppose I suggest God as a 'possible object'. What would constitute a fact about God? If I said 'God has a beard' and you said 'No he doesn't', is one of us right, or both, or neither? I think the uncertainty makes it hard to see how a proposition about God can be fitted into a truth table.

Londoner wrote:I think we have to think about language when we think about logic; ordinary language isn't necessarily logical. Truth tables are fine when dealing with Ps and Qs, but supposing those letters represent a proposition that is more complex, or maybe self-contradicting?

Yes I do recognize that natural language differs in certain respects from formal logic, but I don't agree that logic is independent from language, in fact logic is derived from the natural language, the whole point of doing logic is to formalize our ordinary ways of thinking, so logic really derives it's meaning from the natural language. To take a trivial example, negation in logic obviously comes from negation in natural language and it's truth table is derived from the way we judge negated proposition (in what circumstances are they true or false etc.). Again, that's the point of logic: to formally represent sentences and thoughts in natural language, that's why philosophers use logical notation all the time in their work. Just take Russell's "on denoting" that I mentioned earlier (that you seem to be familiar with), and how he used Frege's newly invented predicate calculus to solve philosophical problems by analyzing the logical structure of ordinary language statements. It's just as far-fetched to say that logic has nothing to do with actual language, as to say that mathematics or geometry have nothing to do with reality and thus denying the obvious success of science (or philosophy, especially of language).

But in this case, 'possible object' isn't a new phenomenon in the scientific sense - it isn't like an unexplained observation.

The point is that everybody knows that there are truths about possible objects. Again it would be crazy to deny that there are going to exist new people in the future which don't exist today (and we can know a lot of things about them, such as that they are going to have hearts, taller then 2 cm etc.), so it's not a contentious philosophical theory but a self evident fact about reality.

Suppose I suggest God as a 'possible object'. What would constitute a fact about God? If I said 'God has a beard' and you said 'No he doesn't', is one of us right, or both, or neither? I think the uncertainty makes it hard to see how a proposition about God can be fitted into a truth table.

It's an open question whether God is a possible object (or actual for that matter), but how is that relevant?

Actually, we can even talk about impossible objects such as "there are no people who are taller then themselves", "there are no square circles" etc.

Consul

It depends on whether you think that reference is existence-entailing, such that if x refers to y, both x and y exist. Anyway, my point is that the subject matter of "Vixens are female foxes" are vixens rather than linguistic or mental representations of vixens. And the subject matter of "Centaurs are men with horse's legs" are centaurs rather than linguistic or mental representations of centaurs. That vixens exist and centaurs don't doesn't make any difference.

I think some references are existence entailing, some aren't. Which is which is important if we are discussing the synthetic.

I think our understanding of 'centaurs' includes the notion that they are creatures of imagination; if we say something like 'centaurs have hooves' and meant 'centaurs have hooves (and centaurs and their hooves exist)', exactly like 'foxes have fur', then we need to make this unusual meaning clear. Because it would be right for somebody to respond 'centaurs that exist and have hooves are not centaurs, because centaurs are fabulous'

General statements of the form "Xs are Ys" (or "An X is a Y") are logically interpreted as universally quantified conditional statements: "For all z, if z is X, then z is Y." And such statements lack existential import. "Vixens are female foxes" is synonymous with "For all x, if x is a vixen, then x is a female fox", which statement doesn't imply the existence of vixens.

I agree with this.

And, again, the subject matters of "Vixens are female foxes" and "'Vixen' means 'female fox'" are different: a statement about vixens is not a (metalinguistic) statement about "vixen".

I also agree, except that as I mentioned earlier, in normal speech "Vixens are female foxes" is ambiguous; it can be understood as the second. (You needed to rephrase it and use quotes to make it clear what you meant.)

If I say vixens is a 'concept' it is to allow that words are not nailed to sensory objects. As I say above, both 'vixen' and 'centaur' are nouns, both have particular ideas associated with them, yet they are different sorts of things.

I looked at your quotes. The first one seemed to beg the particular question we are discussing, by talking about 'analytical truths'. If we say we are discussing truths, then we will read all our examples as being the sort of things that can be either true or false, but in this discussion we were questioning whether certain sorts of propositions were propositions at all, i.e. whether they had any meaning that could be true or false. As I suggested in another post, if we substituted the examples used in the quote for ones involving 'God', I don't think the argument would look so convincing.

Anyway, as I said earlier, it isn't that I disagree with you, it is that I don't think it affects my argument that a statement about a 'possible being' can qualify as a 'synthetic a priori', which was where I came in.

-- Updated May 13th, 2014, 5:14 pm to add the following --

Yes I do recognize that natural language differs in certain respects from formal logic, but I don't agree that logic is independent from language, in fact logic is derived from the natural language, the whole point of doing logic is to formalize our ordinary ways of thinking, so logic really derives it's meaning from the natural language.

I disagree. I think it is like maths. You point out later in your quote:

Just take Russell's "on denoting" that I mentioned earlier (that you seem to be familiar with), and how he used Frege's newly invented predicate calculus to solve philosophical problems by analyzing the logical structure of ordinary language statements.

But he concludes from this that a lot of what constutes normal language is meaningless or ambiguous (and hence a lot of philosophical problems are unreal). In order to use logic on language you need to create a 'logical language' (see Wittgenstein).

The point is that everybody knows that there are truths about possible objects. Again it would be crazy to deny that there are going to exist new people in the future which don't exist today (and we can know a lot of things about them, such as that they are going to have hearts, taller then 2 cm etc.), so it's not a contentious philosophical theory but a self evident fact about reality.

'Possible object' seems to have shifted in meaning.

Yes, we can say things about 'people in the future' because you have specified that they will be 'people' and we know what goes with being a person. If you added to this description and said 'blue eyed people in the future' we would also know they would have blue eyes. But the 'truths' we are discovering are limited to the ones you provide. If I go outside those boundaries and ask questions like 'Do we know for a fact these people in the future will exist?' the answer is 'No'. (Maybe the world will have ended etc.)

And suppose my possible object is 'Martians'. What truths can we discover about them? OK, they don't exist, but neither do 'people of the future', so surely what we can do with 'possible people' we should be able to do with 'possible Martians'.

It's an open question whether God is a possible object (or actual for that matter), but how is that relevant?

It means he cannot be turned into a term that can be processed in a truth table. Such terms have to be capable of being either true or false; since we don't know what God might be, we can't know what the difference between a true or a false statement about him would be - if anything!

In the sorts of discussion we have on these boards, this is our problem. We don't agree on what terms (e.g. 'a priori') mean. Logic and truth tables can't come in until we have fixed a meaning, but fixing a meaning is the difficult bit. It is like maths; great at working out any given sum, but the problem is formulating the sum that matches the real world problem.

Actually, we can even talk about impossible objects such as "there are no people who are taller then themselves", "there are no square circles" etc.

Talk: yes. Make sense; no! 'No people' is not an object. 'No square circles' is not an object either. Again, the introduction of the word 'are' might suggest existence of a 'thing', but it applies to the negative term that immediately follows. Just as to say something 'is not' isn't an oxymoron, that 'is' does not contradict the 'not'.

Another misleading feature in ordinary speach might come from treating 'no', meaning zero, as another number. 'We have no bananas' is understandable, but makes no logical sense. The same would be true of 'there are no people'.

Londoner wrote:But he concludes from this that a lot of what constutes normal language is meaningless or ambiguous (and hence a lot of philosophical problems are unreal). In order to use logic on language you need to create a 'logical language' (see Wittgenstein).

This is not an accurate description of Russell, and Wittgenstein was clearly opposed to this kind of view, especially in his later work. Once again, you are simply making assertions without any arguments. There are countless examples one can give in which logic fits natural language (like the example of negation I gave), and the fact that philosophers use logical formalisms all the time to clarify their reasoning and argumentation is just overwhelming evidence that logic is very intimately connected with language.

'Do we know for a fact these people in the future will exist?' the answer is 'No'. (Maybe the world will have ended etc.)

The question of knowledge is irrelevant, what I say is that there could be facts in reality about non actual states of affairs whether we know them or not. And besides, my first example about the 5 and 6 meter tall men are facts which are known for certain.

It means he cannot be turned into a term that can be processed in a truth table.

Truth tables don't "process terms", they represent the truth functions of logical connectors, and they have nothing to do with God or any other concrete beings.

Such terms have to be capable of being either true or false; since we don't know what God might be, we can't know what the difference between a true or a false statement about him would be - if anything!

What it has to do with my argument?

In the sorts of discussion we have on these boards, this is our problem. We don't agree on what terms (e.g. 'a priori') mean. Logic and truth tables can't come in until we have fixed a meaning, but fixing a meaning is the difficult bit. It is like maths; great at working out any given sum, but the problem is formulating the sum that matches the real world problem.

But meaning of what? What meanings you have to "fix" to understand logic or truth tables?

Talk: yes. Make sense; no! 'No people' is not an object. 'No square circles' is not an object either. Again, the introduction of the word 'are' might suggest existence of a 'thing', but it applies to the negative term that immediately follows. Just as to say something 'is not' isn't an oxymoron, that 'is' does not contradict the 'not'.

You simply assume your view in advance and interpret all the examples that I give in a bizarre and nonsensical fashion without any argument. I don't see any point continuing the discussion like this, we are getting nowhere.

Londoner wrote:I think some references are existence entailing, some aren't. Which is which is important if we are discussing the synthetic.

The truth of most predications depends on the existence of the subject.

Londoner wrote:I think our understanding of 'centaurs' includes the notion that they are creatures of imagination; if we say something like 'centaurs have hooves' and meant 'centaurs have hooves (and centaurs and their hooves exist)', exactly like 'foxes have fur', then we need to make this unusual meaning clear. Because it would be right for somebody to respond 'centaurs that exist and have hooves are not centaurs, because centaurs are fabulous'.

"Centaurs have hooves" is true by definition or conception of the fictional creatures called centaurs. So it's an analytic truth. Now you might object that fictional and thus nonexistent objects don't (really) have any properties such as having hooves. That's true, but one could reply that if that statement is interpreted either conditionally as "If something is a centaur, then it has hooves" or counterfactually as "If centaurs existed, they would have hooves", then this doesn't imply that centaurs are (really) property-bearers.

Is "Foxes have fur" an analytic truth? Analytic truths are necessary truths which don't allow any exceptions. So if it is an analytic truth, there is no possible world where furless foxes exist. But having fur doesn't seem to be an essential property of foxes. (Compare: there are hairless cats.) If it isn't, then "Foxes have fur" is not an analytic truth.

Londoner wrote:I looked at your quotes. The first one seemed to beg the particular question we are discussing, by talking about 'analytical truths'. If we say we are discussing truths, then we will read all our examples as being the sort of things that can be either true or false, but in this discussion we were questioning whether certain sorts of propositions were propositions at all, i.e. whether they had any meaning that could be true or false. As I suggested in another post, if we substituted the examples used in the quote for ones involving 'God', I don't think the argument would look so convincing.

Frege held that sentences containing proper names or definite descriptions which refer to nothing or to something nonexistent (e.g. "Pegasus is a winged horse", "The present king of France is bald") are neither true nor false, whereas Russell held that they are false. In this debate I side with Russell and endorse negative free logic. However, to be precise, there are some exceptions, because sentences such as "Zeus doesn't exist" and "The ancient Greeks worshipped Zeus" are true despite Zeus's nonexistence.

Londoner wrote:Anyway, as I said earlier, it isn't that I disagree with you, it is that I don't think it affects my argument that a statement about a 'possible being' can qualify as a 'synthetic a priori', which was where I came in.

Do you have an example?

Fafner

This is not an accurate description of Russell, and Wittgenstein was clearly opposed to this kind of view, especially in his later work.

I do not think that is right.

The question of knowledge is irrelevant, what I say is that there could be facts in reality about non actual states of affairs whether we know them or not.

I cannot make any sense of that!

But meaning of what? What meanings you have to "fix" to understand logic or truth tables?

I don't think you are reading my posts very carefully any more. I'm saying you have to fix the meanings of the terms you want to turn into symbols that can be used in logic. We had Russell's example of 'the present king of France is bald' earlier. Before we can convert that into a logical symbol that is either true or false, we have to work out what it means.

You simply assume your view in advance and interpret all the examples that I give in a bizarre and nonsensical fashion without any argument. I don't see any point continuing the discussion like this, we are getting nowhere.

So I should have found a way to interpret your example of a 'square circle' in way that made it seem a rational idea? Beyond my powers, I'm afraid.

But I agree we are just recycling the same old stuff. Perhaps we can find another topic, another time.

Londoner wrote:I do not think that is right.

Then you should give some evidence from Russell's and Wittgenstein's writings (and anyway, I can use examples from Russell without subscribing to his views, so it just doesn't matter whether he would agree with me or not).

I cannot make any sense of that!

The idea is that a sentence like "the first person who is going to be born in the year 2017 will be a female" is either true or false, and if it's a true then it's a fact about the world, whether we can know it or not. Epistemological questions are beside the point.

I don't think you are reading my posts very carefully any more. I'm saying you have to fix the meanings of the terms you want to turn into symbols that can be used in logic. We had Russell's example of 'the present king of France is bald' earlier. Before we can convert that into a logical symbol that is either true or false, we have to work out what it means.

I don't think it's correct. It's possible to write the truth table of a sentence like "if something is a Glog then it's also a Quog" without knowing what the terms mean (and in fact they mean nothing).

So I should have found a way to interpret your example of a 'square circle' in way that made it seem a rational idea? Beyond my powers, I'm afraid.

Where did I say that it's a "rational idea"??? It was just an example to illustrate that there are true sentences which describe logically impossible objects, like the example "there's no square circles". Do you really dispute that it's a true statement?

If Syamsu's posts be tidied up a little I propose that they'd be examples of the logically valid but that they'd be devoid of meaning or advance in knowledge because the premises mean nothing.