This sentence is short.
This sentence is false.
Why is the first truth apt but not the second? — fdrake
Could you continue on to an explanation of what counts as an alternating truth value? Is that what makes it self-negating? If it's true, it is false, etc... — creativesoul
It has truth conditions. — creativesoul
I asked you to explain why the truth table says that. — frank
Why doesn't "This sentence is false" have truth conditions when "This sentence is short." Does? — fdrake
A contradiction can't be true and the liar sentence leads to a contradiction meaning that the liar statement has to be false, but that means it is true which means it is false...ad infinitum or ad nauseum, depending on your constitution. The liar statement is a paradox.
I'd like to run the following argument by you and others about a possible "solution":
A = this statement is false
P = A is true
~P = A is false
R = A is a proposition
S = A has a truth value
1. If R then S
2. If S then (P or ~P)
3. If P then ~P...................................the liar paradox in action when A is taken as true
4. If ~P then P...................................the liar paradox in action when A is taken as false
5. R...............................assume for reductio
6. S...................1, 5 MP
7. P or ~P.......2, 6 MP
8.P.........................assume for CP
9. ~P.....................3, 8 MP
10. P & ~P............8, 9 Conj
11. If P then (P & ~P)..................8 to 10 CP
12. ~P.................................assume for CP
13. P....................................4, 12 MP
14. P & ~P...........................12, 13 conj
15. If ~P then (P & ~P)..........12 to 14 CP
16 (P & ~P) or (P & ~P)........7, 11, 15 CD
17. P & ~P..........................16 Taut ( a contradiction)
18. ~R.................................5 to 17 reductio ad absurdum
~R means A is NOT a proposition.
The logical conclusion it seems is that the Liar statement (A) is NOT a proposition. — TheMadFool
S = A has a truth value — TheMadFool
Unless I'm working from a misunderstanding of the two, truth value results from following the rules of correct inference. Whereas truth conditions are what makes a belief true. True belief are prior to language acquisition, and definitely during. Being true does not require following the rules of correct inference. Having truth value does. Truth value is not equivalent to truth. — creativesoul
Truth value is not equivalent to truth.
That would mean things can be true but have no truth value or vice versa. — TheMadFool
6. (is truth & ~has truth value) or (has truth value & ~is truth)
Can you give me an example for the first disjunct of line 6 - a truth that doesn't have a truth value. — TheMadFool
This sentence is short.
This sentence is false.
Why is the first truth apt but not the second? — fdrake
So contradictions and sentences without any clear reference, are meaningless. Contradictions don't have any clear reference either. A contradiction is saying two opposing things about the same thing. One cannot be both a bachelor and a married man. Which one are they? They can't be both and claiming that they are both leaves no room to know which one they actually are until you observe the man wearing a wedding ring or not. Observations resolve contradictions by supplying the truth, and using our definitions, we find the other simply can't be the case when the other is the case.When held up in isolation of all else, "This sentence is false" is incapable of being false. It is also incapable of being true. It is neither coherent nor sensible. Meaningful... Sure. That's what makes it seem so puzzling. It's tempting to say "if it's false, it's true", or "if it's true, it's false"... that's what makes it puzzling... basing subsequent thought on the presupposition that it is even capable of being true or false.
It's not.
It has no empirically verifiable/falsifiable content. It has no truth conditions. There's nothing that can make it true/false.
"This sentence is false" is something often uttered when the speaker is pointing to a specific sentence that they believe contradicts what's happened and/or is happening. Excising "This sentence is false" from the only sensible context to say it in leaves something very important behind. Crucial. The referent of "this sentence".
Sentences that can be false have truth conditions. The Liar does not. Sentences that have referents and truth conditions are meaningful. Sentences that have neither referent nor truth conditions are utterly meaningless.
When properly accounted for - while it's in total isolation from it's normal use - "This sentence is false" is utterly meaningless. — creativesoul
This sentence is short.
This sentence is false.
Why is the first truth apt but not the second? — fdrake
So contradictions and sentences without any clear reference, are meaningless — Harry Hindu
It seems to me that if you are saying "This sentence is false" isn't either true or false, then the reason it isn't true or false is because it doesn't actually refer to anything. — Harry Hindu
They would only be meaningful if they were seperate statements on their own, not asserting two opposing qualities of the same thing.Contradictions are not meaningless. Rather, contradiction requires a plurality of meaningful statements. — creativesoul
Which is the same as saying it is meaningless.There is nothing that can make it true/false. That's the reason that it is neither. It doesn't have what it takes in order to be either. — creativesoul
Perhaps because the first has some determinant truth-condition (even if arbitrary, e.g. fewer than 10 letters) whereas the second doesn’t. — Michael
I’m partial to Kripke’s take on this. It doesn’t seem to mean anything for the liar sentence to be either true or false. There’s no evaluable fact. — Michael
Jack is a married bachelor" is meaningless because it doesn't refer to anything real. When you assert two opposing qualities about same entity you arent saying anything meaningful about that entity. — Harry Hindu
Married and bachelor are two seperate and opposing qualities.Jack is a married bachelor
Jack is sleep-walking — 3017amen
Let's press on the "determinant" thing there. One way to look at the conditions under which a statement is true or false is to submit it to a T-sentence and see what happens. At face value, you can T-sentence the Liar:
"This sentence is false" is true if and only if this sentence is false.
The T-sentence (in a deflationary manner) sets out the truth conditions for the statement. Whether it provides a full account of what it means for a sentence to be true doesn't seem too relevant to me here, it's about whether arbitrary sentence interpretation requires the universal applicability of the T-sentence. — fdrake
One cannot be awake while being asleep. — Harry Hindu
Then what do you mean by being asleep and being awake? Why use two different terms if they actually mean the same thing? What is the purpose of having two terms to refer to the same event?Just to break it down slowly, that would not be correct. Because, a person is in-fact awake, while being asleep. — 3017amen
Then what do you mean by being asleep and being awake? Why use two different terms if they actually mean the same thing? What is the purpose of having two terms to refer to the same event? — Harry Hindu
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