Which Sentences Are Lying About Exclamation Marks?

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The discussion centers around a paradox involving three sentences, each making claims about the truthfulness of the others. Sentence A asserts that all sentences ending with an exclamation mark are lying, which leads to a contradiction if assumed true. This contradiction implies that A must be false, making B true, as it correctly identifies A as a lie. Consequently, C, which claims B is lying, must also be false. The resolution highlights the importance of classical logic principles, such as the law of non-contradiction, in determining the truth values of the sentences. The conversation also touches on the confusion surrounding the implications of punctuation in assessing truthfulness. Ultimately, the consensus is that B is true, while A and C are false.
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data:

A.each sentence which ends with exclamation mark is lying!
B.sentence A is lying!
C.sentence B is lying.

which claim is wright regarding these sentences?
1.A and C are truthful and B is lying
2.C is truthful while A and B are lying
3. B is truthful while A and C are lying
4.C is lying while A and B are truthfulthat exclamation mark thing makes me confused
sentence A contradicts itself
 
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some_one said:
data:

A.each sentence which ends with exclamation mark is lying!
B.sentence A is lying!
C.sentence B is lying.

which claim is wright regarding these sentences?
1.A and C are truthful and B is lying
2.C is truthful while A and B are lying
3. B is truthful while A and C are lying
4.C is lying while A and B are truthful


that exclamation mark thing makes me confused
sentence A contradicts itself

A and B can both be truthful if it is really sentences that end in period that are lying.
 
3. B is truthful while A and C are lying

A contradicts itself if assumed to be true. The only way to avoid the contradiction is to assume it is false. Therefore, B is true, and C is false.
 
a period meens nothing

how did come to this answer
how did you solve this exclamation mark thing??
 
A proposition is either true or false, bot nut both (law of excluded middle + law of non-contradiction). The question clearly suggests that there is a way to assign truth values to the propositions without creating any inconsistency. Proposition A is either true or false. If we assume it is true, we obtain the following:

a. Sentence A is true.
b. Sentence A is a sentence which ends with an exclamation mark.

c. Therefore sentence A is false.

This is inconsistent; we have obtained both the statements "sentence A is true" and "sentence A is false" from the assumption that A is true. Therefore sentence A is not true. Therefore, it must be false. That said, we are forced to accept that B is true, and then that C is false.

To be noted: some propositions are not classifiable as either true or false, this being perhaps the biggest failure of classic Aristotelian logic. For example, the sentence "This sentence is false." leads to a contradiction whether we assume it is true or false. However, like I said, the question suggests that there is a way to assign truth values without contradictions, and so you may assume the laws of classical logic can be applied.
 
some_one said:
that exclamation mark thing makes me confused
sentence A contradicts itself

There are 3 possibilities:

1. All sentences that end in an exclamation mark are lying.
2. All sentences that end in an exclamation mark are truthful.
3. Some sentences that end in a "!" are lying, and some are truthful.

The trick here is that many people do not think of or consider possibility #3.
 
some_one said:
a period meens nothing

how did come to this answer
how did you solve this exclamation mark thing??

You're right, I meant to say that A was internally consistent with a lie if such was the case, because in saying that exclamation marks are lies - that is a lie. It doesn't mean all exclamation mark sentences are lies however.

B in calling A a lie is merely making a correct observation.

And C of course is a lie because B is True.
 
thanks i understand this question now
 

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