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Thread: A liar says he tells truth. So he is a liar. But he just told he tells truth.Solution

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    Senior Member x3bnm's Avatar
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    A liar says he tells truth. So he is a liar. But he just told he tells truth.Solution

    A liar says I am a truthteller. But he is a liar. He can't be a truthteller. He is a liar. But the liar said he is a truth teller. We have reached a contradiction.


    What is the solution?
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    Re: A liar says he tells truth. So he is a liar. But he just told he tells truth.Solu

    Why is a liar saying he is a truth-teller a paradox? Since he is a liar what he is in NOT true- he is not a truth-teller.

    IF "liar" and "truth-teller" are the only options then it would be a "paradox" for a liar to say "I am NOT a truth-teller" or for a truth-teller to say "I am a liar".
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    Re: A liar says he tells truth. So he is a liar. But he just told he tells truth.Solu

    How have you reached a contradiction. You already pointed out that he lied. His statement was a lie. There is no contradiction. And what sort of "solution" are you seeking?
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    Senior Member x3bnm's Avatar
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    Re: A liar says he tells truth. So he is a liar. But he just told he tells truth.Solu

    Quote Originally Posted by SlipEternal View Post
    How have you reached a contradiction. You already pointed out that he lied. His statement was a lie. There is no contradiction. And what sort of "solution" are you seeking?
    Let me rephrase it how I reached a contradiction. It is called Liar paradox.

    "'I said in my alarm, Every man is a liar!' Is David telling the truth or is he lying? If it is true that every man is a liar, and David's statement, "Every man is a liar" is true, then David also is lying; he, too, is a man. But if he, too, is lying, his statement: "Every man is a liar," consequently is not true. Whatever way you turn the proposition, the conclusion is a contradiction. Since David himself is a man, it follows that he also is lying; but if he is lying because every man is a liar, his lying is of a different sort."
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    Re: A liar says he tells truth. So he is a liar. But he just told he tells truth.Solu

    Quote Originally Posted by x3bnm View Post
    Let me rephrase it how I reached a contradiction. It is called Liar paradox.
    That is very different from what you stated. The Liar's Paradox is another well known example of paradox through self reference.
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    Re: A liar says he tells truth. So he is a liar. But he just told he tells truth.Solu

    Quote Originally Posted by x3bnm View Post
    > > > A liar says I am a truthteller. < < < But he is a liar. He can't be a truthteller. He is a liar. But the liar said he is a truth teller. We have reached a contradiction.


    What is the solution?
    x3bnm, your English did not communicate what you intended. What I emphasized above means that a liar said that you, x3bnm, are a truthteller. That is not what you meant.
    You needed to have put what the liar said in quotes. (I did not realize this until I read your post to the end.)

    Here is what you should have posted:

    A liar says, "I am a truthteller."
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    Senior Member x3bnm's Avatar
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    Re: A liar says he tells truth. So he is a liar. But he just told he tells truth.Solu

    Quote Originally Posted by greg1313 View Post
    x3bnm, your English did not communicate what you intended. What I emphasized above means that a liar said that you, x3bnm, are a truthteller. That is not what you meant.
    You needed to have put what the liar said in quotes. (I did not realize this until I read your post to the end.)

    Here is what you should have posted:

    A liar says, "I am a truthteller."
    Sorry for the miscommunication from my part.
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    Re: A liar says he tells truth. So he is a liar. But he just told he tells truth.Solu

    A and B always lie. They are chatting between themselves.
    A says, 'You are a truth-teller.'
    B replies, 'I'm not a liar.'

    Is there a word for such situations?
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