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Liar Paradox (Eubulid or Epimenides Paradox)


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220 replies to this topic

#181 Concuror

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Posted 15 November 2009 - 11:40 AM

The real paradox is not the one in the story!

It goes: is I say "I always lie" - am i telling the truth or not?

I can't be telling truth because then my phrase is true and I am telling lie.

If I am lying - it can mean two things:
1) I am always speaking the truth - which makes the paradox
2)I sometimes lie - no paradox - so not interesting at all

So let us lend at axiom that people can either tell only lie or only truth and never speak some of one and some of other!

And now who am I when i tell "I always lie" - lier or no lier???
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#182 djsynergyuk

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Posted 16 November 2009 - 12:04 AM

1.A Cretan sails to Greece and says to some Greek men who are standing upon the shore: "All Cretans are liars." Did he speak the truth, or did he lie?

Answer: He couldn't be telling the truth, since he is a Cretan himself. So he lied - all Cretans are not liars, just this one so far!

2.A week later, the Cretan sailed to Greece again and said: "All Cretans are liars and all I say is the truth." Although the Greeks on the shore weren't aware of what he had said the first time, they were truly puzzled.

Answer: We have established that not all Cretans are liars from his last visit. Could the Greeks have met the only Cretan liar?!

If someone says "I always lie", are they telling the truth? Or are they lying?

Answer: They can't be telling the truth. They don't ALWAYS lie, just on this particular occassion!!
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#183 zeno123

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Posted 24 November 2009 - 05:18 AM

What the cretan is basically saying in both scenarios is that he speaks the truth. If he's lying about all cretans lying then he's clearly telling the truth. he says the same thing in the second statement but confirms that he speaks the truth which is what was implied in the first scenario.
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#184 Chato

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Posted 21 December 2009 - 05:25 PM

I say to some the truth is a lie and to some a lie is the truth, therefore, regardless of who says what to whom how and when, the matter lie solely in the definition of the words!!
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#185 phil

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Posted 18 January 2010 - 03:58 AM

I just thought of something random:
There are two people. I ask the first person a question (it doesn't matter what) and he nods his head.
Then, the second person interrupts by saying that whenever the first person nods, he actually means 'no,' and when he shakes his head, he means 'yes.'
I ask the first person: 'Is this true?'
He responds by nodding.
What does that mean?
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#186 GrandChasePlayer3

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Posted 06 February 2010 - 01:10 AM

Spoiler for here's what I think

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#187 Nox

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Posted 14 February 2010 - 09:28 PM

The sucker way:
"all" is such a dangerous word. There are individuals among Cretans who are infants and their bodies aren't even able to gesture, let alone speak. Thus this statement is irrational. Therefore the Cretan who said this statement, is wrong. We can't however say he was lying, he might have not taken in consideration the babies, it's not lying if your unconscious of all the facts.

The orthodox way:
The trick is in the "time". Simply stating X is a liar doesn't translate to X being unable to tell the truth, ever. It merely states that X has a vice of telling lies. Therefore both possibilities can non/simultaneously be in/correct.
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#188 pjhollywood

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Posted 18 February 2010 - 08:56 PM

1. A Cretan sails to Greece and says to some Greek men who are standing upon the shore: "All Cretans are liars." Did he speak the truth, or did he lie?
2. A week later, the Cretan sailed to Greece again and said: "All Cretans are liars and all I say is the truth." Although the Greeks on the shore weren't aware of what he had said the first time, they were truly puzzled.

"All Cretans are liars" - could be true...All Cretans could have the capacity to lie. I agree with other members that the accepted meaning of "being a liar" is that they sometimes tell lies. If this is the way you read it then there is no paradox...The statement could be true and all Cretans could be able to lie...the sailor may just not be lying at that point in time. The statement could also be untrue and only some Cretans have the ability to lie - of which he would be one!

I prefer the more "puzzling" interpretation of "liar"...i.e. All Cretans are incapable of telling the truth. If this were true then the Cretan would be physically unable to announce the fact - it cannot therefore be true. The statement must be a lie - the truth of the matter being that only some Cretans are incapable of telling the truth - this one at least!

You could of course tease yourself further by interpreting this lie as necessarily meaning "All Cretans are incapable of lying" - which would bring you back round into a painful circle...if Cretan's cannot lie then the sailors statement must be true - but how can it be? etc etc etc!
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#189 Emma_H

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Posted 24 March 2010 - 07:40 PM

if he's telling the truth it means he's a lier which doesnt make sense at all.
so he must be lieing therefore not all cretans are liers, just because he's a lier doesnt mean they all are...
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#190 Red Dragon

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Posted 17 May 2010 - 07:31 PM

The paradox is not the riddle. The fact that in the second statement the Cretan words it slightly differently, "All Cretans are liars and all I say is the truth.", doesn't settle anything.

The riddle is in the statement following the paradox: '"I always lie." Is he lying or telling the truth.' The statement "I always lie." is an emphatic statement meant to reveal a truth. But since he says "I always lie" gives the lie to his statement. So, he's lying.
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