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Johnny Pneumatic
01-21-2006, 07:45 AM
If a person who never tells the truth tells you that they never tell the truth, are they telling the truth?
Widget
01-21-2006, 08:06 AM
no.
Johnny Pneumatic
01-21-2006, 08:19 AM
no.

But if they're not telling the truth, then they somtimes tell the truth. But it's been established that they in fact never tell the truth. Harder than it seems at first, eh, Widget?
Widget
01-21-2006, 08:23 AM
it's a cleverly worded sentence... easy to get confused.
JoeP
01-21-2006, 08:53 AM
If a person who never tells the truth tells you that they never tell the truth, are they telling the truth?
Is this something to do with a girl you like, SJ?
Johnny Pneumatic
01-21-2006, 09:33 AM
Is this something to do with a girl you like, SJ?

Nope, just something I thought up for a reason I forgot. Or maybe there wasn't a reason, so I had nothing to forget.
I'll help you guys and gals out, I think it's impossible to answer: it's a paradox from the best I can tell. I've given myself headaches trying to come up with an answer and haven't been able to.
slimshady2357
01-21-2006, 11:09 AM
It's just basically a re-worded version of the Liar's Paradox (http://mathworld.wolfram.com/LiarsParadox.html).
The Lone Ranger
01-21-2006, 11:58 AM
As worded, it is a paradox. It's a logical impossibility.

A person who never told the truth could not utter the words "I never tell the truth." As soon as he said those words, he'd have uttered a truth, and would no longer be someone who never tells the truth.


Cheers,

Michael
JoeP
01-21-2006, 10:34 PM
All of which demonstrates that the paradox is not in the statement but in the unwritten assumptions: that anyone could make all their statements consistent with each other and with rules like "never tells the truth", all the time; and that anyone could have perfect knowledge of the truth-value of any given statement before uttering it. The former's logically impossible, as the paradox shows, and the latter is at least humanly impossible. Perhaps logically impossible too, if Godel's work applies.
Chatter
01-21-2006, 11:17 PM
All of which demonstrates that the paradox is not in the statement but in the unwritten assumptions:In the liar's paradox, the paradox is in the statement itself. The utterance of the statement "This is a lie" entails a contradiction.

The problem lies with the property of being true. In formal languages, it isn't even expressible.