h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Umm... it seems to me it should be quite simple really... the Welshman is lying: not ALL Welshmen are in fact liars. Just him, and probably some others.

It seems a pretty basic use of logic that just because NOT ALL frogs are green, that doesn't mean that NONE of the frogs are. Two separate ideas.

My apologies if it's been pointed out in this forum already. I haven't time right now to go through the messages—just enough time to type my response so someone can get upset with me.

AH... If he is the liar then the paradox still holds doesn't it. It's the same as saying "This statement is untrue"

Think about it carefully (no offence taken BTW, that's what forums are for)


The other comment you make is not related, that is the fault of inductive reasoning "All the frogs I've ever seen are green so the next one will be too" is not true as we well know
don't forget that the whole of scientific research has been based on induction "It's always done that in the past therefore it will next time" not a sound reason but a good guess

Oh, I did think about it carefully! That's what's got me so confused.

The statement is "all Welshmen are liars." Now, if all Welshmen are liars, then he is a liar. Therefore the statement is untrue—all Welshmen are not liars. So it follows that if not all Welshmen are liars, but he is a liar, then some Welshmen are, obviously, liars.

And then you sort of wonder what makes you so sure that he's a liar, when it's him being a liar and lying that made him a liar in the first place, which is a bit circular, but you see he's obviously a liar because there's no other way anything could work out. You can come to that conclusion working backwards from the parts you found before, sort of like calculus, which is, of course, evil, and must be stopped.

This is not the point.

The point is that it can all come together rather smoothly if you assume that he's a liar in that not all Welshmen are liars, but he is.

Er, but I suppose you're sort of right about the induction thing.

I think the main problem is that you are trying to read too much around the problem. As you pointed out yourself, it is circular, it's not meant to be an in depth argument about his past, whether some are some aren't etc
Take it as perfectly boolean, yes or no, true or false, otherwise the logic starts to gt very hazy.

All this bollocks is the kind of rubbish my ex-girlfriend (a philosophy student) used to spout.
I agree, boolean logic can get you very far in life (and search engines).

I agree with KM. This "paradox", and the closely related one - where Epimenides said "Epimenides is a liar" are both weak and insubstantial compared to the hard, pure "this statement is false". Just because someone is a liar doesn't even mean (s)he lies all the time - I'm a tea-drinker but I'm not having a cup right now.

If you want a really thought-provoking discussion on the mathematical equivalent of this paradox, Goedel's theorem, read "Goedel, Escher, Bach, an Eternal Golden Braid" by Douglas R. Hofstadter.

As for induction, if I see a black crow, does that help prove all frogs are green?

Or maybe Epimenides was the Cretan. Or maybe a cretin

Reddit (said the frog of no definite color)

Why is everyone reading too much into this? Straight statements, true and false, I'm not talking about human nature now you know.

He was, I didn't know whether anyone would reply if I called it the Cretan Paradox.

Er... all right, I'll stop reading into it. But that shall require that I stop reading it, as it really was obvious to me that "not all" does not equal "all not." You see. You see?

Anywat, that's all right. I've no trouble with not reading it anymore. I just shan't go to that article anymore. If only more problems could be solved that way!

If I can't see "it", "it" can't see me. That's how I solve my problems.

A perfectly healthy attitude towards problems

Oiv jusd dribbled doan moi bibb

That is not helpful, but at least you didn't dribble in your key board

Dang! Dat's de wurd oi wuz loogin four.

This method of problem solving is chiefly applied in politics often known as "ignore it and hope it goes away" logic.

(more effectively by some politicians than others). And it helps not to leave your semen anywhere near the problem as you can be traced back to it. . .

Or it to you.

Indeed.
Although it's safest to just not go squirting it in inappropraiate places to begin with.

But there are so very few appropriate places. Let the politicians have their fun, eh.