sorry for the corny title but there's something in this.

http://en.wikipedia.org/wiki/The_har...ic_puzzle_ever

can the BAUT brains tackle this?

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A slight inclination of the cranium is as adequate as a spasmodic movement of one optic towards an equinine quadruped utterly devoid of any visionary capacity.

Random - He can just get away with the answer because you cannot tell whether he is a Liar or telling the truth .

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Jean
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"The important thing is not to stop questioning. Curiosity has its own reason for existing." - Albert Einstein

"The good life is inspired by love and guided by knowledge " - Bertrand Russell

I've loved this solution to these types of problems since I first saw this strip.

Minor language warning. Order of the Stick.

As for a real solution, I've got something in mind, but I can't seem to make it work. I think the first step would be to isolate Random, but that has to be done in a way that also makes it clear which word is yes, and which is no. That's where I'm stuck.

Once you get it down to True and False, with a known yes or no, it will only take one question to work them out.

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I'm not evil.
An evil person would do the things I think up.

I'd guess you could start with something along the lines of asking god A "Would god B and God C give the same answer to the question 'are you a liar'?". Haven't got time to work it out but I'd have thought you might even do it in less than three questions.

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Spike
:)

The word "liar" is imprecise. We can describe as a liar someone who speaks falsely on occasion, not necessarily in every statement. Probably you meant the indirect question to be "do you always speak falsehood?".

Putting aside what the indirect question is for the moment, if one of B and C was the random one, then A couldn't know whether B and C would give the same answer to a given question on any given occasion. I suspect that asking a question to which the answer could be undeterminable is bending the rules of the challenge, as you are only allowed to ask yes/no questions.

But also you seem to be asking a paradoxical question ("do you always speak falsehood?")which someone who always speaks falsehood would find impossible to answer without ruining their reputation. I think that asking such a question, even in an indirect way, must also be against the rules.

The challenge as worded does not tell us whether the gods are aware of the propensities of the others. However I see that the proposed answer to the challenge is based on the assumption that they do know each other's propensities.

Is the answer 42 by any chance

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But you're sure the astronauts are lying; you just don't seem to know what they're lying about: Jayutah


I are Learnding.

Let's see if this works:
The gods are A, B and C. A(T) means A is the one who always tells the truth, A(L) means A always lies, A(R) means A answers randomly true or false.

Start with some true assertion, such as "Water is wet".

Ask this question of B: "If I asked A if water is wet, would A answer 'yes'?"

Here are the options:

1. B(T) and answers 'yes'. Then A must be A(T) therefore C(R)
2. B(T) and answers 'no'. Then A must be A(L) therefore C(R)
3. B(L) and answers 'yes'. This would mean A(L) also so could not happen (**)
4. B(L) and answers 'no'. Then A is either A(T) or A(R)
5. B(R) but this time answers truthfully and answers 'yes'. Then A must be A(T) therefore C(L)
6. B(R) but this time answers truthfully and answers 'no'. Then A must be A(L) therefore C(T)
7. B(R) but this time lies and answers 'yes'. Then A must be A(L) therefore C(T)
8. B(R) but this time lies and answers 'no'. Then A is A(T) therefore C(L)

** Oops, spotted at least one mistake. The assertions about A missed out the complication of A(R). Based on the assumption that A is not A(R), then the rest holds and only statement 4 doesn't identify all cases. Thus the second question just needs to establish whether A is answering randomly and also resolve A's identify for question 4. So not quite there yet...

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Spike
:)

I think the real nature of the challenge is to determine exactly why this can't be done in the number of questions it allows, and determine the minimum number of questions it would take.

I recall discussing a much easier (but still very thorny) version of this problem in a class. Ultimately it came down to figuring out whether a particular god was Liar or Random. In desperation, one of the students suggested "Ask him Are you a god?" On the grounds that a god who answers truthfully even some of the time, would never humiliate himself by answering "No".

I forgot the precise phrasing of that particular version.

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Fiction has to be plausible. Reality is under no such constraint.