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[quote="The Baffled King"][quote="waitingforgo"]I eventually muddled through this (thanks to the hints here), but I'm not sure this is solvable unless you make some assumptions about what "lying" is. (I've read many books by Raymond Smullyan, so this is a topic that is close to home.)

If I'm understanding correctly, M. is assuming that everything that a liar says is a lie. However, it seems at least as likely that a liar merely needs to lie... in other words, some aspect of their statements are untrue.

For example, let's say you know I'm a liar, and I say, "Bob and I were at the store today."

Regardless of my statement, there are actually four possible outcomes for Bob and I having been at the store:

1) Bob was at the store. I was at the store.
2) Bob was at the store. I was not at the store.
3) Bob was not at the store. I was at the store.
4) Bob was not at the store. I was not at the store.

In only one case -- #1 -- would the statement I made be true. In all other cases, I'm lying; it is not the case that "Bob and I were at the store today" is true.[/quote]

Yes, exactly.
"Lie" just means "untrue" here, or "not true". So a "liar" can say "A and B", when A is true and B is not true.

[quote]Similarly, take Subject #5 (Margarette)'s statement: "Francisqui and I are humans."

Again, regardless of Margarette's statement, there are only four possibilities:

1) Magrarette is a human. Francisqui is a human.
2) Magrarette is a computer. Francisqui is a human.
3) Magrarette is a human. Francisqui is a computer.
4) Magrarette is a computer. Francisqui is a computer.

If we assume that Margarette is a human, then the logic train is clear (#1 is the only possible answer). However, if we assume Margarette is a computer, then it gets muddier; both #2, 3, and 4 would all render Margarette's statement untrue, but I believe for the puzzle to work you need to assume that #4 is reality if you conclude that Margarette is lying.[/quote]

No, I don't think so -- Margarette lying just means that (1) is out of the question. (Well, of course, it also means (3) is out, because (3) *says* she's human.)[/quote]

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