Nicholas asked:

If you had a machine that could only answer truthfully to any question asked, what question would
you give it in order for the machine to answer incorrectly?

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Come on, you're not serious, are you? The easy and obvious answer is: "Is the statement: 'This
statement is false' true or false?" You just set up a paradox. Think about it. Of course, you have to
make sure you do it in the highest meta-language the machine can handle, otherwise it will just say,
"That is a paradox in the object-language" in the next-highest meta-language it has available. The
question is, what about a language like a naturallanguage such as English in which there is no
highest meta-language? Then what? In that case, I do not see how to ask such a question as a
formalquestion... but my feeling is, that given a machine that could speak such a language fluently
(which does not exist), you could trip it up the same way you can now trip up a person, because it
would have to handle language the way a human handles it. But that's another, long, discussion.

But my question to you is, what's the point? Why do you ask this question? Just to trip us up, or
because you really are interested in paradoxes? If the latter is true, take a look at the references we
gave to Paul's question, below.

Steven Ravett Brown