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Which Alice?

Which Alice?

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ALICE IN PUZZLE-LAND<br />

satisfy the five basic conditions which characterize Looking-Glass<br />

logicians."<br />

"Why is that?" asked <strong>Alice</strong>.<br />

"Oh, that's very easy to prove!" replied Humpty Dumpty.<br />

"Suppose a person is completely honest and also believes all and<br />

only those statements which are false. Since he is honest, then of<br />

course he satisfies Condition One. As for Condition Two, suppose<br />

he claims a statement to be true. Then he really believes the<br />

statement (because he is honest). Therefore it is false that he doesn't<br />

believe the statement. But he believes everything that is false—even<br />

false things about his own beliefs! So, since it is false that he doesn't<br />

believe the statement, and since he believes everything which is<br />

false, then he must believe the false fact that he doesn't believe the<br />

statement—in other words, he believes that he doesn't believe the<br />

statement. And since he believes that he doesn't believe the statement,<br />

then he claims he doesn't believe it (because, we recall, he is<br />

honest). Therefore he satisfies Condition Two.<br />

"As for Condition Three, take any true statement. Since it is true,<br />

he cannot believe it. Since he doesn't believe it, then he must believe<br />

that he does believe it (because all his beliefs are wrong!). Then, since<br />

he believes that he believes it, then he must claim that he believes it<br />

(again, since he is honest). This proves that he satisfies Condition<br />

Three.<br />

"Conditions Four and Five are obvious," continued Humpty<br />

Dumpty. "Take any statement and its opposite. One of them must<br />

be true and the other must be false. Therefore he believes the false<br />

one and doesn't believe the true one. So he doesn't believe both of<br />

them, hence he satisfies Condition Four, but he believes at least one<br />

of them, so he satisfies Condition Five.<br />

"And that," concluded Humpty Dumpty, "is the entire story: A<br />

Looking-Glass logician is honest but totally deluded. Conversely,<br />

anyone who is both honest and totally deluded satisfies the five<br />

conditions of being a Looking-Glass logician. Now you have the<br />

key."<br />

"One thing still puzzles me," said <strong>Alice</strong>. "Why is it that a Looking-<br />

Glass logician never claims any statement and also claims its<br />

opposite, and yet he will claim that the statement and its opposite<br />

are both true?"<br />

124

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