80-150 The Nature of Reason
Summer Two 2001, Dirk Schlimm
Homework No. 1
TTT, p. 3-16.
Puzzle. Solve the following puzzle
and explain your solution in a few sentences (in other words, display
Imagine you are on an island whose inhabitants are called "knights" and
"knaves". Knights and knaves are impossible to distinguish by appearance.
In fact, there is only one characteristic that seperates them: Knights
always tell the truth, whereas knaves always lie.
Now suppose you meet three individuals, A, B, and C, each of whom is either
a knight or a knave. Also, suppose two people are of the same type
if they are both knights or both knaves.
A says, "B is a knave".
B says, "A and C are of the same type."
Question: What can you say about C's identity?