PHLA10H3 Lecture Notes - Lecture 3: Alf Landon, The Literary Digest, Sample Size Determination
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In the land of the knights and knaves. A says either i am a knave or 2+2=5 . If a was a knight that would be true, but it can"t be because 2+2=5 isn"t true. But if he"s a knave, then what he"s saying is true (that he is a knave). You meet three individuals, a, b, and c. a says all of us are knaves . B says exactly one of us is a knight . A cannot be a knight so he must be a knave. C must be a knave. (that"s the only solution) Logic and argument (continued: deductive arguments conditionals, a basic argument structure: If x then y, x; therefore y. (note we defined validity using a conditional: valid versus invalid conditionals, four forms: X > y, x; therefore y (valid; x gives you y, so if you have x, you have y) X > y, y; therefore x x.
