PHIL120 Lecture Notes - Lecture 10: If And Only If

• School: University of Alberta
• Department: Philosophy at St Joseph's College
• Course: PHIL120
• Professor: Katalin Bimbo

Document Summary

Today we"re going to go to yet another island, the island of silent knights and knaves. Every inhabitant is a knight or a knave, but not both. Knights always tell the truth and knaves always lie. Inhabitants only respond to yes-no questions, and they do so by flashing a red or black card (but never both) for yes or no . As it stands, abercrombie is unsure of the meaning of the cards. Now we can look at the first question. Abercrombie met an islander and asked him whether the red card meant yes , the islander responded by flashing him a red card. In the following table a will stand for the inhabitant; y for the colour of the card used for yes ; b for black; r for red; and p for the statement the red card means yes" . Once again k will stand for knight and n for knave.