A very special island is inhabited only by knights and knaves. Knights always tell the truth, and knaves always lie. You meet 6 inhabitants: Mason, Samuel, Emily, Charlotte, Victoria, and Harper. Mason asserted: "If Samuel is a knight then Emily is a knave". Samuel said, "Harper is not a knight." "Samuel is a knave if and only if Mason is a knave" - Emily. Charlotte said that Emily is not a knight. Victoria commented, "Charlotte is a knight or Samuel is a knight". "Victoria is a knight if and only if Harper is a knight," Harper declared. So who is a knight and who is a knave?
Mason is a knight, Samuel is a knave, Emily is a knave, Charlotte is a knight, Victoria is a knight, and Harper is a knight.
(1) Mason is a knight
(2) Samuel is a knave
(3) Emily is a knave
(4) Charlotte is a knight
(5) Victoria is a knight
(6) Harper is a knight
Assume Mason is a knight. No contradiction is found in their claim that If Samuel is a knight then Emily is a knave. Assume Samuel is a knight. No contradiction is found in their claim that Harper is not a knight. Harper cannot be a knight, because this would contradict the claim of Samuel that Harper is not a knight. Assume Harper is a knave. No contradiction is found in their false claim that Victoria is a knight if and only if Harper is a knight. Assume Victoria is a knight. No contradiction is found in their claim that Charlotte is a knight or Samuel is a knight. Assume Charlotte is a knight. No contradiction is found in their claim that Emily is not a knight. Emily cannot be a knight, because this would contradict the claim of Mason that If Samuel is a knight then Emily is a knave. Emily cannot be a knave, because this would contradict the false claim of their own that Samuel is a knave if and only if Mason is a knave. We have exhausted all possibilities for Emily, so let us go back and reconsider Charlotte. Assume Charlotte is a knave. No contradiction is found in their false claim that Emily is not a knight. Emily cannot be a knight, because this would contradict the claim of Mason that If Samuel is a knight then Emily is a knave. Emily cannot be a knave, because this would contradict the false claim of their own that Samuel is a knave if and only if Mason is a knave. We have exhausted all possibilities for Emily and Charlotte, so let us go back and reconsider Victoria. Victoria cannot be a knave, because this would contradict the false claim of their own that Charlotte is a knight or Samuel is a knight. We have exhausted all possibilities for Victoria and Harper, so let us go back and reconsider Samuel. Assume Samuel is a knave. No contradiction is found in their false claim that Harper is not a knight. Assume Harper is a knight. No contradiction is found in their claim that Victoria is a knight if and only if Harper is a knight. Assume Victoria is a knight. No contradiction is found in their claim that Charlotte is a knight or Samuel is a knight. Assume Charlotte is a knight. No contradiction is found in their claim that Emily is not a knight. Emily cannot be a knight, because this would contradict the claim of their own that Samuel is a knave if and only if Mason is a knave. Assume Emily is a knave. No contradiction is found in their false claim that Samuel is a knave if and only if Mason is a knave.