A very special island is inhabited only by knights and knaves. Knights always tell the truth, and knaves always lie. You meet 6 inhabitants: Jackson, Amelia, Emma, Evelyn, Ava, and Mason. Jackson asserted: "Jackson is a knight if and only if Mason is a knave". As Amelia put it, "Emma is a knave and Ava is a knave". In Emma's words: "Evelyn is a knight and Emma is a knight". Evelyn said, "Jackson is a knight if and only if Emma is a knave." As Ava put it, "Mason is a knight or Emma is a knave". Mason expressed that If Emma is a knight then Mason is a knight. So who is a knight and who is a knave?
Jackson is a knave, Amelia is a knave, Emma is a knight, Evelyn is a knight, Ava is a knave, and Mason is a knave.
(1) Jackson is a knave
(2) Amelia is a knave
(3) Emma is a knight
(4) Evelyn is a knight
(5) Ava is a knave
(6) Mason is a knave
Assume Jackson is a knight. No contradiction is found in their claim that Jackson is a knight if and only if Mason is a knave. Mason cannot be a knight, because this would contradict the claim of Jackson that Jackson is a knight if and only if Mason is a knave. Assume Mason is a knave. No contradiction is found in their false claim that If Emma is a knight then Mason is a knight. Assume Emma is a knight. No contradiction is found in their claim that Evelyn is a knight and Emma is a knight. Evelyn cannot be a knight, because this would contradict the claim of their own that Jackson is a knight if and only if Emma is a knave. Evelyn cannot be a knave, because this would contradict the claim of Emma that Evelyn is a knight and Emma is a knight. We have exhausted all possibilities for Evelyn, so let us go back and reconsider Emma. Emma cannot be a knave, because this would contradict the false claim of Mason that If Emma is a knight then Mason is a knight. We have exhausted all possibilities for Emma and Mason, so let us go back and reconsider Jackson. Assume Jackson is a knave. No contradiction is found in their false claim that Jackson is a knight if and only if Mason is a knave. Mason cannot be a knight, because this would contradict the false claim of Jackson that Jackson is a knight if and only if Mason is a knave. Assume Mason is a knave. No contradiction is found in their false claim that If Emma is a knight then Mason is a knight. Assume Emma is a knight. No contradiction is found in their claim that Evelyn is a knight and Emma is a knight. Assume Evelyn is a knight. No contradiction is found in their claim that Jackson is a knight if and only if Emma is a knave. Amelia cannot be a knight, because this would contradict the claim of their own that Emma is a knave and Ava is a knave. Assume Amelia is a knave. No contradiction is found in their false claim that Emma is a knave and Ava is a knave. Ava cannot be a knight, because this would contradict the claim of their own that Mason is a knight or Emma is a knave. Assume Ava is a knave. No contradiction is found in their false claim that Mason is a knight or Emma is a knave.