A very special island is inhabited only by knights and knaves. Knights always tell the truth, and knaves always lie. You meet 6 inhabitants: Evelyn, Aurora, Ella, Charlotte, Abigail, and Isabella. According to Evelyn, "Abigail is a knight and Charlotte is a knight". Aurora noted, "Isabella is not a knight". Ella stated, "Evelyn is a knave and Abigail is a knight". In Charlotte's words: "Ella is not a knave". In a statement by Abigail: "Ella is a knight or Aurora is a knight". Isabella told you that Evelyn is a knave. So who is a knight and who is a knave?
Evelyn is a knave, Aurora is a knave, Ella is a knave, Charlotte is a knave, Abigail is a knave, and Isabella is a knight.
(1) Evelyn is a knave
(2) Aurora is a knave
(3) Ella is a knave
(4) Charlotte is a knave
(5) Abigail is a knave
(6) Isabella is a knight
Assume Evelyn is a knight. No contradiction is found in their claim that Abigail is a knight and Charlotte is a knight. Assume Abigail is a knight. No contradiction is found in their claim that Ella is a knight or Aurora is a knight. Ella cannot be a knight, because this would contradict the claim of their own that Evelyn is a knave and Abigail is a knight. Assume Ella is a knave. No contradiction is found in their false claim that Evelyn is a knave and Abigail is a knight. Assume Aurora is a knight. No contradiction is found in their claim that Isabella is not a knight. Isabella cannot be a knight, because this would contradict the claim of Aurora that Isabella is not a knight. Assume Isabella is a knave. No contradiction is found in their false claim that Evelyn is a knave. Charlotte cannot be a knight, because this would contradict the claim of their own that Ella is not a knave. Charlotte cannot be a knave, because this would contradict the claim of Evelyn that Abigail is a knight and Charlotte is a knight. We have exhausted all possibilities for Charlotte and Isabella, so let us go back and reconsider Aurora. Aurora cannot be a knave, because this would contradict the claim of Abigail that Ella is a knight or Aurora is a knight. We have exhausted all possibilities for Aurora and Ella, so let us go back and reconsider Abigail. Abigail cannot be a knave, because this would contradict the claim of Evelyn that Abigail is a knight and Charlotte is a knight. We have exhausted all possibilities for Abigail, so let us go back and reconsider Evelyn. Assume Evelyn is a knave. No contradiction is found in their false claim that Abigail is a knight and Charlotte is a knight. Assume Abigail is a knight. No contradiction is found in their claim that Ella is a knight or Aurora is a knight. Assume Ella is a knight. No contradiction is found in their claim that Evelyn is a knave and Abigail is a knight. Assume Aurora is a knight. No contradiction is found in their claim that Isabella is not a knight. Isabella cannot be a knight, because this would contradict the claim of Aurora that Isabella is not a knight. Isabella cannot be a knave, because this would contradict the false claim of their own that Evelyn is a knave. We have exhausted all possibilities for Isabella, so let us go back and reconsider Aurora. Assume Aurora is a knave. No contradiction is found in their false claim that Isabella is not a knight. Assume Isabella is a knight. No contradiction is found in their claim that Evelyn is a knave. Charlotte cannot be a knight, because this would contradict the false claim of Evelyn that Abigail is a knight and Charlotte is a knight. Charlotte cannot be a knave, because this would contradict the false claim of their own that Ella is not a knave. We have exhausted all possibilities for Charlotte, so let us go back and reconsider Isabella. Isabella cannot be a knave, because this would contradict the false claim of Aurora that Isabella is not a knight. We have exhausted all possibilities for Isabella and Aurora, so let us go back and reconsider Ella. Ella cannot be a knave, because this would contradict the false claim of their own that Evelyn is a knave and Abigail is a knight. We have exhausted all possibilities for Ella, so let us go back and reconsider Abigail. Assume Abigail is a knave. No contradiction is found in their false claim that Ella is a knight or Aurora is a knight. Ella cannot be a knight, because this would contradict the claim of their own that Evelyn is a knave and Abigail is a knight. Assume Ella is a knave. No contradiction is found in their false claim that Evelyn is a knave and Abigail is a knight. Aurora cannot be a knight, because this would contradict the false claim of Abigail that Ella is a knight or Aurora is a knight. Assume Aurora is a knave. No contradiction is found in their false claim that Isabella is not a knight. Assume Isabella is a knight. No contradiction is found in their claim that Evelyn is a knave. Charlotte cannot be a knight, because this would contradict the claim of their own that Ella is not a knave. Assume Charlotte is a knave. No contradiction is found in their false claim that Ella is not a knave.