A very special island is inhabited only by knights and knaves. Knights always tell the truth, and knaves always lie. You meet 6 inhabitants: Joseph, Liam, Zoey, Isabella, Mason, and Henry. Joseph asserted: "Isabella is a knight and Henry is a knave". In a statement by Liam: "Zoey is a knight". As Zoey put it, "Isabella is not a knave". "If Henry is a knight then Mason is a knight," Isabella mentioned. Mason commented, "Joseph is a knight". Henry said, "If Mason is a knave then Liam is a knave." So who is a knight and who is a knave?
Joseph is a knave, Liam is a knave, Zoey is a knave, Isabella is a knave, Mason is a knave, and Henry is a knight.
(1) Joseph is a knave
(2) Liam is a knave
(3) Zoey is a knave
(4) Isabella is a knave
(5) Mason is a knave
(6) Henry is a knight
Assume Joseph is a knight. No contradiction is found in their claim that Isabella is a knight and Henry is a knave. Assume Isabella is a knight. No contradiction is found in their claim that If Henry is a knight then Mason is a knight. Henry cannot be a knight, because this would contradict the claim of Joseph that Isabella is a knight and Henry is a knave. Assume Henry is a knave. No contradiction is found in their false claim that If Mason is a knave then Liam is a knave. Mason cannot be a knight, because this would contradict the false claim of Henry that If Mason is a knave then Liam is a knave. Mason cannot be a knave, because this would contradict the false claim of their own that Joseph is a knight. We have exhausted all possibilities for Mason and Henry, so let us go back and reconsider Isabella. Isabella cannot be a knave, because this would contradict the claim of Joseph that Isabella is a knight and Henry is a knave. We have exhausted all possibilities for Isabella, so let us go back and reconsider Joseph. Assume Joseph is a knave. No contradiction is found in their false claim that Isabella is a knight and Henry is a knave. Assume Isabella is a knight. No contradiction is found in their claim that If Henry is a knight then Mason is a knight. Assume Henry is a knight. No contradiction is found in their claim that If Mason is a knave then Liam is a knave. Mason cannot be a knight, because this would contradict the claim of their own that Joseph is a knight. Mason cannot be a knave, because this would contradict the claim of Isabella that If Henry is a knight then Mason is a knight. We have exhausted all possibilities for Mason, so let us go back and reconsider Henry. Henry cannot be a knave, because this would contradict the false claim of Joseph that Isabella is a knight and Henry is a knave. We have exhausted all possibilities for Henry, so let us go back and reconsider Isabella. Assume Isabella is a knave. No contradiction is found in their false claim that If Henry is a knight then Mason is a knight. Assume Henry is a knight. No contradiction is found in their claim that If Mason is a knave then Liam is a knave. Mason cannot be a knight, because this would contradict the false claim of Isabella that If Henry is a knight then Mason is a knight. Assume Mason is a knave. No contradiction is found in their false claim that Joseph is a knight. Liam cannot be a knight, because this would contradict the claim of Henry that If Mason is a knave then Liam is a knave. Assume Liam is a knave. No contradiction is found in their false claim that Zoey is a knight. Zoey cannot be a knight, because this would contradict the false claim of Liam that Zoey is a knight. Assume Zoey is a knave. No contradiction is found in their false claim that Isabella is not a knave.