A very special island is inhabited only by knights and knaves. Knights always tell the truth, and knaves always lie. You meet 6 inhabitants: Sofia, Zoey, Liam, Abigail, Aria, and Charlotte. According to Sofia, "Liam is a knave or Zoey is a knave". Zoey told you that Abigail is not a knight. In Liam's words: "Sofia is not a knave". Abigail noted, "Liam is a knight". "Liam is a knave if and only if Liam is a knight" - Aria. As Charlotte put it, "Abigail is a knight if and only if Sofia is a knave". So who is a knight and who is a knave?
Sofia is a knight, Zoey is a knave, Liam is a knight, Abigail is a knight, Aria is a knave, and Charlotte is a knave.
(1) Sofia is a knight
(2) Zoey is a knave
(3) Liam is a knight
(4) Abigail is a knight
(5) Aria is a knave
(6) Charlotte is a knave
Assume Sofia is a knight. No contradiction is found in their claim that Liam is a knave or Zoey is a knave. Assume Liam is a knight. No contradiction is found in their claim that Sofia is not a knave. Zoey cannot be a knight, because this would contradict the claim of Sofia that Liam is a knave or Zoey is a knave. Assume Zoey is a knave. No contradiction is found in their false claim that Abigail is not a knight. Assume Abigail is a knight. No contradiction is found in their claim that Liam is a knight. Aria cannot be a knight, because this would contradict the claim of their own that Liam is a knave if and only if Liam is a knight. Assume Aria is a knave. No contradiction is found in their false claim that Liam is a knave if and only if Liam is a knight. Charlotte cannot be a knight, because this would contradict the claim of their own that Abigail is a knight if and only if Sofia is a knave. Assume Charlotte is a knave. No contradiction is found in their false claim that Abigail is a knight if and only if Sofia is a knave.