Murphy wrote: > One of Smullyan's lesser-known diversions involves sane and insane > islanders, who believe only things that are true resp. false, and > then knights and knaves say only things that they believe are true > resp. false. Then there's the island's native language, where you > know which words mean "yes" and "no" but don't know which is which.
>From the abstract of the aforementioned paper: "A sentential utterance is true or false according as its indicated topic of concern is true or false. Hence, delaratives, interrogatives, and imperatives may all be classified as true or false. But honesty or dishonesty is a function (explained in the paper) of the expressed concern, rather than of the topic of concern. Hence, although utterances of all sentential forms are hones or dishonest, their honesty or dishonesty is logically independent of their truth or falsity".
