On Logics of Knowledge and Belief

Much later, this kind of theory was taken up and applied by theoretical computer scientists and game theorists.1 The formal semantic project gained new interest when it was seen that it could be applied to contexts with multiple knowers, and used to clarify the relation between epistemic and other modal concepts.Edmund Gettiers classic refutation of the Justied True Belief analysis of knowledge (Gettier, 1963) was published at about the same time as Hintikkas book, and it immediately spawned an epistemological industry a project of attempting to revise the refuted analysis by adding further conditions to meet the counterexamples. Because knowledge implies truth, it would be false, in such a case, that the agent knew that /, but the agent could not know that she did not know that / without having inconsistent beliefs. [...]to capture the fact that our intended concept of belief is a strong one subjective certainty we assume that believing implies believing that one knows. Since all possible worlds outside of any D-set will be invisible to worlds within it, one could drop them from the model (taking the set of all possible worlds to be those R-related to the actual world) without aecting the truth values (at the actual world) of any sentence.