Self-reference, knowledge, belief, and modality
Donald R. Perlis · 1986
An apparently negative result of Montague has diverted research in formal modalities away from syntactic (“first-order”) approaches, encouraging rather weak and semantically complex modal formalisms, especially in representing epistemic notions. We show that, Montague notwithstanding, consistent and straightforward first-order syntactic treatments of modality are possible, espe-cially for belief and knowledge; that the usual modal treat-ments are on no firmer ground than first-order ones when endowed with self-reference; and that in the latter case there still are remedies. I.