TY - JOUR T1 - Languages with self-reference II : Knowledge, belief, and modality JF - Artificial Intelligence Y1 - 1988 A1 - Perlis, Don AB - Negative results of Montague and Thomason have diverted research in propositional attitudes away from syntactic ("first-order") approaches, encouraging modal formalisms instead, especially in representing epistemic notions. We show that modal logics are on no firmer ground than first-order ones when equally endowed with substitutive self-reference. Nonetheless, there may still be remedies, hinging in part upon a distinction between "dynamic" and "static" notions of provability and belief (an earlier version of this paper emphasized a somewhat different distinction). VL - 34 SN - 0004-3702 UR - http://www.sciencedirect.com/science/article/pii/0004370288900380 CP - 2 M3 - 16/0004-3702(88)90038-0 ER -