@article {15969, title = {Languages with self-reference II : Knowledge, belief, and modality}, journal = {Artificial Intelligence}, volume = {34}, year = {1988}, month = {1988/03//}, pages = {179 - 212}, abstract = {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).}, isbn = {0004-3702}, doi = {16/0004-3702(88)90038-0}, url = {http://www.sciencedirect.com/science/article/pii/0004370288900380}, author = {Perlis, Don} }