We consider a language containing partial predicates for subjective knowability and truth. For this language, inductive hierarchy rules are proposed which build up the extension and anti-extension of these partial predicates in stages. The logical interaction between the extension of the truth predicate and the anti-extension of the knowability predicate is investigated.
"A Kripkean Approach to Unknowability and Truth." Notre Dame J. Formal Logic 39 (3) 389 - 405, Summer 1998. https://doi.org/10.1305/ndjfl/1039182253