 Given Hintikka’s non-standard semantics, it is a bit difficult to pin down whether he would accept a normal modal logic as the logics of knowledge and belief, but if so, then S4 and KD4 would be the closest candidates (see Hendricks &amp; Rendsvig 2018 for this point). By contrast, for knowledge von Kutschera argued for S4.4 (1976), Lenzen suggested S4.2 (1978), van der Hoek argued for S4.3 (1993), and Fagin, Halpern, Moses, and Vardi (1995) and many others use S5 for knowledge and KD45 for belief.