  The logical aspects of modal epistemic logic were not significantly developed after Hintikka’s 1962 presentation; instead, the philosophical literature (which is not extensive, compared with many other topics in the area) concentrates on the issue of hyperintensionality, or closure of epistemic attitudes under logical consequence. This topic is especially challenging, turning out to be closely related to the semantic paradoxes, and the philosophical literature is inconclusive. Intuitions seem to conflict, and it is difficult to find ways to model the important phenomena using logical techniques.[35]