 Perhaps the most plausible hyperintensional environment is the realm of intentional concepts: notions that involve states of the mind which are directed towards contents, situations, etc. The two most studied such notions are knowledge and belief. Since Hintikka (1962), these have been understood in epistemic logic as modal operators: restricted quantifiers over possible worlds. Knowledge and belief are characterized in terms of what is true throughout a set of worlds which represent ways things could be, for all the cognitive agent knows, or given the agent’s evidence, etc. If \(K\) expresses the agent’s knowledge or belief state, \(w\) is a possible world, and \(R\) an epistemic accessibility relation on the space of worlds \(W\), the Hintikkan characterization goes: