A central issue in the treatment of attitudes is that of logical omniscience: humans are cognitively limited agents, and are not aware of all the consequences of their beliefs and desires. On this basis, Kamp (1990) argues that the objects of thought should not be seen as purely model-theoretic entities, for example a set of belief worlds, as is common in logics of belief from Hintikka (1962) onwards. Rather, the logic of belief and other attitudes must involve structured mental representations.