Research Article

Frontiers of Philosophy in China

, Volume 5, Issue 2, pp 294-311

First online:

Toward model-theoretic modal logics

  • Minghui MaAffiliated withDepartment of Philosophy, Tsinghua University Email author 


Adding certain cardinality quantifiers into first-order language will give substantially more expressive languages. Thus, many mathematical concepts beyond first-order logic can be handled. Since basic modal logic can be seen as the bisimular invariant fragment of first-order logic on the level of models, it has no ability to handle modally these mathematical concepts beyond first-order logic. By adding modalities regarding the cardinalities of successor states, we can, in principle, investigate modal logics of all cardinalities. Thus ways of exploring model-theoretic logics can be transferred to modal logics.


model theory first-order logic modal logic graded modalities