 The epistemology of modality is importantly connected to the epistemology of the  a priori,  as many believe that at least some modal knowledge is purely a priori (modal rationalism). Some philosophers have proposed that either  intuition  or understanding, or both of them combined, can provide an account of a priori knowledge and justification, which may be fruitfully applied to the epistemology of modality. Others have explicitly offered an intuition-based or understanding-based account of modal knowledge. (For an empirically informed discussion of intuition see entry on  experimental philosophy.)