Khunaji's Categorization of Modal Propositions in the Context of the Logic of Temporal Modals

Referring to Khunaji’s categorization of modal propositions, we can find a set of 34 members. Though Fifteen members of the set had been proposed by logicians before Khunaji, he added nineteen categories of his own. Probing the manner of the formation of these categories by Khunaji, one can realize that two categories are missing and the rest are divided into a main group with 13 members and a secondary group with 19 members. The present article first describes and comments on the propositions. Facing with the modal propositions, the new logicians tried to formalize the propositions through giving a symbolic direction to them. The efforts made include those of Nicolas Rescher which were to some extent successful. The reason we say “to some extent” is because there are some missing elements in the formalization. For example in the modal proposition set, direction is not the sole variable; there is another variable which has not been dealt with adequately. We have called it time temporal variable. The present paper is an attempt to overcome this deficiency by introducing the time temporal variable in a way that has led to a more appropriate formalization of the modal propositions.