Modal Propositions: A Philosophical or a Logical Issue?

The issue of modals (necessity, possibility, and impossibility) and modal propositions is discussed in both philosophy and logic. Muslim logicians very often, during their discussion of types of propositions, divide predicatory propositions into modal and non-modal (absolute) propositions, and then discuss about their subdivisions and their predicates. Philosophers also divide concepts or quiddities into three categories of necessary being, contingent being, and impossible to be. The question to be investigated pertains to the difference between the logical and philosophical meaning of matters and modalities, and whether it is essentially a logical or a philosophical issue. Muslim thinkers have answered in three ways: a) difference in meaning; b) same meaning in different spheres; and c) same meaning and sphere.In this article, the author reviews two former answers and then discusses the third option as the idea favored by Mulla Sadra. According to his theory, this issue is basically a philosophical problem, and if discussed in logic, it would be a peripheral discussion. Then the author criticizes this idea and tries to show its flaws, including the confinement of modals to specific types of predicatory propositions. Finally, he suggests a fourth option, according to which the difference between logical and philosophical modes is described by reference to modes pertaining to truth, and modes pertaining to existence.