A Criterion for Distinguishing the Three Logical Modes from Philosophical Contingency and Necessity

There have been four theories for discussing the necessity of distinguishing or not distinguishing between three modes in philosophy and logic. Some have basically denied any distinction while some others have determined different domains of usage of the three modes. A third group has regarded this distinction as a necessity, proposing a criterion there. The present article is seeking to suggest a forth theory to find a solution for the following two problems: firstly, why should we distinguish the three modes in logic from the contingency and necessity in philosophy? Secondly, what is the criterion for this distinction in logics and philosophy? To answer the former question, the authors argue that some important objections, including that of Hume and that of Kant, have been put forward for the metaphysical argumentations such as ‘ontological argument’ and ‘the argument from contingency and necessity’ and ‘the argument of the truthful ones’. The way out of this challenge is the distinction between the three logical modes and the philosophical contingency and necessity. To answer the latter question, they show that according to the criterion of the three modes in logic, if the predicate is the essence, one of the essentials or one of the requisites of the essence of its subject would be necessary. On the other hand, if the predicate is the opposite of essence, the opposite of one of the essentials or the opposite of one of the requisites of the essence of its subject would be impossible. And if the predicate is something other than the subject’s essence or its opposite, other than one of its essentials or its opposite, the proposition would be contingent. The criterion for contingency and necessity in philosophy, however, is being dependent or independent of cause. Since the philosophers’ analyses of causality are different, here we focus on interpretation presented by Avicenna and Mullā Sadrā.