Ma`aref-e Manteqi

One of the concepts that plays a role in increasing the knowledge of logic, and its traces can be found in a wide range of topics of this knowledge, is the concept of necessity. Necessity means a necessary connection between two things in such a way that their separation is impossible. This meaning in discussions such as implication, five generalities, conditional proposition, derivation of analogies and derivation of propositions, has created conditions that result in the increase of logical accuracy and the function of logical rules in these discussions. Nevertheless, the main importance of necessity in the knowledge of logic is devoted to the discussion of conditional proposition, and the word necessity in this knowledge evokes the necessity between the antecedent and the consequent in the conditional proposition. For this reason, the present paper tries to explain the necessity in conditional propositions, which separates the necessary proposition from the accidental proposition, and the division of the necessary proposition is the result of the difference in the type of necessity between its components. In this regard, in addition to explaining the necessity in conditional proposition and its types and conditions, various aspects of the necessity itself and its types in logic are pointed out in order to ground the discussion of the conditional proposition arising from it.