According to the theory of normativity of belief, understanding the idea that there is a normative relationship between the mental act of believing and the content of belief reinforces the concept of propositional attitude of belief. The issue of how to formulate the aforementioned normative relationship- which can also be called the issue of norm-based formulation, for short-is the one which is abundantly studied in relevant philosophical literature. In the philosophical literature of two or three recent years, two kinds of (...) norm-based formulation are proposed. First, correctness of a proposition is the necessary condition for the permissiveness of the belief in that proposition; second, correctness of a proposition is the necessary and sufficient condition for the permissiveness of the belief in that proposition. Providing a brief account of the theory of normativity of belief and reviewing older norm-based formulations, the present paper argues for the first view and against the second one. Seyyed Ali Kalantari[1] [1]. Assistant professor of philosophy department, Isfahan University. (shrink)