Necessity and modal systems: an essay on modal terms

Abstract

The purpose of this paper is to determine if our ordinary-language notions of modal terms furnish a basis for the development of modal logics, and if so, how and to what extent. I shall begin by distinguishing the "use" of a modal term and the "ground" for it. Briefly, the logical relations between statements are due to the uses of their terms, and the grounds for a statement are the reasons we would produce to justify its assertation. In Chapter One I shall distinguish five uses of modal terms, and in Chapter Two I shall enumerate a number of grounds for sentences containing modal terms. In the next two chapters I shall employ the results of Chapter One and Chapter Two in connection with the two most important problems facing modal logic: Iterated modalities and statements in which a quantifier binds a variable which is within the scope of a modal term.