Existence and Reference in Medieval Logic

Abstract

``The expression `free logic' is an abbreviation for the phrase `free of existence assumptions with respect to its terms, general and singular'.''1 Classical quantification theory is not a free logic in this sense, since its standard formulations commonly assume that every singular term in every model is assigned a referent, an element of the universe of discourse. Indeed, since singular terms include not only singular constants, but also variables2, standard quantification theory may be regarded as involving even the assumption of the existence of the values of its variables, in accordance with Quine's famous dictum: ``to be is to be the value of a variable''3.