A restriction in Frege's use of the term “true”

Abstract

As is well known, Frege introduced the distinction between the sense (Sinn) and the referent (Bedeutung) of a proper name to account for the cognitive significance and truth-value of an identity sentence. The sentence "The morning star is the evening star" (where "is" must be read "is none other than" or "is the same as") is true because the referents of the names are the same object; the sentence is significant because the senses of the names (that is, the public meanings or ways in which the object is given in each case) are different. Further, Frege recognized that in certain cases of indirect reference a sense may be the object referred to.1 And finally, Frege clearly distinguished cases in which the name or a linguistic expression itself may be the object referred to by another name. In the latter case, he used quotation marks around a word to indicate that its referent was the linguistic entity only.2 Frege felt this last step was important in order to avoid confusing the objects of mathematics with the linguistic expressions by which they were named and so to avoid the formalistic thinking of his contemporaries.3 Frege carried this analysis over directly in his treatment of the sentence as a whole as a proper name. He identified the sense of the sentence as the thought or proposition (Gedanke) and the referent of the sentence as its truth-value, the object, The True or The False.4 Further, he found that the sentence used indirectly had its normal sense, the thought, as referent or object named. And finally, a sentence in quotation marks was merelv a proper name with the sentence itself as the object referred to (as for any other linguistic expression in quotation marks). The problem of this paper centers upon Frege's use of the term "true" and the limitations of the usage of this term in comparison with current treatments of this problem. The subject matter of this paper will be restricted primarily to that portion of Frege's thought found in his "Ueber Sinn und Bedeutung" wherein he states most clearly his notion of truthvalues.