Frege’s view of Identity, considering “Begriffsschrift” and “Über Sinn und Bedeutung”

Identity is one of the most important and at the same time controversial topics in Frege’s writings. In this essay we discuss his account of this subject and try to explain and criticise it’s different interpretations. Our main question is about the elements that Identity is a relation between them. First of all we explain Frege’s view of Identity in “Begriffsschrift” (Conceptual Notation). The last considerations of Frege about this subject are represented in another well known work of him which is called “Über Sinn und Bedeutung” (On Sense and Reference), therefore in the next section we examine the concept of identity in this essay. The aim of this essay is not criticizing the view of Frege, but primarily to understand it, because that is the only way that we can grasp crucial issues like the essence of number in “Die Grundlagen der Arithmetik” (Foundations of Mathematics) and Russell’s paradoxes concerning the fifth axiom of “Grundgesetze der Arithmetik” (Basic Laws of Arithmetic)