Incommensurability is a concept that entered into the literature of contemporary philosophy of science through Thomas Kuhn and Paul Feyerabend. Any discussion of this concept is related to semantics and methodology, and brings up a debate on the possibility of translation between languages. A review of Kuhn’s works shows that, over several decades, he has presented different interpretations of the incommensurability of scientific theories, while he is mainly well-known for his early excessive position, emphasizing incommensurability between scientific mega-theories and paradigms. Indent Such a position has caused challenges in contemporary philosophy of science. Some scholars argue that Kuhn has gradually moved away from his early position, so that he has recognized, in his later positions, a kind of comparability of scientific theories and paradigms.This paper, making use of Howard Sankey’s approach, presents a comprehensive classification of different features and variants of Kuhn’s conception of incommensurability, examines the change of this concept in his philosophy of science, and shows that he, in his later positions, has restricted incommensurability to untranslatability between some terms of natural kinds. This, showing the rationality of empirical science and the process of selection between scientific theories, would make possible to do comparison between rival scientific theories.