Abstract
In this paper I will attempt to show how incommensurability between theories is usually manifested, framing this notion in a sense similar to the Kuhnian one in certain aspects, though very different in others. Further, I will show that it is possible, and desirable, to rid Kuhn’s thesis of the idea that in many important theories a certain part of the theoretical nucleus partially contains in a more or less vague sense, synthetic a priori or even analytic statements. Alternatively, I present a motive for the change of meaning in the basic terms of a theory wherein fundamental laws maintain their synthetic a posteriori character. Incommensurability in this case has to do with the change of lexicon for internal properties, independently of whether or not there is a change in the meaning of the primitive terms of the theory.