The article presents a careful analysis of the idea of the "open texture" of language and vagueness of concepts in the way that they were formulated by Friedrich Waismann as well as related problems of verification. It shows that empirical statements are not conclusively verifiable for, at least, the open texture of the terms involved. We cannot conclusively verify statements in which empirical concepts are used, because we cannot define these concepts in an exhaustive way due to their open texture. The author proposes interpreting the open texture as a possibility of vagueness; vagueness can be remedied by giving more accurate rules, the open texture cannot.