 A physical theory \(T\) consists, among other things, of a group of laws which are formulated in terms of certain concepts. But an apparent circularity arises when one considers how the laws of \(T\) and the concepts acquire their content, because each seems to acquire content from the other — the laws of \(T\) acquire their content from the concepts used in the formulation of the laws, while the concepts are often “introduced” or “defined” by the group of laws as a whole. To be sure, if the concepts can be introduced independently of the theory \(T\), the circularity does not appear. But typically every physical theory \(T\) requires some new concepts which cannot be defined without using \(T\) (we call the latter “\(T\)-theoretical concepts”). Is the apparent circularity concerning the laws and the T-theoretical concepts a problem? Some examples will help us assess the threat. 