In this commentary, I will only raise a couple of methodological questions that may help clarify the rich content of Barberousses's paper.While taking into account an interesting feature in the evolution of physics – the process of making explicit the content and meaning of a physical theory – Barberousse tries to develop an important topic, namely the central difficulty one encounters when comparing scientific theories and considering scientific revolution: how to define the parameters of what we call "a theory." In fact it is often difficult to apply to concrete cases Kuhn's notion of "normal science" and the various features he attributes to it. Barberousse gives some examples of these difficulties in the case of "classical mechanics."