  Rather than argue about these intuitions and hence argue as to which is the correct formulation of the Principle we may distinguish different formulations, and then discuss which, if any, of these are correct. To that end a distinction is commonly made between intrinsic and extrinsic properties. Here it might initially seem that extrinsic properties are those analysed in terms of some relation. But this is not correct. For the property being composed of two concentric spheres is intrinsic. For present purposes it suffices to have an intuitive grasp of the intrinsic/extrinsic distinction. (Or see Weatherson, 2008, §2.1.)