[T]here are no clear actual cases of individual substances discernible only with respect to relational and haecceitistic properties. On the other hand, there do seem to be pairs of possible individuals which differ only with respect to such properties. Max Black has argued that there is a possible universe containing only two qualitatively indiscernible brass spheres. These spheres will have the same mass, shape, color; be made of the same kind of stuff; and so on. But they will differ with respect to spatial relational properties involving the haecceity of what they're made of, such as being made of this matter, as well as differing with respect to purely haecceitistic properties like being this and impurely haecceitistic properties like being this brass sphere. If, as seems plausible, there are possible universes of the sort Black envisions, then there are individuals that cannot be distinguished save relationally or haecceitistically.

And thereupon, behold, a knight on a black horse appeared, clothed in jet-black velvet, and with a tabard of black linen about him.

My first trip was a shopping run to the Red Hook section of Brooklyn, where the Acadia swallowed a cartful of groceries without even folding the third-row seat.

The priest would bring salvation while the garbo took the rubbish.