  In addition to this rejoinder, it should be noted that in only slightly more complicated examples the identification strategy is rather less persuasive than in the two sphere case. Consider the example of three qualitatively identical spheres arranged in a line, with the two outside ones the same distance from the middle one. The identification strategy would first require the two outer ones to be identified. But in that case there remain two qualitatively identical spheres, so these must in turn be identified. The upshot is that it is not merely the two spheres we took to be indistinguishable that are said to be identical but all three, including the middle one which seemed clearly distinguished from the other two by means of a pure relational property.