Qualitative vs Numerical Identity

Qualitative identity and numerical identity are different in that you can have multiple instances of a thing qualitatively but you cannot have multiple instances of the same numerical thing. Shoemaker uses a suitcase as an example. You can have multiple suitcases that have the same qualities, that it is a certain color, a certain shape, made of a certain material, or even have the same model number. Two people can buy the same suitcase in this sense. But numerical identity is a stronger claim in that it is really unique in what it points out. This numerical identity has an indiscernibility. So for example, if I have a Pen A, and I want to know that it is identical to Pen B, there should be no property that A has that B doesn’t have. So even if I have the same model number of pen, that Pen A is in my left hand while Pen B is in my right shows that there is something Pen A had that Pen B doesn’t, which is a particular location, and would thus be qualitative identity. There would be no such differences in numerical identity.