Material Coincidence and the Indiscernibility Problem

It is often said that the same particles can simultaneously make up two or more material objects that differ in kind and in their mental, biological and other qualitative properties. Others wonder how objects made of the same parts in the same arrangement and surroundings could differ in these ways. I clarify this worry and show that attempts to dismiss or solve it miss its point. At most one can argue that it is a problem we can live with.