  Despite Lewis's presentation, the Problem of the Many is not a problem about change. The salient feature of these examples is that, in practice, change is a slow process. Hence whenever a cathode, or a human, is changing, be it by shedding electrons, or shedding skin, there are some things that are not clearly part of the object, nor clearly not part of it. Hence there are distinct sets that each have a good claim to being the set of parts of the cathode, or of the human, and that is what is important.