It is at least a good reason to reject set theory for certain theoretical applications. Imagine you're a linguist trying to develop a theory of compositional na

It is at least a good reason to reject set theory for certain theoretical applications. Imagine you're a linguist trying to develop a theory of compositional natural language semantics. You want to have a good theory of what is entailed by a sentence of "Bill ate cheerios." You decide that pluralities are sets because that seems intuitive. Does that mean that when you say that Bill ate cheerios, he might have only eaten a singleton cheerio? That seems like the wrong prediction. It is clear that one cannot simply say that pluralities are sets, they are sets plus certain conditions, at least. This isn't only a philosophical exercise. This is about building a predictive model of natural language meanings where one doesn't want to make spurious predictions. The complexity of using sets to represent plurals, collections and groups quickly ramps up in this domain. This is a practical issue.