In fact, science, including mathematics, is a discipline defined for a better understanding of the objective world. It is just a relative frame of reference, which brings us convenience and a way to know the world. But people are alive, so you should use them according to the conditions, not generalize. How can we understand the world without approximating some uncertainties? People know the world subjectively, and unify the whole by part, because it is impossible for people to count all the individuals, and there is no need to do that. Don't say that he violated any principles or principles. Everything we define is not to limit our work, but to better understand the world. We want results, not methods. Because any defined concept will have human defects, that is, the limitations of the concept.