When you want to organize knowledge. you will be careful to base the classification upon essential qualities. You will thus derive classes in which the members have the greatest amount of resemblance to one another and the greatest amount of difference from the members of other classes. But suppose that, instead of organizing knowledge, you set out to organize ignorance and prejudice. You will then do precisely the opposite.You will keep the classification vague and flexible, so that it can be made to include just whatever individuals you choose.