You see, I divide men into three categories: those who have a lot of money, those who have none at all and those who have a little. The first want to keep what they have: their interest is to maintain order; the second want to take what they do not have: their interest is to destroy the existing order and to establish one which is profitable to them. They each are realist, people with whom one can agree. The third group want to overthrow the social order to take what they do not have, while still preserving it so that no one takes away what they have. Thus, they preserve in fact what they destroy in theory, or they destroy in fact what they seem to preserve. Those are the idealists.
Jean-Paul Sartre, in "The Devil and the Good Lord"