Explaining Out Group Hostility

Every individual thing, and consequently every individual person, strives to preserve and to increase his or her individuality, against the threat of being overcome and absorbed by external forces. The drive to self-assertion, and to an aggressive sense of my own power and distinctiveness as a person, is always present, and some of this sense of unity and this aggressiveness is transferred to communities of persons. Nothing is more useful to a person, [Spinoza] claims, than the added strength that comes from the union with other persons in community, which then becomes itself an individual thing, with its own drive to self-preservation. The aggressive maneuvers of Churches and sects in the seventeenth century, and of nation states in the nineteenth and twentieth centuries, are intelligible within Spinoza's natural philosophy and his idea of history. It is natural that every composite entity, whether a nation or a religious sect, should hold itself together by trying to extend its freedom of action and its power as far as they will go, exactly as an individual person does.

Hampshire, Stuart introduction to Ethics by Benedict de Spinoza, xiii. New York: Princeton University Press (Penguin Books), 1994.