Individual freedom, voluntary association, and being against the state are important beliefs of anarchism. There are also big differences between anarchist philosophies on things like whether violence can be used to bring about anarchy; the best type of economy; the relationship between technology and hierarchy; the idea of equality; and the usefulness of some organization. The word "authority" is not clear, but anarchists are not against some types of authority (e.g. the authority of someone skilled in self-defence over someone that wants to learn self-defence), they are only against control by force.