Universalisms are theories or doctrines that claim to be valid for or of everyone. What they hold to be universal, what aspects of people they are meant to apply to and in what way, varies enormously. There is a multitude of often competing universalisms in metaphysics, epistemology, natural science, anthropology, social theory, and religion, and an even greater number of challenges to their claims to universality. Even within moral and political philosophy, there has been little agreement among universalists about what qualities, values, or principles are universal, or how they are universal. Contemporary political theory has tended to focus its discussion of universalism on the nature and scope of moral and political principles, norms, or values, such as human rights or justice.