Subsidiarity, i.e., “the principle of subsidiarity,” i.e., “the principle of subsidiary function/responsibility,” i.e., the principle that it is unjust for a higher authority (e.g., the state’s government and law) to usurp the self-governing authority that lower authorities (e.g., in families or other civil associations), acting in the service of their own members (groups and persons), rightly have over those members, is a presumptive and defeasible, not an absolute, principle. But it excludes any general policy or aim of assuming the control or managerial direction of lower groups. Its deepest rationale is the intrinsic desirability of self-direction (not least in cooperatively associating with other persons), a good that is to be favored and respected even at the expense of some efficiency in the pursuit of other goods. Though arising out of Aristotelean moral and political theory, it denies or strongly disambiguates a cardinal principle of Aristotelean political theory. It is reflected in the work of Aquinas, Taparelli, Mill and Maitland, before its articulation by Pius XI (1931).
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