Communitas Perfecta

Communitas Perfecta ("Perfect Community") or Societas Perfecta ("Perfect Society") is the Latin name given to one of several ecclesiological, canonical, and political theories of the Catholic Church. The doctrine teaches that the Church is a self-sufficient or independent group which already has all the necessary resources and conditions to achieve its overall goal (final end) of the universal salvation of mankind. It has historically been used in order to define Church–State relations and to provide a theoretical basis for the legislative powers of the church in the philosophy of canon law.

Its origins can be traced to the Politics of Aristotle, who described the Polis as a whole made of several imperfect parts, i.e. the consummation of natural communities such as the family and the village. The "perfect community" was originally developed as a theory of political society. The most sovereign political organization (the Polis) can attain the end of the community as a whole (happiness) better than any of the subordinate parts of the community (family, village, etc.). Since it can attain its end (telos) by its own powers and the resources within itself, then it is self-sufficient. It is self-sufficiency that is the defining element of the polis.

The idea of "perfect community" was also present in medieval philosophy. In direct reference to Aristotle, Thomas Aquinas mentions the State (civitas) as a perfect community (communitas perfecta).

During Enlightenment period, the Societas Perfecta doctrine was strongly affirmed in order to better protect the Church from secular encroachments. It was also mentioned in the Magisterium of the Thomistic revivalist pontiffs such as Pius IX. And especially Leo XIII, in his encyclical Immortale Dei, explains this teaching in relation to the Church:

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