The Church´s social doctrine is not a third way between liberal capitalism and Marxist collectivism, nor even a possible alternative to other solutions less radically opposed to one another: rather, it constitutes a category of its own. Nor is it an ideology, but rather the accurate formulation of the results of a careful reflection on the complex realities of human existence, in society and in the international order, in the light of faith and of the Churchs tradition. Its main aim is to interpret these realities, determining their conformity with or divergence from the lines of the Gospel teaching on man and his vocation, a vocation which is at once earthly and transcendent; its aim is thus to guide Christian behavior. It therefore belongs to the field, not of ideology, but of theology and particularly of moral theology.
John Paul II. Sollicitudo Rei Socialis