The document Mater Populi Fidelis of the Dicastery of the Doctrine of the Faith, specifically in numbers 17 and 18 gives a undeservedly over-simplified overview of this important doctrine of the Catholic Faith. The fact that Our Lady cooperated in the work of the Redemption, at least mediately, is a de fide teaching. To doubt it would incur theological censure.
For a clear and comprehensive overview of the main lines of this teaching and its historical development, I refer the reader to J. A. de Aldama, S.J., “De Corredemptione,” in Sacrae Theologiae Summa, vol. 3, Madrid, BAC, 1961, pp. 413-443. (English translation by Fr. Kenneth Baker, S.J., vol. IIIA, pp. 441-466.) A further and more detailed explanation can be found in J. Carol, O.F.M. “Our Lady’s Coredemption,” in Mariology, vol. 2, Milwaukee, Bruce, 1957, pp. 377-425.
The usage of the title of Our Lady as Co-Redemptrix is one which has been historically ascertained as being theologically certain. de Aldama notes that “it is not licit to doubt about its suitability.” The opposite theological note to this would be an “error in theology.”
It is a sad consequence of the times in which we live that there exist voices which aim to subvert the traditional teachings of the Church by exploiting the lower-grades of theological certitude to attempt to discourage the use of theologically valid and sound arguments from Scripture, Tradition and the Magisterium. In this specific instance, such opinions are aimed at Our Blessed Lady’s mediate and, furthermore, immediate cooperation in Our Lord’s work of redemption. Even the latter is asserted within the teachings of the Papal Magisterium dating back to Pius IX and Leo XIII, and even is found in the post-conciliar teachings of John Paul II. Mater Populi Fidelis grossly oversimplifies the theological reflection which has been expounded by the Pontiffs when it states: “some Popes have used the title “Co-redemptrix” without elaborating much on its meaning.” In the interests of brevity, a full catalogue of these papal teachings on co-redemption can be found in the reference cited above. One need only refer to the bull “Ineffabilis” of Pius IX; the encyclicals “Iucunda Semper” and “Supremi Apostolatus” of Leo XIII; the encyclical “Miserentissimus Redemptor” of Pius XI; as well as the encyclicals “Mystici Corporis” and “Ad cæli Reginam” of Pius XII and the bull “Munificentissimus Deus” of the same Pius XII.
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