Pius XII issued the encyclical Mystici corporis [Acta Apostolicae Sedis 35 (1943) 193–248] on June 29, 1943. The encyclical was in part a reaction against a vague and diffuse tendency discernible in some quarters of Catholic theology, especially in the years between the two world wars, toward what has been labeled a romantic vitalism or biologism in ecclesiology. Nonetheless the encyclical is primarily a positive document, designed to present a doctrinal view of the militant Church as the Body of Christ (pars. 11, 90). Its obvious effort to synthesize the achievements of the past, both theological and magisterial, around the theme of the Body of Christ supports the view that the document's chief concern is not merely terminological exactitude but doctrinal formation.
Among the chief orientations found in the encyclical the following deserve notice: (1) there is a decisive turning away from a non-Incarnational and asocial concept of Christian grace, which tends to regard grace's outward dimension as a purely provisional and transient reality; (2) hence the socio-sacramental reality of the Church as the communal life of grace is itself a true component of the total Christian grace, and thus Christ's Church Body cannot be the anomaly of a nonbody in which the vital relationships between Head and members tend to be unchurched; (3) this theandric ecclesiology is grounded on a pneumatology in which the role of Christ's Spirit, insofar as He is at once immanent in and transcendent to Christ's Church Body, is analogous to His role in Christ's physical Body, i.e., He is sent to invest Christ's Church, in whole and in its parts, with Christ's own life and energies, and thus to assimilate it, Body and members, to Christ, its paradigm and Head; (4) Christ is the "sustainer" of His Body (51–52), its hypostasis in some mysterious sense, without prejudice to His own transcendence or to the distinct personalities of His many members.
Against this larger background it is easier to situate the following positions of the encyclical: (1) the identification of the Roman Catholic Church with the mystical body of christ on earth; (2) the delineation of the inward-outward grace of membership in a way clearly affirming the outward factors, without, however, any unilateralism; (3) the refusal to admit any basic dislocation between the Church of law and the Church of love, indeed the affirmation of the complementariness of the pneumatic and the juridic missions in the Church; (4) finally, the strong sense of Christian communion, or of the total common life of the Church, conceived as an inward-outward total grace, with a variety of members gifted in Christ, comprising both the lowly and the exalted, each serving together in his way the upbuilding of the Body in Christian love.
Mystici Corporis 's direct identification of the Church of Christ as the Roman Catholic Church has been qualified by the ecumenical position expressed in Vatican II's Lumen gentium that "the unique Church of Christ… subsists in the Catholic Church, which is governed by the successor of Peter and by the bishops in communion with him. Nevertheless, many elements of sanctification and of truth are found outside its visible confines."
The encyclical concerns itself chiefly with the NT "militant Church" (1); hence it does not stress the OT ἐκκλὴσία as the forerunner of the NT Church Body of Christ, nor is any special relief given to the heavenly Jerusalem as the final realization of the Church's earthly pilgrimage. The encyclical does not attend to the question whether the NT "Body" theme has, over and above its assured metaphorical sense, a prior realistic sense, related to Christ's real Body, dead to sin on the cross, risen again to new life, and now gloriously reigning in heaven. The profound nexus between Christ's Eucharistic Body and His Church Body, though by no means passed over (81–84, 18), is not as centrally placed in the encyclical as, e.g., in patristic ecclesiology. The question is left open whether the Holy Spirit may be considered the soul of the Mystical Body in any proper sense (see soul of the church).
It has been noted that the encyclical omits the Biblical theme of the Church as the people of god and to that extent constricts the overall viewpoint from which the mystery of the Church can profitably be regarded. The metaphorical theme of God's people is proposed as a useful complement to the Body theme, particularly advantageous in that it enables the theologian to reflect better on the historical continuity between the two covenants, old and new, and between the two covenant peoples, according to God's total plan of salvation. Any effort, however, to invest the Biblical theme of the Body of Christ with theological disfavor, as an infratheological construct, or to dislodge it from its notable place among the many Biblical themes or images cumulatively employed and required to draw out that measure of fruitful understanding that man may reach in this life of the mystery of Christ's Church, is a disservice marked for failure.
Bibliography: j. hamer, "Signification et Portée del'Encyclique Mystici Corporis," L'Église est une communion (Paris 1962) 11–34. f. malmberg, "Die Enzyklika Mystici Corporis: Dogmatischer Wert und innere Struktur," Ein Leib-Ein Geist (Freiburg 1960) 43–54. a. michel, Dictionnaire de théologie catholique, Tables générales ed. a. vacant et al. (Paris 1951) 1: 1116–18. w. bartz, Lexicon für Theologie und Kirche, ed. j. hofer and k. rahner (Freiburg 1957–65) 7:731–732.
[f. x. lawlor/
d. m. doyle]