Whereas in the traditional understanding, the true body of Christ had been realized in the celebration of the Eucharist that culminated in communion in the mystical/sacramental body, in this late medieval understanding, the celebration of the Eucharist becomes the rite by which the priest effects the miracle of the true body of Christ, which then exists quasi-independently. The Church as a community recedes from history into the ‘mystical body of Christ’; the visible Church that remains splits into the institutional priesthood that has power to make present the verum corpus Christi and the laity.
So far as the word ‘mystical’ is concerned, what has happened is that it has been wrenched from its traditional meaning as identical with sacramental and cast adrift. Whereas in the older usage, the primary meanings of ‘mystical’ applied to something evident – the scriptural text, or the sacramental elements, and indeed anything used in a liturgical context – to affirm that its real meaning lay deeper, now the term corpus mysticum Christi applies to something not evident: ‘mystical’ in this sense means precisely the Church as not manifest, the ‘real’ Church as distinct from the institutional Church. The term ‘mystical’ becomes opaque; instead of designating something that is a sign of something hidden, it designates the hidden reality itself. It acquires a quite different charge.
Andrew Louth, “Afterword” to the new edition of his The Origins of the Christian Mystical Tradition: From Plato to Denys (Oxford, 2007) 209-210.
Father Louth proceeds to consider the implications of the shift in meaning that the phrase “mystical body of Christ” underwent in the twelfth century. He draws on Henri de Lubac’s Corpus Mysticum which shows how this phrase had previously referred to the Eucharistic elements as is consonant with the patristic use of the term “mystical” outlined earlier. However, in the twelfth century the consecrated bread of the Eucharist became the “true body of Christ”, while the Church came to be seen as the mystical body of Christ. This did not refer to the Church in its institutional aspect however, but rather to an invisible Church spanning heaven and earth. Thus the consecrated elements come to be abstracted from the community that celebrates them. This community becomes itself more vague and not identifiable with the actual life of the Church, and yet at the same time the distinction between clergy and laity takes on a new and more entrenched meaning.
Instead of the consecrated elements, through communion, being a sign that effects and deepens the incorporation of the baptized Christian in the body of Christ, so that the mystical/sacramental body points to the true body to which all Christians belong, the consecrated host becomes an end in itself, an object of adoration. (209)
It is in this context that we should view the development of “mystical” movements in the late Middle Ages. The flowering of such movements provided people with the possibility of direct access to God by they were able to bypass (or sometimes challenge) priestly power over the sacraments. This is particularly the case in the women’s spirituality of this period
women, excluded by their sex from the priesthood, find in themselves, I their dreams, in their bodies hidden signs – mystical signs, particularly of Christ’s wounds – that establish access to a divine power to rival that of the priesthood. Such claims do not always challenge the reality of priestly power – mostly they do not – but they claim an equivalent power: the most famous woman making such a claim was St Catherine of Siena. The mystical is now thoroughly individualized, and from the late Middle Ages onwards, there is a conflict between the mystical and the institutional… (210)
The Fathers understood the mystical to refer to Scripture, the liturgy and the hidden reality of Christian life. However, it is now only this third meaning that remains, stripped moreover of the ecclesial context into which it traditionally fitted. Christian mysticism, then, emerges, not as an expression of some universal religious phenomenon, but as
one of the elements of the fragmentation of the Western Christian tradition that took place in the later Middle Ages and issued in, among other things, the Reformation. (211)
This obviously has far-reaching implications which I am not going to discuss now – perhaps another time!