Transubstantiation

The word transubstantiation is doing philosophical work. Aristotle distinguished the substance of a thing, what it fundamentally is, from its accidents, the properties by which it is perceived: colour, taste, texture, shape, chemical composition. On that scheme a thing's identity is not simply the sum of its observable properties.

The doctrine, defined at the Fourth Lateran Council in 1215 and set out at length by the Council of Trent in 1551, holds that at the words of consecration the entire substance of the bread becomes the substance of Christ's body and the entire substance of the wine his blood, while all the accidents of bread and wine remain. Nothing perceptible changes, and Catholic theology says so plainly: the change is not a matter for observation, and a chemical analysis of a consecrated host will find bread.

Two corollaries follow that outsiders often miss. First, concomitance: because the risen Christ is not divided, the whole Christ is present under either species, which is why communion in the bread alone was for centuries held to be complete. Second, the presence persists after the rite, which is why consecrated bread is reserved in a tabernacle, carried to the sick, and made the object of adoration in Benediction and Corpus Christi processions. Traditions that hold a real presence only in the act of receiving draw no such conclusion.

Trent was careful to say that transubstantiation is a fitting and proper name for the change rather than an explanation of its mechanism, which remains mystery. Later Catholic theologians, uneasy with Aristotelian physics, proposed reformulations such as transsignification and transfinalisation, describing a change in meaning and purpose. Paul VI responded in 1965 that such accounts are inadequate if offered as replacements: whatever language is used must affirm that what is there after the consecration is no longer bread.

Christian accounts of the Eucharist can be laid out as a series of answers to one question: in what sense is Christ present?

Transubstantiation, the Catholic position, says the substance changes and the appearances remain. Eastern Orthodoxy affirms an equally objective change, calls the elements the body and blood without qualification, and has generally refused to specify how, treating the Latin analysis as an intrusion of philosophy into mystery; the Greek term metousiosis appears in later confessions but carries less theoretical weight.

Sacramental union, the Lutheran position, holds that Christ's body and blood are truly present in, with and under bread and wine that remain bread and wine. Luther grounded it in the plain words this is my body and in his conviction that Christ's humanity shares the attributes of his divinity and can therefore be present anywhere. He refused to explain the mechanism and rejected transubstantiation as speculation. The label consubstantiation is a later coinage that Lutheran theologians usually disown.

Spiritual or pneumatic presence, the Reformed position associated with Calvin, holds that the bread and wine remain what they are and that the believer, by the work of the Holy Spirit, is genuinely fed on Christ, who is in heaven. It is a real communion with a real Christ, mediated rather than local.

Memorialism, associated with Zwingli and dominant among Baptists, Anabaptists and much of evangelicalism, treats the rite as a remembrance and a proclamation, with the bread signifying rather than conveying.

The division is old and consequential. Luther and Zwingli met at Marburg in 1529 and agreed on fourteen articles out of fifteen; the fifteenth was this one, and the Reformation split there and did not reunite. Because eucharistic teaching governs who may receive at whose table, the disagreement is also the most visible practical barrier between the churches to this day.