Today’s feast is focused in the first place on a person, not on a doctrine. We celebrate Jesus, present to us as our food and the source of our communion in the Eucharist. This however is likely to prompt doctrinal reflection. How, we might naturally ask, can what seems to be bread be the Body of Christ? Indeed, in what sense of the word ‘body’ could this even conceivably be so? Nor are these questions merely possible: non-Catholic Christians ask them frequently, as do various non-Christian critics of Catholicism, often in less than polite tones. For many people, transubstantiation sits at the top of a list of ridiculous things believed by Catholics. This, it should be urged, is not unreasonable. (And I speak as a defender of the doctrine).
As is so often the case, what critics reject with regard to the Eucharist is not what the Church believes. Roughly, their target is the thought that at the moment of consecration God makes some bread vanish, and replaces it with human flesh, disguised as bread. Thus all those pious stories about bleeding hosts and gushing prose about the ‘prisoner of the tabernacle’.
The Church rejects this view, in spite of the aggressively professed orthodoxy of some of its champions. Christ is not present on the altar as I am present at this computer keyboard. The ‘species’ of bread is not a disguise, but a sign. Christ is not vulnerable, or constrained by, his eucharistic presence. In fact, most of our talk of the Eucharist has to take the form of denials: ‘he is not present like this’, ‘this is not bread’. The purpose of these denials is to preserve the coherence of our trust in the Lord’s promise to be present with us in the Eucharist. We cannot understand the nature of that presence itself, because that would be to understand the Lord’s Risen Body and the nature of the creative act by which he is made present. As the hymn puts it, “thou art here we ask not how”.
And that he is here is central to the Catholic faith. We express it, not primarily in words but in a way of life – genuflecting, kneeling, burning incense, going from the Mass to be the Body of Christ in the world. However, we do need to believe the claim behind these actions (“This is my Body”). On that subject I can do no better than recommend Elizabeth Anscombe’s excellent essay On Transubstantiation.