Transubstantiation

Besides the Real Presence which faith accepts and delights in, there is the doctrine of transubstantiation, from which we may at least get a glimpse of what happens when the priest consecrates bread and wine, so that they become Christ's Body and Christ's Blood.

At this point, we must be content with only the simplest statement of the meaning of, and distinction between "substance" and "accidents", without which we should make nothing at all of transubstantiation. We shall concentrate upon bread, reminding ourselves once again that what is said applies in principle to wine as well.

We look at the bread the priest uses in the Sacrament. It is white, round, soft. The whiteness is not the bread, it is simply a quality that the bread has; the same is true of the roundness and the softness. There is something there that has these and other properties, qualities, attributes- the philosophers call all of them "accidents". Whiteness and roundness we see; softness brings in the sense of touch. We might smell bread, and the smell of new bread is wonderful, but once again the smell is not the bread, but simply a property. The something which has the whiteness, the softness, the roundness, has the smell; and if we try another sense, the sense of taste, the same something has that special effect upon our palate.

In other words, whatever the senses perceive-even with the aid of those instruments men are forever inventing to increase the reach of the senses- is always of this same sort, a quality, a property, an attribute; no sense perceives the something which has all these qualities, which is the thing itself. This something is what the philosophers call "substance"; the rest are "accidents" which it possesses. Our senses perceive "accidents"; only the mind knows the "substance". This is true of bread, it is true of every created thing. Left to itself, the mind assumes that the "substance" is that which, in all its past experience, has been found to have that particular group of "accidents". But in these two instances, the bread and wine of the Eucharist, the mind is not left to itself. By the revelation of Christ it knows that the "substance" has been changed, in the one case into the "substance" of His Body, in the other into the "substance" of His Blood.

The senses can no more perceive the new "substance" resulting from the consecration than they could have perceived the "substance" there before. We cannot repeat too often that senses can perceive only "accidents", and consecration changes only the "substance". The "accidents" remain in their totality-for example, that which was wine and is now Christ's blood still has the smell of wine, the intoxicating power of wine. One is occasionally startled to find some scientist claiming to have put all the resources of his laboratory into testing the consecrated bread; he announces triumphantly that there is no change whatever, no difference between this and any other bread. We could have told him that, without the aid of any instrument. For all that instruments can do is to make contact with the "accidents", and it is part of the doctrine of transubstantiation that the "accidents" undergo no change whatever. If our scientist had announced that he had found a change, that would be really startling and upsetting.

The "accidents", then, remain; but not, of course, as "accidents" of Christ's Body. It is not His Body which has the whiteness and the roundness and the softness. The "accidents" once held in existence by the "substance" of bread, and those others once held in existence by the "substance" of wine, are now held in existence solely by God's will to maintain them.

What of Christ's Body, now sacramentally present? All we shall say here is that His Body is wholly present, though not (so Saint Thomas among others tells us) extended in space. One further element in the doctrine of the Real Presence needs to be stated: Christ's body remains in the communicant as long as the accidents remain themselves. Where, in the normal action of our bodily processes, they are so changed as to be no longer "accidents" of bread or "accidents" of wine, the Real Presence in us of Christ's own individual body ceases. But we live on in His Mystical Body.

Saint Thomas Aquinas gives three reasons why it is fitting that God intervenes in this miraculous way (III, 75, 5).

     Because it is not customary but horrible for men to eat human flesh and drink human blood; hence Christ’s flesh and blood are given to us under the species of those things more commonly consumed by men.

     Lest this sacrament might be derided by unbelievers, were we to eat the flesh and blood of Jesus under his own proper species.

     That while we receive Our Lord’s Body and Blood invisibly, this may redound to the merit of faith.

Hence there is no parallel to this in all of nature where there is a complete change of substance, while there is no change in the external sense-perceptible characteristics of the original substance. In fact, every time the priest at Mass pronounces the words of consecration there is a double miracle wrought by the power of God, a miracle not witnessed by the senses, but known only by the light of faith:

     The miraculous change of the substance of the bread and wine into the substance of Christ’s Body and Blood;

     The miracle by which God sustains in existence the perceptible qualities or characteristics of the bread and wine, although the underlying substance no longer exists.

Saint Thomas wrote so beautifully of this mystery in the eucharistic hymn sung at Benediction of the Blessed Sacrament: "Praestet fides supplementum, sensuum defectui." (Faith supplies what the senses cannot perceive)

Glossary of Theological/Philosophical Terms used on this page.