Commentaria in Summam contra Gentiles, Liber IV

The truth of the sacrament of the Eucharist having been laid down, St. Thomas intends to resolve the objections of the heretics¹. And first, he sets forth the objections themselves; second, he answers them, in the following chapter.

As to the first point, he says first that, just as when Christ uttered the aforesaid words certain of the disciples were troubled, saying, This saying is hard, etc., so too heretics have risen up against the doctrine of the Church, saying that the body and blood of Christ are not really in this sacrament, but only significatively. Whence, when Christ said, pointing to the bread, This is my body, the meaning is, This is a sign and figure of my body; according to which manner also the Apostle said in I Cor. 10, And the rock was Christ. And so they speak concerning the other authorities.

He says second that they take the occasion for an opinion of this kind from the words of the Lord, who, speaking about this matter, so that the scandal of the disciples that had arisen might be calmed, as it were explaining himself, said: The words that I have spoken to you are spirit and life.

He says third that they are also led to dissent from the many difficulties that seem to follow upon this doctrine of the Church.

II. The first is how the body of Christ begins to be upon the altar, since it is manifest that it was not always upon this altar. For this does not seem able to come about through the conversion of something into the body of Christ, since nothing is converted into a pre-existing thing, because that into which something is converted begins to be through a conversion of this kind. But it is manifest that the body of Christ pre-existed. — Likewise, neither can it come about through local motion. First, because it would be necessary to say that when Christ begins to be upon this altar, he ceases to be in heaven. — Second, because no local motion is terminated simultaneously at two places. But it is manifest that this sacrament is celebrated simultaneously upon diverse altars.

The second arises from place. First, because it seems, since in this sacrament the bread and the wine are separate in distinct places, that Christ does not remain whole, because the parts of something separated in diverse places are not contained while it remains whole. Second, because it seems impossible that the true body of Christ should be whole and entire where the bread is seen to be, since it is impossible for a greater body to be enclosed in the place of a lesser. Third, because it happens that this sacrament is celebrated in several places, but it is impossible for one body to exist in several places.

The third difficulty arises from those things that we perceive by sense in this sacrament. For we perceive all the accidents of bread and wine. But accidents of this kind can neither be in the body of Christ as in a subject, nor in the air, because, since most of them are natural, they require a subject of a determinate nature. — Nor can they exist per se, since the being of an accident is to be in, and accidents cannot be individuated except through a subject. — From which it remains that they are in the substance of bread and wine. And consequently, that the substance of the body of Christ is not there, since it seems impossible for two bodies to be together.

The fourth arises from the passions and actions that appear in the bread and wine after consecration just as before. For if the wine were consumed in great quantity, it would inebriate; and the bread would strengthen and nourish. They are also seen to putrefy², etc. Which things cannot belong to the body of Christ.

The fifth difficulty arises from the breaking of the bread. Which indeed can neither be without a subject, nor can the body of Christ be its subject.