Abstract

This chapter considers St. Thomas Aquinas’s theology of the eucharistic conversion, weaving together the four texts in which St. Thomas provides the most systematic treatment of this topic: his Scriptum on the Sentences of Peter Lombard, his commentary on St. Paul’s first letter to the Corinthians, the Summa Contra Gentiles, and the Tertia Pars of the Summa Theologiae. The eight sections of this chapter correspond to the eight articles of Tertia Pars, Question 75. In Article 1, St. Thomas establishes the fact of the real presence of Christ’s body and blood in the Eucharist. In Article 2, he argues that this real presence is only possible if the bread and wine do not remain after the consecration. In Article 3, he clarifies that this does not mean that the bread and wine are annihilated. Rather, he explains in Article 4, they are converted into the body and blood of Christ. In Article 5, St. Thomas reflects on why it is that the accidents of bread and wine endure after their underlying substances pass away. In Article 6, he argues that not even the substantial form of bread remains. Article 7 seeks to demonstrate that the conversion is instantaneous. And last of all, Article 8 concerns how we may and may not speak about this miraculous eucharistic conversion. The overall movement is from the real presence to transubstantiation. According to St. Thomas, the conversion of the whole substance of bread into the whole substance of Christ’s body is the only possible way that his body could come to be present in the sacrament of the altar. The real presence absolutely depends upon transubstantiation; transubstantiation is the necessary condition of the real presence.