Augustine is the most-interpreted of all the Church fathers. Any genius (including Luther), precisely because of his nuanced mind, lends himself to varied interpretation.
The claim that Augustine had a “spiritualizing” view of Eucharistic presence goes back to Erasmus. It spawned the “sacramentarian” movement in the Low Countries which, many scholars believe, made its way down the Rhine and influence Zwingli to his extreme “merely symbolic” view (Calvin was not so extreme).
I think Augustine taught a genuine real presence, not a merely spiritual presence. Erasmus was wrong. But Dugmore and others popularized it and it’s now taken for granted by a lot of scholars.
You can interpret Augustine to support completely opposite viewpoints (e.g., on free will). I think it’s pretty clear that he had a full corporeal presence doctrine.
It all turns on what the meaning of spiritual is. Spiritual can mean “merely symbolic” or something between corporeal and merely symbolic (Calvin) or “sacramentally corporeal.”
The Catholic teaching is that the presence is corporeal but a unique kind of corporeality that is not sense perceptible, because obviously Christ’s presence is not visible or tangible in the Eucharist. “Sacramental” (special kind of corporeal) and “spiritual” are synonyms for those who believe in real but sacramental corporeal presence. But for those who believe in real absence (Zwingli) or spiritual but not corporeal (Calvin), “spiritual” is pitted against real and it means “sacramental” but sacramental understood as uncorporeal.
The history I just outline helps explained why Schaff and others claim that Augustine taught a spiritual presence. Isn’t that convenient, Augustine used the same word Calvin did. But did he mean the same thing as Calvin? I say no, Schaff says yes.
Alasdair Heron (mentioned in my preceding comment) also says no. He says Augustine did believe in real presence, not merely spiritual presence. Heron prefers to use “sacramental” to describe this real presence because “spiritual” can mean so many different things. We Catholics can also call the real corporal presence Sacramental presence because it’s not the same as everyday corporeal presence. We don’t mean quite the same thing as Heron means by “sacramental” but at least Heron doesn’t try to fit Augustine to a procrustean Calvinist bed. He remains a Reformed but he’s aware that Augustine didn’t exactly teach what Calvin taught and that Catholics are probably closer to Augustine’s real meaning. Heron does give more credence to Dugmore’s line of reasoning than I would, but still, he’s at least a Reformed thinker one can reason with.
Maybe in the West. In the East, he is a minor saint, quite obscure.
“Up the Rhine,” of course. What came down the Rhine was Swiss sectarianism.
FWIW - one of my ‘take ways’ from Schaff is that the Church Fathers wrote without the following controversies in mind. This makes it tough for us to read what they meant with confidence.
For example, I’ve heard many Baptists sermons talk about considering the bread to be the broken body of Christ. NONE of those pastors meant transubstantiation, yet a Catholic hearing them might interpret them that way.
Now, add in to that this question - is it a sacrifice for atonement, or thanksgiving? The name suggests the latter, as do the passages in the scripture abut remembrance and proclamation. I see no passage of scripture that indicates it is for forgiveness.
John 6 needs to be interpreted in context. “26Jesus answered them, “Truly, truly, I say to you, you are seeking me, not because you saw signs, but because you ate your fill of the loaves. 27 Do not labor for the food that perishes, but for the food that endures to eternal life, which the Son of Man will give to you...32Jesus then said to them, “Truly, truly, I say to you, it was not Moses who gave you the bread from heaven, but my Father gives you the true bread from heaven. 33For the bread of God is he who comes down from heaven and gives life to the world.” 34They said to him, “Sir, give us this bread always.” 35Jesus said to them, “I am the bread of life; whoever comes to me shall not hunger, and whoever believes in me shall never thirst.”
Catholics read that as discussing Eucharist, which Jesus had never discussed before. It makes far more sense in context of the feeding of the 5000 in verses 1-15 of the same chapter.
Verses 52-53 follow 35: “whoever comes to me shall not hunger, and whoever believes in me shall never thirst.”
I doubt I’ll convince a single Catholic. However, I don’t think it is fair to say the Catholic interpretation is the only one possible.
In the end, the question of whether it is a sacrifice of thanksgiving (eucharist) or atonement is settled for me by Hebrews 10: “Where there is forgiveness of these, there is no longer any offering for sin.” There are too many passages where the sacrifice of Jesus is spoken of in the past, and as “once for all”. It is not a perpetual sacrifice we can re-partake in weekly. Not according to the word of God.