The vast majority of Christians who walked upon this earth for 2000 years have accepted on simple faith that "this is my body" and "this is my blood" and "do this in memory of me" mean literally what they say.
Last I checked, Christian truth is determined by God, not by majority vote of fallen humanity. But even so, the notion of "literal" presence as "explained" by transubstantiation is alien to the first few centuries, and nothing identifiable as transubstantiation appeared until Radbertus circa 9th Century. Here's the problem with that. Until an issue like this gets hashed out by vigorous, Scripturally grounded debate, as happened with Athanasius (contra mundum, no less), ambiguities exist in the meaning of the early writers. They did not have the conceptual template of the later generations, least of all Aquinas' use of Aristotle to describe the removal of the substance of the bread and wine. When an early writer speaks of the bread as the body of Christ, are they doing so with substance swapping in mind? Or are they simply asserting that what the symbol represents, what lies in back of it in history, is real, or is somehow made manifest through the elements of the sacred meal, with no effect on the actual substance of the bread or the wine?
If you follow these arguments on FR for any length of time, you come to realize that for every patristic writer who seems to speak in literal terms, there is another who speaks in more symbolic terms, and sometimes the same writer will use both frames of reference. This is an important clue that their model (or models) for thinking about the Eucharist are not obedient to modern models, nor consistent with transubstantiation, even when taken as merely explanatory (though Trent compels the use of that "explanation" on pain of anathema for failure to do so).
Which is why the court of first and ultimate resort must be the divine teaching of Scripture. The early patristic testimony is helpful but not decisive. Augustine further confounds the matter by being decidedly against key principles of transubstantiation, favoring the symbolic sense. So we are not talking about some tiny backwater of the ancient world, but a central figure in the early formation of the Christian model of truth. Thus Protestants see many of their own beliefs represented as threads that at first dominate the early writings, but over time must compete with other threads evolving toward a more literal sense. So rejection of a hyper-literal, anti-linguistic realism does have very early roots, and unlike transubstantiation is not grounded in human theories of time, or categories of substance versus accidence, but most primitively in the plain words of Christ, when He Himself explained the puzzle could only be solved in spiritual terms, not fleshly. See John 6:63. I'm sure you've seen it before.
And if you try to counter this by charging that using metaphorical analysis is "vain human philosophy," I will respond that you are (doubtless unintentionally) saying the entire teaching ministry of Christ is vain philosophy, because when did He
not teach in public using parables? And what are parables but extended metaphors? And how may we understand a metaphor without recognizing it as such? Indeed, metaphor is so basic to human thought and language I doubt we could say much of anything without it.
Again, I'm reasonably certain you know the drill. We both know Jesus is not a door or a vine, etc. Yet He taught that He was. And He was telling the truth. The metaphor conveyed truth. The human mind has no trouble with this way of accessing truth. We spot the cross-mapping between two distinct domains, and immediately pick up on the transferred attributes, the teaching about one thing using another thing. Thus, to reject at least the possibility of metaphor in these teachings on Christ's body and blood is to reject a central feature of human communication as God Himself designed it to work. It is anti-linguistic, and a severe case of special pleading, because the rules applied here are not applied equally in less controversial matters where metaphor does no harm to later-developed doctrinal speculations. Double standards are no friend of good doctrine..
One of my favorite examples is this metaphor from Shakespeare, where Romeo says of Juliet, "Shall I compare thee to a summer's day." Here the metaphor is indirect. The fact that a comparison is being made is set forth explicitly in the word "compare." The teaching value is that we can learn about Juliet, whom we don't know, by comparing here to a pleasant summer day, which we do know. That's the whole point of metaphor, learning about something of which we have no direct experience, by comparison with something we have experienced.
But direct metaphors are just as useful as a teaching device and just as easy to spot. If I show you a paper map of Texas, and say to you, "This is Texas," you would have no trouble whatsoever recognizing that the paper I'm holding isn't really Texas. That's because you're wired for metaphor, just like everybody else. It's how God made you. You see "is," the verb of being, linking two very different types of objects, and you immediately spot the direct metaphor. You realize the paper stands for the geometry of the boundary of Texas, and you can therefore learn something about Texas by studying the paper. And that's just garden variety metaphor, found everywhere and all the time in human communication. It's not vain philosophy. It's a hard, empirical fact about how our minds work, how we learn about things with which we have no direct experience.
The reality is, if the Roman system had not evolved away from Scriptural usage, this would be uncontroversial. No one would have trouble with Jesus' "Bread of Life" discourse. He is using bread to teach about Himself. Bread satisfies the hunger of the stomach. Jesus satisfies the hunger of the heart. Our bodies will pass away, as will all the hungers thereof. But our spirit is eternal. It is our spirit that feeds on Christ as our nutrition. We do not live by bread alone, but by every word that comes from the mouth of God. Like Jesus, our favorite food is to do the will of our Heavenly Father. Which is why Jesus must redirect the confusion of his listeners, who were not learning from the metaphor, because they didn't really believe in Him. He tells them this isn't about the flesh, but the spirit, that His words are spirit. Sit and digest that for a moment. In the end, Peter understood: There is nowhere else to go; only Jesus has the words of eternal life.
And this rendering is consistent with Jesus' teaching style, following closely the pattern of His other metaphorical teachings. Consider for example His teaching on the new birth to Nicodemas. Remember in that passage Nicodemas also has trouble mixing up spiritual and fleshly categories. He thinks Jesus is saying something about going back into his mother's womb and coming back out again, which, taken literally, makes no sense whatsoever. Jesus has to disabuse him of his hyper-literalism and remind him to distinguish between the corporeal and the spiritual, exactly as He does in John 6.
John 6:35 And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst.
Come to Jesus, and you wil never hunger. Believe on Him, and you will never be thirsty. His words are spirit. And they are life. If you believe.
My time is up for now. There is more to say, but perhaps later.
Peace,
SR
If you follow these arguments on FR for any length of time, you come to realize that for every patristic writer who seems to speak in literal terms, there is another who speaks in more symbolic terms, and sometimes the same writer will use both frames of reference. Absolutely! That's exactly what I've found as well.
But you still cannot wring a skeptical position out of them!
Calling something a "symbol" doesn't necessarily mean it is only a symbol. My children are a symbol of my love for my wife and also a real product of that love. So reread carefully all those Patristic quotations that describe the Eucharist as a symbol. See if they also give some indication of belief in the Real Presence or a change in substance--many do.
I remember someone here cited what they thought was the knock-down quotation "proving" the Eucharist was only a symbol--wish I could remember what Father they were citing. Anyway, I did some digging, and not a few paragraphs away from that quote, that Church Father said explicitly that the Eucharistic elements retain their appearances but change their substances.
So it is a mistake to rely on the "symbol" quotations to reinforce a skeptical position. What we actually need is something akin to the black rubric of the Book of Common Prayer:
It is hereby declared, That thereby no adoration is intended, or ought to be done, either unto the Sacramental Bread or Wine there bodily received, or unto any Corporal Presence of Christ's natural Flesh and Blood. For the Sacramental Bread and Wine remain still in their very natural substances, and therefore may not be adored; (for that were Idolatry, to be abhorred of all faithful Christians;) and the natural Body and Blood of our Saviour Christ are in Heaven, and not here; it being against the truth of Christ's natural Body to be at one time in more places than one.
Now THAT is unambiguous.
Make a little gradient of Patristic Eucharistic belief. On the plus side are all those passages where it is taken literally. On the zero mark are all those where it is uncertain or called a symbol without further explanation. On the minus side are all those passages where a literal interpretation is denied, as in the Black Rubric.
Presence Denied-----SYMBOLIC/UNCLEAR------Presence Affirmed
----------------------------------------0+++++++++++++++++++++++++
Dollars to doughnuts every single passage you find in the Patristic sources will be zero or higher--that not a single one will be negative.