Okay. This is not a defense. I'm just trying to articulate and adumbrate the question from my POV.
The word “materialist” is often used in a disparaging way. That's not the way I'm using it. Your objection is consistent with a materialist view.
My “thinking,” if you'll pardon the self-flattery, about what a “thing” IS shows a line of thought influenced by “hylomorphism,” by Aristotle viewed through the Aquinas lens.
I think that the “what-it-is-ness” of bread is different from what it is made of and its organization. We can have corn bread and barley bread and it's not, in my view, merely convention that they are both called “bread.”
Still, with all that as the conceptual background to Aquinas's development of transubstantiation, I think it's important to remember that it's taught as a unique miracle. It's SORTA LIKE using, as we did when I grew up, an old radiator as a mooring anchor. (Is it still a radiator or is it now an anchor?) Similarly, a simple annulus of precious metal is called a “wedding ring” not because of the specific metal or a particular shape but because of its being at thing of value given to represent a marital commitment.
It's LIKE those, but it's taught as a unique change in “what-it-is-ness” done in defined circumstances by an act of God.
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Remember the word “Real” in the phrase “Real Presence” does not mean anything even close to “material.” “Realism” in the terms of discourse is about the way triangles or “triangularity,” or “virtue” or “equality” are real. “Realists” in this sense think at least some things we think of, some “ideas” are “real. A triangular prism exists, is “real,” as an object contemplated by the intellect of men and angels. The glass prism you get at an optical supply house is an instantiation, and only an approximate one, of the “real” prism.
The rock that hit me in the eye is more material, but less “real” than the hatred that led to its being thrown.
Again, I'm not defending. I'm trying in haste to present another way of looking and talking about what a thing is.
So ... it's a difficult conversation to do well.
No, using a material for different purposes is simply not analogous to asserting that something in substance is really something that it is not what is really is except by the eye of faith, and contrary to how the the Source emphasizes its reality. Rather than a Christ who breaks bread as representative of His body which is to be "broken" (dâkâ'=bruised Is. 53:5,10) and states, "Behold my hands and my feet, that it is I myself: handle me, and see; for a spirit hath not flesh and bones, as ye see me have" (Luke 24:39) you have a christ which basically asserts, Behold bread which really does not exist, that it is I myself, though if you handle it and see that bread hath not a body of flesh and bones, as ye see me have, and like as My Body, it is what it appears to be as regards the flesh, yet you are to believe it by faith alone."
For we are talking about "Take, eat: this is my body, which is broken for you: this do in remembrance of me"(1 Corinthians 11:24) a body that really was incarnated as human, and that really was crucified and rose, and only appeared and would scientifically test as human in this dimension in which He was crucified, and which manifest physicality is emphasized as identifying the true Christ versus one whose appearance was an illusion, not being what He really was via the incarnation, and who never appeared as a mere and non-existent inanimate object in His interactions with souls after that. Pagans can (wrongly) say that an inanimate object is God, but the apostles dis not preach that a loaf of bread was really Christ.
Yet Catholics are told that a bit of bread or sip of wine, "independently of our mind...have ceased to exist after the consecration," having been “substantially changed into the true and proper and lifegiving flesh and blood of Jesus Christ our Lord,” down to the smallest visible particle becoming the “true Body of Christ and his true Blood," "the very body which he gave up for us on the cross, the very blood which he "poured out for many for the forgiveness of sins, with His human body and human soul, with His bodily organs and limbs and with His human mind, will and feelings," "under either species alone" for "the bread and wine no longer exist but have been totally changed into the body and blood of the Saviour..." being corporeally present whole and entire in His physical reality,” consequently, eating and drinking are to be understood of the actual partaking of Christ in person, hence literally” through which “the work of our redemption is carried out,”as long as the Eucharistic species subsist."Even though contrary to the incarnated Christ of Scripture, "the presence of Christ's true body and blood in this sacrament cannot be detected by sense, nor understanding, but by faith alone..."
That is "until the Eucharist is digested, physically destroyed, or decays by some natural process," in which case "Christ has discontinued His Presence therein." Likewise, "if the quantity of water added exceeds that of the Precious Blood, although similar in appearance, it is no longer integrally what it once was." Sources. (Note that while appearance is to be discounted in believing the Eucharist to be the true body and blood of Christ, in order to avoid technical problems such as the possibility of particles being airborne and thus God ending up in the carpet, etc., and of invisible molecular decay occurring from the point of formulation, then it is theologically held that in the case of decay then visibility is a necessity.)
Remember the word “Real” in the phrase “Real Presence” does not mean anything even close to “material.” “Realism” in the terms of discourse is about the way triangles or “triangularity,” or “virtue” or “equality” are real. “Realists” in this sense think at least some things we think of, some “ideas” are “real. A triangular prism exists, is “real,” as an object contemplated by the intellect of men and angels. The glass prism you get at an optical supply house is an instantiation, and only an approximate one, of the “real” prism. The rock that hit me in the eye is more material, but less “real” than the hatred that led to its being thrown. Again, I'm not defending. I'm trying in haste to present another way of looking and talking about what a thing is. So ... it's a difficult conversation to do well.
None of these gymnastic attempts to justify what is not what the NT church manifestly believed would be necessary if the most logical and Scriptural explanation was accepted. Which is that the apostles and NT church, being very familiar with metaphorical language, including the Canannite being said to be "bread" for Israel (Num. 14:9) and drinking water plainly being called "blood" since the noble men who obtained it risked their lives in so doing and thus David refused to drink it but poured it out unto the Lord; (2 Samuel 23:16-17) And with hearing the Word being called eating and drinking, ("eat ye that which is good, and let your soul delight itself in fatness. Incline your ear, and come unto me: hear, and your soul shall live; and I will make an everlasting covenant with you, even the sure mercies of David:" (Isaiah 55:1-3), then it is most reasonable that rather than the questioning and protesting Peter along with doubting Thomas and the rest of the apostles quietly believing in transubstantiation at the last supper, then they well understood the broken bread and poured wine as representing the body and blood of Christ. And in no place interpretive of the gospels (Acts thru Rev.) - not even in Hebrews - is there any discourse on this, and in the only epistle in which there is a clear description of the Lord's supper (with what was consumed stated to be "this bread"), it is the body of Christ not being recognized is that of the church, being "one bread." And with only the word of God being described as spiritual food. There is simply no reason for laboring to read into Scripture a meaning that is not what the totality of and especially the epistles teaches or manifests was believed. we ought therefore to desire Him in order that we may have life, and to devour Him with the ear, and to ruminate on Him with the understanding, and to digest Him by faith. (Tertullian: On the Resurrection of the Flesh, Chapter 37; http://www.newadvent.org/fathers/0316.htm)