The problem with this objection is that it fundamentally fails to understand who Christ is; it communicates an ignorance of Christ Himself. Christ is Lord and King of all creation, and as such is Lord and King of time as well. Christ's Crucifixion happened only once, but its effects are eternal, stretching at once back to the dawn of time and forward to the end of time. All ages at once were incorporated into the one true sacrifice of Christ, and all ages participate in it -- this must be true, because Christ died for the sins of all humanity, not just for the sins of those living in the day and age in which He walked the Earth.
Christ's sacrifice was not only temporal; it was eternal. It is therefore not unreasonable in the least to suggest that He could share His own body, broken, with the gathered apostles at that Last Supper, even though the temporal event -- the Aristotelean notion of "accidents" may be relevant here as well -- of his suffering had not yet occurred.
One other objection is sometimes based on verse 29, above, but to this it serves to note that Christ Himself said that He "is the true vine" (John 15:1) -- if the wine is the fruit of this vine that is Christ, then let it be His blood just as He said it was.
Christ's true revelation in the breaking of the bread is later confirmed by His appearance to the disciples on the road to Emmaus, as chronicled in Luke, chapter 24.
[24] Some of those who were with us went to the tomb, and found it just as the women had said; but him they did not see."
[25] And he said to them, "O foolish men, and slow of heart to believe all that the prophets have spoken!
[26] Was it not necessary that the Christ should suffer these things and enter into his glory?"
[27] And beginning with Moses and all the prophets, he interpreted to them in all the scriptures the things concerning himself.
[28]So they drew near to the village to which they were going. He appeared to be going further,
[29] but they constrained him, saying, "Stay with us, for it is toward evening and the day is now far spent." So he went in to stay with them.
[30] When he was at table with them, he took the bread and blessed, and broke it, and gave it to them.
[31] And their eyes were opened and they recognized him; and he vanished out of their sight.
This account actually also lays out the basic structure of the Mass, which begins with an exploration and teaching not only of the Word of God, but of the unity therein; the readings from the Old and New Testaments are chosen specifically to demonstrate that the New fulfills the Old, and that the Old foretells the New.
And once the Scriptures are opened, the bread is broken, and Christ Himself is revealed.
Notice the structure of events here. The two disciples have no idea that it is Christ to whom they are speaking; they think him only an especially wise fellow-traveller. And out of politeness and concern, they invite Him in off of the road in the evening, lest He risk being set upon by bandits as He continues in His way. It is only at the exact moment that Christ breaks the bread -- in a direct repetition of His action at the Last Supper -- that His full nature is made known to them. They saw but a man, but in the breaking of the bread they saw Christ fully revealed, and (for an instant) fully present in their midst.
St. Paul takes all of this into account in his sharp rebuke to the Corinthians (1 Cor 11). There is a real problem in the Corinthian church, which Paul briefly details:
[20] When you meet together, it is not the Lord's supper that you eat.
[21] For in eating, each one goes ahead with his own meal, and one is hungry and another is drunk.
Essentially, there was disunity in the Corinthian church, and (what is more) there was needfulness which was being ignored. Those who were wealthy and had food ate and feasted, while ignoring the needs of those who had little, and yet still came to remember in celebration the Last Supper; Paul tells them, essentially, that in coming together to receive Christ when they have been ignoring the needy, they essentially commit a wretched blasphemy.
[22] What! Do you not have houses to eat and drink in? Or do you despise the church of God and humiliate those who have nothing? What shall I say to you? Shall I commend you in this? No, I will not.
He then goes on to correct them, continuing his rebuke now with an explanation of just why their actions and inattentions have the gravity that they do.
[23]For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread,
[24] and when he had given thanks, he broke it, and said, "This is my body which is for you. Do this in remembrance of me."
[25] In the same way also the cup, after supper, saying, "This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me."
[26] For as often as you eat this bread and drink the cup, you proclaim the Lord's death until he comes.
[27]Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord.
[28] Let a man examine himself, and so eat of the bread and drink of the cup.
[29] For any one who eats and drinks without discerning the body eats and drinks judgment upon himself.
[30] That is why many of you are weak and ill, and some have died.
[31] But if we judged ourselves truly, we should not be judged.
[32] But when we are judged by the Lord, we are chastened so that we may not be condemned along with the world.
[33]So then, my brethren, when you come together to eat, wait for one another --
[34] if any one is hungry, let him eat at home -- lest you come together to be condemned. About the other things I will give directions when I come.
Paul pulls no punches here -- he plainly says that if the Corinthians come together in remembrance of Christ's Last Supper when some among them are hungry from lack of food, the whole assembly will be condemned by their act of remembrance. Verse 29 spells out the vector by which this condemnation arrives: " any one who eats and drinks without discerning the body eats and drinks judgment upon himself." And in Verse 27, Paul is again very plain in his meaning: "whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord."
How can one eat and drink judgement if one is eating mere bread and drinking mere wine? Do bread and wine have power to condemn a man? No! Only Christ has that power...and indeed, the bread and wine are Christ Himself. How else can one profane Christ by receiving the bread and wine in an unworthy manner? Christ must be really, truly, and materially present in the bread and wine for these verses to make one iota of sense. For how can bread alone condemn a man? Christ has power to condemn, bread does not. If in eating the bread, a man can be condemned by it, then the bread must be literally Christ.
And moreover, it is a participation in Christ, and in His one true sacrifice. A common canard one encounters is that Catholics "re-sacrifice" Christ. This is not the case; the Eucharist is a participation in the aspect of the one true sacrifice which is eternal, and which reverberates through all ages of history. It is like the loaves and the fishes -- Christ gave his once-broken body to the disciples, and He gives it to us as well.
The Church uses the term "transubstantiation" to describe the moment at which the bread ceased to be bread and becomes the body of Christ, and the moment at which the wine ceases to be wine and becomes the blood of Christ. That is a term borrowed from Aristotelean philosophy, to describe a process by which something becomes something else save for its external attributes.
Many Christians object to this philosophy as an example of old paganism corrupting Christ's truth. But that doesn't make much sense when Christ Himself that the gates of Hell would not prevail against His Church, against His Bride. How can mere natural philosophy -- which was not specifically related to pagan worship, but instead to how the Greek philosophers understood the world -- corrupt something which Hell itself cannot prevail against?
The assertion is ludicrous on its face, and demonstrates again a fundamental misunderstanding of Christ. And funnily, it is on this specific objection to transubstantiation that I often find Christians and atheists in agreement.
What I find both ironic and tragically interesting about Christian and atheist objections to the reality of Christ in the Eucharist is how they often seem to be founded on the same core thesis: "that's magic talk; it's not real!" Oh, differences in approaches exist -- the Christian objector will tend to follow up his declaration with a handful of verses of Scripture (often cited in a manner that is grossly out of context), while at the same time denouncing as pagan (and therefore necessarily incorrect) theological concepts like transubstantiation. The atheist objector, meanwhile, will attack the same theological concepts from an empirical standpoint.
And every once in a while, the two sides will switch it up -- the atheist will be the one citing Scripture, the Christian the one citing empiricism. It's a strange reversal, but it has happened. But the reversal is not the point, O Reader -- the point, such as it is, is that Christian and atheist find common cause, and employ essentially common means, in pursuit of an unknowingly unified anti-Catholic goal.
What is even more tragic, in the case of Christian denunciations of the Eucharist, is that many of the same people who would denounce the rather literal Catholic interpretation of, especially, John 6:53-56, absolutely insist on a literal interpretation of Genesis 1 through 9. Present them with Christ specifically commanding that His flesh be eaten and His blood consumed, though, and you will be greeted with a litany of hasty denials: Catholics are misinterpreting Scripture, Christ isn't speaking literally, Catholics aren't understanding Christ's real meaning, and so forth.
It's a strange dichotomy, that they are willing to place more faith in the literal meaning of the words of the author of Genesis than they are in the words of He who supposedly is their Lord.
In the end, Scripture itself is remarkably consistent on this matter: Jesus promised He would be present when we gather in His name, He commanded that we eat His flesh and drink His blood (which he will give), and He bade us to take that which was bread and that which was wine and consume them in a manner that was a fitting remembrance of Him. To counteract the despair and doubt of His disciples, He appeared again and was revealed to them in a repetition of His actions at the Last Supper -- the eyes of the disciples perceived Christ, literally and truly present in their midst, in the moment the bread was broken. And St. Paul completes the teaching, warning that practicing the remembrance Christ commissioned in a manner that was disrespectful either of the bread and wine or of other members of the community would bring -- in the act of consumption -- condemnation.
And yet, in the end, it comes down to faith. We can have all the words in front of us and still not perceive the full truth of the matter, and faith must step in where understanding fails. When we come to Mass and step up to receive Christ, we receive what appears to be bread, and we drink what appears to be wine. Shape, taste, feeling, and scent all suggest bread, and the mind desires to label that which looks like a duck as a duck.
But the disciples on the road to Emmaus made that mistake too. They had seen Christ die, or had heard of His brutal death. They had seen Christ buried, or had heard that he had been placed in the tomb. And they had heard that His body had gone, and they thought Him stolen. They had concluded, at the end of all these events, that the Lord their God had been a great prophet, but ultimately just a man who had been murdered and who was gone now, forever.
And who could blame them for thinking so? They had seen Christ die, as surely as they had seen others die in the past.
And yet, they were wrong.
And so are we, if all we see is bread and wine.
In the end, it is a question of faith. Now, I can understand if people cannot, in their faith, accept that Catholics don't receive mere bread and wine from the altar. It is, as the Jews noted too, a hard teaching to accept. And I respect that not all Christians can believe this hard teaching.
But some Christians go beyond that, and into formal denunciation of the teaching itself. Jack Chick's famous "Death Cookie" tract stands out here as one of the best examples, although he and others have produced volumes of writings in an attempt to illustrate where Catholics have gone wrong. For these Christians, it would be easy to feel contempt, given how obviously and plainly their words and beliefs so obviously contradict the plain meaning both of St. Paul's teachings and Christ's own statements.
But for such Christians, I instead feel pity. For their issue is not that one of faith; it is one of fear. Let us be plain: Catholics encounter, in the Eucharistic meal, Christ...directly. He's right there in front of us, right there with us, literally and truly present among us. We stand, but for a moment, in the ante-chamber of Heaven itself, and for a brief while are in the holiest place in all the Universe: we are at Christ's very feet.
And some Christians seem to hate and fear that Catholics experience Christ that closely, that intimately. "It can't be," they say. "It's a lie," they insist. "It's false teaching," they exclaim. But their words are empty, and their thinking muddled by their own fear of such a close and personal encounter with Christ. They often talk of accepting Christ as one's personal Lord and Saviour, and in that they do well. But Catholicism takes a person one step, or perhaps several steps, further than that. We do not just accept Christ...we see Him, greet Him, and are touched by Him.