Transubstantiation literally means “the change of substance.” It is not dependent on Aristotelian philosophical terminology (though it would help to know it). Transubstantiation rests upon the distinction between accidental change (outward properties are transformed) and substantial change (creation of something new altogether). The Eucharist is a supernatural substantial change in which all physical properties remain unchanged. (Water changing into ice/steam is a natural accidental change. Food changing into ATP is a natural substantial change. The multiplication of the loaves in Mt 14:19 was a supernatural accidental change.)
Weak Philosophical Objections
Transubstantiation requires a lot of faith and is grounded in Scripture. It is beyond reason but not opposed to it. If God can become Man, then it cannot be deemed impossible for bread and wine to become the real body and blood of Jesus. If God can become incarnate (become part of the material world) in order to save the world from sin, then the materials of bread and wine can become God in order to fill us with grace.
Real Presence of Christ in the Eucharist
John 6:47:63,66
“ ‘Truly, truly, I say to you, he who believes in me has eternal life. I am the bread of life. Your fathers ate the manna in the wilderness, and they died. This is the bread which comes down from heaven, that a man may eat of it and not die. I am the living bread which came down from Heaven; if anyone eats of this bread, he will live forever; and the bread which I shall give for the life of the world is my flesh.’ The Jews then disputed among themselves, saying ‘How can this man give us his flesh to eat?’ So Jesus said to them, ‘TRULY, TRULY, I say to you, UNLESS you eat the flesh of the Son of man and drink his blood, you have no life in you; he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. For my flesh is food INDEED, and my blood is drink INDEED. He who eats my flesh and drinks my blood abides in me, and I in him. As the living Father sent me, and I live because of the Father, so HE WHO EATS ME will live because of me. This is the bread which came down from Heaven, not such as the fathers ate and died; he who eats this bread will live forever.’ This he said in the synagogue, as he taught at Capernaum. Many of his disciples, when they heard it, said, ‘This is a hard saying; who can listen to it?’ But Jesus, knowing in himself that his disciples murmured at it, said to them, ‘Do you take offense at this? Then what if you were to see the Son of man ascending where he was before? It is the spirit that gives life, the flesh is of no avail; the words that I have spoken to you are spirit and life.’… After this many of his disciples drew back and no longer went about with him.”
James Cardinal Gibbons comments on what is so plain: “If the Eucharist were merely commemorative bread and wine, instead of being superior, it would really be inferior to the manna; for the manna was supernatural, heavenly, miraculous food, while bread and wine are a natural, earthly food….” Of course, Jesus says that the bread (who He is) is superior.
Among the Jews of Jesus’ time, the phrase ‘eat the flesh’ was a metaphor for a grievous injury. It is obvious that our Lord did not use the phrase in this sense (which would have been nonsensical), so it is altogether reasonable to conclude that he intended a literal meaning. When Protestants claim that Jesus meant only to “believe” in him, or to “accept” him spiritually and symbolically by faith, they are violating their own hermeneutical tenet of interpreting Scripture according to the Jewish customs, idioms, and usages of the time. The Protestant metaphorical interpretation dates back only to the 16th c.
Surely Jesus would not condemn people to eternal punishment (Jn 6:53) for the neglect of something that they never even comprehended in the first place! Rather, it was the rejection of a divine revelation due to its difficulty that was the cause of the loss of eternal life (6:57-58). The hearers, it is true, did not grasp the miraculous, sacramental way in which Christ was speaking (6:60-61) and balked (somewhat understandably) at the notion of what they imagined to be some sort of grisly cannibalism (6:52). Jesus countered with a statement that his natural human body would ascend to Heaven and not remain on the earth (6:62), and that spiritual wisdom and grace are necessary in order to understand his words (6:63, 65).
The non-acceptance of Jesus’ message was not due to mental incomprehension but rather willful disobedience and the resisting of the Spirit (Jn 6:63-65; cf Mt 13:10-23). Projecting this lesson to modern day Christians, I sincerely hope it is the case that Protestants simply do not fully understand the Eucharist rather than willfully disobey this command of Jesus. Only here in the New Testament do we have an account of followers of Christ abandoning him for theological reasons (Jn 6:66). But Jesus reiterates his teaching of eating his flesh no less than four times! He doesn’t soften his rhetoric but rather kicks it up a notch.
In the Greek, Jesus switches terms for “eat.” At first the word is “phago,” (used nine times in Jn 6:23-53) a generic term for eat used throughout the New Testament. But in Jn 6:54-58, the word used (four times) is more graphic and particular: “trogo,” which literally means “gnaws” or “chews.” Trogo occurs only here and in Mt 24:38 and Jn 13:18. The literal meaning is unmistakable.
This is My Body
Lk 22:19-20 “And he took bread, and when he had given thanks he broke it and gave it to them, saying, ‘This is my body which is given for you. Do this in remembrance of me.’ And likewise the cup after supper, saying, ‘This cup which is poured out for you is the new covenant in my blood’” (see also Mt 26:26-28; Mk 14:22-24)
Jesus says “This is my body” (but which has the appearance of bread), not “here is my body,” which would infer more so the Lutheran view, whereby his body is present along with the bread and wine (consubstantiation). The position that these words are only symbolic− “this represents my body”− is a strained interpretation, since, as in Jn 6, a figure of speech not in common usage (at that time, for that culture) would have deceived the hearers. Bread and wine are not even particularly natural, analogous symbols of body and blood. When the word “is” in Scripture has the meaning “symbolizes,” this sense is readily apparent (e.g. Mt 13:38; Jn 10:7, 15:1; 1 Cor 10:4), whereas in this case it is not.
Moreover, Jesus and his disciples were celebrating Passover, which involved a literal sacrificial lamb. It strains credibility that the disciples missed the profound significance of Jesus’ words. Indeed, Passover to the Jews was no mere remembrance: they believed that the celebration transcended time in such a way that they were experiencing THE very moment of Passover at every celebration. This is very similar to the Catholic understanding of the Eucharist.
Other passages
1 Cor 10:16 “The cup of blessing which we bless, is it not a participation in the blood of Christ? The bread which we break, is it not a participation in the body of Christ?” (see 1 Cor 10:14-22 for context)
1 Cor 11:27-30 “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. Let a man examine himself, and so eat of the bread and drink of the cup. For anyone who eats and drinks without discerning the body eats and drinks judgment upon himself. That is why many of you are weak and ill, and some have died.”
These verses clearly demonstrate that the celebration of the Eucharist was practiced by the earliest Christians.
The second one, the more insightful one, clearly equates the bread and wine as the body and blood of Jesus in his admonition against “profanity.” It also emphasizes the seriousness of this practice, whose desecration is even punishable by death (reminiscent of Levitical priests dying in the Holy of Holies in the Old Testament where God Himself was present!). Again, are these early Christians getting sick and dying over some mere metaphor?! The enormity of their crimes can only be derived from a belief in the Real Presence of Christ in the Eucharist.