The reason I am raising this question is not so much to understand communion as to understand:

  • "one substance with the Father" (since that seems at odds with Hebrews 1:1-3 to me)
  • "consubstantiation"
  • "transubstantiation"

My thought is by understanding this specific I might have a better idea of what they might mean.

So if someone eats Jesus' body does "same substance", "consubstantiation" or "transubstantiation" suggest that Catholics are they eating the Father's substance?

Again, these are probably ignorant questions but the answers might clarify for me what the Catholic theologians are on about.

  • I'd want someone more knowledgeable with Catholic theology to confirm, but I expect the answer is that it is the divine nature of Christ the Son of God that is consubstantial with the Father, whereas it is only the human nature of Christ that is consumed in the eucharist. – curiousdannii Oct 30 '18 at 12:59
  • Also, consubstantiation is considered heresy by the Catholic Church, but is accepted by some Lutherans. – curiousdannii Oct 30 '18 at 13:01
  • Oh boy. Well I'll have to modify my question then; thanks. – Ruminator Oct 30 '18 at 13:02
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    @Ruminator haha! I'm Catholic and have no idea xD – Joseph Hinkle Oct 30 '18 at 18:15
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    Possible duplicate of this question: On the Eucharist and Human Digestion? – Ken Graham Nov 3 '18 at 12:31

Catholics believe in transubstantiation, that the substance of the bread and wine is, after consecration, completely replaced by that of Christ's Body and Blood.

Consubstantiation (or impanation) is a heresy.

Perhaps you're confusing "consubstantiation" with "consubstantial." The latter term is used to describe that the Persons of the Holy Trinity have the same divine essence.

Do Catholics eat the substance of the Father during “communion”?

The substance, which immutable because God is immutable, does not perish when one receives Communion.

As St. Thomas Aquinas commentates on John 6:27:

The food that sustains the body is perishable, since it is converted into the nature of the body; but the food that sustains the spirit is not perishable, because it is not converted into the spirit; rather, the spirit is converted into its food. Hence Augustine says in his Confessions: “I am the food of the great; grow and you will eat me. But you will not change me into yourself, as you do bodily food, but you will be changed into me.”

(source: this answer)

  • Yes, I was confused by consub*. Thanks! – Ruminator Oct 30 '18 at 21:31
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    I don't think you've really answered the question about the substance of the Father. What does the CC say about communion in relation to the two natures of Christ? – curiousdannii Oct 30 '18 at 23:26
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    @curiousdannii Also related: the whole Christ is contained under each species of this sacrament. – Geremia Oct 30 '18 at 23:47
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    @Geremia That would be better to include in the answer yes. Hmm, so the CC really does teach that you consume the divine essence of God in communion. I find that entirely troubling, but at least the theology is consistent. – curiousdannii Oct 31 '18 at 0:33
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    "completely replaced by that of Christ's Body and Blood, respectively". I have to contest the "respectively" part. It is understood that both the Body and the Blood are present in the bread and the wine. Perhaps you didn't mean to make the impression that the bread contains only Body and the wine contains only Blood. This is how, if in absolute necessity, only bread or only wine can be given and it would still be valid. – fredsbend Oct 31 '18 at 5:24


Transubstantiation is a Latin word consisting of trans (a transition or change) and substantia (substance, or what [makes a thing what] a thing is). Properly, then, it means 'change of what it is.'

This was naturally adopted by a Christians (the East use the Greek equivalent, however, metaousia), who believed that the words of consecration, "This is my body" were literally true of the bread, but not that this demanded the makeup of bread to disappear from it physically—it was a change by God of what the thing now is.

St. Cyril of Jerusalem's words sum this belief up quite well (Catechetical Lectures, 22):

For you have just heard him say distinctly, That our Lord Jesus Christ in the night in which He was betrayed, took bread, and when He had given thanks He broke it, and gave to His disciples, saying, Take, eat, this is My Body: and having taken the cup and given thanks, He said, Take, drink, this is My Blood. Since then He Himself declared and said of the Bread, This is My Body, who shall dare to doubt any longer? And since He has Himself affirmed and said, This is My Blood, who shall ever hesitate, saying, that it is not His blood? ... Consider therefore the Bread and the Wine not as bare elements, for they are, according to the Lord's declaration, the Body and Blood of Christ; for even though sense suggests this to you, yet let faith establish you. Judge not the matter from the taste, but from faith be fully assured without misgiving, that the Body and Blood of Christ have been vouchsafed to you.

As such, Catholics don't believe that Jesus' body is of one substance with the Father (but that the Son is). The Son is distinct from the body He assumed, given what this sentence just said. Nor do they even believe that Jesus is of one substance with His body (the Son and the body being conflated in such a case). They believe that the substance of the bread has become the substance of the body of Jesus, which is united to His soul and divinity (given that He is a real man with a soul, and the incarnate God).

In other words, they believe it is true when Jesus says, "This is my body" (not 'this bread' is my body; nor a game of charades).

(All accusations of 'cannabalism' will fall on deaf ears, too, when it comes to Catholics, since we know and have always known that there is no change in the accidents—the bread is the same to us before and after and to our body, physically. What has changed alone is the spiritual benefit when recieved, since "God has called" (Acts 10:15; Luke 22:19) it the Bread of Life, which is "[Jesus] flesh" (John 6:51). And so it is in all but appearance.)

  • Okay, so my supposition that "consubstantiation" and "transubstantiation" speak of the same thing as "same substance with the Father" is off; they speak of the body only and that in complex terms but ultimately expressing the idea of a "symbol" acting as proxy for something else? – Ruminator Oct 30 '18 at 13:53
  • Consubstantiation is not the same thing, no. Consubstantiation is the 'withizing' of something in Latin, since it means 'with the substance.' Christ's body isn't 'with' the bread, the bread becomes (changes substance) the body of Christ. Consubstantiation would be a Lutheran doctrine which says Christ is 'with' what remains bread. And once again, that the Son shares one and the same divine nature with the Father is not the same as his body being one substance with the Father. The Eucharist is not a symbol of the body of Christ in Catholicism or Orthodoxy. It is such. – Sola Gratia Oct 30 '18 at 14:23
  • I'm reminded of the Talmud where such discussions are routine. Okay, thanks. – Ruminator Oct 30 '18 at 14:28
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    @ruminator I agree that it is a bit confusing, especially since the Nicene Creed says Jesus is "Consubstantial with the Father". You might remember consubstantial be translated "One in being" (after Vatican II), but went back to being "Consubstantial" (in 2008 or thereabouts) since apparently those two ideas are not consubstantial. – Peter Turner Oct 30 '18 at 15:39
  • @SolaGratia you are correct about "consubstantial" when used in connection with understanding the Eucharist, but it might be useful to notice that the Latin version of the Creed referring to Christ being of one substance uses the term "consubstantialem" == consubstantial. Same word, similar meaning, different application – eques Oct 30 '18 at 15:57

Just in case it helps, while transubstantiation does mean that the bread and wine of the eucharist become the actual body and blood of Christ, Aquinas, I know, argued (working from Aristotle) that while the substance of the bread and wine really does change, that needn't mean that one is actually consuming blood and flesh (as though the bread and wine change into a rare steak or something), since those qualities are "incidental" to the real substance.

The "of one substance" language isn't directly related to the Eucharist, as far as I'm aware. It comes from the Council of Nicea (325 A.D) and its ruling on the relationship between Christ and God the father, who it said to be "of one substance" (gk. homoousios). The term is more related to Christology than to the eucharist.

"Consubstantiation" is normally connected to Martin Luther's take on the eucharist, who believed that the "real presence" of the body and blood of Christ exists, in a way, right alongside the bread and wine. So the bread and wine don't change substance, but the real presence of Christ is there in the sacrament.

  • To an outsider like me it appears that Catholic theology is written in its own language – Ruminator Oct 30 '18 at 23:27
  • " that one is actually consuming blood and flesh " This part is inaccurate at best. The definition of substance means what something really is. So you cannot say it is the body and blood and then not actually consume blood and flesh. Substantially, it is body and blood. It is not carnally that because it lacks those accidents. – eques Nov 2 '18 at 18:18
  • @Ruminator not so much its own language as in the language of Western Philosophy – eques Nov 2 '18 at 18:18
  • @eques Ah, that makes sense, thanks. – Ruminator Nov 2 '18 at 18:19
  • Eques: Sorry if I wasn't entirely clear. I am thinking of the Thomistic differentiation between substance and accident. For Aquinas, substance is the true nature of a thing--what it really is divorced from any accidental characteristic. – Mark Bruce Nov 5 '18 at 1:06

Sorry, adding this as an addition answer since it was too long for a comment:

Eques: Sorry if I wasn't entirely clear. I am thinking of the Thomistic differentiation between substance and accident. For Aquinas, substance is the true nature of a thing--what it really is divorced from any accidental characteristic.

For example, we might see accidental variation in dogs when we see them in different colors, shapes, sizes, times and places, but it would be absurd to say define "dog" in terms of any of those accidental characteristics (if we see a brown dog on a street corner at noon, we don't, for that reason, conclude that anything that shows up wearing brown on a street corner at noon is a dog).

Aquinas makes that distinction between the substance of the body and blood of Christ in the sacrament and the accidental characteristics like the flavor, texture, color, etc. of flesh and blood. The substance of the eucharist is the body and blood of Christ, and that doesn't change. So, while the substance of the bread and wine really do change into the substance of the body and blood of Christ, the accidental properties don't change--hence we really are consuming the flesh and blood of Christ even though we're experiencing the accidental properties of bread and wine (which is why those are the things we taste). This is an important distinction because if we, by this reasoning, were only looking at a transformation from flesh and blood into bread and wine, the real presence of Christ wouldn't be there in the sacrament; only accidental properties will have changed, like turning a chocolate lab yellow. It's also sort of important to our own sensory experience, since we know we're tasting bread and wine. (It's also part of the difference between the sacrament and cannibalism!) Hope that's more clear.

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