The Instigator
Pro (for)
3 Points
The Contender
Con (against)
2 Points

The Catholic doctrine of transubstantiation is false

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Voting Style: Open Point System: 7 Point
Started: 4/3/2014 Category: Religion
Updated: 2 years ago Status: Post Voting Period
Viewed: 1,824 times Debate No: 51582
Debate Rounds (3)
Comments (18)
Votes (2)




I have exactly 1376 forum posts (it may be different by the time you read this since I plan to post some more), and since Section 1376 of the Catechism of the Catholic Church contains the definition of "transubstantiation," I thought this would be a good time to initiate a debate on the subject.

According to the doctrine of transubstantiation, when the bread and wine of the eucharist are consecrated, they cease to be bread and wine and literally become the body and blood of Jesus.[1] I am going to argue that this doctrine is false.

I will have the burden of proof, so my opponent need not prove that the doctrine is true. My opponent only needs to refute my arguments.

The first round is for acceptance, clarification, definitions, and well-wishes.

The rest of the rounds are for arguing.

Please don't accept the debate unless you think there's a really good chance you'll be able to complete it. I don't want anybody to forfeit.

I would prefer to debate a Catholic, but if somebody wants to play devil's advocate, I guess that's okay. No trolling.

I put a 6000 character limit instead of the usual 8000 to encourage voting and discourage forfeiting.

Good luck, whoever you are.

1. Catechism of the Catholic Church, section 1376


I am Catholic and accept your challenge. I will defend the Catholic doctrine of Transubstantiation.

I am only going to use this round solely for acceptance and will tailor my response and any clarifications or definitions to the argument that you make.

Thank-you for the interesting topic. Let's have a good debate.
Debate Round No. 1


To keep things short, I'll refer just to "the bread" instead of "the bread and wine," but whatever I say about the bread should apply just as well to the wine.

There's only one of two ways that transubstantiation could happen. Either the material from which the bread is made (i.e., the molecules, atoms, and subatomic particles) remain there but rearrange themselves so that they cease to be bread and become human flesh, or all of the material from which the bread is made is completely replaced by the material of Jesus' flesh, kind of how wood is petrified by replacing molecule after molecule of wood with molecules after molecule of mineral until there is no longer any wood, but just mineral where the tree used to be.

Either scenario creates problems with identity. By "problem with identity," I mean the problem of what makes the flesh in the Eucharist actually be Jesus' own flesh rather than a replication of Jesus' flesh or somebody else's flesh.

Rearrangement of parts

Let's say transubstantiation works by the bread turning into human flesh by the parts rearranging themselves. Obviously, the bread was not Jesus' flesh before the transubstantiation. So there's nothing that could be done to the bread to make it Jesus' flesh. If none of the parts are members of Jesus' flesh before the transformation, then none of the parts could be members of Jesus' flesh after the transformation. No rearrangement of the parts could cause it to be Jesus' flesh.

If a scientist was able to grow skin in a lab that happened to resemble your flesh down to the DNA structure, but he didn't use any of your actual body parts to grow it from, but rather made it from scratch, then it could not be your flesh. The only way it could be your flesh is if you wore it and it was attached to the rest of the actual body you are animating. If it is completely discontinuous with your body, then it can't be your body. It would be like a person painting a perfect replica of the Mona Lisa. The replica would not be the Mona Lisa itself, but only a perfect duplicate.

Flesh ex nihilo

Now, let's say transubstantiation works by completely replacing all the parts of the bread with human flesh. This creates pretty much the same problem. In this case, the bread basically ceases to exist, and human flesh is created ex-nihilo where the bread used to be. This happens so quickly that nobody who was watching could tell. If that were to happen, then the flesh that came into existence could not be Jesus' flesh. It could, at best, be a perfect replica of Jesus' flesh.

Imagine a wizard causes a cat to pop into existence out of thin air, and imagine the cat is an exact duplicate of another cat down to the molecule. It would still not be the same cat because one cat can't be in two different places at the same time. It would just be a duplicate. in the same way, if human flesh pops into existence that's just like the flesh of Jesus himself, then it still can't be Jesus' flesh. At best, it can only be a duplication of Jesus' flesh.

Conservation of mass

The first transubstantiation was supposed by the Catholic Church to have happened at the last supper when Jesus broke the bread, said, "This is my body," and passed it around for the disciples to eat (Luke 22:19). There is no indication in the story that Jesus lost any body parts during this meal, and I've never heard a Catholic claim that's what happened. Jesus' actual body was located at a specific place in space during this meal, so if the bread became human flesh, by either of the means mentioned above, then it could not have been Jesus' flesh. Assuming it became human flesh, that would mean more human flesh came into existence than was there before, and since all of Jesus' flesh was accounted for by being attached to the body he was then animating, the flesh being passed around for consumption could not have been his flesh.

It's even worse today. Mass takes place all over the world on Sunday, and there are probably tons of wafers that are all supposedly transubstantiated. Jesus' physical body is made of a particular amount of stuff--roughly the same amount as any man. So it is impossible that all those millions of wafers around the world could all be Jesus' body. There isn't enough of Jesus' actual body to go around.


But the problem is worse than that because the bread of the eucharist is not human flesh at all because it doesn't have any human properties. Now, Catholics are right to make a distinction between essential properties and accidental properties. An accidental property would be like a round ball of wax being shaped into a cube. Although the wax changes shape, it remains the same piece of wax. So the shape of the wax is an accidental property. An essential property would be what makes it wax. If you changed the chemical composition, then it would no longer be wax.

Catholics claim that during the process of transubstantiation, the flesh retains the accidental properties of bread, but it has the essential properties of Jesus' flesh. But the problem is that it retains all of the properties of bread and it gains none of the properties of human flesh. To be human flesh, it would have to have a human cellular structure with human DNA. But the bread of the eucharist does not. It is impossible for it to be human flesh since it has none of the properties of human flesh.

Imagine if I told you that your computer was actually a Christmas tree, but that it just happened to have all the properties of a computer and none of the properties of a Christmas tree. That would obviously be absurd. Or, imagine I told you that a square could have all the properties of a circle and none of the properties of a square and still be a square. You'd know immediately that I was talking crazy. In the same way, if the eucharist has all the properties of bread and none of the properties of human flesh, then it can't be human flesh.


Therefore, it's impossible for the doctrine of transubstantiation to be true.

Thank you.



For the most part Pros arguments are straw man arguments because his arguments are not what the Catholic Church teaches about Transubstantiation.

From the Baltimore Catechism

884. After the substance of the bread and wine had been changed into the substance of the body and blood of Our Lord, there remained only the appearances of bread and wine. [1]

885. By the appearances of bread and wine I mean the figure, the color, the taste, and whatever appears to the senses. [1]

And St. Thomas Aquinas wrote in the Summa Theologica:

The presence of Christ's true body and blood in this sacrament cannot be detected by sense, nor understanding, but by faith alone, which rests upon Divine authority. [2]

So the Catholic Church does not teach that the Eucharist becomes in any way discernibly different to the senses. But it teaches that what it truly is has changed.

As an (imperfect) analogy I have red, white and blue silk. Now I weave it it into a flag with stars and stripes and it has become something completely different. Yet to those who have no idea of its true nature it is just silk threads. They have the same chemistry and properties, yet now it is something that some people would die for, while still being the same fabric that it always was. That is because its "substance" has changed, but its "appearance" hasn't.

In the Jewish Passover meal you had to eat the sacrificed lamb with unleavened bread, [3] as Christ's covenant is the perfection of the old Christians have to eat the body of the sacrificed lamb. Through God the unleavened bread of the Eucharist is truly the Lamb of God.

Finally God is not bounded by time or space. As the Catholic concept of God is that he created space and time [4] thus all of history is in the present to God. Christ instituted the Eucharist by saying this is my body, this is my blood. The priest is in "Persona Christi" at mass because Christ gave his authority to the Apostles and through them to their successors. So when the priest repeats the words of consecration, they are simultaneously linked, by Christ's own authority, through time and space to Christ own words and his sacrifice on the cross. Thus it is the true flesh and blood of Christ, presented in an unbloody manner.

This is what the Catholic Church teaches and what Pro has the burden of disproving.


1. Rearrangement of parts.

As previously noted this is a straw man attack. The Church teaches that while the bread and wine do become the body and blood of Christ, it maintains that the physical nature in which this is veiled still appears in every physical manner to be bread and wine.

2. Flesh ex nihilo

Essentially the Church teaches that the true "substance" of the bread is replaced with the true substance of "Christ".

Con is arguing that this means that the Eucharist is a replica of Jesus. Yet as shown earlier the Church does not teach this. The Christian notion of God is that he is omnipresent. However, for our benefit he makes himself present in the Eucharist in a very real and tangible way. For God, this happens simultaneously with the sacrifice at Calvary. It is only for us that it happens at discreet moments in time. Thus to us it appears to come into being, but to God it happens simultaneously throughout history.

3. Conservation of Mass

Con argues that there just isn't enough Jesus to go around. He fails to understand Catholic teaching on the topic. In the Gospel of John there is no discourse on the Last Supper. That is because John discusses the Eucharist in the feeding of 5000.

Jesus told the apostles to feed the people themselves - just as the Catholic priests feed the multitudes. He then turned 5 loaves and 2 fishes into enough to feed the multitude. After this he tells the apostles to "Gather up the leftover fragments so that nothing will be lost." This is j
ust what Catholics do with the precious crumbs of the Eucharist.

If Christ is able to feed 5000 on a couple of fish and a few small loaves of bread, while having more left than he began with, then he is obviously capable of sharing his flesh with the whole world.

4. Properties

I have already addressed this argument in my opening statement, however since I have some space left I'll answer this using another analogy:

Imagine that we have a person in a hospital bed all hooked up to a bunch of life support machines. We can all agree that he is a person. Now let's suppose that something happens and he is now brain dead, but all the machines are still running keeping all of his physical attributes fully functioning.

His "appearance" is the same, the body will still bleed if you prick it and the blood will continue to move oxygen and whatnot around his body, but his "substance" has changed. It is no longer a person, it is just a body.

Let's take this argument further. Imagine that a supercomputer has been built into which the person could transfer his consciousness. The supercomputer would go from just a machine into being a person. And yet there would be no discernible difference to observation. It is just another machine running a program.

Now, if that supercomputer is able to reach out to all the computers around the world, one person could simultaneously be in a virtually infinite* number of places.

While this analogy is not perfect it provides consistency with my arguments.


I believe that, since Pro has accepted full burden of proof for this debate, he must disprove the Catholic understanding of God to win this debate. The Catholic teaching on transubstantiation is intricately linked to the Catholic understanding of God (as limited as God can be understood). Thus he must show that an omnipotent, omnipresent, omniscient God is incapable of making himself truly present in the Eucharist.

I look forward to Pro's arguments.

* not infinite - just millions of places.
Debate Round No. 2


Unforunately, we're having some misunderstandings.

What is transubstantiation?

Con accuses me of making a strawman argument by misrepresenting the doctrine of Transubstantiation. However, his definition is exactly the same as mine. We both agree that transubstantiation entails the substance of bread and wine changing into the substance of Jesus' body and blood with only the appearance of bread and wine remaining. I cited the Catholic Catechism in the first round to this effect, and the definition I gave there is exactly the same as the definition given by Con's citation of the Baltimore Catechism.

Con's flag analogy does not fit transubstantiation at all because even when the silk threads are part of the flag, they remain silk threads. There is no change in substance. Silk threads are the parts that make up the flag. It is not the Catholic position that bread is a part that makes up the body of Christ. So if anything, Con is misrepresenting the Catholic position with his analogy.

Con's attempted rebuttals

In the previous round, I gave two ways transubstantiation could happen and showed that both were problematic.

1. Rearrangement of parts

Con accuses me of strawman here, but didn't show it. He states that although the bread and wine become the body and blood of Jesus, they maintain the appearance of bread and wine, which is irrelevant to my argument. My argument is that if you rearrange the parts to turn bread into wine, even if you arrive at human flesh, it cannot be Jesus' flesh. There is a problem of identity. I gave a thought experiment to demonstrate this fact, which Con ignored.

I'll use another one. Suppose instead of saying, "This is my body," Jesus had said, "This is John's body." And suppose the exact same thing happened--the bread turned into human flesh. What makes it John's body rather than Jesus' body? All Jesus can do is turn the bread to flesh. But there is nothing he could do in addition to that to cause it to be one person's body rather than another's.

2. Replacement of parts

Con reveals in his response that he has completely misunderstood my argument. I am not claiming that the Catholic Church teaches that transubstantiation only results in creating a replica of Jesus. As I have said, they teach that the bread actually becomes Jesus body itself. My argument is that given how transubstantiation must occur, it is impossible it could be Jesus' body itself. If you replace all the parts of bread with flesh, the best you could get is a replica, not Jesus' actual body. That's why the Catholic doctrine is impossible.

I used a thought experiment that Con ignored. I'll use another one. Imagine Jesus has a cube in his hand, and he wants that cube to be in your hand, too. *POOF* A cube appears in your hand just like the one in Jesus' hand, yet it never left his hand. Is it even possible that these two cubes could be the same cube? Of course not! That is logically impossible since they are located in two different places.

In the same way, when Jesus said, "This is my body," it is impossible that the bread he was handing out was the same body as the body that was reclining at the table that Jesus was animating.

So transubstantation by replacement of parts would be a violation of the law of identity. That's why I say the Catholic doctrine is impossible rather than merely unlikely. God himself cannot violate the laws of logic.

Conservation of mass

Con attempts to make a parallel between Jesus multiplying fish when feeding the 5000 to the priest multiplying Jesus' flesh during Mass. If Jesus started with 2 fish and created 4998 more, it is not possible for them to all be the same fish. It's possible they're all perfect replicas of the original 2 fish, but it is not the Catholic position that the Eucharist is a replica of Jesus' flesh. To make this parallel work, Con would have to argue that 5000 fish were actually the same 2 fish, which is a contradiction.

Perhaps Con thinks there remained only two fish, but they got bigger. But that is clearly not analogous to what happened at the last supper. Jesus didn't grow fatter, then cut off parts of his body. He remained in tact, and more flesh came into existence that was not connected to Jesus' body. Since Jesus didn't lose any parts, it's not possible the bread could be his body. And since Jesus has a physical human body, even in his resurrection body, it's not possible that all those wafers on Sunday morning could all be Jesus' body.


Con claims he already responded to this argument, but he hasn't. I argued that it is impossible for an object to have all the properties of one thing, and none of the properties of another thing, and yet be that other thing. Con only claimed that his church teaches the body and blood keep the properties of bread and wine. But that's the very teaching I object to, so pointing out that it's what his church teaches doesn't amount to a rebuttal. Con needs to answer my argument. Is it possible for a computer to have all the properties of a Christmas tree and none of the properties of a computer, and still be a computer?

His analogies are woefully inadequate. A human body remains a human body even right after death. But then it ceases to have any of the properties of personhood, so it's not a person.

If it were possible to upload your consciousness in a computer, then download it to multiple computers, that wouldn't result in you being in multiple places at once. That would result in copies of you being in multiple places at once. God could easily create another copy of you and plant all of your mental states in it, but it would still just be a copy of you, and not you yourself. By the indiscernibility of identicals, if anything is true of person A that is not true of person B, then they cannot be the same person. So a simultaneous multiply located person is impossible.


Transubstantiation is impossible because it violates the fundamental laws of logic. It isn't merely unlikely; it is logically impossible.



Opening Remarks

I was under the impression that Pro's first arguments did not include the substance/accident issue because he listed that last instead of first. As such I interpreted it as 2 separate arguments.

Additionally, I fully accept that my analogies are imperfect (I clearly stated so in the previous round) because it is impossible to create a perfect analogy for the Eucharist. The shamrock was used to symbolize the Trinity, yet one can show how all sorts of errors with the analogy. However, those who are willing to try to understand the concept the analogy is trying to portray can understand it.


Pro has ignored my arguments that the nature of the Eucharist is linked to the very nature of God. By Catholic definition God is infinite and omnipresent. Now Pro is trying to argue Jesus, who is the second person of the Trinity, cannot be infinite nor omnipresent. His argument is that God must be finite and singularly located. This is the only illogical argument being presented in this debate.

In John 20:19

So when it was evening on that day, the first day of the week, and when the doors were shut where the disciples were, for fear of the Jews, Jesus came and stood in their midst and said to them, “Peace be with you.”

Now did Jesus rearrange the air particles to appear, or did he replace the air particles when he appeared in the room? As the nature of Jesus' glorified body is beyond the confines of the natural sciences, it is unknowable in nature. As I previously stated in the previous round Pro has to show that the Catholic concept of God is wrong, which he never attempted.

Perhaps another analogy would add further clarity. Plato's allegory of the cave states that we are like people in a cave seeing the shadows of real objects on the wall. Assume we see the shadow of a piece of bread on the wall. If we replaced the bread with a person, but the shadow still looked like bread, we would still perceive that the object is bread, but it is really a person. If that same person were projected many times on the walls from a variety of light sources you would have what looks like multiple pieces of bread, yet is it all just one person. Once again this is an imperfect analogy, but I believe that the readers of this will understand the analogy being made.

1. Rearrangement of Parts

I have shown that the Catholic teaching is that God is infinite. If Christ is God, as Catholics claim, then his glorified body is infinite in nature as well. Thus God is able to continue to give his body to us endlessly if only we desire to receive it from him.

2. Replacement of Parts

Con's Primary argument both for this and the rearrangement of parts argument is that it breaks the Law of Identity. The basic definition of this is that "each thing is the same with itself and different from another”: “A is A and not ~A” [1] - eg. A chair is a chair and not a table.

However, this does not apply to the Christian God. The concept of the Trinity violates this law. God is 3 distinct persons in one Godhead. This is why the Trinity is referred to as a mystery. It is ultimately beyond our understanding because our understanding is limited to the concepts of the physical world in which we live. Likewise the Church refers to the Eucharist as a mystery:

1402 In an ancient prayer the Church acclaims the mystery of the Eucharist [2]

Pro argues that if Jesus had a cube, and he wanted you to have a cube as well, and it appeared simultaneously in your hand, it could not be the same cube. Without doing some mumbo-jumbo space-time quantum physics improbability drive argument, this is true.

Why? Because the nature of the cube is to be a cube within the 4 dimensional time-space continuum. However, the nature of God is to be omnipresent. Thus, if the nature of God is to be omnipresent, then his ability to be truly present in every Eucharist is in accordance with his nature and does not violate logic.

3. Conservation of Mass

Pro attempts to dodge the issue with the feeding of 5000. Just how does God violate the laws of logic by feeding 5000 with a few fish and loaves of bread and ending up with more fish and more bread? Ultimately it is not a violation of laws. God choosing to introduce something else into nature does not violate nature any more than you adding a piece to your Lego set violates the Lego construction you previously made.

I believe that the previous arguments have already refuted this argument. Infinite and omnipresent nature of God, etc...

4. Properties

As shown in my modified Allegory of the Cave analogy, Con is basing his argument of the physical realities of the Eucharist. I showed that from the teachings of the Catholic Church that it agrees that there is no discernible physical alteration to the bread and wine. And this is why I claimed that this is a series of straw man arguments.

What we are dealing with is a true spiritual reality. This is why I used an analogy of a person who dies, but his body is still being kept in operation by machinery. The human spirit has left the body. It is no longer a united body and spirit, it is just a body. Its substance has changed, though its appearances has not.

I have already admitted that my analogies are not perfect, but they describe the concepts that I am trying to impart and I believe the readers can understand the point being made.


As I noted in the previous round, and have reinforced in this round, the Catholic understanding of the Eucharist is deeply tied to the Catholic concept of God. I believe that I have shown that the two are consistent and intricately linked and logically consistent. Thus it is clear that the only way to disprove the Eucharist is to disprove the Catholic concept of God. This is a task that Pro failed to even attempt in whole or in part.

I wish to thank philochristos for an entertaining debate and also everyone who took the time to read this debate through.

Debate Round No. 3
18 comments have been posted on this debate. Showing 1 through 10 records.
Posted by Geogeer 2 years ago
Congrats on the win philochristos. This is the second debate that iamanatheistandthisiswhy has come in and sunk for me. You cannot beat voting bias in some people.
Posted by Geogeer 2 years ago
Thank-you to iamanatheistandthisiswhy for taking the time to vote on this debate. I disagree with your reasoning because the catholic doctrine of transubstantiation is what was being debated as such I defended what the Church actually teaches about transubstantiation.
Posted by Geogeer 2 years ago
Thanks to Sojourner and zmikecuber for their honesty in not voting and guaranteeing me a victory...

We hope you at least enjoyed the debate.
Posted by zmikecuber 2 years ago
Idk... I'm a little bit biased on this issue, so I probably shouldn't vote.
Posted by Geogeer 2 years ago
Thanks to actionsspeak for taking the time to come and vote.
Posted by Sojourner 2 years ago
I won't be voting on this as my personal bias would certainly skew my objectivity. However, I just wanted to say that I enjoyed reading the debate. My thanks to you both.
Posted by philochristos 2 years ago
I'm all about the element of surprise. ;-)

Yeah, the downside of having such a short character limit is not being able to define your terms in detail. On the other hand, that's part of the challenge for me--being succinct. The thought experiments I used in this debate were thought experiments I came up with on the fly during a discussion on the Stand to Reason blog one time. If you want to see how other Catholics responded to them, here's the discussion:

I'm "Sam."
Posted by Geogeer 2 years ago
I hope I won't be branded a heretic for any theological errors that I made in this argument! Teaching the doctrines requires finesse of language taking multiple factor and teachings into account. I know that sometimes I'm trying to explain one thing, but through imprecise language I trample a bit on another doctrine.

Anyways it was fun, and took me completely by surprise!
Posted by philochristos 2 years ago
Oh no, thank YOU! I had been wanting to debate this for a while and couldn't find any Catholics to take me up on it.
Posted by Geogeer 2 years ago
Thanks for the entertaining debate philochristos.

I was expecting more of a theological debate, but this was unexpectedly fun.
2 votes have been placed for this debate. Showing 1 through 2 records.
Vote Placed by iamanatheistandthisiswhy 2 years ago
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Total points awarded:30 
Reasons for voting decision: The arguments Pro presented for the irrational idea that bread can become flesh in transubstantiation stands. Con tried to disprove this by shifting the goal posts, however the argument was not about catholic belief in god it was about the bread and wine. Con never contested that the bread does in fact become flesh to counter Pros arguments, as such Con loses argument points.
Vote Placed by Actionsspeak 2 years ago
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Total points awarded:02 
Reasons for voting decision: Con's sources were greater in quality, greater in quantity, and supported his arguments better.