Friday, February 02, 2007

why logic is crucial in theology

A Mormon buddy was witnessing to me over email the other day, citing Stephen Robinson on the a priori reasonableness of God having a body:

"The logic is not difficult: Jesus is God; Jesus has a body of flesh and bones; therefore, God, in the person of the resurrected Son, has a body of flesh and bones."

It took me a second. It took me another second. And then I realized: categorical logic is finally going to come handy. Okay, first, I took a prima facie look at Dr. Robinson's "not difficult" "logic":

S is P
S is R
Therefore, P is R


Okay, but why? Let's rewrite this a bit:

S - the person of Jesus Christ.
P - God
R - a body of flesh and bones.

So Dr. Robinson's logic, using the above key:

S is P;
S is R;
Therefore, P (in S) is R.

Problems are as follows. First, he uses four terms, and you can only have three terms in a syllogism. The fourth term is 'P (in S)' and this is neither P nor S. This is called either equivocation or four-term fallacy. Second, terms distributed in the conclusion must be distributed in the premises. Yet the group of statements does not have P (in S) distributed in the premises; it doesn't even show up in the premises; P itself is undistributed. This is sometimes called illicit process. Thus, he has broken two rules in this simple syllogism. Invalid.

My Mormon friend told me at this point that I was trying to refute him on a "technicality." I really wasn't.

On the contrary, I even considered collapsing that fourth term to be "God." The problem is that even with three terms like that, it is still invalid, because God is undistributed in the conclusion but not in the premises. That's illicit process of the minor term, as I mentioned. In other words, it is also wrong if thought:

1) Jesus is God.
2) Jesus has a body of flesh and bones.
3) Therefore, God has a body of flesh and bones.


1) Jesus is God (undistributed).
3) Therefore, God (distributed) has a body of flesh and bones.

This in itself does not mean that the conclusion is false, but just that the "argument" used to support it is invalid. Invalid reasoning is used to falsely support true conclusions all the time.

My reasons for rejecting the notion that God is immaterial are fairly common and so I will not lay them out here. But anyway, that was my beginner's analysis of what seemed to be a hopeless example of "not difficult" "logic," from a highly respected Mormon scholar. Does anyone know a way to salvage or rewrite Robinson's group of statements, so as to make a valid argument?


Blogger Ariel said...


"My reasons for rejecting the notion that God is material are fairly common and so I will not lay them out here."

I wrote "immaterial," which gives quite the opposite impression. I'll correct it in the post, but right now editing the blog is giving me trouble.

10:49 AM  
Anonymous Anonymous said...

It depends on what your definition of 'is' is.

1) Jesus is God.
2) Jesus has a body of flesh and bones.
3) Therefore, God has a body of flesh and bones.

If the 'is' in the premise "Jesus is God" creates a univocal relationship between the subject and predicate then Robinson's argument becomes valid. The undistributed term becomes distributed because the terms are interchangeable.

2:50 PM  
Anonymous Jeremy Pierce said...

Should a Mormon be admitting that God can have a body in virtue of Jesus having a body?

6:26 PM  
Blogger AmericanPascal said...

In response to the anonymous entry:

If one says that Jesus and God are exactly the same in every way (i.e., to say that they are NOT different in person) is nonsensical. If Jesus was the same person as God, then why would Jesus talk to God the father? There is plenty of evidence to show that Jesus is not the same “person” as God, so why would someone pretend that they are the same person in support of this current argument? Don’t confuse personage with essence.

7:23 PM  
Blogger Ariel said...


That is an interesting point, but materially impossible in this case. Neither Mormon nor Christian theologies treat "God" and "Jesus" as interchangeable. In Mormonism, "God" is predicable upon a potentially infinite number of distinct beings, of whom "Jesus" is one of many. In biblical Christianity, as Americanpascal was getting at, "God" is predicable upon three distinct persons, though God is one being. It is possible that that this Mormon scholar, attempting to dialogue, misunderstood Christian trinitarianism to be as you have said - that one and only one subject in fact takes divinity, since we believe that God is one being.

Jeremy Pierce:

It seems the answer is no. I don't think Mormons do believe in the possibility of God's materiality just in virtue of Jesus having a body; there are other sources for their belief, for example, the metaphysical teachings of Joseph Smith. rather, the aim of this argument was to persuade Christians that they shouldn't necessarily have a problem with the Mormon doctrine. As in, "you believe this, so..."


6:16 AM  
Blogger Douglas Beaumont said...

I think that these categorical statements are incomplete - this is not how the phrases should be set out in order to properly evaluate them (categorical statments often sound odd when spelled out, but this is how it has to be done to work). If the Mormon were to argue this way I think it would be valid:

KEY: S - persons that are Jesus Christ; P - persons that are God by nature; R - persons that have a body of flesh and bones by nature.

All J is P
All J is R
Therefore some P is R.

So all they are really doing is proving that our view is our view - i.e., that a person can have two natures. But this does not help the Mormon because their view is that God has a body by nature AS GOD, not as a person who is God by nature and ALSO has a human body. For the analogy to hold they would need Jesus to have a body of flesh and bones AS GOD.

1:15 PM  
Blogger Anders said...

Hello! I found your website. My name is Anders Branderud, I am 23 years and I am from Sweden.

By practising Torah, like the historical Jesus, non-selectively we make the world a better place to live in!

Neither the historical Jesus nor his followers did ever claim he was divine.

To realize that one can follow two polar-opposite masters — the authentic, historical, PRO-Torah 1st-century Ribi from Nazareth – the Messiah - and the 4th-century (post-135 C.E.), arch-antithesis ANTI-Torah apostasy developed by the Hellenists (namely the Sadducees and Roman pagans who conspired to kill Ribi Yәhoshua, displaced his original followers (the Netzarim) and redacted the NT); is a step in that direction!

So who then was the historical Jesus? His name was Ribi Yehoshua.
The research of world-recognized authorities (for example Barrie Wilson; in this area implies that Ribi Yehoshua was a Pharisee (a Torah-practising Jewish group - who according to 4Q MMT (a Scroll found in the Qumran-caves) practised both written and oral Torah (oral Torah in an unbroken chain since Mosheh (Moses); commanded by Mosheh in Torah; oral Torah is recorded Beit-Din (Jewish Court)-decisions of how Torah shall be applied).. As the earliest church historians, most eminent modern university historians, our web site ( and our Khavruta (Distance Learning) texts confirm, the original teachings of Ribi Yehoshua were not only accepted by most of the Pharisaic Jewish community, he had hoards of Jewish students.

For words that you don’t understand; se ; the link to Glossaries at the first page.

Ribi Yehoshua warned for false prophets who don’t produce good fruit = defined as don’t practise the commandments in Torah according to Halakhah (oral Torah; see the above definition). See Devarim (Deuteronomy) 13:1-6.

The research of Scholars in leading universities which implies that Ribi Yehoshua was a Pharisee necessarily implies that if you want to follow him you need to practise his Torah-teachings.
So you need to start follow the historical Ribi Yehoshua – the Messiah – by practising Torah (including oral Torah)!

Finding the historical Jew, who was a Pharisee Ribi and following him brings you into Torah, which gives you a rich and meaningful life here on earth and great rewards in life after death (“heaven”)!

From Anders Branderud
Geir Toshav, Netzarim in Ra’anana in Israel ( who is followers of Ribi Yehoshua – the Messiah – in Orthodox Judaism

10:01 AM  
Blogger Don Paco said...

We Catholics all (should) know that the Divine Nature is completely incorporeal. Neither Catholic philosophers nor Catholic theologians have any doubt concerning this.

Looked at as a technical theological issue, however, we could honestly ask whether the statement "God has a body" is true. I would argue that it is true indeed. This is a classic case in the traditional doctrine of the communicatio idiomatum.

The teaching is that, in Christology, concrete names, such as "God," "Christ," "Jesus," etc., refer to the Second Person of the Trinity, and not directly to the natures; whereas abstract names, such as "the divinity," or "the humanity," refer to the natures and not to the persons directly. This is NOT what we philosophers do when speaking of God: since the persons of the Blessed Trinity do not enter into philosophical discourse, we philosophers normally use the term "God" to refer to the divine nature.

Hence, when we say "God has a body" we mean "The Second Person of the Blessed Trinity has a body."

And this is true: since what is true of either of the natures in Christ is also true of the person, and "having a body" is true of the human nature, it follows that "having a body" is true of the Second Person of the Trinity.

In fact, this is the same reason why it is possible to say:

"God died on the cross,"
"God suffered,"
"God was born of the Virgin Mary."

In fact, both Scripture and Tradition do this:

"They crucified the Lord of glory" (1 Corinthians 2:8),

"...with God’s blood we have been redeemed" (Acts 20:28),

"and the word became flesh..." (John 1:14),

"God became man so that may may become God..." (St. Athanasius),

"Holy Mary, mother of God" (the Hail Mary).

The syllogism of the Mormon can be restructured into a Barbara to be made valid (and sound):

Christ has a body.
God is Christ.
Therefore, God has a body...

keeping in mind, of course, that "God" is a concrete name are refers to the Second Person of the Trinity, and not to the divinity or the humanity.

For more on this, I recommend Garrigou-Lagrange's "Christ the Savior", Ch. XIV, Question 12. Here's the link:

Another good treatment is Ludwig Ott's "Fundamentals of Catholic Dogma" (search the topical index for "communication of idioms"). The work has many errors, but it still does offer a good treatment of this topic. You can get a PDF of the work though Ite ad Thomam's Out-of-Print Library:

Also, here is a link to the Catholic Encyclopedia article on the communicatio idiomatum:

3:39 PM  

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