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?

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