I want to thank ASR for participating in this debate and I hope it's of some benefit to the reader. I've certainly learned from, and enjoyed the experience.
Over the course of this debate, ASR and I have been evaluating the probability that Jesus instituted the papacy in Matt. 16:18-19 given certain pieces of evidence.
ASR has proposed a number of such pieces which he believes makes it probable that Jesus instituted the papacy in Matt. 16:18-19 [this thesis is a.k.a. H1], including Peter’s name change, Jesus’ being the new and final Davidic King, and the early Church’s belief in Petrine primacy, etc.
My basic contention has been that H1 is improbable given the relevant evidence, and I’ve sought to demonstrate this in two ways:
First, I attempted to show that the arguments ASR adduced in favor of H1 fail. I did this by showing that his proposed evidence confirms H2 at least as well as H1, or that the proposed evidence shouldn’t be accepted as evidence in the first place. This leaves ASR without a case for H1, but doesn’t necessarily establish that H1 is improbable (i.e., or more importantly, less probable than H2).
Second, I proposed my Main Argument. This argument seeks to show that H1 is false. Since this argument is logically valid, the only way to avoid its conclusions [(4)-(5)] is to reject one of its premises [(1)-(3)].
Now, if my second method succeeded, I wouldn’t really need the first. As I said in a previous post, we can grant ASR’s proposed evidences for H1 and my Main Argument stands untouched. However, I wanted to cover all my bases.
ASR accepted premises (1) and (3) of my Main Argument, but rejected (2). If I could show that his objections to (2) fail, we’d have to conclude, based on the information provided in this debate alone, that the Main Argument succeeds and H1 is false.
Briefly I want to point out how his objections to (2) fail (note, I’ll almost completely be using material I’ve previously posted).
ASR’s Objections and My Responses:
His first objection to (2) was that “Luke did not have need to write the text of Matthew 16:18 in his Gospel, because he would later document and expand upon this doctrine through looking at his next text, the Acts of the Apostles.”
My second question to him implied a rhetorical rebuttal to this objection: why would Luke want to record the institution of the papacy only through descriptions of the papacy in action? Indeed, how could the descriptions of the papacy-in-action describe its institution? I believe ASR would concede that none of the texts in Acts which he believes describe the papacy-in-action explicitly or implicitly deal with Jesus’ institution of the papacy. So, I don’t think his first objection should be accepted.
His second objection to (2) was that “if we are to assume that if a title or a concept is not equally found in the Synoptic Gospels (such as comparing Matthew and Luke) in the same wording, then that particular instance of the terminology must not have been important to the early Christian communities.”
My fourth question addressed this objection, and ASR conceded by saying it is reasonable “to believe that Luke would've been interested in recording such an important ecclesiological event such as the institution of the very foundation of the Church if he was aware of it.” So, I don’t think this objection should be accepted. A fortiori, in conceding this it seems ASR accepts (2) and the debate is over.
His final objection is that the early Church overwhelmingly exhibits a belief in Petrine primacy, and this belief doesn’t make sense unless H1 is true. He cites 13 independent early Church sources (some twice etc.) to illustrate a belief in Petrine primacy.
This objection shouldn’t be accepted because H2 doesn’t imply the early Church wouldn’t believe that Peter was the rock or wouldn't believe in Petrine primacy. So if the early Church did believe these things, it couldn’t count against H2. As I stated earlier, H1 is not that Peter is the rock or that the NT/early Church clearly exhibits Petrine primacy. H1 will include a very particular understanding of Peter being the rock and Petrine primacy, but Peter’s being the rock and Petrine primacy can certainly exist apart from H1 (that is, on H2). So, these cannot be used as evidence for H1.
For instance, Clement of Alexandria speaks very highly of Peter in ASR's provided quote, but on the basis of texts other than Matt. 16! So, this quotation can’t illustrate a belief in Petrine primacy relevant to which interpretation of Matt. 16 is correct.
Interestingly, we both cited Tertullian’s On Modesty. How is that we could both cite the same text for two different ends? It’s because all ASR finds in the On Modesty citation is Tertullian saying Peter is the rock. However, as I showed, Tertullian is arguing against H1 here! In James White’s debate with Butler and Sungenis, the exact same thing happened. They both cited this text. Butler only cited it because it said Peter is the rock, White quoted it because Tertullian contradicts Rome. White calls such methodology (citing simply because it says Peter is the rock) the Peter Syndrome.
Sub-Conclusion:
No proposed objection to the Main Argument succeeds and the argument should be accepted as sound (logically valid with true premises).
Bayes’ Theorem:
The Main Argument concerns the probability that Jesus instituted the papacy in Matt. 16:18-19 given Lukan Silence.
Recall that Lukan Silence is the failure of Luke, in his parallel to Matt. 16:18, to record any element in Matt. 16:18-19 that Roman Catholics believe evidence H1. Let’s call this Lukan Silence, L, for simplicity.
So, symbolized, the probability the Main Argument is concerned with is:
P(H|L & K)
Given the Sub-Conclusion above, L supplies a fatal objection to H1: H1 has nearly no explanatory power over L at all. This makes for the following probability:
P(L|H1 & K) = 0.1 [This means the probability of Lukan Silence given H1 and our background knowledge is incredibly low]
However, it’s great for H2:
P(L|H2 & K) =0.8
Recall that to discover the posterior of these hypotheses given (L & K), we also need to calculate the following priors: P(H1|K), P(H2|K) and P(L|K).
Once we’ve got these numbers we can plug them into the following formula:
P(H|E & K) = P(H|K) * P(E|H & K) / P(E|K)
What is the prior probability of L? That is, how probable does our background knowledge make L? Well, as I've demonstrated, Luke was interested in compiling strong historical evidences to secure those sayings about Jesus’ life and teachings given to Theophilus. He probably traveled widely to interview witnesses and cross examines sources. So, L should only be surprising to us (given K), if we think Matt. 16:18-19 contains things Luke would've recorded if he could, given his historical/doctrinal interests. This may sound like Catholics would have to place L's prior very, very low; but, they also believe Luke was inspired! So, God Himself inspired L. Therefore, its prior will actually be very, very high for Catholics (and Christians in general).
Interestingly, it doesn’t really matter how you calculate H1’s and H2’s priors…H1’s posterior will almost certainly turn out to be improbable!
Because H1’s explanatory power of L is so incredibly low, the only way to get H1’s posterior > 0.5 is to drastically increase H1’s prior and substantially decrease L’s prior. Try it out and you’ll see what I mean.
The problem is that, L’s prior will almost certainly drop no lower than 0.2 (for those considering L on a purely historical basis!) and H1’s prior can raise no higher than 1. As noted, Catholics will have to assign a very high probability to L’s prior, probably something like 0.8! This makes for the following calculations:
1.0 * 0.1 / 0.8 = .12 !
Let’s drop L’s prior to 0.3 and see if that helps:
1.0 * 0.1 / 0.3 = .33!
(Note that giving H1 a prior of 1, and L a prior of < 0.4 is crazy lol)
H2’s posterior is quite high.
We can find out what H2’s prior is by subtracting H1’s from 1: P(~H|K) = 1 - P(H|K). H2 is just another way of saying ~H since it’s simply the denial of H1. There’s no way I’m giving H1 a prior of 1! In fact, for *me* it’s be extreeemely low. However, let’s give both priors a 0.5 to be fair. H2’s posterior still skyrockets:
0.5 * 0.8 / 0.4 = 1
You could tweak with L’s prior to try and save H1…raise it 0.8, you’ll still have a H2 posterior of 0.5, which is greater than H1. However, since H1 and H2 are mutually exclusive hypotheses, their probabilities must add up to 1. So, H2's will almost always be far, far greater than H1's.
So, I really can’t see a way the Catholic can get out of this.
Conclusion:
I feel quite confident that I've established my basic contention. The probability that Jesus instituted the papacy in Matt. 16:18-19 given Lukan Silence is incredibly low, such that it’s irrational to believe H1, given L.
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