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The Last Supper Is Not Historical: An Application of Bayes Theorem?

01 Sep
The Last Super or The Lord's Supper or the “Eucharist” (Greek for “thanksgiving”, see 1 Cor 1.2: ευχαριστω τω θεω::eucharisto to theo “I give thanks to god”) ceremony is first attested to in 1 Corinthians 11.23-26. However, this part of 1 Corinthians might be an interpolation. If its earliest witness is not Paul, then it would first show up in its more recognizable form in the canonical gospels c. 70 CE. Besides the canonical gospels, the earliest non-canonical witness to the Eucharist in its most recognizable form is Justin Martyr writing around 150 CE: 
For the apostles, in the memoirs composed by them, which are called good news, have thus delivered unto us what was enjoined upon them; that Jesus took bread, and when he had given thanks, said, “This do in remembrance of me, this is my body”. And that, after the same manner, having taken the cup and given thanks, he said, “This is my blood”; and gave it to them alone. Which the wicked devils have imitated in the mysteries of Mithras, commanding the same thing to be done. For, that bread and a cup of water are placed with certain incantations in the mystic rites of one who is being initiated, you either know or can learn. – First Apology ch 66
Here Justin intimates that Mithraists had a similar meal with similar incantations to the Eucharist while he was alive.
 
Of course, there is a thanksgiving ceremony in the Didache (c. 100 CE), but this differs in fundamental ways from the one described in the canonical gospels, 1 Cor 11.23-26, and Justin Martyr's First Apology. Namely, the one in the Didache never makes a reference to the ceremony being initiated by Jesus. It never says that the bread represents the body of Jesus nor that the wine represents his blood. It seems to be just a communal meal ceremony, much like what was argued was the original context before the interpolation in 1 Cor 11 in the link I provided earlier; which itself is similar to communal meals described in the Dead Sea Scrolls.
 
Mithraism and Christianity both seem to have started around the same time, in the 1st century. However, unlike Christianity, Mithraism being started in the first century is due to the appearance of temples dedicated to Mithras in the first century; the earliest archaeological evidence of that type for Christianity is the third century. So there could be a case that Mithraism predates Christianity, using Christianity's actual emergence relative to its earliest archaeological evidence as a reference. It seems as though Mithraism is derived from some sort of originally Persian religion; so the terminus post quem would be first contact between Romans and the remnants of the Persian Empire.
 
Mithraism seems to have been a mystery cult that Roman soldiers followed. Similarly, Christianity also seems to have started out as a sort of mystery cult. So we do not have any idea whether the Christian Eucharist preceded the Mithraist “Eucharist”, or vice versa.
 
More generally, we don't have any instances of other pagan religions borrowing things from Christians, but we do have instances of Christians borrowing ideas found in their wider pagan society. The virigin birth is the most obvious one. Most scholars know that Isaiah 7.14 has nothing to do with Jesus, but is Isaiah using a contemporary pregnant (or soon to be pregnant) woman as a sort of chronological marker for when the two kingdoms that threaten king Ahaz will be defeated, as the wider context of Isaiah 7.12-17 shows. In other words, there is no precedent in Jewish culture for anyone of renown being born from a virgin (besides the contemporary 1st century story of Melchitsedek, which might have had similar influence on itself as the Christian virgin birth but more “Judaized”).
 
However, Christians knew about the very popular idea that the gods, heroes, kings, and saviors of their pagan neighbors were born from virgins. Romulus and Remus (the founders of Rome) were born from a virgin. Perseus was born from a virgin. Asclepius was born from the god Apollo and a human woman. So was Hercules. Almost every popular pagan hero and king in antiquity was claimed to be born from the union of a god and a woman. It would not be much of a surprise to find that Christians had adopted this idea from other pagans and inserted it into their myths about Jesus.
 
Besides the virgin birth more than likely being adopted by non-Jewish Christians from their pagan neighbors, there are also some healings that were taken from pagans. Here's a story of the emperor Vespasian healing someone: 
At Alexandria a commoner, whose eyes were well known to have wasted away …fell at Vespasian's feet demanding with sobs a cure for his blindness, and imploring that the Emperor would deign to moisten his eyes and eyeballs with the spittle from his mouth.
Vespasian …. did as the men desired him. Immediately … daylight shone once more in the blind man's eyes. Those who were present still attest both miracles today, when there is nothing to gain by lying. – Tacitus, The Histories, 4.81 (c 110 CE)
This healing is similar to how Jesus heals the blind in Mark and John. Which is more likely, that Tacitus borrowed this type of healing from Christians, or Christians borrowed this type of healing from the stories about a very well known – and still living (c 70 CE) – emperor?
 
Much like the virgin birth and this healing, there is no precedent in Jewish culture for symbolically eating the flesh and blood of one of a revered Jewish sage or elder. As a matter of fact, this symbolic cannibalism would seem to be borderline anathema to 1st century Jews since it seems to be a ritual specifically for conjuring a god. But this was not seen as a problem for pagans; there would not have been anything especially scandalous about a pagan symbolically eating the flesh and blood of one of their gods as a form of incantation.
 
A basic syllogistic argument might look like this:
 
P1: Christians borrowed many ideas from their wider pagan matrix
P2: The Eucharist ceremony has a parallel in their wider pagan matrix
C: Therefore Christians borrowed the Eucharist ceremony from their wider pagan matrix
 
Justin Martyr's argument (cleaned up to look more respectable than how he presents it [i.e. getting rid of an appeal to demons]) might look like this:
 
P1: Christians practice the Eucharist ceremony
P2: Mithraists practice a similar ceremony
C: Therefore Mithraists borrowed their ceremony from Christians 
 
Which is more likely? I think I might try Bayes theorem to find out. But before that, I want to illustrate how Bayes theorem works. This is from this webpage, which is what I'll use to do the actual math: 
Suppose a woman is the daughter of a carrier of hemophilia, and therefore is known to have a 50/50 chance of being a carrier herself. If she subsequently has a normal child, how does this affect the likelihood that she is a carrier[?]
 
1. Replace the generic hypoth[e]sis names (Hyp 1, Hyp 2, etc.) with short names for the two alternative hypotheses. Eg: “Carrier”, and “Non-Carr”.
 
2. Place the prior probability under each hypothesis description. Eg: 0.5 and 0.5 for the two alternatives. The prior probabilities you enter into this row must always add up to 1.0
 
3. Replace the generic outcome names (Outcome 1, Outcome 2, etc.) with short names for the possible outcome scenarios. Eg: “Hemophil”, and “Normal”.
 
4. Place the conditional probabilities for each outcome under each hypothesis. For example it is known that a carrier has a 50/50 chance of producing a normal child or a hemophiliac; whereas a non-carrier will always produce a normal child. So under the “Carrier” column enter 0.5 in the “Hemophil” row and 0.5 in the “Normal” row; and under the “Non-Carr” column enter 0.0 in the “Hemophil row” and 1.0 in the “Normal” row. Note that for every column (every hypothesis) the conditional probabilities in that column must add up to 1.
 
5. Click the checkbox in front of the outcome that actually occurred. You must click one and only one checkbox.
 
6. Click the Compute button. The revised probabilities associated with each hypothesis appear at the bottom of the table.
 

Hypotheses:

Prior Probabilities:

Revised Prob:

 
And there we have it. So this lady, in the example, had a kid who did not have hemophilia. Because of having a non-hemphiliac child, this means that she has a 33% chance of having hemophilia herself and a 66% chance of not having hemophilia.
 
Bayes Theorem is this formula:
 
P(A | X) = P(X | A) * P(A) / [P(X | A) * P(A)] + [P(X | ~A) * P(~A)]
 
In the example above, A is the hypothesis that the woman has hemophilia; its prior probability – P(A) – is 0.5. Since I picked the scenario where the woman did not have a hemophiliac child, X is the existence of not having a hemophiliac child, and P(X | A) or the probability of not having a hemophiliac child given that you are a hemophiliac is 0.5. The probability of not having a hemophiliac child given that you yourself are not a hemophiliac, or P(X | ~A), is 1.00; P(~A) is the same as P(A) since they're both 0.5. Doing the math in the formula moves the 50% prior probability of the woman not having hemophilia to the posterior probability of her not having hemophilia to 66% if she had a non-hemophiliac child.
 
Concerning the Eucharist we have two options that have the highest probability: Christians borrowed the Eucharist from pagans, or pagans borrowed the Eucharist from Christians. Or more generally, Christians borrowed ideas from pagans, or pagans borrowed ideas from Christians. Here is a list of themes and ideas that Christians borrowed from pagans for our prior probability (that is, prior to the Eucharist):
 
1. Hell*
2. the Logos (from the Stoics)
3. Virgin births
4. Idea of a Heavenly Man (i.e. Platonism and Forms, cf 1 Cor 15.44-49)
5. Gods descending in the form of an avian creature (cf Mark 1.10)
6. Healing the blind with spit (Mark 8.22-26; John 9.1-7)
 
Here is a list of themes and ideas that pagans borrowed from Christians prior to the Eucharist:
 
Zero or unknown.
 
There are, of course, quite a few themes and ideas that Christians inherited from their Jewish background, like the very concept of a christ, use of the Jewish bible, proto-midrash, etc. But I fear this avenue does not count because we have absolutely no precedent for Jews symbolically consuming the flesh and blood of one of their revered sages.
 
Of course, a final hypothesis would be that Jesus – as the son of the god of the Jews in the flesh, who knew that he was going to die – actually did initiate the Last Supper Eucharist. This position is basically the traditional / canonical explanation for why the Eucharist ceremony began in Christianity. More explicitly put, this position assumes the integrity and historical reliability of the gospels – but since this is an assumption that is not really supported by the evidence, it would similarly get a pretty “low” prior probability. This also implies that the two religions sharing a similar ceremony is a coincidence. Again, that also seems like a pretty low probability. Also, it seems to me that if the Eucharist ceremony was in the earliest traditions of Christianity, it would seem like an argument that favors Jesus mythicism.
 
So all four of these hypotheses have to equal 100% prior probability when put together.
 
Out of the seven things I have listed (I include the “unknown” just to be a bit fair in calculation) six of them are themes that existed prior to the advent of Christianity that Christians seem to have adopted from pagans. So my meager understanding of Bayes Theorem puts the prior probability of Christians taking ideas from the wider pagan matrix at a “high probability”. And even so, these are the things that I can think of off the top of my head, there are probably a lot more things I could list (but this is a blog, or υπομνήματα::hypomnemata [notes], not in depth research!).
 
The prior probability of pagans borrowing ideas from Christians – as Justin Martyr is arguing – I would put at generally “low” probability. Christians getting it from their Jewish background seems to me to be zero, but to be fair I think I'll just give that the subjective “lowest”. And Christians getting it from Jesus himself (i.e. reading the gospels literally) depends on the integrity and historical reliability of the gospels; from a more scholarly point of view, it depends on the idea that (in a historical-critical context) Jesus as a normal Jewish sage, somehow knew that he was going to die and, as a faithful Jew, initiated a ceremony which his closest followers symbolically eat his flesh and blood. This seems incredibly unlikely to me and actually seems like a strong argument for mythicism. Even so, if Christians did get it from Jesus himself, then the existence of the communal meal in the Didache makes no sense. Why would they get it from Jesus, lose it in 40 – 70 years, and then get it back again by the time of Justin Martyr?
 
So out of the two highest prior probabilities, what would we expect to happen if Christians had adopted the Eucharist ceremony from followers of Mithras? What would we expect to happen if followers of Mithras had taken the Eucharist ceremony from Christians? 
 
For example unrelated to this, let's say that I wanted my belief that the gospels were written in Greek to pay rent. If the gospels were indeed written in Greek, then I would expect to find puns or plays on words that can only make sense in Greek and not any other language. John 3.1-8 is one such passage wherein the conversation can only make sense if it is happening in Greek. The Greek word ανωθεν::anothen can mean either “again” or “from above”. It has no equivalent single word in Hebrew, Aramaic, Latin, or for that matter English; which is why the rhetorical strength of the conversation is lost on modern readers. Think of ανωθεν as a rough equivalent of the English phrase “taking it from the top”. That phrase can either literally mean doing something from a high vantage point, or more colloquially doing something again. Nicodemus' confusion can only happen in a Greek conversation; the writer of John was a bit too smart for his own good.
 
Back to the task at hand. Since followers of Mithras were generally Roman soldiers, we might expect other military themes or ideas to find its way into Christian culture if Christians had contact with and syncretized with Mithraists. It just so happens that words like “Gospel” (from euaggelion [evangelion] > good news > god spell > gospel) and “Parousia” (para ousia, literally a presence next to; usually reserved for the arrival of royalty or a military ambassador) were both originally used in military applications in a Greco-Roman context. On the flip side, if Mithraists syncreticized ideas from Christians, I would expect followers of Mithras to adopt some other Christian culture besides the Eucharist if they indeed did adopt it from Christians. Maybe something like refering to Mithras as a christ. We have no evidence that they did so. Granted, there is very little evidence for the inner workings and language of Mithraism in general so it's not saying much.
 
So my P(A), that Christians borrowed the Eucharist ceremony from Mithraists, is “high” since they borrowed other themes from pagans. So I'll use 55% for this prior probability P(A). X is the presence of military terminology in Christian language. The P(X | A), that is, the probability of military terminology in Christian language given that Christians borrowed the Eucharist ceremony from Mithraists, I would say is high (we would expect this); so I would put it above 50%. Since I don't actually have a number other than the subjective “high”, I'll just use 60% like Richard Carrier does in that previous post of mine I linked to. Conversely, the P(X | ~A), or the probability of military terminology being in Christian language if they didn't borrow from Mithraists I would say is “low”; less than 50%. Then we have the probability that Christians got it from Jesus himself – which depends on the historical reliability of the gospels and/or the validity of mythicism – so that is lower than the previous. Christians getting the symbolic consumption of Jesus' flesh and blood from a Jewish milieu I would put at the lowest probability. And since all numbers have to equal 100%, for P(X | ~A) I'll have that at 40%; from Jesus (i.e. the canonical gospels are historically reliable) at 4%, and from some Jewish tradition at 1%.
 

Hypotheses:

Prior Probabilities:

Revised Prob:

 
Running through Bayes Theorem, this puts the probability that Christians took the Eucharists ceremony in its current incarnation from Mithraists at 73%. Which means, I'm surmising, that there's a 73% chance that the Last Supper is not historical, at least in the symbolically eating the flesh and blood of Jesus way. There probably was some sort of original ceremonial meal, as in the Didache and the probable original version of 1 Cor 11, but was overlapped by the current Mithras-like thanksgiving.
 
So maybe a Roman soldier joined Christianity after having been a Mithraist and ported the Mithraist “Eucharist” into Christianity. It might even be that, the first gospel Mark was written by a Roman soldier. It's certainly possible and explains some other oddities/Latinisms in Mark (like the term Syro-Phoenitian), but is it probable? Who knows. That would take some more involved Bayesian judo.
 
So this is my meager attempt at applying Bayes Theorem to historical reasoning. Just like in syllogistic logic, the conclusion is driven by the strength of the premises, or in Bayes terminology, “priors”.
 
Just to show the alternative – the hypothesis that Mithraists borrowed it from Christians – using the same priors and conditionals, here are the numbers if we had some evidence of Christian terminology being used by Mithraists:
 

Hypotheses:

Prior Probabilities:

Revised Prob:

 
If we had that sort of evidence, then it puts it at a 59% probability that Justin Martyr's argument was correct and 40% chance that he was incorrect.
 
[*] The concept of Hell was actually adopted by the Pharisees (cf Josephus AJ 2.8.14) as opposed to the Essenes and Sadducees. Pharisees, of course, got this idea from the Greeks. Much like the Logos, Christians therefore must have either gotten this idea from the Greeks indirectly via the Pharisees, or they got it directly from the Greeks. 
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1 Comment

Posted by on September 1, 2011 in Bayes

 

One response to “The Last Supper Is Not Historical: An Application of Bayes Theorem?

  1. beowulf2k8

    September 5, 2011 at 5:04 pm

    This post has been removed by the author.

     
 
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