The Tyranny of Assumptions in the “Jesus Tomb” Calculation

Well, I thought I was done writing on this for a while, but I thought I would post once more about the “math” behind the “Jesus Tomb” show.  I’m prompted by an article in last Friday’s Wall Street Journal (March 9, 2007) titled “Odds of ‘Lost Tomb’ Being Jesus’ Family Rest on Assumptions” by Carl Bialik (the WSJ’s “Numbers Guy”).  [Click here to read — I do not think subscription is required.]

I appreciate that the WSJ article brings out some things about mathematical work that often aren’t mentioned — chief among them: how dependent the mathematician is on the assumptions he makes or, to a great extent in this case, those given to him.  And I appreciate, as well, that Professor Andrey Feuerverger’s work is being seen in a better light (which means that he, himself, is hopefully being seen in a better light) than that cast by the horrible presentation of his work in the documentary.

For example, one of the key assumptions in the calculation is that the “Mariamene e Mara” tomb is Mary Magdalene.  Without that key assumption, according to Professor Feuerverger as quoted in the article, the mathematical results would be “statistically not significant.”  The assumption that “Yose” is so rare nickname for Joseph that it should be treated distinctly from the more common “Yosef” is also a key presupposition.

This is one of the places in which I thought the “docudrama” went south, and did so in a fairly contrived way on the backs of the filmmakers’ biases.  (Please note: I am not pretending to be unbiased myself!)  I recall the narrating voice of Mr. Jacobovici pointing out the crucial role identification of one of the ossuaries with Mary Magdalene played in the calculation.  Then, with an air of “Da Vinci Code” suspense, we see laid out the “case” for this identification.  Sadly, at this point in which honest scholarship should have played a key role, it was ignored and left to watch from offstage as Jacobovici, Tabor and company perform their “magic” and make the identification of “Mariamene e Mara” with Mary Magdalene seem an “air tight” conclusion.

Thankfully, many more responsible scholars have stepped forward to fill the gap, and anyone who has kept up with the matter has been able to learn what is not told on the TV program: the identification of “Mariamene e Mara” with Mary Magdalene is far from air tight.  In fact, even the translation of “Mariamene e Mara” has been debated, with a number of possibilities seeming as probable as “Mary the Master,” if not more probable — regardless of how confident Dr. Tabor sounds when he expresses his opinion.

But I’ve gotten a little off track.  In the article, Ivo Dinov, assistant professor of statistics at UCLA says, “I wouldn’t be comfortable coming up with a number like this, because the general audience will not understand that it is very, very subjective.”  And that is exactly right.  When I was working as an actuary (a mathematician for an insurance company), the audience’s interpretation of my conclusions always had to be foremost in my mind.  Often this lead to frustration between my department and, say, the marketing department, when they would want to use the numbers to say one thing, but we would have to rein them in because it was not an accurate use of the numbers.  Or, the numbers we would publish had to be explicitly qualified by an accompanying statement of the key assumptions behind them so that those assumptions could be considered by others for their reasonableness.  If others are going to be making decisions based on your numbers, then you want them to have all the info that they need to make a responsible decision.  Anyone deciding on the “truth” of Mr. Jacobovici’s proposal about this tomb based on “1-in-600” odds without understanding the elaborate set of assumptions made to get to that figure has made a horribly ill-informed decision.

In the WSJ article, Professor Feuerverger seems to recognize the deficiency in how his work was presented on the show when he says, “There is a mismatch between how the media works and how academia works.  Obviously it would have been a whole lot better if I had completed the paper [before the documentary aired].”  The “paper” in question would be his documentation of how he arrived at his result and the nature of his assumptions, which would have been reviewed and critiqued by his mathematical peers and relevant experts.  That’s the way that real science works, though none of it was on display on the Discovery Channel that evening.

I really do hope that Prof. Feuerverger is given a break by those who critique his calculation.  He seems (from what I’ve read) to be a decent fellow whose assistance to some filmmakers is earning him more notoriety than he would ever wish for.  As he says towards the article’s end: “When doing the calculation, I was naively unaware of the extent to which the filmmakers might be depending on the ultimate result of it.”  I hate to speak for him, but I would think that he probably regards this as his one mistake in this matter.

I would, however, offer that he has made one other.  One of the warnings given to us as actuaries by the Society of Actuaries was to beware the temptation to work with assumed confidence and competence outside your usual bounds of experience.  It seems to me that an error related to this warning has come into play here.

The Wall Street Journal article briefly references another critique of the calculation on the website of Scientific American, which I suspect is the article here.  As reported in the SA article, emphasis mine:

“I did permit the number one in 600 to be used in the film-I’m prepared to stand behind that but on the understanding that these numbers were calculated based on assumptions that I was asked to use,” says Feuerverger. “These assumptions don’t seem unreasonable to me, but I have to remember that I’m not a biblical scholar.”

Essentially, the calculation is incredibly assumption dependent.  That is the nature of the beast in this sort of work.  Prof. Feuerverger was asked to use certain assumptions, and he checked them against his own sense of reasonableness, yet he admits that he lacks the expertise to accurately decide how reasonable they truly are.  In most truly scientific publications he could communicate that uncertainty, but it doesn’t make for “compelling television,” which — as Mr. Jacobovici said in the hour long “discussion” that aired after the show — was the filmmaker’s goal.  And how certain should we be about the assumptions behind the “1-in-600” calculation?  As Scientific American states:

…the calculations made by Feuerverger and others rest on premises that must be decided by historians and archaeologists, who are still far from agreement on even the basics of the Talpiot tomb.

However sincerely or innocently done, the filmmakers’ misuse of Prof. Feuerverger’s calculation — using it to add an unearned sense of solidity to what is, by its very nature, a house of cards — is regrettable.  And the anxiety that the professor admits he has gone through since the show aired is also regrettable.  But he says in the WSJ article that the distress will make him a stronger human being and a stronger statistician, and I hope this is the case.  And, I hope those who look into how mathematics was used in this film come away more educated about the role mathematics plays in such things.  The presence of mathematical results brings an air of authority to one’s conclusions, but hopefully we will learn that it should not be an authority that goes unquestioned or unchallenged.

5 thoughts on “The Tyranny of Assumptions in the “Jesus Tomb” Calculation

  1. Hi, Mr. Smith! I hope that your return to this comment will find you in good shape after your trip.

    As you know (being someone who works with numbers and computers), the adage “GIGO (Garbage In, Garbage Out)” applies forcefully to mathematics. One’s results are only as good as one’s premises and one’s data, and mathematics is just as subject to logical fallacies and factual errors as is reasoning in verbal language.

    So as not to get dizzy from the arguments and counter-arguments on the mathematical level, I just take the testimony of the Gospels (and their Jewish and Gentile opponents of the time) at face value and see where they lead. It makes no sense in their light that Jesus and his family ever had a “family tomb” in Jerusalem at Talpiot, let alone that Jesus was buried there. Christianity would have died, not in the cradle, but in the womb!

  2. Trev

    You write that you hope that we will give Feuerverger a break.

    He could have saved his reputation if he had issued a simple and explicit statement, on his web site, stating that the calculation presented in the film and in the publicity campaign was not a fair and accurate representation of his work.

    He should have issued that statement long ago, before the film aired. He should have issued it when the first press releases were published, in February, using his name and reputation to endorse a calculation which is clearly incompetent and/or dishonest.

    Why didn’t he issue such a statement? Did he sign a contract (in return for payment) guaranteeing that he would not criticize the filmmakers, no matter how badly they misrepresented his work? If so, then he effectively sold his professional and academic reputation to a pair of hoaxers.

    Only limited sympathy is due, if any.

  3. I’ve studied the Talpiot Tomb find for years, long before it became public knowledge following that TV documentary in 2007. I believe the find is serious, and warrants further study. I’m afraid critics of the magnitude of this discovery prevail for the time being because of the vehemence of their assertions, rather than the logic of their substance.
    The critics basically argue:
    1. That the Jesus family would be buried in Nazareth, not Talpiot;
    2. That the ‘Jesus’ ossuary would have been inscribed ‘of Nazareth’;
    3. That the Jesus family couldn’t have afforded a tomb like the Talpiot tomb;
    4. That the “Jesus son of Joseph” ossuary is not inscribed “Yeshua” (Jesus) at all;
    5. That the names inscribed on these ossuaries were supposedly common;
    6. That the “Mariamne” ossuary didn’t contain the remains of Mary Magdalene, but of two other women;
    I believe the first five of these allegations against the book’s premise don’t carry much water. The sixth argument actually supports the conclusion that this is the real thing. My comments:
    1. Talpiot is the right place for Jesus’ family tomb- Per Luke, 2:3-4, the family’s LEGAL residence was Bethlehem, not Nazareth. The fact that Joseph and the pregnant Mary could not take the census in Nazareth but had to take it in Bethlehem indicates that Bethlehem was their DOMICILIUM under Roman Law. That basically means that they had no intention to reside in Nazareth permanently. Therefore it would have made little sense for them to have a family tomb in Nazareth, that they wouldn’t be able to frequently visit at a later stage in their lives. They would have wanted a family tomb close to Bethlehem and Jerusalem, easily accessible also to future generations of the family. The fact is indeed that Mary and her children moved to Jerusalem around 30 AD.
    2. The traditional name of Jesus in Hebrew, as reflected also in the Talmud, is “Yeshu Hanotzri.” This appellation stems from “Netzer” (Shoot or Branch). It alludes clearly to Isaiah 11:1, indicating the Royal birth of Jesus, to substantiate his claim for Jewish messiahship. Not to indicate the place he comes from.
    There’s actually no evidence in Jewish sources, such as the Old Testament or the Mishna and Talmud, that a place called “Nazareth” even existed in or before the first century. I’m not disputing the evidence per the NT, that there was indeed a place called Nazareth. But to the best of my knowledge, there’s no mention of Nazareth at all in any ancient writings outside the New Testament. So the place existed, but nobody knew about it. And those in close proximity in Galilee who did know about it, obviously thought derogatorily of it , cf. “can anything good come from Nazareth?” (John 1:46.) Therefore there was no reason to call Jesus “of Nazareth.” Either in life or on an ossuary. He was called “Jesus the Branch” (of David) in Hebrew/Aramaic.
    The line of argumentation detracting this discovery around the supposed Nazareth origin of Jesus’ family may therefore be based on a very shaky foundation.
    3. Talpiot is located about 2.5 miles North of Bethlehem. Jesus’ family, of Davidic descent according to the New Testament, could have held the burial cave there even before it moved to Nazareth. Davidic birth was absolutely the most exalted in Judaism, always. The suggestion that any person of Davidic descent could be of the lowest social echelon, that couldn’t fund or get funding for a burial cave, doesn’t make much sense, if any. There’s substantial evidence to the contrary, e.g. 1. Jesus had some very wealthy active supporters like Joseph of Arimatea and Nicodemus (known as Nakdimon ben Gorion in post biblical Jewish sources-one of the richest Jews in Judea;) 2. Josephus, A.J. XX, 9:1. Note the prominence of James, brother of Jesus.
    4. The inscription on the Jesus ossuary does say “Yeshua bar Yehosef” (”Jesus son of Joseph”)to my eye. All letters but one are quite clearly there. The only letter which is somewhat more difficult to discern at first blush is the second letter- “Shin”. That’s because it’s written in a somewhat irregular form (in a regular Shin there are three teeth in the fork, pointing upwards. Here there are two teeth, pointing sideways to the right.) But that particular irregularity appears also on other ossuaries- notably numbers 9 (this one has two “Shin”- one with three teeth pointing to the right, and one with TWO teeth pointing to the right. Exactly like the subject inscription) and 121 in the Rahmani catalogue, which both feature also a “Yeshua.”
    Still, the name “Yeshua” on this ossuary is among the most, if not the most, difficult to read names of all ossuaries listed in Rahmani’s catalogue of Jewish ossuaries. It is almost written as a person’s complex signature on a check. Contrast that with the patronymic following the first name. This is written in a simple straightforward fashion, which is very easy to read. There’s no other example in Rahmani’s catalogue of a first name that has to be deciphered, and a patronymic that’s so plain and clear. Is this merely a coincidence?
    5. Mr. Huston on 3/13/07 made the following comment to my post:
    “The inscription, Pfann said, is made up of two names inscribed by two different hands: the first, “Mariame,” was inscribed in a formal Greek script, and later, when the bones of another woman were added to the box, another scribe using a different cursive script added the words “kai Mara,” meaning “and Mara.” Mara is a different form of the name Martha.
    According to Pfann’s reading, the ossuary did not house the bones of “Mary the teacher,” but rather of two women, “Mary and Martha.’”
    Here’s my thought about that:
    If the Mariamne ossuary indeed housed the bones of Mary and Martha, these are two sisters of NT fame. One of them could have been married to “Jesus son of Joseph.” -Whether or not she was Mary Magdalene (Maybe the Mary who anointed Jesus’ feet and then dried them with her hair- very intimate scene.) The other sister would than also automatically belong in the family. It still fits. Actually it increases the statistical odds that this is the real thing quite substantially.
    This is a very intriguing possibility indeed, fitting perfectly with John 12:3. Intimate contact with a man, as described in this NT passage, was allowed only to a woman who was an immediate blood relative of that man, his wife (…or a working woman.) That’s all. Therefore Mary of Bethany was quite possibly by elimination Jesus’ wife or in the process of becoming his wife. In that context, Margaret Starbird already theorized that similar anointing with spikenard oil was part of pre marriage ritual of a Davidic king, per certain passages in the Song of Songs. Note also that intercourse by itself was sufficient under Jewish Law in certain circumstances to constitute valid marriage. That practice, termed Bi’ah marriage, was abolished in the 6th century, but it was lawful in Jesus’ time.
    Mary of Bethany could have become pregnant by Jesus while he stayed at her house, shortly before his crucifixion. In that case it’s quite possible that she bore Jesus’ son posthumously and named him “Judah.” And in that case both she and her sister Martha would have become part of Jesus’ family, which earned them a place in the Talpiot family tomb..
    Reminds me of the reaction to this find of a BBC reporter in 1996- It seems like all balls in the national lottery coming one by one.
    I have no knowledge of Greek, so I can only discuss the two propositions. Assuming that the ossuary does say “Mary and Martha”, here’s what I think the names are:
    * 1.”Jesus son of Joseph”(”Yeshua bar Yehosef” in Hebrew/Aramaic script;)
    * 2. “Mary” (”Marya” in Hebrew/Aramaic script);
    * 3. “Joseph” (”Yose” in Hebrew/Aramaic script. Precise nickname of Jesus’ second brother- cf. Mark 6:3);
    * 4. “Mary and Martha” (”Mariame kai Mara” in Greek)-they must have been sisters because Jewish law didn’t allow burial together of two unrelated women;
    * 5. “Matthew” (”Matya” in Hebrew/Aramaic script)- Name of Jesus’ first cousin, son of his father’s brother Alphaeus/Clophas. As James Tabor suggests in a different context, Matya could also well have been Jesus’ half brother, considering a certain specific rule of the Torah (Deuteronomy 25:5-10.) This rule was applied in Jesus time- see Matthew 22:24-28;
    * 6. “Judah son of Jesus”(”Yehuda bar Yeshua” in Hebrew/Aramaic script.)
    * Therefore out of eight names actually inscribed on these ossuaries (including the “Joseph” father of Jesus on the first ossuary) four names undoubtedly relate to Jesus’ immediate family, and three other names relate to the same with a somewhat lower probability. In any event, they all relate to Jesus’ extended family. Note that first century Jewish family tombs were usually a clan thing.
    * The eighth name is “Yehuda bar Yeshua”- must have been the son of Jesus and one of the sisters Mary or Martha. More likely Mary, as explained above.
    6. While the full versions of all these names were indeed common in Jesus’ time, the derivatives, nicknames and contractions were not. Thus “Yeshua” for Jesus was less common than “YeHOshua;” ditto “YeHOsef” instead of “Yosef” for Joseph; “Marya” for Mary was extremely rare in Hebrew/Aramaic script; “Yose” for Joseph is unique. Therefore out of these eight names, two are irregularities, one is a particularity, and one a singularity. Statistical studies should factor these facts, and all 7 names.
    BOTTOM LINE- Ask yourself inversely a hypothetical question- If the Talpiot tomb hadn’t yet been found, how would Jesus’ family tomb have looked , which ossuaries would it have contained, to when would it have been dated and where would it have been located.
    I would have thought of a tomb just like the tomb we’re discussing. It fits perfectly with what I’d have expected Jesus’ family tomb to be. Right place, right period, right names. I therefore believe that this matter, delicate as it obviously is, warrants further investigation. This could include opening and examination of the adjacent tomb, and forensic examination of the skeletal remains found in the Talpiot ossuaries, and apparently reburied back in 1980. These could hopefully be relocated by comparison to the mithochondrial DNA samples already taken from two of these ossuaries.

  4. Thanks for your comment, Mr. Bernstein — and on such an old post, too!

    I think you bring up several points worth mulling over, but no silver bullets, so to speak. Drawing conclusions about the find requires dipping into multiple fields, and when one allows himself to fully wade into those other fields to put together all of the evidence that relates to the subject, I do believe that the conclusion that this is Jesus’ tomb is still a shaky one and one still very much vulnerable to the choice of assumptions.

    That said, I absolutely agree with you that the matter should be investigated and looked into by those professionals equipped to do so. If one of Christianity’s central tenets — the literal resurrection of Jesus Christ — cannot be held up for examination, then it would be a weak tenet. I do believe that the resurrection does stand up well to such scrutiny, and I welcome investigations such as these as, I think, anyone should.

    Thanks, again, for your comment.

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