My prayers have been answered: the Discovery Channel has posted up a PDF file summarising the evidence that the supposed "Lost Tomb of Jesus" really did belong to the Biblical Jesus. It reveals the methodology used in the statistical analysis which previously made me so uneasy.
The numbers are, to say the least, unconvincing.
The analysis begins by looking at the frequencies with which the names "Jesus son of Joseph", "Mariamne", "Maria", and "Yose" (Joseph) appear. One can express these as the number of occurrences of the name in question divided by the total of all inscribed names, to give the fraction of inscribed names represented by each of the four in question. (A full quarter of all names were Maria!) Then these fractions are all multiplied together and a fudge factor is thrown in, to give what is supposed to be the probability of any one tomb containing this collection of names. The analysis then assumes there were 1000 tombs in Jerusalem from the appropriate period (twice as many as I supposed, and, as far as I can tell, nothing but a guess), and multiplies the probability by 1000 to give the odds, 600 to 1, that this tomb belonged to the Holy Family.
I remain unconvinced that this figure is in any way meaningful. Suppose the average tomb contains six ossuaries, and thus six names. The chances of the tomb containing "Jesus son of Joseph" will--naively, at least!--jump from 1 in 190 or .005 (as given in the PDF, as a probability of occurrence among names) to 1-(189/190)6=0.031 or only about 1 in 32 (as a probability of occurrence among tombs), a substantial increase. Analyse the data like that and you'll get totally different results, and the coincidence of names will start to seem a lot less significant.
Do I think this 1 in 32 figure is more meaningful than the 1 in 190 used in the analysis? Not really. Without more data on how many ossuaries one finds in the average tomb and how various names tend to be correlated within a tomb (names are often handed down through families, after all; it wouldn't be too surprising at all if a Jesus son of Joseph named his son after his father) and how many tombs there actually are or were in Jerusalem, none of these numbers means a gosh darned thing.
Posted by aloysius at February 27, 2007 06:38 PM |