I’d be more impressed if it were the Tomb of Brian

February 28, 2007

[Cross-posted to HNN: Revise & Dissent]

I’ve been working through the statistical analysis of the Tomb of Jesus data provided by the Discovery Channel (PDF download). They argue that the chances of their tomb not being the tomb of Jesus are one in six hundred. I looked through it and found two major errors. One is simple to see if you’re a historian, and the other should be blindingly obvious to a statistician.

The odds were calculated by Prof Andrey Feuerverger, Professor of statistics and mathematics at the University of Toronto. He was given names found on four ossuaries, boxes for holding skeletal remains, from a tomb in Jerusalem. The names were in English translation Jesus son of Joseph, Mary, Jose, a dimuntive of Joseph and Mariamne. It’s argued that Mariamne is Mary Magdelene and Jose is a diminutive of Joseph, which makes hime Jesus’s brother. What Prof. Feuerverger did was look at how often these names turn up in this historical record and then calculate the probability that these would turn up in a tomb somewhere.

He started by saying:

Jesus,
son of Joseph
Jose Mary Mariamne Total
1/190 1/20 1/4 1/160 1/2,432,000

Then he divided by four to allow for historical bias. Why four is never explained. This gives a probabilty of finding the names in one tomb as 1/608,000. Obviously there was more than one tomb in Jerusalem in the first century CE. Prof Feuerverger uses a figure of 1000. This reduces the odds of finding a tomb which could be said to belong to Jesus to 1 in 608. Generally social scientists get interested around odds of 1 in 20, so this looks impressive.
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gene genie

February 17, 2007

Sonic hedgehogLike genetics? Like blogs? Then you’re going to like the latest blog carnival, gene genie.

The first issue at ScienceRoll contains lots of good stuff, including Bye Bye, Sonic Hedgehog.


The Orientation of Roman Camps

February 17, 2007

I’m working on a problem which means I have to work out if a given set of astronomical alignments are significant. I have a possible solution, so now I’m testing it one someone else’s data. What I’m doing is treating the data as a Binomial Distribution. I have a few aims with this technique. First it has to give reliable results. Next I have to understand it. Thirdly and equally importantly I have to be able to describe it so that archaeologists and historians can follow the argument. If they can’t then it gets pointless writing. My analysis may not be correct, so I’m putting it up here and submitting that to Carnival of Mathematics and Tangled Bank to see if people think the maths is wrong. I’m also putting it up on Revise and Dissent where it will get submitted to the History Carnival and Four Stone Hearth to see if it’s intelligible and sounds reasonable to Historians and Archaeologists.

Roman Camps and their Orientations reconsidered.

There is currently a debate in the pages of the Oxford Journal of Archaeology on the orientations of Roman camps and forts. Richardson (2005:514-426) argues that the orientation of these camps is non-random and relied on some form of astronomical observation. He presents data which he argues supports his case. Recently Peterson (2007:103-108) has argued this relies on a flawed use of the Chi-squared test. I accept Peterson’s findings that Chi-squared is not a useful method. However examining the camps as a binomial distribution would be feasible and would make explicit the archaeological and astronomical assumptions made in the argument.

What is a Roman Camp?

The sites being examined are Roman camps and forts in England. One of the major advantages that the Roman army had over the native opposition when occupying new territory was their organisation. The Roman army was effectively a professional army taking on amateurs. Their camps reflect this organisation. Typically their early camps a ditch surrounded by a bank in a playing-card shape. They followed a set design. The rationale for this was if there were attacked by surprise equipment and people would be in the same place at each camp, minimising the effects of the surprise.

Wallsend fort
A Roman fort at Wallsend. Photo from Google Earth

The ancient sources give some detail on how to lay out a Roman camp. The main gate should face the enemy, or the line of advance (Vegetius 1.23, Hyginus 56). The rear gate should be on the higher ground to aid surveillance. Sites overlooked by hills were considered a bad idea, as were sites near woodlands which would allow the enemy to sneak up on the camp. The basic layout of the camp could be set up quickly by surveyors using gromae, surveying tools for laying out lines at right angles. Hyginus (chapter 12) states that you set up your groma at the junction at the centre of the camp and lay out your roads to the gates from there.

This would appear to be an efficient method of laying out a camp. Were observations to orientate the camp also part of the method? It doesn’t seem necessary, but Richardson (415,422-23) provides quotes from ancient sources which suggest this is plausible hypothesis in some circumstances.
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The Tangled Bank: Valentine Edition online

February 14, 2007

The latest edition of the Tangled Bank is online at Lab Cat. It’s been action-packed period for Darwin, but there’s plenty of other stuff too.


Microdiesel: microbiology and sustainable science

February 12, 2007

Biodieseli-Science is pretty big on sustainability these days, so I thought this post about the drawbacks of biodiesel and a possible microbiological solution might be of some interest.

And if you’re not convinced of the need to combat climate change, maybe this video from the Blue Man Group might help: