SEEC and ye shall find – Review Part Two

It is taking an inordinately long time for all the presentations to make it to the internet, and although all credit is due to those who are editing them and making them ‘fit to print’ as it were, it’s beginning to look as if some will never make it to the airwaves. As predicted, many, perhaps most, are simple re-iterations of the same old memes, generally presented with evangelistic fervour, as if the presenter was unaware that exactly the same lecture had already been given several times already during the course of the conference, or that almost every one of their audience was as familiar with their material as they were. Very few indeed attempted to present something new, of whom (apart from those mentioned in Part One) only Tom McAvoy merits a serious response, so although I could entertain my fellow medievalists with a whole post full of absurdities, I think the nicest thing to do is to leave them in obscurity unless somebody else thinks they require further attention. Let the two I have chosen as exemplars (David Keys and Mark Antonacci) stand for them all.

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Dr Tom McAvoy and I have discussed his hypothesis that the intensities of the UV fluorescence photographs correlate to the intensities of the neutron flux at those points as calculated by Bob Rucker, so for a more detailed exploration of the background, readers are referred to ‘Coincidence or Correlation,’ and ‘Analysing the UV Photos,’ elsewhere in this blog. However at St Louis, McAvoy presented some more recent considerations which are worth examining.

If the diagram below represents a more or less accurate model of the body of Christ in the tomb, Rucker predicts that across the width of the Shroud, the effect of the neutrons will be greatest in the middle, where the cloth is more or less in contact with the midline of the body, next greatest towards the edge of the cloth closest to the back wall of the tomb, where some of the neutrons initially missing the body bounce back and contribute to the effect, and smallest towards the edge of the cloth furthest from the wall, where there is no ‘bounce-back’ effect. From end to end, the dorsal side will be more affected than the ventral side – the ‘bounce-back’ effect again – and the torso area, being closest to the most massive part of the body, will be most affected because it will receive the most neutrons.

McAvoy has previously shown that neutron irradiation can stimulate fluorescence in linen, so if the Shroud were irradiated with neutrons according to the distribution calculated by Rucker, a diagram of the pattern of fluorescence could be modelled, (albeit qualitatively rather than quantitatively), a bit like this:

According to McAvoy, the UV fluorescence photos taken by Vernon Miller demonstrate this pattern, and according to me they don’t, but I’ve discussed that elsewhere. What was new at St Louis was a reference to the UV fluorescence spectra taken by Roger and Marion Gilbert.¹ McAvoy pointed out that the four ‘non-image’ areas they sampled resembled each other, but were all of different brightnesses.

McAvoy said “there’s a variation, so that confirms what the ultraviolet photos were showing […], and since [these areas] don’t have burns or anything else, what that is saying is that the molecular bonds in the Shroud’s linen change with location on the Shroud, exactly what the ultraviolet photos were showing.” He contends that the variation in fluorescence intensity measured by the Gilberts supports his hypothesis that the Shroud’s observed fluorescence correlates to Rucker’s hypothesised neutron intensity.

But does it? Here is the Gilbert’s plan of where they took their samples, with the non-image areas highlighted.

Unfortunately for McAvoy’s hypothesis, this is almost the opposite of his predictions, and further demonstrates that the random variation of fluorescence over the Shroud does not relate to any hypothetical neutron radiation density.

ADDENDUM SOME WEEKS LATER

For the sake of completion, it should be mentioned that McAvoy presented a graph illustrating all of the Gilberts’ fluorescence findings, in a way that was, possibly unintentionally, extremely misleading. Here is the graph:

It appears to show four series of measurements, all decreasing in value along a ‘G&G table position,’ which does not exist in the Gilberts’ paper. It gives the impression of some kind of systematic decrease, as if along some kind of profile on the Shroud, when in fact it is no such thing. McAvoy has taken measurements from four separate graphs, and taken the values, from highest to lowest, of each one. As we have seen above, the “clear” values do not match McAvoy’s hopes regarding the fluorescence on the Shroud, and for the sake of completion, here are the others.

Insofar as they mean anything at all, none of them does anything to support McAvoy’s hypothesis.

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David Keys had the doubtful privilege of being almost the first to have his presentation posted on YouTube, so perhaps I have given him undue attention. After a lengthy but sensible discussion about the difference between knowledge and belief, Keys came up with a mathematical way of assessing one’s belief in something, based on two criteria applied to whatever information you have about it, namely the importance of the information, labelled ‘ω’ (scale 1 to 10) and its trustworthiness, labelled ‘t’ (scale -1 to +1).

Say somebody stole my chocolate, and the information is that George is fond of chocolate, and that George opened my locker door. The first is well known, and has a trustworthiness of +1, but most people are fond of chocolate, so it’s not very significant to the case. I give it an importance of 2 out of 10. The second would be very important evidence if it were true (importance = 8), but only two people say they saw George at my locker, and they don’t like him anyway. I’m not sure they’re reliable: trustworthiness, say, -0.5.

The formula for assessing the quality of my belief in George’s guilt is given by:
BELIEF = Σ (ti x ωi) / Σ (ωi)
— In this case, BELIEF = ((1 x 2) + (-0.5 x 8)) / (2 + 8) = (2 – 4) / 10 = -0.2

On the other hand if the witness to George at my locker was the scrupulously honest janitor, the trustworthiness of that information might rise to 0.8
— In this case BELIEF = ((1 x 2) + (0.8 x 8)) / (2 + 8) = (2 + 6.4) / 10 = 0.84

Keys suggests that a result of over 0.75 “might be the chosen point where one gives intellectual consent.”

So far so good, although we must bear in mind that all the input figures are entirely subjective, and this is a method of determining the level of one’s own personal conviction, not a way of convincing anybody else. Somebody else may not trust the janitor as much as I do, and therefore they do not find the BELIEF value to be over 0.75.

Unfortunately, this clear and sensible rationale for establishing degrees of personal belief was then abandoned in favour of a kind of mathematical soup of various ‘probabilities,’ and a summary slide of such random figures that not even Keys had any idea what it meant. Dividing his lecture into four questions, this first one, ‘Who is the figure in the Shroud,’ occupied so much of this speculative guesswork (concluding, of course, that there is only a one-in-a-squillion chance that the image is not Jesus), that the second one, ‘How was the image made,’ was reduced to a five minute statement that it must be a miracle because no other explanation is possible. This was lucky, because it meant that Keys didn’t have to bother with the last two questions, Where, and Why, was the image created.

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Another travesty of mathematical incompetence came from Mark Antonacci, the modesty of whose title, ‘How to Solve the Greatest and Most Controversial Questions of Science and Humanity’ surely had its tongue firmly planted in its cheek. If the content of his presentation reflects the title, then the single most controversial question of science and humanity is how to calculate the age of the Shroud. Antonacci began with the radiocarbon dating, of course, and almost everything he said was either wrong or too muddled to make sense, from the number of measurements of the Carbon-14 actually taken to the age range of the samples. He seemed to think that the number of Carbon-14 atoms in the sample was calculated by understanding the areal density of the cloth, which is confused, and he claimed that the results were not sent to the G. Colonnetti Institute of Metrology, which is wrong. He doesn’t understand how averages work or what they’re for, he briefly discussed the “Trondheim” experiment, which doesn’t exist (he was thinking of Burleigh, Leese and Tite, 1986), but he misunderstood it anyway, and he said that the radiocarbon teams did not consider the possibility of neutron enrichment, which is wrong.

Then he went into an extensive ramble around Chlorine-36, which I think he understands, but I bet his audience didn’t. “You take the percent of the total, the 30%, and that tells you how old it is, and you take the 70%, and that tells you how long ago it happened.” Well, in my book, “how old it is,” and “how long ago it happened” are exactly the same. What Antonacci is trying to say is this:
Chlorine is naturally found as Chlorine-35 and Chlorine-37, and a minute amount of Chlorine-36, which is formed from Argon-36 in the atmosphere by neutron collision in the same way as Carbon-14 is made from Nitrogen-14. As Chlorine-36 has a half-life of over 300,000 years, an artefact buried in the ground for a couple of thousand years has substantially the same proportion of Chlorine-36 as the same artefact made today. If an excavated artefact were found to have a greater proportion than is present today, then it may have been subject to an unusual burst of neutrons, whose intensity could be calculated. What you would not be able to calculate is when that neutron burst occurred. However, you could then model the effects such a neutron burst would have had on the carbon of the artefact, and, given that Carbon-14 has a much shorter half-life (5730 years), how much Carbon-14 would be present had that event happened at various different times in the past, producing a calibration graph, against which the actual Carbon-14 content of the artefact could be compared. That would tell you the age of the artefact.

Unfortunately there is minimal chlorine in linen, but there is some in blood (about 1 mg/mL), which, if enough could be collected off the Shroud, would give us the ability to measure the Chlorine-36/Chlorine-35 proportion. Antonacci manages to muddle this as well, and thinks that because blood is “chemically richer” than linen, that bombarding it with neutrons would make it appear to date even further into the future than a similar bombardment of the linen it is lying on. Which isn’t true.

An exactly similar calculation could be made using calcium, which usually consists almost entirely of Calcium-40 and a trace of Calcium-41, which could be enriched by neutron radiation. It is unlikely that enough calcium could be collected from the Shroud, but a chip off the Holy Sepulchre would serve a very similar purpose. However, Antonacci says “the tomb has not been opened yet; the opening has been made but the tomb has not been opened.” Which isn’t true.

“Because they never shared anything with the Institute of Metrology, nobody knew until Tristan Casabianca [et al.] filed a Freedom of Information Act against the labs and the British Museum.” This is nonsense. The British Museum itself recognised, and published, the fact that the raw data were inhomogeneous, and Riani, Atkinson et al. related the data to the position of the samples on the cloth. Casabianca’s paper added a bit of meat to the bone, but nothing new to the overall conclusion.

By the end, letting his enthusiasm completely drown his reason, Antonacci didn’t recognise where the radiocarbon sample strip came from, but cheerfully announced, “It’s the worst area of all. STuRP knew every inch of the cloth, every centimetre of the cloth, and they would have never taken one [a sample] from there.” On the contrary, STuRP specifically designated exactly that spot for one of their samples to be taken from. Then Antonacci announced that the area contained scorch marks and a water stain, which of course it doesn’t.

[Pam Moon corrected this, saying it wasn’t water stain but dye, and that the 1.5N solution of Hydrochloric Acid used by Oxford would not have removed it. This is incorrect. She was referring to Ray Rogers, who said that the ‘dye’ was not decomposed by 1.5N HCl. However, he also said it was soluble in water, so although the acid might not have decomposed the dye, it was certainly adequate for flushing it away.]

Enough already. Eventually Antonacci’s presentation petered out in incoherence, so I’ll leave it there. At the end of my Review Part One I said I was looking forward to hearing from John Jackson, Joe Marino and Teddi Pappas, of whom only Marino has made to the web so far, delivering a rather tired list of “misconceptions” about the Shroud, really more of a list of disagreements between medievalists and authenticists than genuine misconceptions, but highlighting one or two of the more common ones. As for the others, well, I’m not holding my breath.

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1). Roger and Marion Gilbert, ‘R., Jr. and M.M. Gilbert, ‘Ultraviolet-Visible Reflectance and Fluorescence Spectra of the Shroud of Turin,’ Applied Optics, Vol. 19, 1980