Miracle of the Shroud II: The Second Coming

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Slowvehicle said:
Your invention, that the results fairly imply that there is a 5% chance that the three cloth samples are from different cloths, is not supported by the article.
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That's not my invention, and that's not what I said. However it does our argument no good to ignore the fact that the X-squared figure for the Shroud was vastly different from the equivalent figure for the controls. It is an anomaly, and it has to be explained. As I actually did say, there are various possible explanations, and, from the data alone, one cannot distinguish between their probabilities. From the Nature data alone, 'Shroud' dates from different materials cannot be ruled out.

But of course, as Dinwar says, there is other data. I do not believe in any conspiracy to muddle the samples, and I do not believe in the patch, the reweave or the interweave hypotheses, and have done more than most to demonstrate why. My first article as editor for the BSTS Newsletter was a detailed demolition of most of the arguments in favour of it. Nevertheless, the Riani/Atkinson paper demonstrating a chronological gradient is sensible, and, as I have suggested above, may result from a zero-C14 addition of some kind, which could have had the overall effect of shifting an estimated date of about 1340AD back to that of about 1280AD, which I believe is is better interpretation of the Nature data as it stands.
 
hugh farey said:
I'm afraid I disagree. A 5% "probability of obtaining, by chance, a scatter among the three dates as high as that observed" raises a variety of possible scenarios, one of which is certainly the possibility that the samples came from different materials. Another is that the 1-in-20 chance just came up (as it could do again, were the Shroud tested in the same way another 40 times or so), and another is that the errors were greater than quoted, which is what the Nature editors actually went on to justify, as I said in my earlier comment.

The X-squared figure does not imply that the Shroud, or any other tested fragment, is 2000 years old, but we cannot deny that it is present, and clearly differentiates the Shroud samples from the results from the controls.
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hugh farey said:
That's not my invention, and that's not what I said. However it does our argument no good to ignore the fact that the X-squared figure for the Shroud was vastly different from the equivalent figure for the controls. It is an anomaly, and it has to be explained. As I actually did say, there are various possible explanations, and, from the data alone, one cannot distinguish between their probabilities. From the Nature data alone, 'Shroud' dates from different materials cannot be ruled out.

But of course, as Dinwar says, there is other data. I do not believe in any conspiracy to muddle the samples, and I do not believe in the patch, the reweave or the interweave hypotheses, and have done more than most to demonstrate why. My first article as editor for the BSTS Newsletter was a detailed demolition of most of the arguments in favour of it. Nevertheless, the Riani/Atkinson paper demonstrating a chronological gradient is sensible, and, as I have suggested above, may result from a zero-C14 addition of some kind, which could have had the overall effect of shifting an estimated date of about 1340AD back to that of about 1280AD, which I believe is is better interpretation of the Nature data as it stands.
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The suggestion that the data can fairly be interpreted as supporting the possibility of the three samples being from different cloths is NOT presented in the Nature data; it is, in fact, your invention, your sensational danbrowning of actual data. Not to mention that you appear to be trying to have your cake and eat it, too, as your invention of "multiple sources for the samples" contradicts your adoption of the supposed "chronological gradient" of a single sample. You should distinguish between rational data analysis and fanfic.
 
hugh farey said:
That's not my invention, and that's not what I said. However it does our argument no good to ignore the fact that the X-squared figure for the Shroud was vastly different from the equivalent figure for the controls. It is an anomaly, and it has to be explained. As I actually did say, there are various possible explanations, and, from the data alone, one cannot distinguish between their probabilities. From the Nature data alone, 'Shroud' dates from different materials cannot be ruled out. .
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Yes, that is true. Of course, the obvious answer is that "the originally assigned error limits were too small."

Because this happens all the time in physical measurements. In fact, it's a possibility that is addressed in standard statistical books (I remember it being addressed in Bevington).
 
Slowvehicle is correct that the Nature paper itself does not speculate much upon why, for the Shroud samples alone, "The spread of the measurements for sample 1 is somewhat greater than would be expected from the errors quoted." Nor did I say it did. However, the unexpected spread of the measurements surely entitles any interested party to ask; why? And as I did say, various possibilities present themselves, which, on the data alone, cannot be ruled out. Some of those possibilities may be mutually contradictory. One possibility is that the samples came from different materials. Another possibility is that the sample was progressively contaminated. Another possibility is that it was just luck. Another possibility is that the sample was homogeneous but that the error measurements quoted by the laboratories were smaller than they really were. There may be further possibilities involving secret agents or aliens. On the statistical data alone, it is not possible to ascribe probabilities to these alternatives. We must then use other data to distinguish between them. On the basis of that other data (mostly the detailed examination of the samples by the laboratories), the Nature paper authors assumed that the reason for the anomaly was erroneous errors ("It is unlikely that the errors quoted by the laboratories for sample 1 fully reflect the overall scatter.") and proceeded accordingly.

It is a common feature of authenticist arguments that they pretend that anomalies in their information simply do not exist. That saves them the bother of having to explain them. It is important that non-authenticists do not fall into the same error, I think. I bow to Dinwar's expertise in radiocarbon dating, but I fear I do not think that "Those percentages are essentially meaningless" (even if largely true) is a sufficient way of explaining the difference between the X-squared result for the Shroud (6.4) and the contemporaneous Control Sample 4 (the St Louis Cope) - 2.4. If it were, then there would have been no need for the authors of the paper to comment on it.
 
hugh farey said:
That's not my invention, and that's not what I said. However it does our argument no good to ignore the fact that the X-squared figure for the Shroud was vastly different from the equivalent figure for the controls. It is an anomaly, and it has to be explained. As I actually did say, there are various possible explanations, and, from the data alone, one cannot distinguish between their probabilities. From the Nature data alone, 'Shroud' dates from different materials cannot be ruled out.
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Presumably all properly published C14 measurements report an error figure, whether larger or smaller than the 5% in the Nature paper. In fact, just off the top of my head, that same question probably applies to everything science ever measures.

Does that mean you would argue that everything that has ever been dated or measured should be suspected of being invisibly repaired with various different materials from wildly different eras?

As you know, there were 10 years of discussion before the church and STURP agreed to the C14 and decided which piece of the cloth could be cut for the C14. And that cutting and examination was viewed by dozens of people, and it was filmed too. The whole point was to be sure that the cut sample was well clear of any repairs or damage etc.
 
hugh farey said:
Slowvehicle is correct that the Nature paper itself does not speculate much upon why, for the Shroud samples alone, "The spread of the measurements for sample 1 is somewhat greater than would be expected from the errors quoted." Nor did I say it did. However, the unexpected spread of the measurements surely entitles any interested party to ask; why? And as I did say, various possibilities present themselves, which, on the data alone, cannot be ruled out. Some of those possibilities may be mutually contradictory. One possibility is that the samples came from different materials. Another possibility is that the sample was progressively contaminated. Another possibility is that it was just luck. Another possibility is that the sample was homogeneous but that the error measurements quoted by the laboratories were smaller than they really were. There may be further possibilities involving secret agents or aliens. On the statistical data alone, it is not possible to ascribe probabilities to these alternatives. We must then use other data to distinguish between them. On the basis of that other data (mostly the detailed examination of the samples by the laboratories), the Nature paper authors assumed that the reason for the anomaly was erroneous errors ("It is unlikely that the errors quoted by the laboratories for sample 1 fully reflect the overall scatter.") and proceeded accordingly.

It is a common feature of authenticist arguments that they pretend that anomalies in their information simply do not exist. That saves them the bother of having to explain them. It is important that non-authenticists do not fall into the same error, I think. I bow to Dinwar's expertise in radiocarbon dating, but I fear I do not think that "Those percentages are essentially meaningless" (even if largely true) is a sufficient way of explaining the difference between the X-squared result for the Shroud (6.4) and the contemporaneous Control Sample 4 (the St Louis Cope) - 2.4. If it were, then there would have been no need for the authors of the paper to comment on it.
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Woo!-of-the-gaps argument, buggering the concept of the word, "possibilities"*. Not really a problem, except for when disputants such as Mr. Savage claim the the "5%" possibility documented is a "95%" probability that the samples were from different cloths,"because I read that someone said so".

*Possibly the anatomical anomalies, so often lied about by authenticisti, demonstrate that Jesus was really a 'Squatch. Possibly the scriptural anomalies are explained by the fact, the fact, I say, that the Squatches mind-controlled the canon councils. And own Zondervan. Possibly at least one of the lab techs at each of the three labs was a yeti/'Squatch/human hybrid, a sleeper agent put in place to protect the secret.
 
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I most certainly agree that a 5% "probability of obtaining, by chance, a scatter among the three dates as high as that observed" does not imply a 95% probability that the different measurements come from different materials. That is merely one of many possible ways of explaining the anomaly, whose probability cannot be assessed from the Nature paper data alone, but which can be discredited on other grounds.

Should you find yourself at http://theshroudofturin.blogspot.co.uk, you will find that your "Possibly at least one of the lab techs at each of the three labs was a yeti/'Squatch/human hybrid, a sleeper agent put in place to protect the secret" is seriously proposed by one Stephen E. Jones. As far as I know he is totally alone in this belief, but it's there none the less!
 
Charles Freeman,

A few pages ago, Hugh introduced your theory here. I responded in this post: http://www.internationalskeptics.com/forums/showpost.php?p=10489702&postcount=1005

I have a question. Is there any image on the reverse side of the shroud? I think that's probably been discussed here in years gone by, but I honestly can't remember. If the shroud does have an image on the reverse, wouldn't any contemporary painting done on gessoed fabric also have a similar ghost image on the back? I don't know if the shroud does. I don't know if other paintings do. I'm just asking.

Ward
 
Good question,Ward. There were two reasons why gesso was applied to a linen, then as now, before the paint was applied. First was to prevent the paint itself being diffused through the material and losing its precision. Secondly it allowed a different painting in the other side. Many of these painted linens were flags or banners with images in both sides.

At one point it was claimed that there was an image of a face in the other side of the Shroud but this has never been confirmed- in fact it seems unlikely. The Quem Queritis ceremony would only have required one side to be gessoed and painted for a congregation to see.

One of the ingredients of gesso is calcium carbonate and STURP found ' large' quantities of this across the Shroud surface. As not a single member of the STURP team knew anything about ancient textiles or painting on linen, they failed to recognise the evidence for what it was, the sign of an original dealing for painting. They though it was no more than an accumulation of dust!!

Of course, they also failed to realise that painted images were only on the outer fibrils of the cloth- as indeed was originally the case on the Shroud. The pigments tended to disintegrate. The best comparative example I know of is the Zittau Veil in Saxony where the pigments of the central panel were steamed off in 1945 from a1492 painted linen leaving shadowy images similar to those in the Shroud. These paintings were very vulnerable which is why we have very few surviving. Unless they were pasted to a board the pigments usually disintegrated when folded or unfolded. The linen underneath would appear discoloured according to how long the pigments had been in place and this may explain why the remaining images in the Shroud appear to be negatives. The thicker the original paint,the lighter the discolouration underneath and vice versa.

All these ideas fit the evidence for the Shroud but need specialist support. There is some evidence from depictions of the Shroud that the original surface pigments disintegrated in the nineteenth century. Until then the images on the Shroud could be seen from a distance.
 
Charles Freeman said:
The linen underneath would appear discoloured according to how long the pigments had been in place and this may explain why the remaining images in the Shroud appear to be negatives.
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This peculiarity has not been discussed here for some time. It once constituted a major element of the Shroudie argument, but for some reason seems now to have less prominence. The dimensionality of the negative images is the most striking feature of the shroud, and accounts for its impressiveness as a supposedly supernatural object.

Another thing that has vanished completely from discussion is the once much-touted coin images over the eyes, which were even declared to be of known issues of local copper coins.
 
P.S. It is just possible that there may have been an original painting on the other side which was erased by scraping off the gesso and pigments before the images on the Shroud were painted on the other side. I know of no evidence to support this but it is a possible line of enquiry.

One must always remember that any study of the Shroud should begin with the mantra 'what we see today on the Shroud is not what it looked like originally.' Once that is accepted then serious research can begin. The second mantra is 'Until some evidence is found to date the material of the Shroud to earlier than AD 1000 it should be treated as medieval'. Then the research becomes really interesting but so far it has hardly begun.
 
Calcium carbonate, generally deriving from ancient chalk, contains no C14, and, if by any chance it were not removed by the cleaning processes, would have the effect of making a radiocarbon date come put older than it should, as seems to have occurred with the Oxford sample.
 
Good point. The STURP team could obviously only work from their tapes but there does seem to have been some variation in how much calcium carbonate was found on the Shroud. If there was an area where the concentration was greater then it would seem that it might well come up with an older date. If this had been a factor working the other way, we would never have heard the end of it!
 
Again, I feel compelled to note that we're dealing with dates 15% of one half-life of C14. Ideally you want to use a dating method with a half-life roughly the same as the thing being dated (not circular--you estimate the date based on other data available). At 15% of the half-life, variation is nearly inevitable. (Same with dates more than three or four halflifes, incidentally.)

Before we look for potential sources of contamination, we need to prove there WAS contamination. A good first step is to look at the variation on other Medieval artifacts from around the same time, and determine if the variation we see is within the normal variation for this method at these dates.
 
I'm only familiar with one similar radiocarbon dating, that of some purported relics of St Francis of Assisi, detailed in "AMS radiocarbon dating of medieval textile relics: The frocks
and the pillow of St. Francis of Assisi", M.E. Fedi et al., Nuclear Instruments and Methods in Physics Research B 266 (2008) 2251–2254. Here three samples from three different artifacts supposedly associated with the saint were dated, and gave (in years BP), 857 +/- 18, 915 +/- 40, 885 +/- 30, and 666 +/- 18. (The middle two readings are from two pillowcases which are found one inside the other). Here the errors are significantly less than the Shroud dating of 20 years earlier, and I have no doubt that the chances of all three samples coming from the same source is considerably less than 1 in 20. In this case, there was no X-squared calculation carried out; since the samples all came from different cloths, the younger one was rejected as not from St Francis's own property without further consideration.
 
Yes. They have to use a different calibration curve, taking into account the uptake of atmospheric CO2 into solution in the sea. I don't know if you followed the carbon dating of the bones of King Richard III, found recently in the UK, which dated to a significant number of years before he actually died. This is attributed to his diet, of which shellfish formed a large part. So if the calcium carbonate found on the Shroud derives from shells, it would still make the Shroud appear older, but considerably less. Rocks, on the other hand, do not have any atmospheric C14 uptake, and have essentially zero C14.
 
hugh farey said:
Yes. They have to use a different calibration curve, taking into account the uptake of atmospheric CO2 into solution in the sea. I don't know if you followed the carbon dating of the bones of King Richard III, found recently in the UK, which dated to a significant number of years before he actually died. This is attributed to his diet, of which shellfish formed a large part. So if the calcium carbonate found on the Shroud derives from shells, it would still make the Shroud appear older, but considerably less. Rocks, on the other hand, do not have any atmospheric C14 uptake, and have essentially zero C14.
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This is a known issue. The very same issue that raised it's head with regard to whether syphilis came from the new world to the old, or vice versa. It is known that a seafood diet will skew carbon dating. Feel free to tell us all what exactly was the diet of the tablecloth. I cannot see what diet a cloth might have had. As far as I know, the tablecloth of turin had no diet whatsoever.
 
abaddon said:
This is a known issue. The very same issue that raised it's head with regard to whether syphilis came from the new world to the old, or vice versa. It is known that a seafood diet will skew carbon dating. Feel free to tell us all what exactly was the diet of the tablecloth. I cannot see what diet a cloth might have had. As far as I know, the tablecloth of turin had no diet whatsoever.
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But maybe Jesus had a diet which could have had an incidence on the dating of the shroud... :rolleyes:
 
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