Arizona

Richard Dawkins on the Shroud

In September of 2009, Richard Dawkins, in his new book, The Greatest Show on Earth: The Evidence for Evolution, seemed to trip over many of these points, directly or by implication:

[Carbon dating] has revolutionized archaeological dating. The most celebrated example is the Shroud of Turin. Since this notorious piece of cloth seems mysteriously to have imprinted on it the image of a bearded crucified man, many people hoped it might hail from the time of Jesus. It turns up in the historical record in the mid-fourteenth century in France, and nobody knows where it was before that. It has been housed in Turin since 1578, under the custody of the Vatican since 1983. When mass spectrometry made it possible to date a tine sample of the shroud, rather than the substantial swathes that would have been needed before, the Vatican allowed a small strip to be cut off. The strip was divided in three parts and sent to three leading laboratories specializing in carbon dating, in Oxford, Arizona and Zurich. Working under conditions of scrupulous independence—not comparing notes—the three laboratories reported their verdicts on the date when the flax from which the cloth had been woven died. Oxford said ad 1200, Arizona 1304 and Zurich 1274. These dates are all—within normal margins of error—compatible with each other and with the date in the 1350s at which the shroud is first mentioned in history. The dating of the shroud remains controversial, but not for reasons that cast doubt on the carbon-dating technique itself. For example, the carbon in the shroud might have been contaminated by a fire, which is known to have occurred in 1532. I won’t pursue the matter further, because the shroud is of historical, not evolutionary, interest. It is a nice example, however, to illustrate the method, and the fact that, unlike dendrochronology, it is not accurate to the nearest year, only to the nearest century or so. [Emphasis mine]

Dawkins is either clueless or selective. One wonders if he even checked Wikipedia. On the matter of the historical record he implies that the absence of evidence is itself evidence or as Donald Rumsfeld famously put it, “absence of evidence is not evidence of absence.” He was trying to justify his belief that there were weapons of mass destruction in Iraq.

Besan

But where are the records for it in Besançon if it was there? The city's Cathedral of Saint Etienne was struck by lightning in 1349 and burned to the ground along with countless records in its archives. That may explain why there are no records before the 1350s. That is not proof, of course. It is not proof of anything. But it does offer an example of why a claim of a lack of any history before the 1350s is not a sound historical argument.

There certainly was a burial shroud relic in Constantinople and there is extensive evidence, both historical and scientific, that this shroud is the same shroud found in Turin. We’ll see that as we proceed. But what about the verdict of the carbon dating from Oxford, Arizona and Zurich, dates “all—within normal margins of error—compatible with each other. . .”? We should not be surprised that the dates seem close. Actually, if we dig a bit deeper, we see that there are some serious statistical problems with the dates the laboratories measured. Dawkins only gives us averages of many tests that the labs performed. He implies this is a final verdict. He is praising carbon dating.

Twenty-One Scientists

Consider that no less than twenty-one scientists from the University of Oxford, the University of Arizona, the Institut für Mittelenergiephysik in Zurich, Columbia University, and the British Museum wrote in a peer-reviewed paper published in Nature in 1989:

The results of radiocarbon measurements at Arizona, Oxford and Zurich yield a calibrated calendar age range with at least 95% confidence for the linen of the Shroud of Turin of AD 1260 - 1390 (rounded down/up to nearest 10 yr). These results therefore provide conclusive evidence that the linen of the Shroud of Turin is mediaeval.

How can anyone argue with this? The radiocarbon measurements were done, not at one laboratory, but at three highly regarded institutions. The authors are emphatic. The results provide not just evidence but conclusive evidence. Does this not suffice to answer the students’ questions?

No, not if we wonder what prompted the questions. The Shroud of Turin is a religious relic. Many people believe it was the burial cloth of Jesus of Nazareth and history. Were the questions prompted by religious beliefs that run contrary to science? Or is there new information that suggests that, indeed, mistakes were made?

Garza-Valdes and the Mayan Jade Artifact

In 1983, Leoncio Garza-Valdes, a medical doctor in San Antonio, Texas, and an amateur archaeologist, was examining a Mayan jade artifact that was assumed to be modern forgery. He was puzzled by lacquer-like coating on the object that he speculated might have been produced by bacteria. Garza-Valdes took the artifact to the radiocarbon dating lab at the University of Arizona. Scientists there were able to scrape off enough of the coating, as well as some bloodstains on the object, to give a date of about A.D. 400. The carving style suggested that the age should have been about 200 B.C.. However, if the bioplastic-polymer, for that is what it seemed to be, had been forming over the centuries, it would be a mixture of older and newer material. So perhaps the object really was 600 years older.

Following the carbon dating of the shroud, it occurred to Garza-Valdes that perhaps the fibers of the shroud were also coated with a bioplastic coating. And perhaps this also affected the carbon dating of mummy 1770. If ancient linen was subject to such a coating, then all bets were off on the carbon dating of the shroud until it was examined.

Garza-Valdes managed to inspect *** in Turin. Stephen Mattingly ****

The Ibis Mummy

Things were heating up. Harry Gove, a prominent radiocarbon dating expert from the University of Rochester in New York, who had wanted to be part of the carbon dating of the shroud and not been selected, was now involved. Ann Rosalie David, who had been part of the team that had studied mummy 1770, was involved as well. They met at the University of Texas Health Science Center in Austin. David brought a mummy of an ibis, a bird that the ancient Egyptians considered sacred. They had been careful to select one that seemed unlikely to have been rewrapped. They extracted samples of both tissue and bone from the bird as well as linen fabric from its wrappings. These they took to the National Science Foundation Accelerator Mass Spectrometry Facility at the University of Arizona, one of the same labs involved with the shroud’s dating.

The linen appeared to be newer than the bird it wrapped. And unless the bird was rewrapped—which seemed implausible to the four researchers—then appearances contradicted reality. They clearly saw something that seemed to be a bioplastic coating. But they entertained another possibility as well: the bird’s diet.

Red Flags Ignored

There were other clues, as well. All of them were warning signs that something might be wrong with the carbon 14 samples:

• Giovanni Riggi, the person who actually cut the carbon 14 sample from the Shroud stated, "I was authorized to cut approximately 8 square centimetres of cloth from the Shroud…This was then reduced to about 7 cm because fibres of other origins had become mixed up with the original fabric …" (emphasis mine)
• Giorgio Tessiore, who documented the sampling, wrote:  “…1 cm of the new sample had to be discarded because of the presence of different color threads.” (emphasis mine)
• Edward (Teddy) Hall, head of the Oxford radiocarbon dating laboratory, had noticed fibers that looked out of place. A laboratory in Derbyshire concluded that the rogue fibers were cotton of “a fine, dark yellow strand.”  Derbyshire's Peter South wrote: “It may have been used for repairs at some time in the past…”
• Gilbert Raes, when later he examined some of the carbon 14 samples, noticed that cotton fibers were contained inside the threads, which could help to explain differences in fiber diameter. This may also explain why the carbon 14 samples apparently weighed much more than was as expected.
• Alan Adler at Western Connecticut State University found large amounts of aluminum in yarn segments from the radiocarbon sample, up to 2%, by energy-dispersive x-ray analysis. Why aluminum? That was an important question because it is not found elsewhere on the Shroud.
• The radiocarbon lab at the University of Arizona conducted eight tests. But there was a wide variance in the computed dates and so the team in Arizona combined results to produce four results thus eliminating the more outlying dates (reportedly they did so at the request of the British Museum, which was overseeing the tests). Even then, according to Remi Van Haelst, a retired industrial chemist in Belgium, the results failed to meet minimum statistical standards (chi-squared tests).  Why the wide variance in the dates? Was it because of testing errors? Or was it because the sample was not sufficiently homogeneous? The latter seems very likely now, and the statistical anomaly indicates something very suspicious about the samples.
• Bryan Walsh, a statistician, examined Van Haelst’s analysis and further studied the measurements. He concluded that the divided samples used in multiple tests contained different levels of the C14 isotope. The overall cut sample was non-homogeneous and thus of questionable validity. Walsh found a significant relationship between the measured age of various sub-samples and their distance from the edge of the cloth. Though Walsh did not suggest invisible reweaving, it is consistent with his findings.

Richard Dawkins

[Carbon dating] has revolutionized archaeological dat-ing. The most celebrated example is the Shroud of Tu-rin. Since this notorious piece of cloth seems myste-riously to have imprinted on it the image of a bearded crucified man, many people hoped it might hail from the time of Jesus. It turns up in the historical record in the mid-fourteenth century in France, and nobody knows where it was before that. It has been housed in Turin since 1578, under the custody of the Vatican since 1983. When mass spectrometry made it possible to date a tine sample of the shroud, rather than the sub-stantial swathes that would have been needed before, the Vatican allowed a small strip to be cut off. The strip was divided in three parts and sent to three leading laboratories specializing in carbon dating, in Oxford, Arizona and Zurich. Working under conditions of scrupulous independence—not comparing notes—the three laboratories reported their verdicts on the date when the flax from which the cloth had been woven died. Oxford said ad 1200, Arizona 1304 and Zurich 1274. These dates are all—within normal margins of error—compatible with each other and with the date in the 1350s at which the shroud is first mentioned in his-tory. The dating of the shroud remains controversial, but not for reasons that cast doubt on the carbon-dating technique itself. For example, the carbon in the shroud might have been contaminated by a fire, which is known to have occurred in 1532. I won’t pursue the matter further, because the shroud is of historical, not evolutionary, interest. It is a nice example, however, to illustrate the method, and the fact that, unlike den-drochronology, it is not accurate to the nearest year, only to the nearest century or so. [Emphasis mine]