When the Sign From God Foundation proclaims that the 1988 carbon-14 dating of the Shroud of Turin is “still hotly contested,” one might imagine a scene of scientific turmoil, with labs divided and headlines crackling with uncertainty. But thirty-five years on, the real story is not one of fresh controversy, but of enduring mythologies—narratives propped up less by new data than by persistent suspicion. They say on their website:
Fact: The widely reported and controversial 1988 carbon-14 dating tests dating the Shroud between the years 1260 and 1390, used by naysayers to disregard the Shroud as a “medieval hoax” is still hotly contested by scientists and Shroud researchers 30 years later.
A good question to ask is: How could a medieval “artist” make or take a photo negative when photography was not introduced to the world until 500 years later in 1839?
Let’s start with Sign From God’s framing. Their preferred term for skeptics of authenticity is “naysayers”—a rhetorical put-down, really, implying that doubt itself is a knee-jerk response. In doing so, they dismiss a broad range of scholars, statisticians, chemists, physicists, and even potential converts to their perspective who simply value rigorous inquiry. It’s a rhetorical brush-off—an ad hominem dressed up in apologist zeal.
To challenge that, we need only turn to Hugh Farey, a longtime Shroud researcher and former editor of the British Society for the Turin Shroud newsletter. Though often labeled a “skeptic,” Farey’s relationship to the Shroud is more nuanced—curious, open to re-testing (believe), and deeply informed. What sets him apart is his insistence on data over drama and his scientific approach.
In a 2023 essay titled The Radiocarbon Data Were Correct (!), Farey offered a detailed forensic review of the 1988 results, including the raw data later made public through the efforts of Tristan Casabianca and others. His verdict? There was no fraud, no cover-up, and no statistical malpractice. The minor discrepancies, rounding oddities, and methodological debates—all noted and publicly discussed at the time—do not amount to scientific deceit. At worst, they are routine footnotes in the process of peer-reviewed research.
The Sign From God Foundation statement would have readers believe that Casabianca’s 2019 paper in Archaeometry “debunks” the 1988 findings. But that paper merely highlighted a known issue: the three labs all dated pieces from the same corner of the cloth, which may have been affected by repairs or contamination. This is not news. It was flagged even in the original Nature article. Nor does it overturn the consensus; it merely urges caution and, possibly, more sampling. Farey himself has welcomed the idea of re-testing—under strict, transparent protocols. That’s not “naysaying.” That’s good science.
In fact, I have never met anyone skeptical or open-minded about the Shroud’s authenticity who didn’t welcome the idea of re-testing. That’s also not “naysaying.” That’s good science.
Meanwhile, the oft-repeated question, snuck into this discussion of the carbon-14 dating—“How could a medieval artist produce a photographic negative image centuries before photography?”—is a calculated diversion. It assumes the image is photographic in essence, rather than merely possessing tonal qualities that reverse under a negative filter. It also presumes intent where none may exist. Again, not knowing how the image formed is not the same as proving it was miraculous. And it has nothing to do with carbon-14 dating, anyway. It sounds desperate.
What’s most troubling is the Sign From God narrative style—part science, part screenplay. Words like “hidden,” “obtained,” and “breakthrough” conjure the feel of a Dan Brown novel. The truth is far duller: the raw data were eventually released through formal, legal means; the 1988 results remain methodologically sound; and the burden of proof still rests with those claiming miraculous origins.
Farey’s criticism of the conspiracy-minded wing of Shroud apologetics is particularly apt. “I’m sorry,” he writes, “that it has become a feature of almost all authenticist criticism… not to need to investigate [scientific findings] analytically, but simply to assume dishonesty, ignorance, incompetence, psychological factors and other personal failings.” In the end, such approaches do not elevate the Shroud; they trivialize it. They undermine both faith and science by treating skepticism as sin and inquiry as sabotage.
If there is a case to be made for the Shroud’s authenticity, let it be made honestly, without scapegoating. Let it stand on better evidence than linguistic sleight-of-hand or numerical cherry-picking. And let the voices of careful thinkers—yes, even skeptics like Hugh Farey (and me)—be heard without disdain.
Verifying
This is a complex subject. I therefore asked Gemini Advance Pro 2.5 Deep Research, a generative artificial intelligence (AI) tool, for an assessment and fact check of this posting. What follows is a short, easy-to-read, three-paragraph assessment and a link to the full, detailed assessment.
Three-Paragraph Nutshell Assessment:
“In a nutshell,” says Gemini,
your essay (blog posting) is largely accurate in its overall assessment and effectively counters the narrative that the 1988 carbon dating is scientifically collapsing. Your points about the Sign From God Foundation’s framing, Hugh Farey’s defense of the 1988 data’s fundamental correctness (against accusations of fraud or major malpractice), and the general persistence of the medieval dating in mainstream science are well-aligned with the broader findings.
Where there’s a slight nuance is in the characterization of the challenges to the 1988 study. While you correctly state that Casabianca’s 2019 paper didn’t overturn the mainstream consensus on the medieval date, it did present a new statistical analysis of previously unreleased raw data which concluded that the 1988 combined result was unreliable due to data heterogeneity. This was more than just highlighting generally ‘known issues.’ Consequently, while the C14 method itself is robust, stating the 1988 results are unequivocally ‘methodologically sound’ without acknowledging these specific, published statistical critiques of the data’s homogeneity and combination might be a bit strong. A 2019 Nature editor noted the 1989 study, while not seen as ‘substantially wrong,’ was also ‘not definitive either’.
However, your essay’s core thrust—that the challenges are often overstated and haven’t dislodged the 1988 conclusion from a mainstream scientific perspective—is accurate.
Dan wrote, “If there is a case to be made for the Shroud’s authenticity, let it be made honestly, without scapegoating. Let it stand on better evidence than linguistic sleight-of-hand or numerical cherry-picking. And let the voices of careful thinkers—yes, even skeptics like Hugh Farey (and me)—be heard without disdain.”
Perhaps from the pro-side: If there’s a case to be made for the Shroud’s non-authenticity, let it be done without giving undue weight to the Shroud’s C-14 dating results. The protocol was not followed, only 1 controversial sample was chosen, and the evidence offered by Ray Rogers, who has been the only one in the world to examine microscopically both samples from the main part of the Shroud and the C-14 area has basically been ignored by non-authenticists. Is this not also cherry-picking? Rogers concluded, based on empirical evidence and supported by other scientists, that the C-14 sample was not representative of the main part of the Shroud and thus not valid for determining the age of the Shroud. In addition, Barrie Schwortz said that any scientist without a horse in the race he ever came across after 1988 said it was unscientific to have chosen only 1 sample to test. Bad science = questionable results.
Right, Joe.
And remember, statistics is just an indicator, not proof of anything. It may indicates (and as many statistical analyses of the Shroud C-14 data due) that there is likely some anomaly in the results (since the test statistics indicate inhomogeneity of the sample which is younger on one side and older on the other). But they do not tell us what is the source of this anomaly. It may be whatever, minor contamination, different neutron flux, carbon monoxide exposure, different procedures by different labs or reweave. Or just random anomaly, which though unlikely, is still possible. Even if statistics did not indicate any anomalies, the results could still be wrong due to any of the reasons previously mentioned (or any other).
The real test is chemical examination -which only Rogers had performed. And was conveniently ignored by many after his death.
I’m not sure who all these medievalists are who have ignored Ray Rogers’s findings. Marco Bella, Luigi Garlaschelli, and Roberto Samperi studied them and had comments printed in Thermochimica Acta, Joe Nickell commented in the Skeptical Inquirer, I wrote two detailed reviews called “Dear Mr Rogers,” and Andrea Nicolotti discusses them in his book The Shroud of Turin. Colin Berry reviewed Rogers’s paper in detail and was contacted by with the author of the research on which Rogers based his conclusions, Stanley Koseiwicz, who wrote:
“The reason Rogers did not include my data is that Rogers falsified it and there never was any data generated by me to support his assertions. For many years I was unaware that Rogers did this.
Another man named Roberto (Bob) Villareal from Los Alamos contacted me to discuss Rogers’ use of my supposed data. I told him it was false. However Bob still went ahead and presented it at a conference on the shroud in Italy I believe.”
It would be truer to say that Rogers’s actual work, like that of most of the scientists who have worked on the Shroud, has been largely ignored by those who simply quote his conclusions because it suits their agenda, rather than examine the experiments and observations on which it is based.
Koseiwicz, it seems to me, is making his opinion the standard for truth. I question his assertion that Rogers falsified data. Barrie Schwortz said that Ray had the most integrity of scientists that he had ever seen. Koseiwicz also seemed to impugn Villareal’s reputation. The former seemed to think that the latter should just have accepted Koseiwicz assertion that it was false. Did he even consider that Villarreal might have believed that his findings were correct and not Koseiwicz? A nine-person team at Los Alamos (including Villarreal) (as well as Dr. John Brown from Georgia Tech) supported what Rogers had found. And might not some of the non-authenticists who questioned Rogers work have found data to suit their own agenda? For example, Joe Nickell was a professional skeptic who worked to disprove anything that might smack of the paranormal. At one point he even questioned whether Jesus even existed. Would you expect him NOT to have found something to pour water on the idea that the Shroud might have wrapped Jesus?
Nickell always claimed that Christians who were for the Shroud were biased. Can anyone explain to me why he’s any less biased as a Christian critic and anti-paranormalist that the Shroud was a forgery?
At the end of the day, with Rogers’ findings or not, the bad science of taking only 1 controversial bad sample is still present. Dan had complained about authenticists using “linguistic sleight of hand.” Non-authenticists could be accused of the same thing in their evaluation of the 1-sample-only protocol.
No one still knows how the image got onto the Shroud, and while that in itself doesn’t prove it’s miraculous or authentic, the longer it goes without someone being able to duplicate it makes it all the more possible that it is what authenticists believe it is.
Of course skeptics had to react somehow to Rogers work. And most simply reacted with attempts to denigrate his integrity, rather than asses his findings thoroughly. Utilizing the fact that the man is dead and cannot defend itself.
I n his “Studies on the radiocarbon sample” Rogers mentioned Kosiewicz only once and his alleged work is not included in the references. Similar in Rogers’ “A chemist perspective on the Shroud of Turin” (on pg. 40). Did they performed such experiments? Rogers said Yes, Kosiewicz said No. But apparently this was never published, and Rogers quotation is based only on personal communication and relation with Kosiewicz. Who may now, if he prefers, claim that such experiments had never been performed and Rogers falsified everything. Really? I rather doubt this. Anyway, whether or not, the point is not how accurate is the age estimation based on the rate lignin decomposition. The point is that based on the vanillin test (as well as other data) the material in Raes/C-14 corner is different than in the other part of the Shroud. Thus 1988 C-14 measurements are invalid.
Anyway here is the relevant quote from Rogers’ “Studies on the radiocarbon sample” ( https://www.sindone.info/ROGERS-3.PDF , an analogous quote is in “A chemist perspective” on pp. 40-41):
Stanley T. Kosiewicz of Los Alamos aged samples that contained lignin at 40, 70, and 100 ◦ C for up to 24 months. Comparison of detection limits among the samples showed the rate of vanillin loss is very low. A suitable chemical-age predictive model therefore could be produced.
Rates of all kinds of chemical reactions are modeled with the Arrhenius expression
(Equation 1)
where α is the fraction reacted at any time t; k is the rate constant, s−1 ; Z is the Arrhenius frequency factor, s−1 ; E is the Arrhenius activation energy, J mol−1 ; R is the gas constant, 8.314 J K−1 mol−1 ; and T is the absolute temperature in kelvins. f(α) is the depletion factor; and it depends on the physical state of the reactant, the type of reaction, and/or the
number of molecules involved in the reaction. Analysis of the time/temperature/detection-limit data gave the following
Arrhenius predictive model for the rate of vanillin loss from lignin.
(Equation 2)
If Kosiewicz did not perform such experiments than someone other should do in order to verify (and modify if needed) Rogers’ model (as well as test the linens of different ages -like those Fanti and his colleagues use for their tests – for the presence vanillin). But no one did. A blame game: “He lied!’, “No, he lied!” is much easier to perform.