SCIENTIFIC METHOD APPLIED TO THE SHROUD OF TURINA REVIEW
Raymond N. Rogers* and Anna Arnoldi**
*University of CaliforniaLos Alamos National Laboratory
Los Alamos, NM
**Department of Agrifood Molecular SciencesUniversity of Milan
2002 All Rights Reserved
After 25 years of scientific study, I believe that three statements can be supported on the basis ofestablished laws of science and direct observations on the Shroud of Turin.
1. The radiocarbon age determination made in 1988 used an invalid sample, and it gave an erroneousdate for the production of the main part of the cloth.
2. The hypotheses that have appeared since the announcement of an AD 1260-1390 date that invokeradiation of different kinds to explain the image and the date can be categorically discarded.
3. The characteristics of the image can be explained by reference to highly probable, well-knownchemical reactions. No miracles are necessary to explain the image.
The Shroud of Turin first came to public notice and was documented early in the 14th Century in Francewhen its custodian claimed that it was the shroud of Jesus. It has been fiercely controversial ever since.
It has very seldom been displayed to the public, and it has been more an object of veneration that ofstudy. Reports on it have been more subjective than objective; however, its religious concomitant doesnot eliminate the possibility of making truly scientific studies on it. It exists as a material object, andanything that can be observed and measured can be studied by objective methods
The Shroud is a large piece of linen that shows the very faint image of a man on its surface. The imageappears to show a man who has been crucified, with blood flows in the appropriate positions. Thesefeatures have been observed by several different, independent scientific techniques.
The Shroud is now preserved in Turin, Italy. A group of scientists produced a plan for study in 1977.This group incorporated as the Shroud of Turin Research Project (STURP). In 1978, the custodianspermitted limited scientific studies to be made. Results of those observations are reviewed below.
All methods used to establish basic beliefs are subject to the test of general reliability, and they areacceptable only if they yield beliefs which prove to be true. Attempts to develop objective philosophicalmethods for reaching truth from observations have resulted in the logical approach known as ScientificMethod. The STURP plan was based on a rigorous application of this method.
The Bishop of Troyes sent a letter to the pope in AD 1389 claiming that the image had been painted;
therefore, that was the primary question to be addressed during the 1978 STURP studies. However, thescientific observations made in Turin in 1978 can and should be used to test any hypotheses involvingthe Shroud.
A summary of the major elements of Scientific Method in the context of Shroud studies follows.
1) Identify and clearly state the goal. The goals of the different studies on the Shroud are not alwaysclearly stated in writings on the subject, and ultimate goals were never agreed upon by all of the personsconnected with STURP. There is a huge difference among the following list of possible goals: 1) testwhether the image was a hoax that used known methods for producing an image; 2) estimate theprobability that the Shroud is an "authentic" shroud; 3) prove that the cloth had been the shroud ofJesus; and 4) test whether the Shroud proved the resurrection of Jesus.
2) Assemble all pertinent data. Two of the most damaging things a "scientist" can do during thedevelopment of a "scientific" study is to include speculations on an equal basis with tested facts andexclude observations he does not like. We have seen both problems in Shroud literature. "I think I see,"seems to be accepted by "true believers" on an equal basis with quantitative measurements. Personswho are devoted to "debunking" the Shroud refuse to accept observations that do not further their goals,and persons who want to prove the resurrection refuse to accept observations that seem to conflict withtheir preconceptions.
3) Hypothesize and innovate. An unproved statement that is intended for study and testing is called an"hypothesis." The Method of Multiple Working Hypotheses encourages a scientist to state as manycredible explanations for an observation as possible. This is an enjoyable phase of science; it is perfectlyvalid to let imaginations run wild. Groups often get together to "brainstorm" all of the hypotheses theycan think of. Unfortunately, few attempts have been made to develop multiple, testable hypotheses onimage formation. Persons with fixed goals wish to prove their points, and they refuse to "assemble allpertinent data." Hypotheses for image formation were discussed in detail after the STURPobservations.
4) Test and confirm. The rigorous application of Scientific Method requires that all hypotheses betested equally, and they must be tested against the same comprehensive set of facts and observations.A person who feels comfortable with Scientific Method enjoys "shooting holes" in his hypotheses. Hardfeelings often result when somebody else's favorite hypothesis is picked to pieces, but that is animportant part of the "self-correcting" nature of science. An important part of confirmation is prediction.Prediction enables confirmatory experimentation. Hypotheses that can not be used to formulate testablepredictions are useless. Miracles can not be tested nor confirmed and are not part of science.
5) Occam's Razor. In any contention, both sides can not be correct; however, both sides can be wrong.Competing hypotheses should be tested with Occam's Razor. We usually state it as, "The hypothesisthat includes the smallest number of special assumptions has the highest probability of being closest tothe truth." Scientists normally do not consider it possible to prove a truth. A miracle is a "specialassumption." If one hypothesis demands a miracle and another can be supported by known science andobservations, the miracle should be discarded.
6) The fallacy of the non sequitur. After weak hypotheses have been eliminated according to knownfacts and laws of nature, you hope that at least one remains. After a comprehensive study of the knownfacts, STURP members reported that, "We really do not have a satisfactory, simple explanation forhow the body image got on the cloth."
Many writers who are supporting a religious/miraculous position take that statement to mean somethinglike the following: "If science can not explain the observation, it must have had a miraculous origin." The
Greeks recognized the fallacy of such an "argumentative leap" before 300 BC. The fact that science hasnot yet found an explanation proves nothing.
ASSEMBLE ALL PERTINENT DATA
The primary goal of STURP was to test the hypothesis that the Shroud's image was painted. Secondarygoals were to observe the Shroud's technology and composition so that statements could be made on its"authenticity" (whatever that is taken to mean) and possible age. In order to accomplish the goals, alarge number of observations were made before, during, and after the Shroud was made available forstudy in Turin. Facts were also assembled from literature surveys. Some of these facts will be mentionedto illustrate the process of Scientific Method. The observations and data can and should be used to testall hypotheses on the Shroud. No facts can legitimately be ignored.
1) The fire of AD 1532:Fortunately for us, the Shroud was nearly destroyed in a church fire in AD 1532. If the image had beenpainted, some colored material had to be added to the cloth. The pigments and vehicles (glair, gums,glues - oils were not used in the 14th Century, but they were also tested) would have been subjected toa violent "chemical test" during the fire. The temperatures, temperature gradients, pyrolysis products,and water used to extinguish the fire would have changed the chemical composition of most foreignmaterials. Before going to Turin in 1978, we did many experiments on the stability of the paintingmaterials. All of these pigments and vehicles were tested by applying them to linen and subjecting thesamples to different kinds of heating.
Figure 1: Results of one "burn test." Linen streaked with blood and differentpainting media with and without pigments was heated intensely in thecenter while it was confined between two stainless-steel plates (1977).
Figure 2: The same sample under UV illumination. The linen was modern andcontained "fabric brighteners." Condensed cellulose pyrolysis products
form an intensely fluorescent ring around the center of heating.
We had expected hematite (Fe2O3) to be the most probable pigment that could have been used to paintthe image. The heating tests proved that much of the red hematite was reduced to black magnetite(Fe3O4) by the pyrolysis products. No such effect could be observed on the Shroud.
All paints were changed by heat and/or the chemically reducing and reactive pyrolysis products(formaldehyde, furfural, organic acids, CO, etc.). Some Medieval painting materials become watersoluble and they would have moved with the water that diffused through parts of the cloth at the time ofthe AD 1532 fire. Observations of the Shroud in 1978 showed that nothing in the image moved with thewater.
STURP concluded that the image was not a painting. Walter McCrone[5,6] insisted that the image waspainted with hematite. Several other people have claimed to reproduce the appearance of the image bydifferent "painting" methods, but none have used the