On the Bible and forensic evidence

Have you ever wondered why some of the rules of evidence in Scripture are so strict? Read the New Testament account of the trial of Jesus. Look at the words of the high priest as he confronts Our Lord Jesus Christ. He is utterly frustrated because of the testimony of the witnesses.

Now the chief priests, the elders, and all the council sought false testimony against Jesus to put Him to death, but found none. Even though many false witnesses came forward, they found none. But at last two false witnesses came forward and said, “This fellow said, ‘I am able to destroy the temple of God and to build it in three days.’”

And the high priest arose and said to Him, “Do You answer nothing? What is it these men testify against You?” But Jesus kept silent. And the high priest answered and said to Him, “I put You under oath by the living God: Tell us if You are the Christ, the Son of God!”

The frustration of the high priest is that, according to the Law and to Talmudic Tradition, it requires three witnesses to a capital crime, and those three witnesses cannot simply substantially agree, they must fully agree. Please realize that this is not the rule in trials in the USA. Rather, we can convict people on circumstantial evidence, and evidence that is not always backed up by good science.

But, wait, what about all those CSI shows on TV, all those investigative shows that use science to undoubtedly prove the guilt of the perpetrator? Well, unfortunately, the science is nowhere near as exact as those shows would like you to believe. Do I have any evidence? Well, yes, think about all the people who have been exonerated by DNA evidence, most of their convictions were based on circumstantial evidence. But, wait, circumstantial evidence is not science and science cannot be wrong, right? Well, I wish that were true, but some of the convictions that have been overturned were based precisely on the type of “science” that figures so prominently in some of the TV programs.

You see, the problem is that many of the techniques used by modern CSI-type laboratories have never been checked by the standard scientific double-blind studies, repeated multiple times to ensure reliability. Let me give you one instance of what I mean:

A small study by the University of Southampton in 2005 put fingerprinting to the test. Researchers at the School of Psychology invited a panel of forensic experts to assess a set of fingerprints. In a twist to the study, the scientists were led to believe that the prints they were comparing did not match — and in a further twist, all of the samples being analyzed by the experts were prints they had “matched” before in previous cases. The results are stunning. Only one participant concurred with his previous assessment that the prints were a “match.” Three scientists changed their original decision, and one expert could not render a definitive decision.

Now fingerprints have been one of the pillars of much of modern forensics. And, yet, partial fingerprints are not as reliable as you may think. Do you remember that in 2004 an innocent USA citizen was found to be involved in the bombing of the Madrid commuter trains based on a fallacious interpretation of a partial fingerprint? He was let loose only because it was so fully impossible that he was involved. The FBI later claimed that it was only due to a degraded fingerprint. Fingerprints are basically a reliable technology, but if they are stretched beyond the limits of their reliability, they can give a bad result. And, the stretching often happens when an “expert” testifies that the partial fingerprint “definitively” belongs to the alleged perpetrator. Even DNA experts seldom, if ever, claim that level of reliability.

Other technologies have a much lower level of reliability. Have you ever seen the TV programs where a perpetrator is identified on the basis of a bite mark on some material? Well, uhm, what few studies have been done show that type of analysis to be quite unreliable. What about partial imprints from a palm or tire tracks, etc. Well, uhm, I hate to tell you this, but they also have been found to have a much lower level of reliability than fingerprints. One of the areas that has been most surprising has been in the area of fires in houses. The accepted pattern of the spread of a fire in an edifice from three decades ago is no longer the accepted pattern. What about the finding of “rare” dirt or bugs on a car, leading to a conviction? Well, that can be one bit of evidence, but it is even more unreliable.

Does this mean that forensic science is fully unreliable? Of course not! But, it does give an explanation of why God may have wanted such high levels of evidence in the Old Testament. Let me put it another way. If one reads the Old Testament, and most especially the Talmud, one sees a hesitancy over punishing someone that is quite unlike the Islamic tendency to punish everyone. And, unfortunately, the Old Testament and the Talmud have a much higher hesitancy to punish someone than we do in the modern USA. In fact, the results of the many investigations by the Innocence Project show just how far we are from the Old Testament ideal that is willing to let a guilty person go rather than punish an innocent one. Frankly, some of the evidentiary rules of the Old Testament and the Talmud would be called rather liberal by many of today’s conservatives. And, uhm, did I mention that anyone testifying in a capital case was himself/herself subject to capital punishment if their testimony was found to be perjury? I wish that were true in today’s capital cases. I suspect it would temper the testimony of quite a few witnesses.