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Scientism = junk science in the courtroom

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Scientism: Believing that all correct answers come from science (and, in practice, that the answers offered on behalf of whatever counts for science in given situation is correct).

How does that play out in the criminal justice system? From Kelly Servick at Science:

… for decades, forensic examiners have sometimes claimed in court that close but not identical ballistic markings could conclusively link evidence to a suspect—and judges and juries have trusted their expertise. Examiners have made similar statements for other forms of so-called pattern evidence, such as fingerprints, shoeprints, tire tracks, and bite marks.

But such claims are ill-founded, a committee at the National Academy of Sciences (NAS) concluded in 2009. “No forensic method has been rigorously shown to have the capacity to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source,” the panel wrote. In other words: Judges and juries were sometimes sending people to jail based on bogus science.

What happens when the public accepts scientism: Jurors treat someone’s findings as an oracle.

In a 2013 study, for instance, online participants had to rate the likelihood of a defendant’s guilt in a hypothetical robbery based on different kinds of testimony from a fingerprint examiner. It didn’t seem to matter whether they were simply told that a print at the scene “matched” or was “individualized” to the defendant, or whether the examiner offered further justification—the chance of an error is “so remote that it is considered to be a practical impossibility,” for example. In all those cases, jurors rated the likelihood of guilt at about 4.5 on a 7-point scale. “As a lawyer, I would have thought the specific wording would have mattered more than it did,” Garrett says. But if subjects were told that the print could have come from someone else, they seemed to discount the fingerprint evidence altogether.

What’s troubling, Gertner says, is that when judges accept junk science, an appeals court rarely overrules them. Attaching a numerical probability to evidence, as CSAFE hopes to do, “would certainly be interesting,” she says. But even a standard practice of critically evaluating evidence would be a step forward. “The pattern now is that the judges who care about these issues are enforcing them, and the judges who don’t care about these issues are not.” More.

What complicates the situation in a modern Western society is that the accused is much more likely to be guilty in real life than in TV whodunits. After all, the whodunit’s story premise is that the accused isn’t guilty. But in real life the prosecution must typically show some results for its crime-fighting budget, and naturally prefers good cases to bad ones.

So the fact that the prosecution’s basic contention of guilt is probably true anyway invests the methods by which the accused is found guilty with a sense of authority that goes beyond those methods’ examined validity.

See also: Forensic DNA evidence in doubt? There is no magic truth machine. That’s the reason courts try to err on the side of innocence.

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4 Replies to “Scientism = junk science in the courtroom

  1. 1
    mahuna says:

    This ignores the function of the DEFENSE attorney, who can of course call his own expert witnesses to raise doubts about the quality of the evidence and the analysis. OJ Simpson was found not guilty for just such reasons. Without proving that contamination of the DNA evidence HAD occurred, the defense suggested that it MIGHT have occurred.

    In American courts, the judge is merely the referee. If the prosecution does a bad job of presenting evidence or the defense does a bad job of creating doubt, the judge MUST remind the jury that they can ONLY consider facts and arguments presented IN COURT. And if either the prosecution or the defense discovers during jury selection that a juror actually KNOWS something about ballistics or financial manipulations or any topic that bares on the case, that juror will be excused. That is, stupid, ignorant jurors are easier to overawe with the authority of the judge and lawyers.

  2. 2
    News says:

    Mahuna, what you say is correct, I expect. But we tend to invest science-based evidence of varying quality with more authority than it deserves if we suspect we already know the big answer. The courts participate in this problem.

  3. 3
    kairosfocus says:

    Another report: http://www.pbs.org/wgbh/frontl.....cientific/ Includes a case where fingerprint identification failed, cf as well this report from PNAS: http://www.pnas.org/content/108/19/7733.full . I add also that with DNA evidence (the current gold standard), the integrity of the chain of contacts, possible contamination and degradation, transmission and custody then testing and reporting are very important questions that may too often be assumed away.

  4. 4
    kairosfocus says:

    More: http://truthinjustice.org/fingerprints.htm apparently in real world situations fingerprint identification may be more of an expert opinion than a straightforward definitive fact, but there is discussion elsewhere of how independent cross checks can help resolve such. That said, the case of the two men with effectively the same partial pattern as it seems, should be reckoned with. We may be back to cumulative evidence weighed to see which is least likely to be false and further under the reasonable doubt standard.

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