Re: [asa] forensic science and wrongful convictions

From: David Opderbeck <>
Date: Tue Sep 12 2006 - 09:22:55 EDT

This is a very interesting point, which bears on my thoughts about all
this: the issue isn't really (or shouldn't be) whether we label some type
of historical investigation as "science" or not; the issue is one of
epistemology. A colleague of mine has published extensively on the question
of forensic evidence and the burden of proof in criminal cases (see his
online vita here: His
articles on the "beyond a reasonable doubt" standard in criminal cases are
pertinent here.

I don't see how there can be any reasonable dispute about the fact that
non-repeatable historical events can be known with substantially less
certainty than repeatable events that are subject to laboratory
controls. But, we send people to the gallows based on what really is a
relatively low degree of certainty concerning non-repeatable historical
events. Despite the fact that we call it "beyond a reasonable doubt," in
many criminal cases where there is a conviction, some degree of doubt isn't
unreasonable at all.

So, I continue to think that whether we call this or that "science" is
mostly posturing by both sides. IMHO, the real issue is what counts as a
warranted belief and the degrees of certainty with which warranted beliefs
can be held.

On 9/12/06, <> wrote:
> This is a reply to Moorad's post: something in the
> web filtering prevents me from including the quotation.
> I recall about 1 year ago there was an article in
> Science Magazine about forensic science:
> There were some rather surprising points, particularly
> "What was unexpected is that
> erroneous forensic science expert testimony
> is the second most common contributing
> factor to wrongful convictions, found in 63%
> of those cases. "
> However, the authors attribute most of this
> to ignorance or lack of adequate training on the part of
> the forensic scientists, pressure and vested interest (my words)
> with respect to expert testimony, and inadequate
> critical analysis. There is little failure attributed to the techniques
> themselves.
> It would not be good to rely on forensic science alone, but neither
> should we rely only on witnesses alone, or any other one thing in making
> a conviction. I would expect that good detectives will search for as many
> avenues as possible to nail down their man. And that is also the best way
> to do good science. The more independent ways you can nail down
> what is going on, the better.

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Received on Tue Sep 12 09:23:12 2006

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