Forensic science’s uncertainties
Regarding the May 30 news article “FBI discloses errors in DNA analysis”:
Shaken baby syndrome, forensic hair analysis and now DNA match probabilities may have been routinely overstated by prosecution witnesses, potentially leading to wrongful convictions and incarcerations and perhaps even executions.
Why do courts allow these matters to be presented to juries as matters of scientific fact? They are not. They have not been empirically proved using the scientific method.
The vast body of technical, scientific and medical testimony is not amenable to scientific proof but is merely consensus of opinion among practitioners, and sometimes not even that. It remains within the realm of theory. Proponents of such pseudo-scientific testimony are disinclined to admit this and apt to overstate its reliability. Opposing lawyers are ill-equipped to force such an admission as it entails challenging an expert witness in his or her field of expertise. Their only realistic option is to present an opposing expert, leaving a jury to toss a coin as to which one to believe — with someone’s life or liberty hanging in the balance. There has to be a better way.
Paul B. Weiss, Hedgesville, W.Va.