Fortunately, the application of scientific evidence in criminal proceedings has grown in proportion to the availability of cutting-edge methods and technologies that can produce answers to critical questions related to guilt or innocence.
Scientific evidence, of course, is a good thing, provided that our courts do their due diligence to ensure that the testimony of expert witnesses and the observations, data, and interpretations upon which they are based are reasonably valid.
The trial attorney whose case is supported by scientific evidence will be the first to sing its praises. For the opposing party, however, cynicism becomes a professional and ethical duty - requiring a concerted effort to subject scientific evidence to good-faith scrutiny. This is how an adversarial system of justice works.
A common criticism of scientific evidence, however, is that it is too "opinionated" - too subjective in nature to reward with the badge of science.
I recently attended a series of online workshops about the causes of erroneous convictions hosted by the University of Illinois at Springfield. The program is taught and managed by Assistant Professor Gwen Jordan, who is also an attorney at the Illinois Innocence Project.
During a video session dedicated to scientific evidence, two interesting comments were offered by guest speakers Lauren Kaeseberg and Dr. John Plunkett. Kaeseberg is a staff attorney at the Illinois Innocence Project. Plunkett is a Forensic Pathologist practicing in Minnesota.
The main theme espoused by Kaeseberg and Plunkett is that our criminal justice system needs science, not opinions.
Here is what Lauren Kaeseberg had to say:
"DNA science is a science that was created in the scientific world. The scientific validity of it is unquestioned because it sort of was created organically. But you contrast that with the forensic sciences that are used in the courtroom every day….they all evolved out of the courtroom. So you had the forensic scientists themselves sort of build the science, and there's no way to ever go back and make it that purely scientific field - and so the security doesn't exist for those fields like it does with DNA."
Similarly, Dr. Plunkett described the importance of "being able to differentiate opinion from science . . . . unfortunately much of what is taught, not only in medicine but in law enforcement and criminalistics is not science at all - it's opinion."
This sentiment, which seems to be emerging in legal circles, is somewhat concerning for a number of reasons. First, it is not rooted in reality. After all, until someone gives an opinion, science really does not exist to the general public or potential end-users.
Take for example the recent discovery announced by scientists who found the presence of a salty ocean on Jupiter's moon, Ganymede - which is the largest known moon in our solar system. As reported by Traci Watson of USA TODAY, scientists used imagery from the Hubble Telescope to observe changes in the moon's auroras (what we would call the Northern Lights here on earth). Using mathematical calculations, they determined that the changes they observed were consistent with effects that would be caused by the electrical currents that could only come from a salty sea.
Based on their work, scientists concluded that Ganymede has a large salty ocean lying underneath a thick layer of ice.
The key here is to understand that this discovery is really nothing more than an expert opinion. In fact, it might be said that opinions are the vehicles that carry science to its stakeholders. Without them, science does not actually exist. Why?
The scientific method exists for the sole purpose of regulating the application of opinions and mitigating society's detrimental reliance upon them. Observations, data, calculations, and the like are lifeless until someone studies them and delivers an opinion about what they mean, what questions they can answer, or what problems they can solve.
The opinion is what gives science a voice.
So this strange argument - that opinions are the antithesis of science - is not accurate.
That being said, our criminal justice system should never assume that scientific evidence is valid just because an expert witness says so. Opinions can be wrong, even those of seasoned professionals.
The first step to testing the validity of scientific evidence, however, is knowing what science is - and that the rendering of opinions is a normal part of the scientific process.
Additionally, many of the forensic sciences used most commonly in our criminal justice system today are every bit as scientific as DNA typing - they are just different. That they have the potential to be incorrect at any one time, does not make them less scientific. It simply makes them deserving of scrutiny.
Regardless of the scientific discipline, whether it be DNA, latent fingerprints, or firearm identification, opinions rendered by expert witnesses must always be limited to what the underlying observations and data allow. That is what science is all about. Nothing more. Nothing less.
Hopefully, our criminal justice system can develop some healthier attitudes about what science really is, and come to terms with the reality that without the formulation of expert opinions, science never really existed anyway.
- Crime Lab Report- New Book Calls For Expert Witnesses To Work Directly For Judges
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- The Expression Of Scientific Certainty By Expert Witnesses In American Jurisprudence
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- An American Decision and the Future of Forensic Science