During the Fellows’ Orientation, one speaker specifically addressed the contrasts between science and the law, which fascinated me. The use of science to solve crimes is a popular premise for TV shows such as “Bones,” and similarly scientists may appear as expert witnesses in court cases, but fundamentally, the process of law and the process of science are different.
One divergence between science and the law is their timelines. To answer a question scientifically, we carry out a study or experiment, analyze the data, and when we are finished, we can produce an answer that is as complete and valid as possible. That investigation often takes years, but it is understood to be the scientific process. In the courtroom, the goal is to produce a swift and definite answer. Cases must be decided on the best information available at the time, even if the data are incomplete or are totally lacking. Judges understand that producing a timely resolution to a case thus implies that available information may change over the years, sometimes indicating that the decision might have gone the other way, but it is also important that court cases are not tried on scientific timelines. The priority of the court is to pass judgment based on the best information available at the time and to allow the parties to get on with their lives.
The standards of proof are also different in the two fields. In law, my understanding is that one party must prove that it is “more likely than not,” or a 51% chance that their argument is true. We all expect a higher standard of science. Looking at the very contentious issue of climate change, around 95% of the scientific community agrees that the Earth is getting warmer, and the change is being caused by human activity. That’s called scientific consensus where as many people as practically possible all agree. Even so, some people still refuse to believe that overwhelming evidence (although they never seem to focus on the idea that just a tiny fraction of scientists have any disagreement with the consensus.) What is tremendously persuasive in the courtroom is not sufficient for scientific proof.
Science and law also are radically different in their rates of change. Science is accustomed to extremely rapid change with new discoveries being announced almost daily. A quick Google search just now showed me news of developments in anthropology, medicine, astronomy, and meteorology. (Apparently it was a slow day in chemistry or we just aren’t as sexy as these other fields.) In contrast, law changes very slowly and incrementally. The courts want precedent and predictability.
Even the training systems are different for the two fields. Scientists are trained in the context of cooperative teams and often share information. The law is premised on an adversarial system; in some cases, there may even be two scientific expert witnesses who are trying to interpret data to the benefit of their side.
For expert witnesses and for judges, a landmark case called Daubert v. Dow (Merrill Dow Pharmaceuticals), was decided by the Supreme Court in the 1980s and set the standard for the use of scientific knowledge in expert testimony. Most significantly, there was a concern that in technical cases, an average jury would not be able to evaluate the quality of scientific evidence from two different expert witnesses. Scientific evidence is expected to be reproducible through multiple trials and by different experimenters and to have been through the peer review system in which a manuscript is sent to multiple anonymous reviewers in the field for comments on the work’s validity before it is published. A jury might be faced with one witness presenting results from studies using standard accepted scientific techniques and a second witness presenting evidence based on experimental techniques that had not been validated and were not broadly accepted in the field. The information provided by the scientific standard is viewed as reliable whereas the evidence of the second is not yet established to be trustworthy, but those distinctions are difficult to make for someone without the right background education in the general field. Thus judges became the gatekeepers who would determine in advance what expert witness testimony met the standard and would be allowed into evidence and what testimony would be excluded.
I immediately wondered how a judge would be better off than the jurors, but our speaker, who was herself a judge, told us an intriguing story of one highly technical case she was assigned and how she was able to pass judgment on the validity of the expected testimony. In conference with the two attorneys, she announced that she had absolutely no idea how to evaluate the scientific arguments, and she needed to learn more of the background. She asked the two lawyers to agree on a local expert who would be willing to come in once or twice a week to tutor her in that specific field so she could evaluate the expert testimony. A professor from the local university was agreed to, and he conducted a weekly class for the judge. The two lawyers also attended every session since neither attorney wanted to be left out or to allow the other person to bias the information. After what amounted to a graduate level course in the field compressed into two months, the judge was fully qualified to make a decision about what testimony met the scientific standard for inclusion.
The speaker actually stopped her story there, but a follow up question elicited the information that after all the scientific training the judge and the lawyers received, the truth of the case became blindingly obvious to all participants to the point where it was settled out of court and did not come to trial. For all their differences, science and law turn out to be compatible after all.