"The Rules--especially Rule 702--place appropriate limits on the admissibility of purportedly scientific evidence by assigning to the trial judge the task of ensuring that an expert's testimony both rests on a reliable foundation and is relevant to the task at hand. The reliability standard is established by Rule 702's requirement that an expert's testimony pertain to "scientific . . . knowledge," since the adjective "scientific" implies a grounding in science's methods and procedures, while the word "knowledge" connotes a body of known facts or of ideas inferred from such facts or accepted as true on good grounds. The Rule's requirement that the testimony "assist the trier of fact to understand the evidence or to determine a fact in issue" goes primarily to relevance by demanding a valid scientific connection to the pertinent inquiry as a precondition to admissibility. Pp. 9-12. (c) Faced with a proffer of expert scientific testimony under Rule 702, the trial judge, pursuant to Rule 104(a), must make a preliminary assessment of whether the testimony's underlying reasoning or methodology is scientifically valid and properly can be applied to the facts at issue. Many considerations will bear on the inquiry, including whether the theory or technique in question can be (and has been) tested, whether it has been subjected to peer review and publication, its known or potential error rate, and the existence and maintenance of standards controlling its operation, and whether it has attracted widespread acceptance within a relevant scientific community. The inquiry is a flexible one, and its focus must be solely on principles and methodology, not on the conclusions that they generate. Throughout, the judge should also be mindful of other applicable Rules. Pp. 12-15. (d) Cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof, rather than wholesale exclusion under an uncompromising "general acceptance" standard, is the appropriate means by which evidence based on valid principles may be challenged. That even limited screening by the trial judge, on occasion, will prevent the jury from hearing of authentic scientific breakthroughs is simply a consequence of the fact that the Rules are not designed to seek cosmic understanding but, rather, to resolve legal disputes. Pp. 15-17." (from the syllabus of the Court's decision)(hyperlinks added by this author).
Daubert implies that judges must now understand the scientific method to some degree in order to make determinations regarding the admissibility of scientific evidence. While this task may seem daunting, many resources are available to assist the judiciary with its task. (Compare the scientific method with the Socratic method familiar to lawyers).
Many commentators have equated the Daubert decision with a rejection of "junk science", that is, science which has not been vetted by, among other things, appropriate or adequate peer review. Conferences held on the junk science question include Junk Science, the Courts, and the Regulatory State (sponsored by the Federalist Society, Washington DC, July 10, 1997). Among the difficulties of evaluating scientific evidence for the non-scientist are questions about what exactly constitute "junk science" and "quack theories" and how much (or what kind of) scientific evidence is necessary to present a persuasive case. How should the non-scientist evaluate scientific evidence? How much science does s/he need? For more information on "junk science" see Part VI, Other Resources.
Of course, judges are not the only legal and public policy professionals who need to understand science. Legislators and other policy makers need training to evaluate varying scientific claims as well, in order to draft appropriate laws and vote wisely when they come up for consideration. For some articles discussing the influence of scientists and the importance of a fair assessment of scientific evidence in lawmaking see the Lawmaking and Science Bibliography.
Related questions involve the responsibility of the media to present both sides of issues involving science and belief fairly, or at least to notify viewers and readers when a program or publication favors one side over the other. See for example the materials on the "search for Noah's ark" film. Another interesting topic to research is the influence (or non-influence) of mainstream science on law and public policy. The traditional view is that after the development of the atomic and hydrogen bombs, scientists had a great deal of influence with the federal government, an influence which has slowly waned as we have become disenchanted with what some see as the "sorcerer's apprentice" let loose by modern scientific research.
In addition to material about Daubert and related developments, these pages contain resources on the image of alternative and questioned science in popular culture, and some links to urban legends.
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