Scientific Evidence as Foreign Law
Cheng, Edward K.
Most contemporary debates about scientific evidence focus on admissibility under Daubert and the Federal Rules of Evidence. That bias is quite understandable-after all, it is the framework imposed by the United States Supreme Court. Daubert, however, rests on a fundamental assumption: that courts should treat scientific facts like any other adjudicative facts ultimately left to the jury. Perhaps the involvement of specialized knowledge requires judges to act as gatekeepers to ensure some basic level of reliability, but under Daubert, scientific facts are still just facts. As I will argue, scientific facts fit awkwardly into the conventional framework for conceptualizing and regulating the proof of adjudicative facts. For one thing, scientific facts are rarely ever unique to the case at hand. They are instead often applicable to a variety of cases, and thus ideally should be decided uniformly. At the same time, proof of scientific facts generally depends on an entire body of knowledge, rather than a specific witness or piece of physical evidence. These attributes as well as others suggest that we should think carefully about the framework for scientific factfinding. Consequently, in this contribution, I look not at how Daubert does or should operate, but rather how the legal system should treat scientific facts more fundamentally. In particular, I suggest that proving scientific facts has much in common with proving foreign law. This perspective shift could prove fruitful for understanding and addressing many of the problems in scientific evidence today. More importantly, the procedural mechanisms developed by conflicts-of-law scholars to handle proof of foreign law can be adapted to the scientific evidence context.