An expert is one who knows more and more about less and less.
-Nicholas Murray Butler
Under the landmark Frye decision, courts were constrained to admit scientific evidence only as long as it is was generally accepted by the scientific community. Under Frye, experts were expected to explain why and how their work met the test of general acceptance. The difficulty arose when the opinion of the expert departed from those generally accepted by the scientific community, regardless of merit. Under Frye, novel theories could not be presented to the jury, even when the expert's credentials and methodology were valid. As a result, experts could not base their testimony on new and innovative approaches until those approaches were adopted or recognized by a larger scientific community. Under this limitation, a community of experts essentially became a form of technical jury that ruled on the validity of the science before it was presented to the jury. At best, this sort of evaluation excluded junk testimony and avoided misleading the judge and the jury. However, it