Writing in 1901, Learned Hand asked this question: how can a jury decide between the conflicting opinions of two experts “founded upon an experience foreign to their own.” 18 Harv. L. Rev. 405. As he noted, “it is just because they are incompetent for such a task that an expert is needed at all.” Hand’s question comes to mind when one reads the recent decision of the New York Court of Appeals in People v. Williams, 2020 N.Y. Slip. Op. 02123, a case involving a subject that Hand could not have imagined: the admissibility of expert testimony about an unconventional DNA test in a criminal case.