This article considers the role of experts and their interaction with the legal system to better understand the benefits and potential dangers of expert evidence to fact-finders in trials. Medical experts are indispensable to the administration of justice as litigation ranges beyond what judges or juries comfortably deal with as facts of everyday life. This would render courts, absent expert evidence, vastly under-equipped in making decisions of fact. However, the dangers of surrendering authority to experts or of misunderstanding their role must be considered to ensure that expert evidence is used to benefit the administration of justice.

This essay examines the origins of physician-patient privilege in the United States. It concentrates an 1828 New York law that protected medical confidentiality in the courtroom—the first statutory guarantee of physician-patient privilege—as well as the rapid spread of privilege statutes throughout the nineteenth century. Using the published notes of the authors of New York’s influential statute alongside other primary sources, I argue that these early statutes are best explained as the result of nineteenth-century efforts to codify American law. The medical profession took little note of physician-patient privilege until much later, indicating that privilege emerged not as a protection of doctors’ professional status, nor as a means of protecting patients in the courtroom, but rather as an inadvertent offshoot of attempts to streamline and simply judicial proceedings. It is perhaps because of these unsystematic origins that physician-patient privilege still remains such an unevenly applied rule in American courtrooms.