Question

For over a century, legal historians treated the emergence of the "beyond a reasonable doubt" standard in Anglo-American criminal jurisprudence as the natural culmination of Enlightenment epistemology. Under this orthodox narrative, the standard arose in late eighteenth-century English treason trials primarily to calibrate the risk of error in empirical fact-finding. As criminal trials shifted from medieval reliance on divine revelation toward secular, juror-centered evaluation of circumstantial evidence, legal theorists sought a probabilistic threshold high enough to operationalize the Blackstone formulation—that it is better that ten guilty persons escape than that one innocent suffer. In this view, the standard was engineered specifically as an evidentiary counterweight to state prosecutorial power, designed to protect the accused from erroneous conviction.

In his revisionist study of early modern legal theology, however, legal historian James Whitman proposed an alternative genealogy. Whitman contends that the reasonable doubt standard was originally forged not to protect the accused, but to protect the jurors themselves from divine retribution. In medieval and early modern Christian theology, passing judgment in capital cases carried immense spiritual peril: to wrongfully condemn an innocent soul was deemed a mortal sin exposing the juror to eternal damnation. Drawing upon medieval scholastic doctrines of tutiorism—the principle that one must choose the safer course when moral certainty is lacking—Whitman argues that eighteenth-century judges introduced the phrase "reasonable doubt" to reassure anxious jurors that they could convict without risking their immortal souls, provided their remaining doubts were purely speculative rather than grounded in articulable reason.

While Whitman's thesis brilliantly illuminates the pre-modern theological undercurrents that secularized accounts routinely obscure, it ultimately proves incomplete as an overarching explanation for the institutional codification of the standard. Court records from the Old Bailey during the 1780s and 1790s indicate that defense barristers, rather than judges or prosecutors seeking to compel convictions, were the primary agents invoking the reasonable doubt formula. Defense counsel wielded the standard precisely as an epistemic shield for defendants facing an increasingly professionalized prosecutorial apparatus. Thus, neither the purely epistemic model nor the purely theological-soothing model alone accounts for the doctrine's trajectory. A comprehensive historiography must recognize that while pre-Enlightenment moral theology supplied the conceptual vocabulary of "doubt," the adversarial mechanics of the late eighteenth-century criminal courtroom transformed that vocabulary into an instrument of defense rights.

What is the primary purpose of the author in the passage above?