The phrase “beyond a reasonable doubt” has an interesting etymology and legal history—interesting and mysterious. Even the U.S. Supreme Court doesn’t seem to know where it originally came from or how it evolved into the so-called “standard of proof” (although in Re Winship  Justice Brennan [or his law clerk, whose identity I have yet to discover] mistakenly attributed the phrase to the early days of U.S. Constitutional law [yes, I know I speak heresy]).
I’ve investigated the origins of this life-or-death phrase and uncovered some interesting “artifacts,” but have yet to prove “beyond a reasonable doubt” where it really came from and what it really means. (By “really means” I mean how a proficient, native-English speaker would parse it today.) Now, I realize that if you’re a reasonable, sane, educated person you probably think this is all “mere semantics.” But I can assure you that semantics is not a “mere” thing and that the law is frequently a quibble over semantics.
I plan to write a number of blogs on this topic, starting with this one, in which I survey the sources I’ve examined and the authorities I found (the experts on the meaning of “beyond a reasonable doubt”).
I began my search with the U.S. Supreme Court’s written decision in Re Winship (1970). Take a look at Justia for a copy of the decision. It lists the sources on which the court relied.
Then I moved on to two textbooks, which the court’s decision cited: 1) McCormick’s Evidence and 2) Wigmore’s Evidence.
I next followed the trail from the citations in these textbooks back to what appears to be the first American legal dictionary, Bouvier, and then further back to Bouvier’s sources.
Unfortunately, what I found was that McCormick’s Evidence merely speculated that the reasonable-doubt standard was well entrenched by 1798. He—McCormick—made no effort to verify this as historical fact.
Recently legal historians have tackled the problem. See especially John Langbein, Barbara Shapiro, and James Q. Whitman. All of these scholars searched the records of the Old Bailey for case law uses of the phrase. (Their references to the Old Bailey led me to a long detour among old English criminal trials—a fertile source of inspiration for a historical mystery writer) However, as far as I could determine, the phrase “reasonable doubt” was rarely used at all before 1790, and the phrase “beyond a reasonable doubt” not at all. Langbein and Whitman, though, propose intriguing origins for the standard of proof. (NB: As a linguist, my interest is in the exact phrase, not its numerous variations, as I will explain in another blog post.)
What, you may ask, qualifies me—a mystery writer—to research the origins of “reasonable doubt”? Well, I have a Ph.D. in 17th-century textual criticism (which is the study of old texts to determine their origins and development).
So, if you are interested, please return here soon for more on my quest for “reasonable doubt.”