jack klompus, welcome to PSE.
The principle is foreshadowed rather in Judaism than Christianity : Genesis 18:32 for example.
The statement "I will not destroy it [Sodom] for ten's sake," Genesis 18:32 ... implies "better P- 10 guilty men escape than ten righteous men be killed," or, dividing both quantities by 10, "better (P- 10) / 10 guilty men escape than one righteous man be killed." Alexander Volokh, 'n Guilty Men', University of Pennsylvania Law Review, Vol. 146, No. 1 (Nov., 1997), pp. 173-216: 177.)
Volokh traces the principle, or prefigurations of it, in scholarly detail via the Ancient Greeks and Romans as well as the Torah.
"[B]etter that ten guilty persons escape, than that one innocent
suffer," said English jurist William Blackstone. The ratio 10:1 has be-
come known as the "Blackstone ratio." Lawyers "are indoctrinated"
with it "early in law school." "Schoolboys are taught" it. In the fantasies of legal academics, jurors think about Blackstone routinely.
But why ten? Other eminent legal authorities through the ages
have put their weight behind other numbers. "One" has appeared on
Geraldo."'It's better for four guilty men to go free than one innocent
man to be imprisoned,"' says basketball coach George Raveling.
However, " [i] t's better to turn five guilty men loose than it is to convict one innocent one," according to Mississippi's former state executioner, roadside fruit stand operator Thomas Berry Bruce, who ought to know. "[I]t is better to let nine guilty men free than to convict one
innocent man," counters Madison, Wisconsin, lawyer Bruce Rosen."'
Justice Benjamin Cardozo certainly believed in five for execution,'
and allegedly favored ten for imprisonment, which is a bit counter-intuitive. Benjamin Franklin thought "[t]hat it is better a hundred
guilty persons should escape than one innocent person should suffer." Mario Puzo's Don Clericuzio heard about letting a hundred
guilty men go free and, "[s]truck almost dumb by the beauty of the
concept . .. became an ardent patriot."'' Denver radio talk show host
Mike Rosen claims to have heard it argued "in the abstract, that it's
better that 1000 guilty men go free than one innocent man be imprisoned," and says of the American judicial system, "Well, we got our
Or, perhaps, the recommended number of guilty men should be
merely "a few," "some,", "several," "many" (particularly, more than
eight), "a considerable amount,"20 or even "a goodly number."2'
Not all commentators weigh the importance of acquitting the
guilty against the value of the conviction of one innocent man. A
Georgia circuit court held in 1877 that it was "better that some guilty
ones should escape than that many innocent persons should be subjected to the expense and disgrace attendant upon being arrested
upon a criminal charge." Moreover, in Judge Henry J. Friendly's
opinion, "most Americans would agree it is better to allow a considerable number of guilty persons to go free than to convict any appreciable number of innocent men." It is unclear whether a "considerable"
number is greater or less than an "appreciable" one. (Volokh: 174-7.)
It appears to be a part of ordinary (Western) moral thinking that it is worse to let a guilty person go free than to cause suffering to an innocent person. It is not clear, to me at least, on exactly what moral principle this relies. I do not quarrel with the principle; I am simply not clear what it is and on what basis it rests.
Blackstone's principle involves a falsely precise metric. It is not possible to calculate, out of all context, how many of the guilty should go unpunished rather than one innocent person should suffer. Admirable sentiment as the principle may be, it is moral rhetoric rather than moral logic.