An Historical Look at Insanity Defenses

Abstract

The Anglo-American benchmark case commonly cited as the historical beginning of the insanity defense is Rex. v. Arnold (1723). At the close of the case, Judge Tracy, addressing the jury, articulated what came to be known as the “wild beast” test of insanity. Contrary to this foreshortened view of the insanity defense’s genesis, this case was neither a landmark nor the beginning of the story: for by the time the wild beast reared his head and roared in the Arnold case, he had already become a familiar, domesticated by centuries of jurists’ papers. Long before the wild beast test became the law of the land, ideas regarding insanity were discussed, questions regarding its nature were debated, and legal approaches that were to have lasting consequences were formulated. Thus, the beast’s roar in Rex v. Arnold was, by then, mere paper tiger purring. It is to the history that preceded the beast that we now turn.