Why English-speaking courts built so many rules about what a jury may hear
A treatise on American evidence law by John Wigmore ran to ten volumes, and in 1898 James Bradley Thayer noted that even English lawyers found the American rules bewildering. That sprawl has a reason. Most of these rules exist because ordinary citizens, not trained judges, decide the facts in common law trials.
Rules of evidence govern how facts get proved in court: what the judge or jury may consider, how much proof is needed and how reliable it must be. Standards range upward from reasonable suspicion through preponderance of the evidence and clear and convincing evidence to beyond a reasonable doubt, and they differ between criminal, civil and family courts.
The ancient world had its own versions. Hammurabi's Code called for oaths and witnesses in laws 10 to 12, and the Old Testament required at least two witnesses to convict. Roman law gave judges wide freedom but held that the burden of proof lies on whoever asserts a fact, and that suspicion alone should never convict. Medieval Roman law then graded evidence finely, counting a lone witness or a private document as half-proof, which could not convict but might justify torture to obtain more. Because continental judges rather than juries weighed evidence, those systems never grew English-style exclusion rules.
England's modern jury trial, taking shape in the sixteenth and seventeenth centuries, changed that. In 1677 the Statute of Frauds and Perjuries barred claims of certain broken contracts unless backed by a signed written document. Hearsay, an out-of-court statement offered as proof of its own truth, was also shut out. Lord Mansfield explained the logic: Scottish and continental judges could hear hearsay and then discount it, but English jurors were sole judges of fact, and nobody could predict its effect on them.
Stanford legal historian Lawrence Friedman traces American complexity to that same pair of forces: a right to jury fact-finding in nearly all criminal cases and many civil ones, and a belief that lay jurors need shielding from distractions. Federal Rule 403 lets judges drop relevant evidence whose value is substantially outweighed by unfair prejudice, confusion or wasted time. Material seized illegally, such as through a search without a warrant, is called fruit of the poisonous tree and normally excluded. In England, confessions obtained by oppression can be thrown out under the Police and Criminal Evidence Act 1984.
Source: Evidence (law)
