Proof beyond reasonable doubt

Reasonable doubt is a term used in jurisdiction of Anglo-Saxon countries. Evidence that is beyond reasonable doubt is the standard of evidence required to validate a criminal conviction in most adversarial legal systems.

Generally, prosecutors bear the burden of proof and are required to prove their version of events to this standard. This means that the proposition being presented by the prosecution must be proven to the extent that there could be no "reasonable doubt" in the mind of a "reasonable person" that the defendant is guilty. There can still be a doubt, but only to the extent that it would not affect a reasonable person's belief regarding whether or not the defendant is guilty. Beyond "the shadow of a doubt" is sometimes used interchangeably with beyond reasonable doubt, but this extends beyond the latter, to the extent that it may be considered an impossible standard. The term "reasonable doubt" is therefore used.

If doubt does affect a "reasonable person's" belief that the defendant is guilty, the jury is not satisfied beyond "reasonable doubt". The precise meaning of words such as "reasonable" and "doubt" are usually defined within jurisprudence of the applicable country. A related idea is Blackstone's formulation "It is better that ten guilty persons escape than that one innocent suffer".

Beyond a reasonable doubt is the highest burden of proof in any court in the United States. Criminal cases must be proven beyond a reasonable doubt.

In English common law prior to the "reasonable doubt" standard, passing judgment in criminal trials had severe religious repercussions for jurors. According to judicial law prior to the 1780s: "the Juryman who finds any other person guilty, is liable to the Vengeance of God upon his Family and Trade, Body and Soul, in this world and that to come." It was also believed "In every case of doubt, where one’s salvation is in peril, one must always take the safer way....A judge who is in doubt must refuse to judge." It was in reaction to these "religious fears" that "reasonable doubt" was introduced in the late 18th century to English common law, thereby allowing jurors to more easily convict. Therefore, the original use of the "reasonable doubt" standard was opposite to its modern use of limiting a juror's ability to convict.

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