ABSTRACT
The theory of probabilities is nothing but common sense confirmed by calculation.
—Pierre Simon La Place (1951, p. 196)
The legal system recognizes that we can never have absolute certainty in legal matters. Instead, we operate with various degrees of uncertainty. In the United States, juries are instructed to decide that someone is guilty of a
crime when they are certain “beyond a reasonable doubt.” This standard was adopted because there is always some small amount of doubt that the accused may be innocent. Jurors are instructed to operate under a different level of doubt when they are deciding about guilt or innocence in a civil case. In civil cases, they are told to deliver a verdict of guilty when the “preponderance of evidence” supports this decision. Thus, jurors are instructed to operate under two different levels of uncertainty depending on whether the case before them is criminal or civil. They need to be more certain when deciding that an accused party is guilty in a criminal case than in a civil case.
