Evidence in its broadest sense includes everything that is used to determine or demonstrate the truth of an assertion. Giving or procuring evidence is the process of using those things that are either a) presumed to be true, or b) were themselves proven via evidence, to demonstrate an assertion's truth. Evidence is the currency by which one fulfills the burden of proof.
There are many issues that surround evidence, making it the subject of much discussion and disagreement. In addition to its subtle nature, evidence plays an important role in many academic disciplines, including science and law, adding to the discourse surrounding it.
An important distinction in the field of evidence is that between circumstantial evidence and direct evidence, or evidence that suggests truth as opposed to evidence that directly proves truth. Many have seen this line to be less-than-clear and significant arguments have arisen over the difference.
Circumstantial evidence is a collection of facts that, when considered together, can be used to infer a conclusion about something unknown. Circumstantial evidence is usually a theory, supported by a significant quantity of corroborating evidence. In law and criminal investigations, corroboration is normally supplied by one or more expert witnesses who provide forensic evidence.
Circumstantial evidence is used in criminal courts to establish guilt or innocence through reasoning.
The distinction between direct and circumstantial evidence is important because, with the obvious exceptions (the immature, incompetent, or mentally ill), nearly all criminals are careful to not generate direct evidence[clarification needed], and try to avoid demonstrating criminal intent. Therefore, to prove the mens rea levels of "purposely" or "knowingly," the prosecution must usually resort to circumstantial evidence. The same goes for tortfeasors in tort law, if one needs to prove a high level of mens rea to obtain punitive damages. In addition, circumstantial evidence -- such as fingerprint evidence -- is usually the best available evidence to support an inference as to the facts of the case.
One example of circumstantial evidence is the behavior of a person around the time of an alleged offense. If someone was charged with theft of money, and was then seen in a shopping spree purchasing expensive items, the shopping spree might be regarded as circumstantial evidence of the individuals guilt.
Direct evidence is testimony/other proof which expressly or straight-forwardly proves the existence of a fact. It is different from circumstantial evidence, which is evidence that, without going directly to prove the existence of a fact, gives rise to a logical inference that such fact does exist.
Direct evidence is evidence which, if believed, proves the existence of the fact in issue without inference or presumption. It is evidence which comes from one who speaks directly of his or her own knowledge on the main or ultimate fact to be proved, or who saw or heard the factual matters which are the subject of the testimony. It is not necessary that this direct knowledge be gained through the senses of sight and hearing alone, but it may be obtained from any of the senses through which outside knowledge is acquired, including the senses of touch or pain.
Reasonable doubt - The level of certainty a juror must have to find a defendant guilty of a crime. A real doubt, based upon reason and common sense after careful and impartial consideration of all the evidence, or lack of evidence, in a case.
Proof beyond a reasonable doubt, therefore, is proof of such a convincing character that you would be willing to rely and act upon it without hesitation in the most important of your own affairs. However, it does not mean an absolute certainty.
Beyond a reasonable doubt is the highest standard of proof that must be met in any trial. In civil litigation, the standard of proof is either proof by a preponderance of the evidence or proof by clear and convincing evidence. These are lower burdens of proof. A preponderance of the evidence simply means that one side has more evidence in its favor than the other, even by the smallest degree. Clear and Convincing Proof is evidence that establishes a high probability that the fact sought to be proved is true. The main reason that the high proof standard of reasonable doubt is used in criminal trials is that such proceedings can result in the deprivation of a defendant's liberty or even in his or her death. These outcomes are far more severe than in civil trials, in which money damages are the common remedy.
The burden of proof is the burden of providing sufficient evidence to shift a conclusion from an oppositional opinion. He who does not carry the burden of proof carries the benefit of assumption. He who bears the burden of proof must present sufficient evidence to move the conclusion to his own position. The burden of proof must be fulfilled both by establishing positive evidence and negating oppositional evidence.
There are two primary burden-of-proof considerations:
1) The question of on whom the burden rests.
2) The question of the degree of certitude the proof must support. This depends on both the quantity and quality of evidence and the nature of the point under contention. Some common degrees of certitude include the most probable event, reasonable doubt, and beyond the shadow of a doubt.
Conclusions (from evidence) may be subject to criticism from a perceived failure to fulfill the burden of proof.