What is Evidence?
Evidence, in law, is any information or object that a court accepts to help decide a case. Evidence may be in the form of oral testimony by a witness, or it may be any kind of object or document. Circumstantial evidence is anything from which an inference or assumption can be drawn that would be of help in deciding a case. This type of evidence is usually not considered as valuable as direct evidence, which does not need any additional explanation to clarify the facts presented or the relationship of these facts to the case. An example of direct evidence is the testimony of a witness that he saw the defendant shoot a man. An example of circumstantial evidence is the statement of a witness that he heard a shot in another room and then saw the defendant run from that room.
Evidence is presented to the "trier of facts," which is the jury if there is one, or the judge if the case is to be tried without a jury. In either case it is the judge who decides on the admissibility of evidence—that is, whether or not it may be presented in court. To be admissible, evidence must be relevant and it must be competent.
How It Works
Evidence is any fact which tends to produce in the mind a persuasion of the existence of some other fact.
The English system of law, which relies on the decision of a jury of persons untrained to weigh up and sift evidence, has rendered necessary the development of a large body of rules relating to evidence and designed to make the task of the jury easier; they are not, however, highly artificial rules, but are based on strict common sense. They fall into three divisions: relevancy, proof, and cogency.
First, it is clear that only those facts should be proved which are in issue, i.e. disputed facts upon which the claim or the defence depends for success, or facts relevant to the issue. The law has consequently laid down certain rules determining what facts are admissible in evidence, and these rules are stricter than the rules of ordinary life: e.g. the fact that A once committed a theft is not legally admissible to prove that he committed the theft with which he is now charged, though in every-day life this would probably be taken into consideration.
Second, the facts must not only be relevant, but must he proved in a proper way. In certain cases no proof is required: the court will take judicial notice of certain facts, e.g. the accession of a sovereign. Other facts must be proved, sometimes by the evidence of a witness, sometimes by documents or the production and inspection of things (eg: of goods asserted to be defective), and the rule is that the best evidence available must be produced. It would be useless to call a witness to say what is in a certain document if the document itself is available.
Evidence may be either direct, going straight to the matter in issue, as an eye-witness's account of a murder; or circumstantial, the evidence of a chemist who sold arsenic to a person accused of poisoning by arsenic. The task of proof may be made easier by the existence of admissions made by the defendant; or again, it often happens that from certain proved facts the law will make presumptions as to the existence of other facts and then the opposing party will be forced to rebut or disprove the presumption, eg: a letter proved to have been properly addressed and posted will be presumed to have reached its destination. Again, the other party may not be permitted to set up and prove a certain fact: thus, if A leads B to believe a certain thing, and B acts upon this belief, A will not be allowed to say that that thing never existed. This is called estoppel. Finally comes the question of cogency, which does not arise until the question of admissibility has been decided and the fact proved. What weight is to be attached to a particular piece of evidence?
The question cannot, of course, be solved by rules, but must always depend on the circumstances. Decision rests with the jury, though the judge can give valuable help by analyzing carefully the evidence. When the evidence does not point beyond reasonable doubt (for the purposes of criminal law) or on a reasonable balance of probabilities (for purposes of civil law) to a fairly clear conclusion of fact, then the case will probably be decided by reference to the "burden of proof". There is a general burden of proof in all cases, and the burden of proving particular matters may shift from side to side during the trial.
Thus in criminal matters the general burden rests on the Crown to establish guilt. But if the Crown establishes matter generally indicating guilt, and the accused depends on a defence of insanity, the burden shifts to the accused to establish the latter. Generally speaking, the burden is on a person alleging something to prove what he alleges; the Courts try to avoid the situation of requiring a person to prove a negative; something peculiarly within the knowledge of a particular person must usually be proved by that person.
Types of Evidence
- Relevancy of Evidence: Evidence is considered irrelevant if it has no connection with the case. It may also be considered irrelevant if it has only a very slight bearing on the case, if it may tend to prejudice or mislead the members of the jury, or if it may confuse the issue at trial.
- Competency of Evidence: For evidence to be competent it must not be of a type that has been designated as inadmissible by the rules of evidence. The following kinds of evidence have been established as inadmissible because of incompetency.
- Illegally Obtained Evidence: Evidence that was obtained in an illegal manner is not generally acceptable as competent evidence. In addition, a confession that has been obtained by means of force is not admitted by the court.
- Hearsay Evidence: A witness is usually not permitted to give evidence about something that someone else has told him. He must confine his testimony to things that he saw or experienced himself. There are exceptions to this rule, such as certain statements made to a witness by a man who knew he was dying.
- Opinion Evidence: A witness is usually not allowed to give his opinion, except when he is an expert who has been called to give a technical or professional explanation of questions relating to the case. Examples of such exceptions are a doctor who is called on to give medical information and a ballistics expert who is called on to give information that will identify a bullet or the gun from which it was fired.
- Privileged Evidence: Because of the intimate nature of certain relationships, witnesses can refuse to give evidence that would betray their privacy. Conversations between a husband and wife, a doctor and a patient, or a priest and a penitent are considered to be privileged. In the United States the defendant in a criminal case can refuse to give evidence against himself, a privilege guaranteed by the Fifth Amendment to the Constitution.