The oath, perhaps the oldest means for encouraging truthful testimony, forms a link between court proceedings and religious belief since, in its usual form, witnesses swear by Almighty God that they are speaking the truth. Though the effectiveness of such an act has certainly diminished in secular societies, this appeal to God has for centuries been considered the surest means of obtaining truth. There are two kinds of oaths, the preliminary and the subsequent. In Anglo-American practice the witness is sworn in before testimony. Under German and other Continental procedures, the swearing-in may occur after testimony as well. The latter method allows the judge to use his own discretion in individual cases as to whether or not the witness should be ordered to swear. In current German practice, very few witnesses are sworn in for testimony in civil proceedings, whereas in criminal proceedings all witnesses have to swear. Some continental European countries allow witnesses who object to oaths to substitute a solemn affirmation, and Denmark has abolished all oaths in legal procedures. The oath of a witness does not have the formal effect of binding the judge or the jury. They must evaluate it and the testimony freely.

Examination and cross-examination

Judges and attorneys in common-law courts regard the opportunity to cross-examine as a guarantee of the reliability and completeness of testimony by a witness. Under the perfect operation of the adversary system it is not the judge but rather the parties or their attorneys who interrogate the witnesses. The plaintiff’s attorney begins the “examination in chief,” which is subject to a number of restrictions. Leading, misleading, and argumentative questions, for example, are not permitted. After the plaintiff’s attorney concludes his interrogation, the defendant’s attorney may cross-examine the same witness. This cross-examination generally consists of leading questions posed with the intent of weakening or invalidating the impression created by the direct testimony of the witness. The cross-examination must ordinarily be limited to subjects covered during direct interrogation. There is a recognizable tendency, however, for cross-examination to become as open-ended as possible. The plaintiff’s attorney has the option, finally, to reestablish the credibility of his witness by reexamination. These interrogations are formally regulated and require a great deal of skill and experience on the part of the attorneys. Such formal questioning of the witness is unknown to the continental European rules of procedure, even though cross-examination is common. Continental rules of procedure require the judge to interrogate the witness first. Frequently, the witness begins with a free narration. Then, after the judge has finished his interrogation, the attorneys of both parties may question the witness. All this is done in an informal manner, and almost any question is permitted. In some countries the interrogation of witnesses is, however, rather formalistic because it is generally limited to questions concerning allegations specified in the evidence judgment. But here too, there is a tendency for the court to allow questions at its discretion.

Scientific examinations of witnesses are especially common in paternity and status proceedings with regard to blood-typing. These methods have now been so much improved that the suspicion of paternity may be definitely dismissed in many cases. In Germany and elsewhere, opinions based on biologic and hereditary evidence are used for these same purposes. The use of fingerprint, ballistics, and DNA evidence, among other types, has become quite customary in criminal cases. In the United States, lie-detector tests are generally not admissible as evidence. The results of such tests are not admissible in England or continental European countries.

The hearsay rule

Hearsay is testimony based on what a witness has heard others say. The hearsay rule limiting this type of testimony is perhaps the most characteristic feature of the Anglo-American law of evidence. It has also been said that, next to trial by jury, the hearsay rule constitutes the most important and original contribution of this system’s practice.

Notwithstanding the obvious dangers involved in its use, free evaluation of the evidence furnished by hearsay testimony continues to be characteristic of continental European law. This somewhat surprising fact may be explained by reference to the historical development already traced here. Until the 19th century the medieval theory of formal evidence strictly prescribed when the judge had to be convinced by the testimony of a witness. Moreover, there was no jury in the Continental countries to be protected by rules of evidence and, therefore, no need to introduce rules of hearsay. When the formal evidence theory was replaced by the requirement that the judge freely consider the evidence, his discretion naturally extended to hearsay testimony.

The creation of a body of rules for the exclusion of hearsay evidence was motivated by the arguments that such testimony could tend to mislead the jury, that the hearsay observer, unlike the legal witness, was not under solemn oath and was inaccessible to cross-examination, that such testimony furnished third-hand evidence, and that it violated the best evidence rule (the rule that the best version possible of a written document be submitted as evidence).

Over the years, exceptions to the prohibition of hearsay testimony had to be permitted, however, and these have become so numerous that the opinion has sometimes been expressed that no exhaustive list of such exceptions could even be compiled. The judge must decide in each case whether testimony based upon hearsay is admissible under an exception to the rule—a further indication that regulations governing the admissibility of evidence are far more important in Anglo-American law than in Continental law. The most commonly cited exceptions to the rule of hearsay relate to statements made by dead or absent persons, statements in public documents, and to confessions and admissions by parties.

Confessions and admissions

Confessions, as a source of evidence, are distinguished from admissions. Whereas a confession is a complete acknowledgement of guilt in criminal proceedings, an admission is a statement of fact in either a civil or a criminal case. In former times the confession was considered the ultimate form of evidence. As soon as the accused confessed—often under duress—no further proof was required. In time, involuntary confession came to be rejected as evidence under English law, and the burden of proving that a confession was voluntary lay with the prosecutor. In the United States the federal rule that confessions are inadmissible if obtained while the defendant was unlawfully detained has not gone quite so far, though the law is still in a state of considerable flux. Involuntary confessions, however, are not admissible for any purpose under Anglo-American law. In continental European law, on the other hand, confessions of the accused are always freely considered by the judge.

Differences between criminal and civil proceedings regarding admissions result mainly from the adversary principle governing civil proceedings. In Anglo-American procedure, if one party in a civil suit admits facts contrary to his interest, such an admission is conclusive and obviates the need for further evidence on the point. The same result follows in German or Swedish courts. Under the Roman-based laws of such countries as France, Italy, and Spain, an admission made before the court is a form of evidence that leads to conclusive proof binding upon the court. But admissions made out of court are subject to free evaluation by the judge and do not exclude further evidence.