§ 175 The Production of Evidence
The second part of the law of evidence consists of rules regulating its production. It deals with the process of adducing evidence, and not with the effect of it when adduced. It comprises every rule relating to evidence, except those which amount to legal determinations of probative force. It is concerned for example with the manner in which witnesses are to be examined and cross-examined, not with the weight to be attributed to their testimony. In particular it includes several important rules of exclusion based on grounds independent of any estimate of the probative force of the evidence so excluded. Considerations of expense, delay, vexation, and the public interest require much evidence to be excluded which is of undoubted evidential value. A witness may be able to testify to much that is relevant and important in respect of the matters in issue, and nevertheless may not be compelled or even permitted to give such testimony. A public official, for example, cannot be compelled to give evidence as to affairs of state, nor is a legal adviser permitted or compellable to disclose communications made to him by or on behalf of his client.
The most curious and interesting of all these rules of exclusion is the maxim, Nemo tenetur se ipsum accusare. No man, not even the accused himself, can be compelled to answer any question the answer to which may tend to prove him guilty of a crime. No one can be used as the unwilling instrument of his own conviction. He may confess, if he so pleases, and his confession will be received against him; but if tainted by any form of physical or moral compulsion, it will be rejected. The favour with which this rule has been received is probably due to the recoil of English law from the barbarities of the old Continental system of torture and inquisitorial process. Even as contrasted with the modern Continental procedure, in which the examination of the accused seems to English eyes too prominent and too hostile, the rule of English law is not without merits. It confers upon a criminal trial an aspect of dignity, humanity, and impartiality, which the contrasted inquisitorial process is too apt to lack. Nevertheless it seems impossible to resist Bentham’s conclusion that the rule is destitute of any rational foundation, and that the compulsory examination of the accused is an essential feature of sound criminal procedure. Even its defenders admit that the English rule is extremely favourable to the guilty, and in a proceeding the aim of which is to convict the guilty, this would seem to be a sufficient condemnation. The innocent have nothing to fear from compulsory examination, and everything to gain; the guilty have nothing to gain, and everything to fear. A criminal trial is not to be adequately conceived as a fight between the accused and his accuser; and there is no place in it for maxims whose sole foundation is a supposed duty of generous dealing with adversaries. Subject always to the important qualification that a good prima facie case must first be established by the prosecutor, every man should be compellable to answer with his own lips the charges that are made against him.477
A matter deserving notice in connexion with this part of the law of evidence is the importance still attached to the ceremony of the oath. One of the great difficulties involved in the process of proof is that of distinguishing between true testimony and false. By what test is the lying witness to be detected, and by what means is corrupt testimony to be prevented? Three methods commended themselves to the wisdom of our ancestors. These were the judicial combat, the ordeal, and the oath. The first two of these have long since been abandoned as ineffective, but the third is still retained as a characteristic feature of judicial procedure, though we may assume with some confidence that its rejection will come in due time, and will in no way injure the cause of truth and justice.
Trial by battle, so soon as it acquired a theory at all, became in reality a form of ordeal. In common with the ordeal commonly so called, it is the judicium Dei; it is an appeal to the God of battles to make manifest the right by giving the victory to him whose testimony is true. Successful might is the divinely appointed test of right. So in the ordeal, the party or witness whose testimony is impeached calls upon Heaven to bear witness to his truth by saving him harmless from the fire. The theory of the oath is generically the same. “An oath,” says Hobbes,478 “is a form of speech added to a promise; by which he that promiseth, signifieth that unless he perform, he renounceth the mercy of his God, or calleth to him for vengeance on himself. Such was the heathen form, Let Jupiter kill me else, as I kill this beast. So is our form, I shall do thus and thus, so help me God.” The definition is correct save that it is restricted to promissory, instead of including also declaratory oaths. A man may swear not only that he will speak the truth, but that certain statements are the truth.
The idea of the oath, therefore, is that his testimony is true who is prepared to imprecate divine vengeance on his own head in case of falsehood. Yet it needs but little experience of courts of justice to discover how ineffective is any such check on false witness and how little likely is the retention of it to increase respect either for religion or for the administration of justice. The true preventive of false testimony is an efficient law for its punishment as a crime. Punishment falling swiftly and certainly upon offending witnesses would purge the courts of an evil which the cumbrous inefficiency of the present law of perjury has done much to encourage, and which all the oaths in the world will do nothing to abate.479