A few years into my litigation practice, a partner in the Toronto law firm where I worked asked me to conduct a trial for the brother-in-law of his legal assistant. The brother-in-law, John, was an independent contractor whose contract had been terminated by a large corporation. John sued the company, claiming that he was an employee rather than an independent contractor and thus was entitled to receive reasonable notice of the termination of his contract.
At trial, John testified about the details of his relationship with the company. After the briefest of deliberations, the judge gave oral reasons dismissing John's claim. Looking down, disapprovingly at John, the judge said, "I find John's testimony to be quite phantasmagorical".
John looked at me, puzzled.
"Blair," John asked, "What does that mean?"
"It means that he doesn't believe you John," I answered.
John seemed relieved. "Okay." was all he said.
In fact, I hadn't believed John either. Although he had been under oath, John had not told the truth. As a young lawyer, I quickly came to realize that taking an oath, or making an affirmation to tell the truth, did not always mean that a witness would do so. I had discovered that witnesses would sometimes "bend" the truth to suit their purposes.
I discussed the matter with a friend, a former associate who had left the firm to pursue a career in criminal law. As circumstance would have it, my friend was writing an article on the subject of perjury. "If I was the other lawyer," my friend said, "I would have charged John with perjury." This time I was the one who was puzzled. I knew that witnesses sometimes lied under oath. In fact, as I gained more experience, I came to expect that someone involved in a proceeding – a party, a witness, perhaps even my own client, would lie under oath. Despite that, very few people are prosecuted for perjury. I wondered if there was a connection.
The Origins Of Oaths
If witnesses so casually ignore the importance of swearing an oath, why is it still a requirement in our judicial system? As one judge put it, "Oaths and their substitutes are designed to emphasize the importance of telling the truth for religious or moral reasons – telling the truth for the sake of the truth." The difficulty appeared to be, is that people who have a motive to lie, will also lie under oath. They might not necessarily tell the truth for the sake of the truth but they will certainly lie for the sake of their case.
The challenge is that, in our adversarial system, oral testimony is the principal item of judicial evidence. Such testimony is the statement of a witness in court which is offered as evidence of the truth of that which is stated. For many reasons, testimony was regarded as more reliable if it was supported by an oath.
Oath-taking has a long history in judicial proceedings going back at least as far as 400 CE. Twelfth century English courts held their judicial proceedings in the open air and upon the most significant hill in the area. A local man of power and authority, such as the sheriff, would preside over the court but the largest local land owners were bound by custom to attend and be the "doomsmen" (judgment-men) of the court. The sheriff took care of the procedures of the court and pronounced the overall sentence but the doomsmen were the participants who found the appropriate "doom" to fit the facts. If the two litigants contradicted each other in fact, there was no capacity for holding a cross-examination and judging the worth of a witness statement. In these circumstances, recourse would be to the supernatural to prove "by God" that one or the other was correct. This proof took three forms: (1) oaths and oath-helpers, (2) ordeal; and (3) trial by battle.
The Oath As A "Self-Curse"
Thus, the practice of administering an oath in judicial proceedings was rooted in the ancient concept of judicium dei, or divine judgment. These forms of proof have been traced to a pre-religious, pre-animistic period of history where supernatural beings were unknown and people were believed to possess magical powers which could be invoked through an uttered curse. In this form, the oath was a traditional self-curse which could be used as security for a promise. A sworn witness who remained unharmed after testifying was presumed to have been adjudged by God to have spoken the truth.
The Origin Of The Affirmation
An affirmation is a solemn declaration allowed to those who conscientiously object to taking an oath. An affirmation has the same legal effect as an oath but is usually taken to avoid the religious implications of an oath. The right to give an affirmation has existed in English law since the Quakers Act, 1695. It has its origins in the refusal of Quakers to swear any oath, which would otherwise have barred them from holding many public positions. Quakers believe in speaking the truth at all times, and so the act of only swearing to truth in court, rather than in everyday life, would have implied double standards.
The Oath In Civil Law Jurisdictions
The practice of administering oaths in judicial proceedings appears to be almost universal. However, there are at least three systems of law which do not make use of oaths or affirmations namely, Chinese law, Slavic law and Swiss law. In each of these jurisdictions, the absence of the oath is attributable in part to the absence of any ancient tradition of swearing oaths as a means of proof in itself.
In Chinese law, the special significance of giving testimony is drawn to the witness's attention by utilizing the same method which is used in private law to emphasize the binding force of an agreement – the written form. A Chinese witness is usually required to sign a bond or recognisance as to the veracity of his statements, either before or after giving evidence. Before signing, he is instructed as to the obligations it entails and the punishment imposed for false testimony. A witness who refuses to sign without good reason is also liable to a small fine.
In Switzerland, a trend towards abandonment towards the oath has also been accelerated by legislation – the Federal Law of Criminal Procedure has reduced the status of an exceptional measure. The Federal Law of Civil Procedure, makes no mention of oaths at all, merely instructing the judge to admonish the witness as to his duty to tell the truth and as to the penalty of false testimony under the Penal Code.
The present day take on Oaths – “ a lingering relic of primordial superstition and primitive mumbo jumbo"
Today, the rationale for swearing an oath to tell the truth is somewhat different:
The historic rationale was that the fear of divine retribution would focus one's mind and heart on telling the truth. Today in our secular, modern, multi-cultural Canadian society, the fear of divine retribution may seem a quaint anachronism, if not a complete irrelevance. The law however still recognizes the importance of an oath even if it is not directly tied to a belief in spiritual retribution. Even in the absence of some religious significance, the solemnity of taking an oath still increases the witness' perception of the importance of telling the truth.
The present day purpose of oath-taking is to “bind the conscience” of the witness to tell the truth. This purpose assumes, of course, that the witness has a conscience. What about criminals and other notorious liars? What use is it to administer an oath or an affirmation to a witness who has no (or little) conscience?
In 1993, the Supreme Court of Canada commented on the efficacy of oaths. The Court was concerned about admitting into evidence, for the truth of their content, prior, unsworn statements that three witnesses had made to the police. At issue were the "traditional hearsay dangers" including the absence of an oath or solemn affirmation when the statements were made. The witnesses in the case were described thusly by the trial judge:
…those three witnesses were obviously and deliberately untruthful in their sworn evidence before me with respect to material matters. Their account of how this fight occurred is not only at odds with the evidence of Steven Wright, Sean Dowling and in my opinion, Ruth Kazan (two independent witnesses), it is at odds with common sense.
…In my opinion, each of these three witnesses lied to me with respect to having lied to the police about what the accused said to them. I have no doubt that their recantations are false. That is that I have no doubt that on this point they were telling the police the truth as they knew it about what the accused said. That finding is not necessarily the same as a finding that the accused made the admissions, but it is tantamount to that finding.
Under the principled exception to the hearsay rule, prior inconsistent statements could be admissible if they met the governing principles of reliability and necessity. The court held that there should be sufficient circumstantial guarantees of liability to allow a jury to make use of the statement, i.e. if the statement is made under oath, solemn affirmation or solemn declaration following an explicit warning to the witness as to the existence of severe criminal sanctions for the making of a false statement. That way, the witness would be clearly made aware of the gravity of the situation and his duty to tell the truth. The court held that while the oath will not motivate all witnesses to tell the truth, its administration may serve to impress on more honest witnesses the seriousness and significance of their statements, especially where they incriminate another person in a criminal investigation.
However, the Court warned it is also clear that the sanction for lying under oath must be one that is a real threat to the witness. Therein lies the challenge.
Why are not more witnesses prosecuted for lying under oath? Primarily for the simple reason that our courts and criminal justice system are presently overburdened and would possibly be under deluge if all witnesses who lied under oath were prosecuted.
Some commentators have discounted the significance of the oath as a means of ensuring reliability for a statement". A
commentator who had written that the oath is "no more than a lingering
relic of primordial superstition and primitive mumbo jumbo".
The Future Of Oaths
Recently, in England, the Magistrates' Association, which represents magistrates in England and Wales, debated a motion to ask witnesses to promise to "very sincerely tell the truth" ( reminiscent of a Munchkins’ line in the Wizard of Oz ) but voted against the plan. One magistrate's alternative oath would be to include an acknowledgement of the duty to tell the truth as follows: "I understand that if I fail to do so, I will be committing an offence for which I will be punished and may be sent to prison."
Law reform commissions in various jurisdictions have considered the utility of oaths and affirmations. The Canadian Task Force on Uniform Rules of Evidence has argued that the principles that apply to the competence of children should also apply to adults who take the oath:
The rationale of these cases is that in our modern secular age a witness need not profess a religious belief either in God or in future rewards and punishments. (Children may not have formed religious beliefs) The object of the law in requiring an oath is to get at the truth by obtaining a hold on the conscience of the witness. 
Punishing Lying Under Oath
That motion was opposed by others who said that the way you stamp out lying under oath is to punish people who do so, not to get rid of the religious oath. So what of the threat of prosecution for perjury?
For a false statement made under oath to be considered perjury, it must be in regard to a material fact in the case. Therefore, not all lying under oath will be considered perjury. To be convicted of perjury, the prosecution must prove that the lying was intentional and that the witness intended to misrepresented the truth.
Statistics in the United States show that perjury prosecutions are extremely rare, arising from both civil and criminal proceedings. In 1996, the US Sentencing Commission indicated that in federal cases, only 86 of 42,436 convicted criminal defendants were found guilty of perjury, encouraging perjury or bribing a witness.
Prosecutors have had difficulty convicting some of the world's most notorious alleged liars. For example, former baseball player, Roger Clemens, was acquitted in 2012 of, among other charges, two counts of perjury and three counts of making false statements when he testified at a deposition and a nationally televised hearing before the US Congress in 2008. The charges centered on his repeated denials that he had used steroids and human growth hormone during his baseball career. A seven year investigation into the major league baseball's homerun record holder, Barry Bonds, yielded a guilty verdict on one count of obstruction of justice in San Francisco, with the jury deadlocked on whether Bonds had lied to a grand jury when he denied knowingly taking performance enhancing drugs.
And perhaps the most notorious liar of all, Lance Armstrong, who lied for years as to whether he used performance enhancing drugs in winning his seven Tour de France titles, escaped prosecution for perjury because prosecutors conceded that Armstrong's intentional lying under oath was "probably too old".
As a result, realistically it is only the threat of prosecution, as unlikely a possibility that such a threat presents, that will serve as a deterrent to lying under oath. Until prosecutors turn that threat into something that is less than hollow, an oath or affirmation will continue to rely on the moral conscience of the witness to tell the truth for the sake of the truth.
 Pomerance, J. in R. v. Carter and Dodd, 2012 ONSC 286, para. 16
 Cross on Evidence, 6th Ed., Butterworth & Co. Ltd., at page 37
 English Legal History, wordpress.com April 28, 2013
 The Law Reform Commission - Ireland, Report on Oaths and Affirmation - 1990
 Wikipedia – Affirmation in Law
 The Law Reform Commission Report on Oaths and Affirmation, Ireland, 1990
 R. v. Nitsiza, 2001 NWTSC 34 at para. 8
 Ian McKenzie, The Truth, The Whole Truth and Nothing but the Truth, Slaw, March 5, 2012
 R. v. B (K.G.) 1993 1 SCR 740
 McKenzie, supra, footnote 8
 Robert Pigott BBC News, October 19, 2013
 Canadian Task Force on Uniform Rules of Evidence
 Pigott, supra, footnote 11
 Criminal Law Attorney – Criminal Law Lawyers Nationwide!!
 Joseph White, Associated Press Sports Writer, published The Toronto Star, June 18, 2012
 Mail Online, January 22, 2013