Introduction

• Author: David M. Paciocco/Lee Stuesser
• Profession: Justice of the Ontario Court of Justice/Professor of Law, Bond University
• Pages: 1-23

1

CHA PTER 1

INTRODUCTION

1. THE ROLE OF THE LAW OF EVIDENCE

Few ca ses ultimately turn on disagreements about the law and wh at

it requi res. Most cases come down to disputes about facts. Typically,

the part ies dis agree over wh at happened. A s a re sult, most c ases turn

on “evidence,” which, of course, is the data fact ual decision-makers

(referred to as “triers of fact”) use when resolving factual controversies.

This is true whether the trier of fact is an adjudicator in an admin istra-

tive hearing, a judge in a “judge alone” trial, or the jur y in a jury tr ial.

The law of evidence is therefore crucial. It determines what data

can be considered, how it can be proved, and the use to which it can

be put. If its rules prevent d ata from bei ng proved or used by the tr ier

of fact, the law of evidence can prevent a litigant from w inning. There

is no sense hav ing a contract, for example, if the party you are t rying

to bind denies you have a contract and you cannot prove that you do.

You will not enjoy the contr act because you do not have the evidence

necessary to trigger the law you want to rely upon. The gateway to the

application of law is therefore evidence, and the law of evidence is the

key that opens that gateway.

We make this point not only to punctuate the importance of the law

of evidence. This point also demonstrates that the law of evidence does

not exist for its own sake. The law of evidence exists to provide a pro-

cess for gaining access to the benef‌its provided by substantive rules. Its

role is therefore facilit ative, secondar y or “adjectival” — it is me ant to

THE LAW OF EVIDENCE2

serve the application of the substantive law. To assist in demonstrating

this it is helpful to introduce the three kinds of ev identiary rules t hat

serve the substant ive law, “rules of process,” “r ules of admissibility,”

and “rules of reasoning.” The operation of these rules is determined by

the presid ing judici al off‌icial (referred to a s the “trier of law”), either

the adjudicator in an administrative hear ing, or the judge in a “judge

alone” or jury trial.

1.1) Rules of Process

Evidence law’s r ules of proce ss ser ve the substantive law by outlini ng

how evidence is presented to tr iers of fact. Those rules provide pro-

cedures designed to enhance t he prospects that witnesses wil l tell the

truth, such as the “promis e to tell the truth,” the oath, and the aff‌ir ma-

tion. And they describe how informat ion is to be communicated to the

court. The law of evidence, therefore, controls the manner in which

questions are posed, the way exhibits are presented, and the conduct of

in-court demonstrations.

1.2) Rules of Admissibility

Where the law of evidence plays its most controversial role i s in deter-

mining “admis sibility” — in identifying what inform ation triers of fact

are allowed to consider. Ideally, the rules of admissibil ity should be

generous. Given its role in serving the application of the substantive

law, the law of evidence should ideally enable triers of fact to have or-

derly access to any information that could help them make an accurate

determination about whether the substantive law applies.

This ba sic “principle of access to evidence” is well recognized. In

R. v. Jarvis the Supreme Court of Can ada elevated it to a constitution-

al level i n criminal cases, referring to t he “principle of fundamental

justice t hat relevant evidence should be available to the [trier of fact]

in the search for the truth.”1 This principle is not, however, pursued

single-mindedly. The rules of evidence frequently impede access to in-

formation. For example, the rule of solicitor-client privilege prevents

lawyers from testify ing about what their clients have said, even though

solicitor-client conversations may produce the most frank and complete

account of the client’s information. The law of evidence has judged that

a competing policy — protecting the conf‌identiality of solicitor-client

communications so t hat clients can be candid and s ecure proper legal

1 [2002] 3 S.C.R. 757.