Introduction

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

1

CHAPTER 1

INTRODUCTION

1. THE ROLE OF THE LAW OF EVIDENCE

Few cases ultimately turn on disagreements about the law and what

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

the parties disagree over what happened. As a result, most cases turn

on “evidence,” which, of course, is the data factual 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 administra-

tive hearing, a judge in a “judge alone” trial, or the jury in a jury trial.

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 data from being proved or used by the trier

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

is no sense having a contract, for example, if the party you are trying

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

You will not enjoy the contract 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 facilitative, secondary or “adjectival” — it is meant 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 evidentiary rules that

serve the substantive law, “rules of process,” “rules of admissibility,”

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

the presiding judicial off‌icial (referred to as the “trier of law”), either

the adjudicator in an administrative hearing, or the judge in a “judge

alone” or jury trial.

1.1) Rules of Process

Evidence law’s rules of process serve the substantive law by outlining

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

cedures designed to enhance the prospects that witnesses will tell the

truth, such as the “promise to tell the truth,” the oath, and the aff‌irma-

tion. And they describe how information 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 is in deter-

mining “admissibility” — in identifying what information triers of fact

are allowed to consider. Ideally, the rules of admissibility 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 basic “principle of access to evidence” is well recognized. In

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

al level in criminal cases, referring to the “principle of fundamental

justice that 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 that clients can be candid and secure proper legal

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