Ambiguity in Statute Law and Common Law

Section 1. Meanings

Detecting and understanding ambiguity is an important part of the process of interpreting law. To explain how this is the case, the starting point consists of the five steps in the author’s model for interpreting law:¹

• Step 1. Rule: Organising the Rule
• Step 2. Issues: Identifying the Issues
• Step 3. Options: Identifying the Options
• Step 4. Reasons: Formulating the Reasons
• Step 5. Decision: Making the Decision

Model for Interpreting Law 

Ambiguity is relevant to Step 3. Options: Identifying the Options. The task is to identify the options before the court. Options for interpreting law have two parts:

1. Meanings. One part consists of the meanings of the ambiguous provision that requires interpretation.
2. Effects. The other part consists of the effect that each meaning will cause if a court determines it to be legally correct. 

This article discusses the first aspect of Step 3. This entails identifying of all of the meanings of the ambiguous provision.² Doing this creates an organising framework for interpretation, which has three aspects:

1. Cause of the Problem. The existence of these two or more meanings is the cause of the problem. It invokes the interpretive function of the court.
2. Focus of the Arguments. The meanings of the provision are the focus for reasons or arguments addressed to resolve the ambiguity. Stating the obvious, an argument must be directed towards or against a particular meaning.
3. Solution to the Problem. The full range of meanings of the ambiguous provision not only identifies the problem, it furnishes the solution. Because of the literal rule,³ the range of every possible meaning of the ambiguous provision both identifies and limits the choices open to a court. A court can choose only one or more of these meanings as the legally correct meaning of the ambiguous provision.⁴ 

Section 2. Detecting Meanings

How can a lawyer or a court identify the meanings of an ambiguous provision? There are three basic techniques. Consult a dictionary. Play with the words and reuse them in other contexts. Refer to a catalogue of ambiguity that classifies meanings; this catalogue is the main subject of this article.

Section 3. Classifying Meanings

Section 3 presents a catalogue of meanings. This catalogue consists of a five-fold classification of ambiguity comprising lexical ambiguity, relational ambiguity, ambiguity of implication, ambiguity of competing versions and ambiguity of competing rules. 

These are not necessarily an exhaustive statement of possibilities but are still useful. The catalogue demonstrates how ambiguity takes different forms and thus provides readers with a catalogue of various types of ambiguity, which can function as a checklist (although it is not necessarily comprehensive). This assists readers in becoming more proficient at detecting ambiguity, understanding its nature and framing arguments to resolve it.

Ambiguity in Statute Law and Common Law (PDF)