LWB145 Week Ten Lecture Notes
LWB145 So Far…
So far this semester we have looked at:
Direct sources of law (in historical and institutional senses).
o Legal history.
o Legal institutions.
The ‘rules’ of statutory interpretation.
The rules of precedent.
Legal problem solving.
These have all been relatively definite or ‘rule-based’ topics (even if some issues can be argued both ways).
This lecture looks at judicial reasoning when it’s broader than just applying a precedent – in other words,
how and why new rules are made.
I.e. how do judges decide a case when there is no binding precedent or applicable statute? What techniques
of argument do they use?
Also, what ‘second order’ sources do they use – the reasons why a rule is made into law. Where do the rules
Relationship with Textbook
Connecting with Law has sections on theories of law (Is it separate from morality? If it is connected with
morality, then whose?) and on activist vs. formalist judges.
This has some connection with this material – some judges will be activist because they think the law should
be more moral, others because they think the law should be more practical (from the perspective of
But this is not actually the topic of this lecture…
Reference Books for this Lecture
This lecture considers the techniques of argument used by judges, and we’ll take it for granted that the less
‘formalist’ judges use the more creative techniques more often.
Content is based on material in MacAdam & Pyke, Judicial Reasoning and the Doctrine of Precedent in
Australia, chapters 14-17 & 19 (reproduced in Pyke and MacAdam, Legal Institutions and Method, 2 -4 th
eds, under same Chapter and paragraph numbers).
See also Cook et al, Laying Down the Law, sec 7.11 to end of Ch 7 (pp 205-24).
1. Specific techniques and sources of argument:
A. Building new rules by small steps from existing precedents using rhetorical techniques (and some
input from common sense).
B. Legal principles and input from morality.
C. ‘Policy’ arguments and input from morality and common sense.
2. Limits on judicial developments of the law.
3. Consequences of this for study and practice.
1A. Building new rules by small steps from existing precedents using rhetorical techniques
Distinguishing a precedent
Case A says the defendant is liable, but this case is different to Case A.
Example: Thornton v Shoe Lane Parking Ltd  2 QB 163.
See Pyke & MacAdam at [14.2]-[14.9]. Extending an analogy
Case A says a rule applies in situation X, and this is situation Y which is similar enough that the same rule
should apply (even though it was not originally stated to extend to situation Y).
Examples: Haseldine v Daw  2 KB 343 re claim against the repairers; Bryan v Maloney (1995) 182 CLR
See Pyke & MacAdam at [14.10]-[14.13].
In Case X the defendant is liable but in Case Y the defendant is not. The current case is a bit like Case X and a
bit like Case Y so it’s arguable either way.
Examples: Haseldine v Daw  2 KB 343 re the claim against the landlord.
See Pyke & MacAdam at [14.14].
What guides the judicial mind when:
Distinguishing a precedent – why is a ticket sold by machine different enough from one sold by a person to
justify a different result?
Extending by analogy – why is a repairer similar enough to a manufacturer to justify the same result?
Something to do with ‘common sense’?
Other techniques appealing directly to ‘common sense’
There are three main forms of simple common sense arguments: Pyke & MacAdam [17.26] – [17.38]
1. Argumentum ad absurdum.
o Pharmaceutical Society of Great Britain v Boots Cash Chemists (Southern) Ltd  1 QB 401
2. Floodgates argument.
o Donoghue v Stevenson  AC 562 - dissenters
3. Reverse floodgates argument.
o Donoghue v Stevenson  AC 562 - majority
Explaining a precedent
Some judgments are quite confusing and really need some explanation.
o [Sometimes the headnote is wrong so that needs explanation! – Jacobs v Davis  2 KB 532 as
explained in Cohen v Sellar  1 KB 536.]
In some cases, judges claim to ‘explain’ a case but are really reinterpreting it.
o Edward Levi claims that this is routine practice – don’t know what the ratio of a case is until it’s
applied in the next case.
o See Pyke & MacAdam at [15.7]-*15.15+ for Levi’s summary of 19 century cases on negligent
The High Court still does this – prefer to ‘explain’ Dixon CJ’s judgments rather than say he was wrong.
Recently the High Court has been ‘explaining’ (reinterpreting?) its own earlier cases – saying ‘you lawyers
didn’t understand what we said last time’ – look for this when you study Const Law.
1B. Legal Principles
Pyke and MacAdam Chapter 16.
Is the common law simply 10,000 rules?
If it is, how do courts decide cases where there are no rules?
o Does the court just make up an ad hoc rule? OR
o Does the court look for wider principles?
And are all the existing rules simply arbitrary or are they all tied together by something broader?
Many judges and legal scholars contend that the common law consists of general principles as well as rules:
“*I+t is said that there is no precedent. The Law does not consist of particular cases, but of general principles,
which are illustrated and explained by *the+ cases.” (Lord Mansfield in R v Bembridge (1783) 99 ER 679 at
681). Legal Principles?
Legal principles are broader and more general than rules.
o While principles are closely related to authority, they are at a higher level of abstraction.
Some examples of legal principles:
o Maxims of equity – e.g. ‘he who would come to equity must come with clean hands’.
o Courts will not permit themselves to be used as instruments of iniquity.
o One that you’ll find evolving in the reading for the Week 11 Tutorial.
Sources of Legal Principles
Where do legal principles come from?
There are two main sources of legal principles claimed by writers like MacCormick and Dworkin:
Source 1: Coherence
The doctrine of precedent is based on the idea that the law should be consistent.
However, the law should also be coherent.
Coherency is a matter of the rules being related to, and consistent with, more general principles.
The drive for coherency means that each individual rule should make sense within the legal system.
Coherence used to make a principle
This involves finding a new principle, or broader rule, by induction:
o When there is a whole range of decisions on separate but similar facts, a judge may feel compelled to
search for a general principle that explains all of the decisions.
o When a new case arises that is not quite covered by any of the precedents, then the principle seen as
underlying the previous decisions will provide support for a decision for one party or the other.
Examples of this are in the readings for the Week 11 Tutorial.
This is similar to extending by analogy, except in analogy the general principle is left unstated, while here it’s
Source 2: Morality
R Dworkin, “The Model of Rules” (1967) 35 University of Chicago Law Review 14:
“The origin of principles lies not in precedent but in a sense of appropriateness developed in the
profession and the public over time. Their continued power depends on the sense of
appropriateness being sustained.”
In this way, morality (not just ‘sex is bad’ but the whole Golden Rule, categorical imperative etc idea) can be
seen as a source of legal principle.
Note judges appealing to morality as well as coherence in Heaven v Pender, Donoghue v Stevenson.
Note that morality is also an aspect of ‘policy’, which will be considered next.
Use of Principles in Legal Reasoning
Legal principles are a source of argument, but they never ab