## 1. Precedent and analogy in legal reasoning




Arguments from precedent and analogy are characteristic of legal
reasoning. Legal reasoning differs in a number of ways from the sort
of reasoning employed by individuals in their everyday lives. It
frequently uses arguments that individuals do not employ, or that individuals
employ in different ways. Precedent is a good example of this. In
individual reasoning we do not normally regard the fact that we
decided one way in the past as raising some presumption that we should
decide the same way in the future. Of course there can be special
circumstances that have this effect--someone may have relied on
what we did before, or may have had their expectations raised that we
would do so again--but absent these special
considerations we do not regard ourselves as being committed in the
future to make the same decision. It is always open to us to
reconsider a decision and change our minds if we no longer think our
original judgement was correct.




Law of course is not alone in attributing a special significance to
precedent. Many institutional and quasi-institutional practices place
weight on what they have done previously in determining what they
should do now. Individuals, by contrast, will often disregard what
they did on an earlier occasion. If they do make reference to the
past, this will normally be due to their belief that what they did in
the past was the right thing to do, or at least is a good guide to
what is the right thing to do now. Normally, then, individuals will
merely be using their past decisions in the belief that they are a
reliable short-cut to working out what is the right thing to do. If
they harbour doubts as to the correctness of the earlier decision then
they will reopen the matter and consider it afresh on the merits. In
institutional settings, on the other hand, decision-makers will often
refer to what has been decided in the past as constraining what should
be done now, regardless of whether they think the original decision
was correct.




Equally, institutional decision-makers often regard earlier decisions
as being relevant even when the decision at hand is different from the
original ones, by citing them as analogies. They will argue that since
an earlier decision was made on some matter, it would be inconsistent
now to decide the present case differently. Individuals, by contrast,
will often simply attend to the merits of the particular question
before them and try to get the decision right. If it is pointed out
that their current decision seems to be inconsistent with how they
treated an earlier question, this may prompt them to reconsider, but
is not in itself a reason to change their decision. At the end of the
day they may conclude that their earlier decision was a mistake, or
they may even embrace the apparent inconsistency, believing that both
the earlier and the later decisions are correct even though they are
not sure how they can be reconciled.




Legal reasoning, then, gives a weight to what has been decided in the
past that is usually absent from personal decision-making. We care
about whether we made the right decisions in the past, but we seek to
make the right decisions now, unconstrained by our earlier views.


## 2. Precedent




Arguments from precedent are a prominent feature of legal
reasoning. But what exactly is a 'precedent'? A precedent
is the decision of a court (or other adjudicative body) that has a
special legal significance. That significance lies in the
court's decision being regarded as having *practical*,
and not merely *theoretical*, authority over the content of the
law. A decision has theoretical authority if the circumstances in
which it was made (the identity of the decision-makers, those involved
in arguing the case, the availability of evidence or time) provide
good reasons for believing the decision to be correct in law. If there
are good reasons to believe that an earlier case was correctly
decided, and if the facts in a later case are the same as those in the
earlier case, then there are good reasons for believing that the same
decision would be correct in the later case. In some legal systems
earlier decisions are, officially, treated in just this way: cases are
cited to courts, but courts may only justify their decisions by
reference to other legal materials such as legislation. As a
consequence the decision in an earlier case is not in itself regarded
as a justification for reaching a decision in a later
 case.[1]




By contrast, precedents have practical authority because they are
regarded as partly constituting the law. Simplifying somewhat, the law
is what the court stated it to be *because* the court stated it
to be such. Putting the matter in these terms is over-simplified,
however, because (a) it may be that what the court *did*,
rather than what it said, that alters the law, and (b) there are
normally a number of limitations on the capacity of a decision to
constitute the law (depending upon the content of the decision and the
status of the body making them). An important consequence of
precedents' practical authority is this: since courts are bound to apply the
law, and since earlier decisions have practical authority over the
content of the law (i.e., over what *is* the law), later courts
are bound to follow the decisions of earlier cases. This is commonly
known as the *doctrine* of precedent, or *stare decisis*
(i.e., standing by things decided).




It should be noted that the modern Common Law endorses a particularly
strong version of *stare decisis*, one that requires later
courts to follow earlier decisions *even if* those cases were
wrongly decided according to the pre-existing law. It is often assumed
by Common Lawyers that a doctrine of *stare decisis*
necessarily requires that later courts be bound by such erroneous
decisions. This follows from the following line of thought. If later
courts were not bound to follow erroneous decisions, then they would
only be 'bound' by earlier, correct judgments. But an
earlier correct judgment simply reaches the conclusion that the law
already supported when it was delivered. So to direct courts to follow
cases that were not erroneous would simply be to direct them to do
what they are legally bound to do anyway (i.e., apply the law),
thereby rendering the doctrine of precedent redundant. The flaw in
this argument lies in the assumption that in every case there must be
a single legally correct outcome, with other outcomes being
wrong. This overlooks the possibility of cases in which the merits of
the dispute are legally indeterminate, so that there is more than one
possible outcome that would not be wrong. To say that a case is
'legally indeterminate' covers a range of situations, such
as the merits of the opposing arguments being, in law, equal, or where
the conflicting considerations cannot be rationally ranked against
each other. In cases such as these the decision alters the law without
making any error. The Common Law, then, might have limited its
doctrine of *stare decisis* by holding that later courts were
not bound by earlier decisions that were wrongly
 decided.[2] 
 Instead it developed a different practice--that of
'overruling', whereby some courts were given a limited
power to deprive earlier decisions of their binding status on the
basis that they were wrongly decided. So the Common Law's
version of the doctrine of precedent does not inevitably flow from the
fact that precedents have practical authority. Nonetheless the idea of
being bound to follow even erroneous decisions is a common feature of
many institutions decision-making, and will be the focus of this
entry.




The precise operation of *stare decisis* varies from one legal
system to another. It is common for courts lower in a judicial
hierarchy to be strictly bound by the decisions of higher courts, so
that Federal Court judges in the United States are bound by decisions
of the Federal Court of Appeals for their circuit, and the English
Court of Appeal is bound by decisions of the House of Lords. The lower
court is 'strictly' bound because it has no power to
overrule the higher court's decision. Equally, most appeal
courts are bound by their own earlier decisions, though they are
generally entitled in certain circumstances to overrule those
decisions. There is enormous variation in the circumstances that are
necessary for a court to overrule one of its own decisions: at a
minimum it must regard the earlier decision as wrongly decided, but
generally more is required than this, e.g. that the decision is
'clearly' or 'plainly'
 wrong.[3].
 Finally, courts are generally not bound by the decisions of lower
courts: the House of Lords for example is not bound to follow
decisions of the Court of Appeal and is free to overrule such
decisions if it takes a different view of how the case should have
been decided.




The most important limitation on the application of precedent is that
the decision in an earlier case is only binding in later cases where
the facts in the later case are the 'same' as those in the
earlier case. It is agreed on all sides that if two cases are the same
then the precedent applies, whereas if they are different it does
not. What makes two cases the same, however, is a matter of
considerable debate, and goes to the root of the question of the
nature of precedent in legal reasoning. In saying that two cases are
the same, it cannot be that they are *identical*. It is obvious
that no two situations are identical in every respect: they must
differ at least in having occurred at different times and/or different
places. In practice the differences between any two cases will be much
more significant than this, and yet they may--legally
speaking--still be the same. For this reason, theorists often
speak of two cases being the same in 'all relevant
respects'. Which of course simply raises the question of what
makes two cases 'relevantly' the same.




This problem is easier to understand if a number of distinct aspects
of legal cases are taken into account. Most cases do not create
precedents: they turn on a dispute about the facts--who did what,
when, and to whom. In these cases the job of the court is to decide on
the evidence before it whose version of the facts to endorse. The
parties in such cases agree about the law that applies to their
dispute, they simply disagree about what actually happened. In other
cases there can be a dispute over the applicable
*law*--one side claiming that on the facts the appropriate
law supports a decision in their favour and the other side disputing
this account of the law and arguing that on those facts the law
supports a decision in favour of them. (It goes without saying that
there are also cases with disputes over both the facts and the law.)
Precedents are those cases which require the courts to resolve a
dispute over the *law*.




A precedent is the *decision* on the law in a
*case* before a court or some similar legal
decision-maker such as a tribunal. Paradigmatically in Common Law
legal systems a judicial decision is given in a
*judgment* which has five aspects to it:


1. a recitation of the *facts* of the case, i.e., an
account of what
 happened[4];
2. an identification of the legal *issue*--the
disputed question of law--which the court is being asked to
resolve;
3. the *reasoning* over the appropriate resolution of
that issue;
4. the *ruling* resolving the issue put before the
court, e.g. that in these circumstances the defendant has breached a
contract, or does not owe the plaintiff a duty of care, or holds the
property on trust for a third party, or made a decision contrary to
natural justice; and
5. the *result* or outcome of the case, i.e., which
party succeeded in the action; which follows from (d).




(For a more detailed discussion, see MacCormick 1987, 170ff.) To take
an example, the court may be faced with a case in which the trustee of
property held on behalf of the plaintiff has wrongfully transferred
that property to the defendant. The plaintiff sues the defendant to
recover the property which was transferred in breach of trust. The
plaintiff argues that since (i) the defendant has received trust
property (ii) in breach of trust and (iii) has not paid for the
property, she should restore the property to the trust. The defendant
argues, on the other hand, that since (iv) the trustee had a good
title to the property, (v) the power to transfer it and (vi) the
defendant acted in good faith, unaware of the breach of trust, she is
entitled to retain it. The court will assess the situation and may
rule that factors (i)-(iii) do give the plaintiff a good action,
i.e., that a recipient of trust property transferred in breach of
trust who has not paid for the property must restore it. In its
reasoning the court will explain why the fact that the defendant
received the property as a *gift* means that it should be
restored to the trust, despite the trustee having the legal power to
transfer the title.




The identification of the subset of factors (i)-(iii) that
constitute the ruling is not always a straightforward task: this has
to be determined from construing the judgment as a whole in the
context of the area of law with which it deals. In particular it can
be difficult to ascertain the appropriate level of abstraction of the
descriptions of factors (i)-(iii). A person is made ill by
drinking an opaque bottle of ginger beer containing a decomposing
 snail.[5] 
 The manufacturer of the bottle is held to be liable to the person
made ill, despite the absence of any contract between her and the
manufacturer. What is the key characterisation of the vehicle of harm
on these facts? The bottle of ginger beer is a beverage, but it
is also a consumable, an article for human use and something capable
of causing injury if negligently produced. (See further Stone 1985,
125). Generally the judgment needs to be read as a whole to determine
the appropriate level: in particular the court's reasoning will
tend to support one level of generality over another. In some cases,
however, the level of generality will not be clear and it will not be
possible to give a very precise account of the ruling. In other cases
the category may be incompletely characterised: there will be examples
of items falling within the category but no general characterisation
of it (see Levenbook 2000, 201-11).




This point brings out an important aspect of the study of
precedent. Lawyers are mostly preoccupied with two issues: (1)
the question of how to determine what a precedent is authority
*for*, e.g. how to characterise the ruling in the case
(beverage? consumable? article?), or how to deal with cases where
there is no single majority judgment in favour of the result, or how to
treat cases which give two alternative bases for the decision; and (2)
the question of when a court will be willing to overrule its own prior
decisions. The most interesting philosophical questions, however,
concern how precedents operate when, as is often the case, there is no
doubt about what the precedent is authority for, and the later court is
not free (or is unwilling) to overrule the earlier decision.




There are three ways in which it has been argued that precedents
should be
 understood:[6]
 (1) as laying down rules, (2) as the application of underlying
principles, and (3) as a decision on the balance of reasons.


### 2.1 Precedents as laying down rules




On the first approach precedents operate by laying down rules which
later courts are then bound to apply to the facts before them. 
(For versions of this view, see Raz 1979; MacCormick 1978 (especially
82-6, 213-28) and 1987; Alexander 1989; and Schauer 1989,
469-71 and 1991,
 174-87.[**7**])
 In holding that (i)-(iii) were the crucial facts for the
resolution of the case, the court is creating a rule that whenever
trust property is transferred in breach of trust to a volunteer (i.e.,
one who does not pay for the property), the volunteer must restore the
property to the beneficiary. The case decides a particular dispute,
but the court creates a rule to deal with that type of dispute and
applies it to the case at hand. On this view, then, precedents are
akin to statutes in that they lay down rules which apply to later
cases whose facts satisfy the conditions for application.




In favour of this interpretation of precedent is the distinction drawn
in legal practice between what is known as the '*ratio*
*decidendi*' of a case and '*obiter
dicta*'. The *ratio* of a case represents the
'holding' or 'ruling', i.e., the proposition
of law for which the case is authority--it is the aspect of the
case which is binding on later courts. *Obiter dicta*, by
contrast, represent other statements and views expressed in the
judgment which are not binding on later courts. On this view of
precedent, the rule laid down in the earlier case is represented by
the *ratio*. 




There are a range of criticisms of the rule-making account of
precedent which argue that it does not fit legal practice very well
(see e.g. Moore 1987, 185-7). Two issues stand out: (i) the form
in which judgments are presented, and (ii) the practice of
distinguishing.


#### 2.1.1 The form of judgments




Although the idea of the *ratio* *decidendi* is a staple
of legal practice, it is notable that it is a construct *from*
a precedent rather than an explicit feature of most legal
judgments. Judgments are highly discursive texts and very rarely
identify their own *rationes*. What is more, even if a court
chooses to explicitly formulate the *ratio* of its decision,
this precise *formulation* is not itself regarded as binding on
later courts. (See Perry 1987, 235-7; Schauer 1989, 455; Simpson
1973, 372; Moore 1987, 185-6; Stone 1985, 123-9.)




It is often said that this creates a marked contrast with statutes,
where a canonical formulation of the legal rule being laid down
*is* provided. Given the flexibility open to later courts
to determine the *ratio* of the earlier decision, it is
misleading to think that decisions lay down binding rules for later
courts. However, although there is a contrast with legislation
here, it can be exaggerated. In both situations the propositions
of law for which a case or statutory provision is authority must be
*derived* from the case or statute and is not identical with the
text of either. The real difference between precedent and statute
lies in the fact that in the case of statutes legal systems have
elaborate conventions of interpretation to assist in the process of
deriving the law from a legislative text, whereas in the case of
precedents they do not. But this simply shows that the law
derived from precedents may be vaguer and more indeterminate than that
derived from (many) statutes; it does not establish that precedents do
not create legal rules.


#### 2.1.2 The practice of distinguishing




An integral part of legal reasoning using precedents is the practice
of *distinguishing*. Distinguishing involves a precedent not
being followed even though the facts of the later case fall within the
scope of the *ratio* of the earlier case. As the later case
falls within the scope of the earlier *ratio* (i.e., within the
scope of the rule), one might expect that the decision in the later
case must be the same (unless the court has the power to overrule the
earlier case and decides to do so). In legal reasoning using
precedents, however, the later court is free not to follow the earlier
case by pointing to some difference in the facts between the two
cases, *even though* those facts do not feature in the
*ratio* of the earlier case.




Take the trust example: in a later case the recipient of trust
property may not have paid for the property, but may have relied on
the receipt in entering into another arrangement (e.g. in using the
property as security for a loan). The later court may hold that the
recipient is entitled to retain the property and justify its decision
by ruling that where (i) the defendant has received trust property
(ii) in breach of trust and (iii) has not paid for the property, but
has (vii) relied upon the receipt to disadvantageously alter her
position, then the defendant is entitled to retain the property.
(This result would still leave the beneficiary with a claim against
the trustee for the value of the property.)




The effect of distinguishing, then, is that the later court is free
not to follow a precedent that, *prima facie*, applies to it,
by making a ruling which is narrower than that made in the precedent
case. The only formal constraints on the later court are that: (1) in
formulating the *ratio* of the later case, the factors in the
*ratio* of the earlier case (i.e., (i)-(iii)) must be
retained, and (2) the ruling in the later case must be such that it
would still support the *result* reached in the precedent
case. In short, the ruling in the second case must not be inconsistent
with the result in the precedent case, but the court is otherwise free
to make a ruling narrower than that in the precedent. Hence the more
accurate statements of the doctrine of precedent are to the effect
that a later court must *either* follow *or* distinguish
a binding precedent--a disjunctive obligation.




At a formal level the practice of distinguishing can be reconciled
with the view that *rationes* are rules by arguing that later
courts have the *power* to modify the rule in the earlier
case. An analogy can be drawn to the power to overrule earlier
decisions: just as judges can *overrule* earlier cases, they
can also *modify* earlier law, thereby paralleling the power of
legislators to either repeal or amend the law. The analogy, however,
is very imperfect. There are two difficulties: (a) Common Lawyers do
not conceptualise overruling and distinguishing in this parallel way,
and (b) the rationale for a power with this particular scope is
unclear.




On the first point, Common Lawyers ordinarily think of precedents as
constituting the law up and until they are overruled. Once overruled
the later decision is (normally) given retroactive effect, so the law
is changed for the past as well as the future. But when a case is
distinguished it is not often thought that the law was one thing until
the later decision of a court, and now another thing. The law will be
regarded prior to the later decision as already subject to various
distinctions not mentioned by the earlier court. Indeed part of the
skill of a good common lawyer is grasping the law as *not*
stated by the earlier court: learning that cases are
'distinguishable' is a staple part of common law
education, and no common lawyer would be competent who did not
appreciate that the law was not to be identified simply with the
*ratio* of an earlier decision. Common lawyers do not, then,
conceptualise distinguishing along lines analogous to overruling.




On the second point, one of the peculiarities of distinguishing is
that it cuts across the normal justifications for having rules, namely
to have a class of cases treated in a certain way despite individual
variation between them, with attendant gains in predictability and
transparency in the decision-making process. Instead, the later court
is free to avoid the result indicated by the earlier *ratio* so
long as it can find some difference in facts between the two cases
that narrows the earlier *ratio* while still supporting the
result in the earlier case. What is more, this power is not merely
given to courts of the same level of authority as the one laying down
the precedent (as is the case with overruling), but is given to every
court *lower* in the judicial hierarchy. So the Court of
Appeal in England cannot overrule a decision of the House of Lords
(nor even its own decisions ordinarily), but it is free to distinguish
a decision of the House of Lords even when the case before it falls
within the *ratio* of the House of Lords decision. So on the
rule-making view of precedent lower courts have the power to narrow
the rules laid down by higher courts, just so long as the narrower
rule would still support the result reached in the earlier case. It is
unclear why lower courts should be given a power to narrow rulings of
higher courts in this particularly circumscribed manner.




Two ways in which distinguishing can be made less idiosyncratic are
these: (a) to argue that the later court is restricted to making a
modification which the earlier court would have made if confronted
with the current facts (cf. Raz 1979, 187-8), i.e., that
distinguishing is a form of *reinterpretation* of the original
*ratio*; or (b) to argue that there is a *presumption*
against distinguishing (Schauer 1989, 469-71; 1991,
174-87). Each of these approaches echo forms of legal reasoning
found in statutory construction. The first, in asking what the earlier
court would have done, assimilates the task of distinguishing to that
of determining the law-maker's intent behind their ruling. This
is parallel to the practice of interpreting statutes in terms of
legislative intent. The alternative approach of there being a
presumption against distinguishing parallels the creation of
*exceptions* to statutory
 rules.[8]




The problem with these two suggestions is that the practice of
distinguishing does not conform to either of these constraints: while
courts *do* consider the earlier decision in order to see if
the *ratio* can be reinterpreted, they also introduce
distinctions without recourse to the earlier court's views; and
they do not typically approach the task of distinguishing as if there
is a presumption against it. As a matter of legal practice, then,
there are no legal restrictions of this kind on the later court.
Distinguishing, then, does not seem to fit easily with the
understanding of *rationes* as creating binding legal
*rules*. (See also Perry 1987, 237-9 on
distinguishing.)




A *third* way which purports to deal with the problem of
distinguishing on the rule model is to argue that the
'rule' for which the decision is binding is not the
precedent court's ruling, but something narrower--the
'material facts' that were 'necessary' for the
result of the case. (See Goodhart 1930, 1959; and see also Burton
1995, 25-58, 60-5 on 'case-specific facts' and
Eisenberg 1988, 51-4 on 'minimalist' and
'result-centred' techniques.) This approach makes use of
the fact that decisions do not provide canonical formulations of the
*ratio* to argue that the *ratio* is not to be
identified with the court's *stated* ruling on the
issue. The effect of such an approach is to narrow what is regarded as
binding in the case to those facts which were crucial to the actual
outcome, rather than the stated ruling applied to those facts. The
difficulties with this approach are three-fold:



> 
> 
>  (1) it goes against general legal practice, which usually does
> identify the *ratio* with the ruling made by the precedent
> court (see Simpson 1961, 168-9; MacCormick 1978, 82-3,
> 1987, 157-8; Raz 1979, 184; Eisenberg 1988,
>  51-61)[9];
> 
> 
> 
> 
> (2) if the precedent court's own characterisation of its ruling
> is abandoned, there is no coherent way to settle on the
> 'material facts' (Stone 1964, 267-80, 1985,
> 123-9). Take the case of the recipient of trust property
> transferred in breach of trust. A key aspect of the facts is that the
> recipient did not pay for the property. But why is this
> 'material'? If the court's own reasoning is put to
> one side, is it because *no* consideration was given (so had a
> token been provided that would have been sufficient); or that
> *inadequate* consideration was provided (so more than a token
> would be necessary); or that a *reasonable* price was not paid;
> or that the price was not what the beneficiary would have been willing
> to accept for the transfer; or that the price is not the best which
> the trustee could have obtained on the open market? All of the
> preceding descriptions of the facts are true, but which is
> 'material'? The requirement for any of them would
> invalidate the transfer. 
> 
> 
> 
> 
> (3) Even if there is some way to characterise the
> 'material' facts, it does not eliminate
> distinguishing. Take later trust case, for example, in which the
> recipient has paid nothing for the trust property but *has*
> acted detrimentally in reliance on the receipt. The recipient is still
> a 'volunteer' who has not transferred anything to the
> trustee for the property, but there *has* been reliance upon
> the receipt. This may well lead a later court to distinguish the
> earlier case, although the facts are otherwise identical to those in
> the original case. On the other hand, if the claim is that the
> precedent case is only binding when *both* (a) the
> 'material facts' are present, and (b) no *other*
> relevant facts are present, then it is no longer a
> 'rule-based' account of precedent--it is simply
> reasserting the minimal requirement that the decision in the later
> case must not be inconsistent with the result reached in the precedent
> case.
> 
> 
> 


### 2.2 Precedents as the application of underlying principles




A different response to the problem of distinguishing is to relocate
the binding force of precedents in the *justification* for the
earlier decision, rather than in the ruling itself. (See Perry 1987,
esp. 234ff and Moore 1987 for two versions of this view.) This
approach has three principal attractions. The first is that it
explains the lengthy expositions of the *reasoning* for the
result found in many decisions. It is the reasons that contain the
gist of the decision, and so it is to this question that most
attention is directed by the courts in justifying their
decisions. Secondly, this accounts for the fact that courts do not
bother (and indeed lack the power) to lay down a precise formulation
of their *rationes*. The *ratio* does not lay down a
rule which must be followed by later courts, but is simply a
convenient short-hand way of referring to the overall effect of the
principles justifying the result in the case (Perry 1987, 235,
239). Thirdly, and most significantly, this approach provides a
natural explanation for the practice of distinguishing. A later case
is distinguishable where the *justification* for the result in
the precedent does not apply to the different facts of that case, even
if it might seem to fall within the *ratio* of the
decision.




Despite its attractions, the 'underlying principles'
account faces three major difficulties: (i) the scope of
distinguishing; (ii) accounting for the role played by
*rationes*; and (iii) maintaining the distinction between
precedent and analogy. The initial difficulty arises from the fact
that distinguishing is not restricted to the application of the
justification provided by the earlier decision. Any good argument can
provide the basis for distinguishing, for example by showing that the
novel facts in the later case provide considerations which
*outweigh* the original justification: it is not that the
original justification is inapplicable to the novel facts, it is
simply that those facts raise additional considerations that are more
compelling. So later courts go beyond what was done in the earlier
decision in determining whether to distinguish the later case.




One possible line of response to these difficulties is to abandon the
idea that what is binding is the *precedent court's*
justification for its decision. After all, the standard view is that
later courts are bound by the ruling in the precedent, not its
reasoning. Instead, it is argued, whether the earlier decision must be
followed in the later case turns on applying the *best
justification* for the earlier decision. But not the best
justification for that decision, taken in isolation. Rather, what is
binding in law is the set of principles which best fit and justify the
totality of the results in past decisions (e.g. Moore 1987, 201, 210;
cf. Dworkin 1975,
 110-23[10]).
 From this perspective, distinguishing is not restricted to applying
the earlier court's justification for its decision, but in
applying the justifications for the doctrine of which that decision
forms a
 part.[11]




The second difficulty, however, applies to both versions of this
approach, *viz.* accounting for the role played by
*rationes*. The practice of precedent involves later
courts being bound to *either* follow *or* distinguish
the earlier decision, but *only* if the facts of the later case
fall within the terms of the *ratio*. The *ratio*
plays an indispensable role in fixing the scope of the later
court's duty to follow or distinguish--it is only if the
facts of the later case fall within the *ratio* that this
question arises. This role is not appropriately captured by
arguing that it is the justifications, and not the *ratio*,
which are
 binding.[12] 
 (Cf. Moore 1987, 185-7, 211-3). What the approach does
help to highlight, on the other hand, is the role played in the
practice of precedent by the justification for decisions. As noted
above, determining the *ratio* is not a mechanical exercise: it
involves understanding what was decided in a case--by reference
to what was said in the judgment, earlier cases, and the general
understanding of that area of the law. The *precedent
court's* own justification for its decision plays an
important role in determining the level of abstraction of the factors
in the *ratio*, and for providing arguments for a narrower or
wider reading of those
 factors.[13]




This is related to another point: if the underlying justification
for a precedent is binding then it undermines the distinction between
arguments from precedent and those by analogy. The *ratio*
of the precedent sets the outer limit of what is *binding* on
later courts--i.e., what a later court is bound to either follow or
distinguish. Analogies (as will be argued below) *are*
grounded in the underlying rationale for earlier decisions, but they do
*not* bind later courts. If the underlying justification
of precedents were binding, rather than the *ratio*, then
analogies would be binding and legal reasoning would have a different
shape.


### 2.3 Precedents as decisions on the balance of reasons




If a precedent is not laying down a rule, nor binding in terms of its
underlying justification, how should it be regarded? One
alternative is to think of the precedent as representing a decision on
the *balance of reasons* in the individual case before the
court that later courts are required to treat as correctly decided
(see Lamond 2005). The precedent court took a range of facts into
account in reaching its decision. Those facts--facts such as the
breach of trust, the trustee having power to transfer the property,
the recipient being a volunteer, and the good faith of the
recipient--ground reasons for reaching some particular legal
conclusion. On this approach, what the *ratio* provides is a
statement of the factors which the court regarded as providing the
reasons that were crucial for reaching its result. So the
*ratio* represents the view of the court that those facts spoke
in favour of the outcome, and that they were not defeated by any
combination of the other factors present in the case. For example, the
court decides that the recipient of trust property must hold the
property on trust if they are a volunteer even though they acted in
good faith. In reaching its conclusion the court must deliberate on
the competing merits of these two parties and decide which is better
supported. Both parties were ignorant of the dishonesty or
incompetence of the trustee, so neither is favoured on that score; the
recipient has acquired property which the trustee did have the legal
power (though not the right) to transfer, so upholding the security of
property transactions favours allowing the innocent recipient to
obtain the complete title to the property (leaving the beneficiary
with a personal claim for damages against the defaulting trustee); the
principle that no-one can transfer a greater interest than they
possess favours the beneficiary. Other considerations favour one or
other of the parties. In making its ruling, the court concludes that
in the circumstances of the case before it the merits favour the
beneficiary of the trust rather than the recipient.




What is the difference between this approach and that in terms of
precedents laying down rules? It lies in the fact that instead of the
*ratio* representing a rule which presumptively settles the
disposition of later cases whose facts fall within its scope, it
provides a *pro tanto* justification for such a disposition,
i.e., other things being equal this is how the later case should be
decided. And it is this that provides a natural explanation for the
practice of distinguishing. The correct statement of the doctrine of
precedent is that later courts are bound by *cases*--not
simply by *rationes*--and bound to either follow or
distinguish them. So later courts whose case-facts fall within the
scope of the *ratio* must *consider* the precedent, but
do so in order to consider whether the differences in facts between
the later and the precedent cases justify deciding the cases
differently. What the later court cannot do, on the other hand, is to
distinguish on the basis of factors that *were* present in the
earlier case (even if they were not part of the decision's
*ratio*), because to do so would be to imply that the earlier
decision had reached the wrong conclusion on the balance of reasons. A
later court cannot treat the *case* as wrongly decided, unless
it is able and willing to overrule it




The idea that a precedent is reaching a conclusion on the balance of
reasons in the particular case at hand makes sense of a number of
other features of common law judgments. It explains the practice of
providing elaborate accounts of the *circumstances* of the
case, even though only a small subset of those circumstances matter to
the *ratio*, since they were the group of factors that the
court considered in reaching its decision. It is also consistent with
the lengthy discussions of the reasons for the conclusion, and the
lack of interest on the part of courts in providing a carefully worded
formulation of the *ratio*: what matters is the substance of
the factors considered in reaching the decision, not the particular
language in which they are couched.




The main challenge for this account of precedent lies in explaining
when a later court is *bound* to follow a precedent which it
regards as having been *incorrectly* decided. In the case of
the trust property, the later court may think the precedent court
mistaken to have concluded that the recipient must return the property
to the beneficiary. May a later court avoid the result of the
precedent by pointing to *any* general factual difference
between the cases (e.g. this is real property rather than personal
property, this is an implied rather than an express trust), and
distinguish the precedent by stating a narrower *ratio*? After
all, the balance of reasons never supported the precedent in the first
place, so shouldn't it be confined to the narrowest possible
statement of its facts? In which case precedents seem to have very
little binding force indeed.




One obvious possibility for avoiding this problem would be to ask how
the *precedent court* would have assessed the facts in later
case. But although this would be satisfactory in theory (if sometimes
difficult in practice), it again does not reflect legal
practice. Courts sometimes approach the question in this way, but
often they do not, and there is no legal *requirement* that
they do so. A better response is this: the basic common law
requirement in *stare decisis* is to treat earlier cases as
correctly decided. A case may be distinguished, but only if that
distinction does not imply that the precedent was wrongly decided. So
in the later case the court must decide whether the factual difference
(real versus personal property, implied versus express trust) provides
a *better* justification against the earlier decision than the
facts of that case on their own. If it does, then the court may
distinguish (citing that differences with the original case), since
that does not imply that precedent was mistaken. If
not--because real property or implied trusts raise no special
considerations in this context--then the precedent must be
followed. This approach, of course, assumes that it *is*
possible to make these sorts of comparative judgements (for arguments
that this is not generally possible see Alexander 1989, 34-7).


## 3. The Justifications for Precedent




Most discussions of precedent focus on the justifications for having a
doctrine of *stare decisis* by which later courts are bound to
follow earlier decisions. There is, of course, a prior question of why
the decisions of courts should be regarded as *making* law at
all. In some Civilian legal systems, such as the French, the official
view is that court decisions do not make law, they merely involve the
application of the law. This follows from a straightforward
understanding of the separation of powers: the responsibility of the
legislator is to make law, the responsibility of the judiciary is to
faithfully apply the law made by the legislator. For the courts to
make law would be to usurp the legislative function, and to usurp a
function to which the courts have no legitimate claim. One distinctive
feature of Common Law systems is the existence of central areas of law
that have no legislative foundations--such as contract, tort,
trusts, and personal property. All of these areas have seen
legislative intervention, but most Common Law jurisdictions still
leave them on a non-statutory footing. Here the decisions of the
courts are the basis of the law.




In practice no modern legal system has functioned without the
decisions of the courts playing at least an auxiliary role in settling
the content of the law. To take one well-known example, in France the
law of civil wrongs (torts, delicts) is based upon five relatively
short articles of the *Code Civil* (SSSS
1382-1386). Formally, the law is found in those five articles,
and a court decision is legally flawed if it does not cite at least
one of them as the basis for its ruling. But there is a vast body of
cases interpreting and applying those articles, and these cases are
regularly cited before the courts to assist them in reaching their
decisions, even though judgments themselves do not mention earlier
cases. In substance, then, if not in form, this area is partly
constituted by judge-made law.




So one question that can be raised about precedent is why it is
justifiable for the decisions of courts to be treated in this way at
all, i.e., for them to help constitute the law. There is a more
specialised question, however. In the Common Law at least, the
doctrine of *stare decisis* requires later courts to follow
earlier decisions even if they were wrongly decided. To say that a
case was 'wrongly decided' is to say that the legally
permissible reasons relevant to the case did not, all things
considered, support the conclusion reached by the court. It should be
emphasised that such a conclusion depends upon and is relative to the
context provided by existing legal doctrine. Take the question of
whether parents should be able to recover for the cost of raising a
healthy child when it has been born as a result of a negligently
performed sterilisation operation on one of the parents. In some legal
systems such costs are recoverable, whereas in others they are
not. Here it is quite possible that these conflicting decisions are
both correct, in the sense that each is correct within its own
doctrinal context. So whether a decision is wrong is not a question of
how the case ought to be decided without any reference to the law, but
whether it goes against the merits of the legally relevant
reasons.




The doctrine of precedent thus raises two justificatory issues: (a)
why treat court decisions as partly constituting the law, and (b) why
require later courts to follow *erroneous* decisions of earlier
 courts?[14]
 The most influential arguments responding to these issues are based
upon considerations of:


1. consistency
2. expectations
3. replicability
4. the need for law-making




(For general discussions of the justification for precedent, see:
Schauer 1987, 595-602, Golding 1984, 98-100, Benditt 1987,
89-93.)


### 3.1 Consistency




The argument from consistency is related to arguments in favour of
'formal' justice, i.e., that two cases which are the same
(in relevant respects) should be treated in the same way. It would
simply be inconsistent to treat them differently. In the case of
precedent this argument is said to favour following the earlier case:
assuming that one cannot change the earlier decision (because it is
too late to appeal, or the party to the case has reasonably relied
upon it, etc), the only way to ensure consistency is for later
decision-makers to treat the earlier decision as a precedent. The
claim of consistency is also sometimes put in terms of
'equality': to treat the later case differently to the
first would be to fail to treat the parties before the courts
equally. This argument is made independently of other concerns such as
parties' expectations or community perceptions of the court
process or the problem of moral disagreement. Arguments of this kind
certainly have weight in some circumstances. If a legal system is
morally legitimate and has authority over those subject to it, then it
is inconsistent for one person to be treated less or more favourably
by the law than another person whose situation is legally
indistinguishable. Other things being equal, legal decisions should be
consistent across time and/or decision-makers. A later case should
only be treated differently to an earlier case when the law itself has
been changed (by the legislator or the courts, including cases where
the court overrules an earlier decision in reaching a decision on the
case before it) So concerns of consistency provide some justification
for treating earlier decisions as sources of law, rather than
approaching each question anew when it arises again.




This fact does not, however, support a doctrine of following earlier
decisions even when they are *wrong*, i.e., for having a strong
practice of *stare decisis*. If the earlier decision was wrong
then the person subject to it may have been treated more or less
favourably than they should have been treated. If they were treated
more favourably then clearly that should have been corrected (e.g. on
appeal). If it was not corrected then the person had an undeserved
slice of good fortune. But that a mistake was made in the earlier case
is not--in itself--an argument for repeating the mistake in
the later case. The first litigant did not deserve their outcome, even
if for reasons of the finality of legal processes they are entitled to
retain it. Equality does not demand the repetition of mistakes. On the
other hand, if the original litigant was treated less favourably than
they deserved then again that mistake should be corrected if it can be
(e.g. by appeal, or, if that is too late, by remedial legislation or
by executive action such as pardon or *ex gratia* payments),
but it is no reason for treating a later litigant unfavourably as
well. Taken in isolation from other considerations (such as
expectations and predictability), equality does not support the
bindingness of incorrect decisions.




By contrast, arguments of equality bite where the court in the
original case was confronted with a situation where the correct
outcome was indeterminate, i.e., where more than one outcome was
possible in light of the legally permissible arguments. This may be
due to each outcome being equally well supported by reason, or by the
outcomes being supported by different, incommensurable, values. In
some of these cases the law has closure rules to settle the matter,
e.g. in favour of criminal defendants, but in others there are no
closure rules as to the appropriate substantive result to endorse. A
possible illustration of such indeterminacy is the position of a
person who quite innocently buys stolen goods. In some legal systems
the purchaser acquires good title to those goods, whereas in others
(such as the Common Law) she does not. Here, arguably, the merits of
the two innocent parties (the purchaser and the original owner) are on
a par, and all the law can do is choose which one is to prevail. So
where an outcome is underdetermined there are arguments of equality
for later courts following the earlier decision rather than adopting
any of the other possible solutions. None of this, of course, is an
argument for following earlier decisions that were wrongly decided,
since these are cases where the earlier court did not make a mistake,
but took one permissible option.


### 3.2 Expectations




Another common argument in favour of precedent is in terms of
protecting expectations: if an institution has dealt with an issue in
one way in the past, then that creates the expectation that it will do
so in the future--an expectation which people use to plan their
lives and enjoy some control over their
 situations.[15] 
 So there are good reasons for an institution to follow its previous
decisions (other things being equal), even if it turns out that they
were mistaken.




The fundamental problem with this line of argument in the case of
precedent is that it suffers from a type of circularity. It is true
that legal systems that follow a practice of precedent create
expectations that earlier decisions will be followed in the
future. But it is important to bear in mind that it is only
*legitimate* expectations which need to be considered in
decision-making, not any expectation which someone forms. The mere
fact that a decision was made in the past provides no reason in itself
to expect that it will be followed in the future, and certainly
creates no entitlement to expect that it will be followed. That a
company orders stationery from a supplier at the start of the year may
raise a hope, and even possibly an expectation, that it will do so
again later in the year, but the supplier does not have a
'legitimate' expectation that it will do so, and the
company does not create a precedent for itself. Where there
*is* an institutional practice of following past decisions, on
the other hand, the reliance of those subject to future decisions may
ground legitimate expectations, but it is always open to the
institution to announce that it will no longer treat past decisions as
binding and will, instead, decide each case on its merits. Equally,
it is a common occurrence in some institutional settings where past
decisions *are* followed for a decision to be made subject to
the proviso that it is 'not setting a precedent' for the
future. 




Whether a past decision creates legitimate expectations, therefore,
depends upon there being good independent reasons for the institution
to follow its earlier decisions, or upon the existence of a practice
of doing so. But the practice itself should only be maintained if
there are good independent reasons for having it: its mere existence
cannot bootstrap a justification for the maintenance of the
practice.


### 3.3 Replicability




The preceding arguments for precedent presuppose that decision-makers
can correctly ascertain the merits of the cases before them, but law
of course operates under non-ideal conditions where decision-makers
make mistakes and disagree among themselves about the merits of
cases. In practice, the outcome of a case may be uncertain not simply
because the correct result is rationally indeterminate, but because
the decision-makers are fallible. Given this, a practice of precedent
in law, it can be argued, has a number of advantages due the fact that
it may make institutional decisions *replicable* (see Eisenberg
1988, 10-12, 23-4, whose coinage it is; and Schauer 1987,
597-8). That a decision is replicable refers to the fact that
it is possible for others to make an informed judgement on the
likelihood of a particular outcome, in the light of the relevant legal
materials, the canons of reasoning used in a system, and an
acquaintance with the general culture from which the decision-makers
are drawn. Replicability means that decisions are more predictable
than if they were made *de novo* each time. This, in turn,
allows individuals to make plans that are consistent with the law and
to avoid falling foul of it, and hence allows them to be guided by the
law.




This provides a rationale both for treating earlier cases as
contributing to the law and for the doctrine of *stare
decisis*. Other things being equal, it is better if the law is
predictable than if it is unpredictable. It should be noted, however,
that such a rationale does not necessarily support as strong a
doctrine of precedent as that found in many Common Law
jurisdictions. The concern for predictability needs to be weighed
against the moral desirability of the law in question. This would
suggest that (a) in some circumstances lower courts should be allowed
to depart from the decisions of higher courts where their view is that
the earlier decision was (in the context of the relevant law) clearly
morally undesirable, (b) giving greater freedom to courts to overrule
their own decisions on the basis that there was a morally preferable
decision (in that legal context).


### 3.4 Law-making




A final justification for the doctrine of precedent is that it is
desirable to give courts the power to *make* law. The thought
here is that it is valuable for the courts to have the power to
improve and supplement the law (Hart 1994, 135-6; Raz 1979,
194-201). The assumption underlying this justification is that
the law is sometimes incomplete and in need of being given greater
specificity, or that it is erroneous and needs to be corrected. On
this view the courts are analogous to delegated legislators: they have
limited powers to make law within a broader framework of doctrine.




Although the need for law-making is often cited as a justification for
precedent, the substance of the argument normally boils down to
concerns with either equality or replicability. If the law has
resolved an indeterminacy in one (acceptable) way in the past, then
precedent helps to ensure that future litigants are treated as
(un)favourably as past litigants, and so all are treated equally. In
addition, if the application of the law is indeterminate, due to the
type of value conflict involved or the nature of the decision-makers,
then it is desirable for judicial decisions to constitute precedents
in order to make the law more replicable in the future. 




On the other hand, if the argument in favour of courts having
law-making power is that they can thereby improve the law, this is
really an argument in favour of having the power to overrule
precedents, rather than an argument in favour of precedent in the
first place. Indeed, the need for a power to overrule only arises if
earlier decisions are binding even when mistaken, since later courts
could otherwise simply disregard decisions that were erroneous. So
the argument from law-making, when distinct from arguments from
replicability and equality, is an argument for the power to overrule,
rather than an argument for *stare decisis*
 itself.[16] 




In conclusion, both equality and replicability provide arguments in
favour of judicial decisions constituting sources of law. And the
value of replicability also supports a doctrine of *stare
decisis* by which later courts are sometimes bound even by the
erroneous decisions of earlier courts. This in turn leads to the need
for courts to have the power to overrule existing law, so that there
is scope for incorrect decisions to be reversed.


## 4. Analogy




An analogical argument in legal reasoning is an argument that a case
should be treated in a certain way because that is the way a
*similar* case has been treated. Arguments by analogy
complement arguments from precedent in two ways: (i) they are used
when the facts of a case do not fall within the *ratio* of any
precedent, in order to assimilate the result to that in the analogical
case; and (ii) they are used when the facts of a case *do* fall
within the *ratio* of a precedent, as a basis for distinguishing the
case at hand from the precedent. The *force* of an argument
from analogy is different to that from precedent. An indistinguishable
precedent must be followed unless the court has the power to overrule
the earlier decision and does so. By contrast, arguments from analogy
vary in their strengths: from very 'close' analogies
(which strongly support a result) to more 'remote'
analogies (which weakly support a result). Analogies do not bind:
they must be considered along with other reasons in order to reach a
result. That an analogy is rejected in one case does not preclude
raising the analogy in a different case.




Analogies, like precedents, arise within a doctrinal context. The
case at hand raises a legal issue, e.g. does the impersonation of a
boyfriend vitiate the victim's consent in the law of rape, is
cross-burning protected 'speech' within the First
Amendment to the US Constitution, does the defence of duress require
the defendant to have acted as a reasonable person would have done?
Other cases dealing with the validity of consent or the scope of
protected 'speech' or reasonableness in defences provide
potential analogies. An analogy may either be to another case or to
another legal doctrine, and the analogy rests on there being some
common characterisation of the facts in both cases or the two
doctrines which is relevant to the issue. So knives may be analogous
to guns if the issue concerns weapons, but knives may also be
analogous to teaspoons if the issue concerns cutlery. Duress may be
analogous to provocation if the issue concerns defences, but duress
may also be analogous to incitement if the issue concerns
complicity. Two doctrines or sets of facts are not analogous in the
abstract, but in the context of a legal
 issue.[17]




Two questions arise about analogical reasoning. Firstly, by what
process does a decision-maker identify the 'common
characterisation' between the case at hand and the analogous
one? Secondly, what type of justificatory force does the common
characterisation provide? On the first question, just as no two cases
are identical in every respect, so no two cases are such that some
common characterisation of the facts cannot be found. But not every
case is thought to provide an analogy, so what limits or directs the
selection of analogies? The answer to this question flows into the
issue of the justificatory force of analogies. What sort of reason
does an analogy provide for deciding the instant case in the same
way?




It is widely agreed that the existence of an analogy depends
ultimately upon the *justification* for the analogical
decision. The facts in a case may fall outside the *ratio* of
an existing precedent, and thus the court is not bound by the
precedent. On the other hand the *justification* for the
earlier decision may apply to the later case, and thus provide an
argument from analogy. Take the case of the impersonation of a
boyfriend in the law of rape. Assume that there is authority for the
proposition that the impersonation of a husband vitiates consent for
the purposes of rape. Whether the impersonation of a boyfriend is
analogous depends upon why such a marital impersonation vitiates
consent. If it is thought that part of the significance of being
married is the sharing of physical intimacy with that particular
person, then the rationale is applicable to other close personal
relationships. If instead the rationale is that consent to an
impersonator involves committing an act of adultery, i.e., an act
different in kind to that consented to, then although the two
situations are obviously very similar, the analogy will fail.




It is often argued that reasoning by analogy and distinguishing
precedents are mirror images of each other: given the facts of two
cases, the question is whether there is a good reason for treating
them differently (e.g. Eisenberg 1988, 87). In the case of
distinguishing, a precedent must be followed unless there are good
reasons for treating it differently. In the case of analogy, it is
said, a precedent must be extended unless there are good reasons for
treating the instant case differently. But this is misleading, since
the symmetry is incomplete. A precedent cannot be distinguished on
grounds that would, in substance, imply that the precedent was wrongly
decided: it must be treated as correctly decided. A precedent need not
be *extended*, however, if later courts regard its rationale as
unpersuasive. A longstanding doctrine of the common law was that a
husband could not commit the offence of rape against his wife. By the
twentieth century the rule was increasingly recognised to be archaic
and objectionable. Thus, unlike the question of impersonation discussed
above, no one suggested that the rule should be
*extended* to cohabiting
 couples.[18] 
 Where a decision is not regarded as misguided, however, it does
provide an argument for being followed. The later court may still
decide, however, that it would not be desirable, all things
considered, to do so.




The explanation for the justificatory force of such resemblances is,
however, controversial. There are two major alternative accounts, the
one relying on principles, the other on reasons.


### 4.1 Principles




An influential view on analogy regards it as grounded in the
*principles* that underlie existing cases (e.g. MacCormick
1978, 152-94; Eisenberg 1988, 83-96; Sunstein 1993). A
body of cases can be examined to determine which principle (or set of
coherent principles) explains and justifies those decisions, in a
process akin to reflective equilibrium. The process is only akin to
reflective equilibrium because the individual cases (the equivalent of
the specific judgements about particular situations) are either immune
from revision, or are highly resistant to revision.
 So the principles must map the decided cases precisely, or must
depart from only a small proportion of them. If the principle(s)
identified in this process apply to the instant case, then that
provides a good reason in favour of the result supported by the
principle.




A number of criticisms question whether this account captures what is
normally going on in analogical reasoning. One criticism focuses on
the fact that the principle must track the existing cases and try to
make the best of them. Unless the decisions are all correct on the
merits, any principle based on them must itself be flawed: for if it
were morally correct it would not support the mistaken decisions. The
question this raises is whether it can be justifiable to use such a
principle to decide a novel case, rather than decide the case on its
own merits. Can there be 'principles' of this kind, which
are neither conventional parts of a practice nor morally correct?
(see further Alexander 1996b, 1998, Alexander and Kress 1995, 1997) A
more common view, however, is that a principle that makes best sense
of a series of cases or aspects of legal doctrine can have some
justificatory force even though the cases or doctrines are morally
imperfect. In the case of tort liability, for example, the cases might
be best explained by the principle that liability will only arise
where the defendant's conduct has been unreasonable, i.e., that
both harm to the plaintiff and unreasonable conduct is necessary for
liability. This principle may be morally mistaken, i.e., there may be
situations where even reasonable conduct should result in legal
liability. Nevertheless the principle may still be regarded as having
some justificatory force in the context of that legal system. A judge
might think that the correct moral principle is that *other things
being equal* there should be no liability without unreasonable
conduct. But although the law is imperfect in this way, the legal
principle still has some force because it is a near enough neighbour
to the correct principle and it explains the existing
 cases.[19]




A separate line of criticism centres on the fact that courts do not
often articulate their use of analogies in terms of some
'principle' inherent in an earlier case. Where principles
are used as arguments for a result, earlier cases tend to be cited as
illustrations of the application of the principle, rather than as
analogies to the facts of the case at hand. If another case
*is* cited as providing an analogy, the emphasis will be on how
'close' the analogy is, i.e., on how specific the common
characterisation of the facts of the two cases is, and how that
characterisation relates to the rationale for the earlier
decision. The more specific an analogy, the stronger; the more
abstract the characterisation, the weaker the argument as an
analogy. The reason for this is that the more specific the analogy,
the less room there is for distinguishing the two cases, whereas the
more abstract the analogy the more grounds on which the two cases may
be regarded as significantly different. So if it is lawful to consent
to tatooing, it is also lawful to consent to a decorative branding,
which is closely
 analogous.[20] 
 On the other hand, the analogy of boxing to sadomasochistic
activities is more remote, although both involve the intentional
infliction of a certain level of
 harm.[21]




This last point relates to the fact that cases are rarely justified
solely on the basis of principles: instead there are a range of
considerations which are applicable and justify the result. A
principle may apply with equal force to two cases with very different
facts, but those differences may make the cases not very
analogous. What this suggests is that while principles do provide
arguments for reaching a certain result, they do not explain the
nature of analogical reasoning.


### 4.2 Reasons




The reasons-based approach to analogical reasoning focuses on the
justifications for the analogical case (for two very different
accounts see Raz 1979, 201-6 and Brewer 1996). It considers the
extent to which the rationale for the decision in the earlier case is
applicable to the case at hand. Take the case of the impersonation of
a boyfriend in the law of rape. Whether this situation is analogous to
the impersonation of a husband depends on the reasons for the latter
vitiating consent. There need be no single principle that underlies
the rationale: it may rest on a number of factors that reinforce the
conclusion.




One consequence of this approach is that if the rationale for the
earlier decision is tied exclusively to the particular category used
in the *ratio*, there will be no scope for analogical extension
to broader categories. In English law duress is not a defence to
murder regardless of the circumstances, due (it is said) to the
uniqueness of deliberate killing and the fact that duress is, at best,
an excuse. On this rationale there is no room for arguing that duress
should be excluded in cases of physically disabling a victim. On the
question of whether duress could be a *partial* defence to
murder, on the other hand, there *is* an arguable analogy to
the excuse of provocation, which operates to reduce murder to
manslaughter. Killing may be inexcusable, but that does not mean that
every deliberate killing warrants a conviction for *murder*. Of
course, duress involves an actual decision to kill, whereas
provocation a temporary loss of self-control. The case for reducing
killing under duress to manslaughter depends upon whether the
rationale for provocation (e.g. as a concession to human frailty)
extends to it. Two factors--the defendant's loss of
self-control and the victim's involvement in the
killing--readily distinguish the two situations, and weaken any
analogy.




The reasons-based approach helps to explain why individual cases, and
individual doctrines, can ground analogies. It also explains what is
accurate in the principles-based approach, since some of the
considerations underlying analogical cases will be principles. But
there are more legal considerations than principles, and these too
play a role in analogical reasoning.


## 5. The Justification for Analogical Reasoning




Why does the law make use of arguments by analogy, rather than simply
deciding novel cases on their own merits? In ordinary moral
deliberation, analogies are used to argue that one disputed situation
is indistinguishable from another situation where the merits are
relatively clear. They leave three main responses open: (a) that the
case is indeed indistinguishable since the same rationale applies to
both; (b) that the case is distinguishable; or (c) that the case is
indistinguishable, but upon reflection the assessment of the original
case was mistaken. (Reflection on another case might, of course, lead
one to conclude that one's original assessment was mistaken, even
though the two cases *are* distinguishable.) As a result,
analogies are useful heuristic devices for deepening and sharpening
reflection on the merits. It is also the case that people are often
more confident in their judgements about various concrete cases than
they are about abstract theories that attempt to account for their
judgements, and so regard this is a more profitable way to approach a
question (see Sunstein 1993, 775-7).




In law, by contrast, analogies carry a weight additional to the merits
of the case. The approach of courts is complex. Some decisions and
doctrines are regarded as mistakes and have no analogical
weight. Other doctrines may be regarded as imperfect--not wholly
correct--but do have analogical weight. Other still may be
regarded as simply correct, and their existence provides further
support for adopting the view in the novel case. There are a number of
possible indirect benefits that accrue from the practice of analogical
reasoning, such as exposing judges to a wider variety of fact
situations than the particular set before them, making them consider
the views of other judges in previous cases and exerting a
conservative pressure on individual decision-makers (see Sherwin
1999). But is there any more fundamental rationale to the form of
reasoning?




Like precedent, analogies cannot be justified by recourse to
expectations. Whether there is an expectation of analogies being
followed, such expectations will only be justified if there are good
independent reasons for using analogies in this way. Consistency may
provide a rationale for a limited exercise of analogy. Where an
earlier case has settled some indeterminacy in the application of the
law, and where the rationale for the earlier decision is equally
applicable to the later facts, then it would be inconsistent to decide
the later case differently.




The strongest justification for analogical reasoning, however, lies in
the value of replicability. This is often put in terms of the
importance of 'coherence' in the law (MacCormick 1978,
153, 187-8; Sunstein 1993, 778-9; see also Raz 1979,
204-6 on 'partial reform'). Arguments in favour of
coherence normally emphasise its instrumental
 value.[22]
 This is tied up with the replicability of legal
decision-making. There are two important characteristics of legal
decision-making. The first is the *fragmentary* nature of legal
materials. The second is the *plurality* of decision-making
bodies. Legal materials--precedents, statutes, conventions,
principles--are fragmentary in two senses: (a) they are the work
of many different hands at different times and with different outlooks
and (b) different areas of law owe more to some hands and times than
others. As a result legal doctrine tends to exhibit only a thin global
coherence, whereas it may possess a thick local coherence. The
pluralism of decision-makers is also two-fold: (a) there are many
individuals making decisions using the same body of materials, and (b)
these individuals do not share a uniform evaluative outlook. Given the
fragmentary nature of legal material and the plurality of
decision-makers there is considerable scope for disagreement when
decision-makers are faced with novel questions.




Analogical reasoning helps to make the outcome of cases more
predictable by giving weight to existing legal decisions and
doctrines. But it only does so against a certain background, one where
despite decision-makers not sharing a uniform normative outlook, there
is a large measure of agreement on the existence and importance of
certain values. A certain level of agreement is required for
decision-makers to see a case *as* analogous, since that rests
on what they judge to be the proper justification for the earlier
decision. It also means that while they may disagree on the resolution
reached in various cases, the disagreement is unlikely to be profound,
but reasonable. (For an argument that this requirement can be
overstated, see Sunstein 1993, 769-73).




The use of analogies in law, then, serves to compensate for some of
the indeterminacy which flows from fragmented materials and the
pluralism of decision-makers. That a close analogy exists usually
provides a good reason for deciding the case the same way, since it
renders the law more replicable than it would otherwise be, and
enables lawyers to predict more accurately how a situation will be
treated by the law. Of course, this is only a relative value:
analogies can be defeated by other considerations if there is a good
basis for distinguishing, or if its merits are too weak. 


## 6. Summary




Precedent and analogy are two central and complementary forms of legal
argument. What makes them characteristic of *legal* reasoning
is the circumstances of decision-making in law. The greatest contrast
is with individual reasoning, where neither precedent nor analogy have
the same significance. An individual may give weight to what she has
done in the past, e.g. because she believes the decision was made
under optimum conditions, or she should not or does not want to
disappoint someone's expectations, or there are special reasons
to treat the two situations identically. Similarly, the comparison of
the problem at hand with another situation may help clarify
one's thinking, but one's judgement on the other case is
only relevant to the extent that it is correct.




In an institutionalised system with many decision-makers and a
heterogeneous group of legal materials there is a tension between
decision-making being relatively predictable for those to whom it will
apply and the law being morally improved. In such a context precedent
and analogy help to shore up the predictability of decisions whilst
leaving room for courts to improve the law. They do this in two
different ways. Precedents are distinguishable (and subject to
overruling), while analogies provide non-conclusive reasons for
reaching a particular outcome. The success of these compromises
depends upon there being a fair measure of background agreement
between decision-makers over the important values served by the
law--both measures would be too weak in the face of widespread
and deep value disagreement. A range of mechanisms exist in law that
help maintain such a relative consensus: legal education, the working
environment, and the selection of candidates for the bench all tend to
produce more convergence than is found in the general community. In
addition, there is an internal feedback element--in deciding
cases, courts are aware that their decisions can be distinguished (as
well as overruled), and that it is only their ruling that are binding
on later courts. This gives them good reasons to press justifications
that are based on values widely endorsed by their brethren.