Arguments from precedent and analogy are two central forms ofreasoning found in many legal systems, especially ‘CommonLaw’ systems such as those in England and the UnitedStates. Precedent involves an earlier decision being followed in alater case because both cases are the same. Analogy involves anearlier decision being followed in a later case because the later caseis similar to the earlier one. The main philosophical problems raisedby precedent and analogy are these: (1) when are two cases the‘same’ for the purposes of precedent? (2) when are twocases ‘similar’ for the purposes of analogy? and (3) inboth situations, why should the decision in the earlier case affectthe decision in the later case?

The study of precedent and analogy is of interest for a number ofreasons:

1. some theorists claim that precedent involves a form of reasoningdifferent to reasoning using rules;
2. although arguments from precedent are extremely common in manyinstitutional and quasi-institutional settings, not merely the law,there is no consensus on the rational basis for their force, nor indeedon whether such arguments have any rational force;
3. some theorists argue that the use of analogies in law is not aform of ‘reasoning’ at all; and finally,
4. even if there is an intelligible form of analogical reasoning, itis unclear why the similarity between two situations provides a reasonfor treating them both in the same manner.

The law presents a useful context for considering these issuesbecause its use of precedent and analogy is well articulated andexplicit. This entry is organised into the followingsections:

• 1. Precedent and analogy in legal reasoning
• 2. Precedent
  • 2.1 Precedents as laying down rules
  • 2.2 Precedents as the application of underlying principles
  • 2.3 Precedents as decisions on the balance of reasons
• 3. The Justifications for Precedent
  • 3.1 Consistency
  • 3.2 Expectations
  • 3.3 Replicability
  • 3.4 Law-making
• 4. Analogy
  • 4.1 Principles
  • 4.2 Reasons
• 5. The Justification for Analogical Reasoning
• 6. Summary
• Bibliography
• Academic Tools
• Other Internet Resources
• Related Entries

1. Precedent and analogy in legal reasoning

Arguments from precedent and analogy are characteristic of legalreasoning. Legal reasoning differs in a number of ways from the sortof reasoning employed by individuals in their everyday lives. Itfrequently uses arguments that individuals do not employ, or that individualsemploy in different ways. Precedent is a good example of this. Inindividual reasoning we do not normally regard the fact that wedecided one way in the past as raising some presumption that we shoulddecide the same way in the future. Of course there can be specialcircumstances that have this effect—someone may have relied onwhat we did before, or may have had their expectations raised that wewould do so again—but absent these specialconsiderations we do not regard ourselves as being committed in thefuture to make the same decision. It is always open to us toreconsider a decision and change our minds if we no longer think ouroriginal judgement was correct.

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

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

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

2. Precedent

Arguments from precedent are a prominent feature of legalreasoning. But what exactly is a ‘precedent’? A precedentis the decision of a court (or other adjudicative body) that has aspecial legal significance. That significance lies in thecourt's decision being regarded as havingpractical,and not merelytheoretical, authority over the content of thelaw. A decision has theoretical authority if the circumstances inwhich it was made (the identity of the decision-makers, those involvedin arguing the case, the availability of evidence or time) providegood reasons for believing the decision to be correct in law. If thereare good reasons to believe that an earlier case was correctlydecided, and if the facts in a later case are the same as those in theearlier case, then there are good reasons for believing that the samedecision would be correct in the later case. In some legal systemsearlier decisions are, officially, treated in just this way: cases arecited to courts, but courts may only justify their decisions byreference to other legal materials such as legislation. As aconsequence the decision in an earlier case is not in itself regardedas a justification for reaching a decision in a later case.^[1]

By contrast, precedents have practical authority because they areregarded as partly constituting the law. Simplifying somewhat, the lawis what the court stated it to bebecause the court stated itto be such. Putting the matter in these terms is over-simplified,however, because (a) it may be that what the courtdid,rather than what it said, that alters the law, and (b) there arenormally a number of limitations on the capacity of a decision toconstitute the law (depending upon the content of the decision and thestatus of the body making them). An important consequence ofprecedents' practical authority is this: since courts are bound to apply thelaw, and since earlier decisions have practical authority over thecontent of the law (i.e., over whatis the law), later courtsare bound to follow the decisions of earlier cases. This is commonlyknown as thedoctrine of precedent, orstare decisis(i.e., standing by things decided).

It should be noted that the modern Common Law endorses a particularlystrong version ofstare decisis, one that requires latercourts to follow earlier decisionseven if those cases werewrongly decided according to the pre-existing law. It is often assumedby Common Lawyers that a doctrine ofstare decisisnecessarily requires that later courts be bound by such erroneousdecisions. This follows from the following line of thought. If latercourts were not bound to follow erroneous decisions, then they wouldonly be ‘bound’ by earlier, correct judgments. But anearlier correct judgment simply reaches the conclusion that the lawalready supported when it was delivered. So to direct courts to followcases that were not erroneous would simply be to direct them to dowhat they are legally bound to do anyway (i.e., apply the law),thereby rendering the doctrine of precedent redundant. The flaw inthis argument lies in the assumption that in every case there must bea single legally correct outcome, with other outcomes beingwrong. This overlooks the possibility of cases in which the merits ofthe dispute are legally indeterminate, so that there is more than onepossible outcome that would not be wrong. To say that a case is‘legally indeterminate’ covers a range of situations, suchas the merits of the opposing arguments being, in law, equal, or wherethe conflicting considerations cannot be rationally ranked againsteach other. In cases such as these the decision alters the law withoutmaking any error. The Common Law, then, might have limited itsdoctrine ofstare decisis by holding that later courts werenot bound by earlier decisions that were wrongly decided.^[2] Instead it developed a different practice—that of‘overruling’, whereby some courts were given a limitedpower to deprive earlier decisions of their binding status on thebasis that they were wrongly decided. So the Common Law'sversion of the doctrine of precedent does not inevitably flow from thefact that precedents have practical authority. Nonetheless the idea ofbeing bound to follow even erroneous decisions is a common feature ofmany institutions decision-making, and will be the focus of thisentry.

The precise operation ofstare decisis varies from one legalsystem to another. It is common for courts lower in a judicialhierarchy to be strictly bound by the decisions of higher courts, sothat Federal Court judges in the United States are bound by decisionsof the Federal Court of Appeals for their circuit, and the EnglishCourt of Appeal is bound by decisions of the House of Lords. The lowercourt is ‘strictly’ bound because it has no power tooverrule the higher court's decision. Equally, most appealcourts are bound by their own earlier decisions, though they aregenerally entitled in certain circumstances to overrule thosedecisions. There is enormous variation in the circumstances that arenecessary for a court to overrule one of its own decisions: at aminimum it must regard the earlier decision as wrongly decided, butgenerally 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 lowercourts: the House of Lords for example is not bound to followdecisions of the Court of Appeal and is free to overrule suchdecisions if it takes a different view of how the case should havebeen decided.

The most important limitation on the application of precedent is thatthe decision in an earlier case is only binding in later cases wherethe facts in the later case are the ‘same’ as those in theearlier case. It is agreed on all sides that if two cases are the samethen the precedent applies, whereas if they are different it doesnot. What makes two cases the same, however, is a matter ofconsiderable debate, and goes to the root of the question of thenature of precedent in legal reasoning. In saying that two cases arethe same, it cannot be that they areidentical. It is obviousthat no two situations are identical in every respect: they mustdiffer at least in having occurred at different times and/or differentplaces. In practice the differences between any two cases will be muchmore significant than this, and yet they may—legallyspeaking—still be the same. For this reason, theorists oftenspeak of two cases being the same in ‘all relevantrespects’. Which of course simply raises the question of whatmakes two cases ‘relevantly’ the same.

This problem is easier to understand if a number of distinct aspectsof legal cases are taken into account. Most cases do not createprecedents: 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 onthe evidence before it whose version of the facts to endorse. Theparties in such cases agree about the law that applies to theirdispute, they simply disagree about what actually happened. In othercases there can be a dispute over the applicablelaw—one side claiming that on the facts the appropriatelaw supports a decision in their favour and the other side disputingthis account of the law and arguing that on those facts the lawsupports a decision in favour of them. (It goes without saying thatthere are also cases with disputes over both the facts and the law.)Precedents are those cases which require the courts to resolve adispute over thelaw.

A precedent is thedecision on the law in acase before a court or some similar legaldecision-maker such as a tribunal. Paradigmatically in Common Lawlegal systems a judicial decision is given in ajudgment which has five aspects to it:

1. a recitation of thefacts of the case, i.e., anaccount of what happened^[4];
2. an identification of the legalissue—thedisputed question of law—which the court is being asked toresolve;
3. thereasoning over the appropriate resolution ofthat issue;
4. theruling resolving the issue put before thecourt, e.g. that in these circumstances the defendant has breached acontract, or does not owe the plaintiff a duty of care, or holds theproperty on trust for a third party, or made a decision contrary tonatural justice; and
5. theresult or outcome of the case, i.e., whichparty succeeded in the action; which follows from (d).

(For a more detailed discussion, see MacCormick 1987, 170ff.) To takean example, the court may be faced with a case in which the trustee ofproperty held on behalf of the plaintiff has wrongfully transferredthat property to the defendant. The plaintiff sues the defendant torecover the property which was transferred in breach of trust. Theplaintiff argues that since (i) the defendant has received trustproperty (ii) in breach of trust and (iii) has not paid for theproperty, she should restore the property to the trust. The defendantargues, on the other hand, that since (iv) the trustee had a goodtitle to the property, (v) the power to transfer it and (vi) thedefendant acted in good faith, unaware of the breach of trust, she isentitled to retain it. The court will assess the situation and mayrule that factors (i)–(iii) do give the plaintiff a good action,i.e., that a recipient of trust property transferred in breach oftrust who has not paid for the property must restore it. In itsreasoning the court will explain why the fact that the defendantreceived the property as agift means that it should berestored to the trust, despite the trustee having the legal power totransfer the title.

The identification of the subset of factors (i)–(iii) thatconstitute the ruling is not always a straightforward task: this hasto be determined from construing the judgment as a whole in thecontext of the area of law with which it deals. In particular it canbe difficult to ascertain the appropriate level of abstraction of thedescriptions of factors (i)–(iii). A person is made ill bydrinking an opaque bottle of ginger beer containing a decomposing snail.^[5] The manufacturer of the bottle is held to be liable to the personmade ill, despite the absence of any contract between her and themanufacturer. What is the key characterisation of the vehicle of harmon these facts? The bottle of ginger beer is a beverage, but itis also a consumable, an article for human use and something capableof causing injury if negligently produced. (See further Stone 1985,125). Generally the judgment needs to be read as a whole to determinethe appropriate level: in particular the court's reasoning willtend to support one level of generality over another. In some cases,however, the level of generality will not be clear and it will not bepossible to give a very precise account of the ruling. In other casesthe category may be incompletely characterised: there will be examplesof items falling within the category but no general characterisationof it (see Levenbook 2000, 201–11).

This point brings out an important aspect of the study ofprecedent. Lawyers are mostly preoccupied with two issues: (1)the question of how to determine what a precedent is authorityfor, e.g. how to characterise the ruling in the case(beverage? consumable? article?), or how to deal with cases wherethere is no single majority judgment in favour of the result, or how totreat cases which give two alternative bases for the decision; and (2)the question of when a court will be willing to overrule its own priordecisions. The most interesting philosophical questions, however,concern how precedents operate when, as is often the case, there is nodoubt about what the precedent is authority for, and the later court isnot free (or is unwilling) to overrule the earlier decision.

There are three ways in which it has been argued that precedentsshould be understood:^[6] (1) as laying down rules, (2) as the application of underlyingprinciples, 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 whichlater courts are then bound to apply to the facts before them. (For versions of this view, see Raz 1979; MacCormick 1978 (especially82–6, 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 theresolution of the case, the court is creating a rule that whenevertrust property is transferred in breach of trust to a volunteer (i.e.,one who does not pay for the property), the volunteer must restore theproperty to the beneficiary. The case decides a particular dispute,but the court creates a rule to deal with that type of dispute andapplies it to the case at hand. On this view, then, precedents areakin to statutes in that they lay down rules which apply to latercases whose facts satisfy the conditions for application.

In favour of this interpretation of precedent is the distinction drawnin legal practice between what is known as the ‘ratiodecidendi’ of a case and ‘obiterdicta’. Theratio of a case represents the‘holding’ or ‘ruling’, i.e., the propositionof law for which the case is authority—it is the aspect of thecase which is binding on later courts.Obiter dicta, bycontrast, represent other statements and views expressed in thejudgment which are not binding on later courts. On this view ofprecedent, the rule laid down in the earlier case is represented bytheratio.

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

2.1.1 The form of judgments

Although the idea of theratiodecidendi is a stapleof legal practice, it is notable that it is a constructfroma precedent rather than an explicit feature of most legaljudgments. Judgments are highly discursive texts and very rarelyidentify their ownrationes. What is more, even if a courtchooses to explicitly formulate theratio of its decision,this preciseformulation is not itself regarded as binding onlater courts. (See Perry 1987, 235–7; Schauer 1989, 455; Simpson1973, 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 downis provided. Given the flexibility open to later courtsto determine theratio of the earlier decision, it ismisleading to think that decisions lay down binding rules for latercourts. However, although there is a contrast with legislationhere, it can be exaggerated. In both situations the propositionsof law for which a case or statutory provision is authority must bederived from the case or statute and is not identical with thetext of either. The real difference between precedent and statutelies in the fact that in the case of statutes legal systems haveelaborate conventions of interpretation to assist in the process ofderiving the law from a legislative text, whereas in the case ofprecedents they do not. But this simply shows that the lawderived from precedents may be vaguer and more indeterminate than thatderived from (many) statutes; it does not establish that precedents donot create legal rules.

2.1.2 The practice of distinguishing

An integral part of legal reasoning using precedents is the practiceofdistinguishing. Distinguishing involves a precedent notbeing followed even though the facts of the later case fall within thescope of theratio of the earlier case. As the later casefalls within the scope of the earlierratio (i.e., within thescope of the rule), one might expect that the decision in the latercase must be the same (unless the court has the power to overrule theearlier case and decides to do so). In legal reasoning usingprecedents, however, the later court is free not to follow the earliercase by pointing to some difference in the facts between the twocases,even though those facts do not feature in theratio of the earlier case.

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

The effect of distinguishing, then, is that the later court is freenot to follow a precedent that,prima facie, applies to it,by making a ruling which is narrower than that made in the precedentcase. The only formal constraints on the later court are that: (1) informulating theratio of the later case, the factors in theratio of the earlier case (i.e., (i)–(iii)) must beretained, and (2) the ruling in the later case must be such that itwould still support theresult reached in the precedentcase. In short, the ruling in the second case must not be inconsistentwith the result in the precedent case, but the court is otherwise freeto make a ruling narrower than that in the precedent. Hence the moreaccurate statements of the doctrine of precedent are to the effectthat a later court musteither followor distinguisha binding precedent—a disjunctive obligation.

At a formal level the practice of distinguishing can be reconciledwith the view thatrationes are rules by arguing that latercourts have thepower to modify the rule in the earliercase. An analogy can be drawn to the power to overrule earlierdecisions: just as judges canoverrule earlier cases, theycan alsomodify earlier law, thereby paralleling the power oflegislators to either repeal or amend the law. The analogy, however,is very imperfect. There are two difficulties: (a) Common Lawyers donot conceptualise overruling and distinguishing in this parallel way,and (b) the rationale for a power with this particular scope isunclear.

On the first point, Common Lawyers ordinarily think of precedents asconstituting the law up and until they are overruled. Once overruledthe later decision is (normally) given retroactive effect, so the lawis changed for the past as well as the future. But when a case isdistinguished it is not often thought that the law was one thing untilthe later decision of a court, and now another thing. The law will beregarded prior to the later decision as already subject to variousdistinctions not mentioned by the earlier court. Indeed part of theskill of a good common lawyer is grasping the law asnotstated by the earlier court: learning that cases are‘distinguishable’ is a staple part of common laweducation, and no common lawyer would be competent who did notappreciate that the law was not to be identified simply with theratio 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 isthat it cuts across the normal justifications for having rules, namelyto have a class of cases treated in a certain way despite individualvariation between them, with attendant gains in predictability andtransparency in the decision-making process. Instead, the later courtis free to avoid the result indicated by the earlierratio solong as it can find some difference in facts between the two casesthat narrows the earlierratio while still supporting theresult in the earlier case. What is more, this power is not merelygiven to courts of the same level of authority as the one laying downthe precedent (as is the case with overruling), but is given to everycourtlower in the judicial hierarchy. So the Court ofAppeal in England cannot overrule a decision of the House of Lords(nor even its own decisions ordinarily), but it is free to distinguisha decision of the House of Lords even when the case before it fallswithin theratio of the House of Lords decision. So on therule-making view of precedent lower courts have the power to narrowthe rules laid down by higher courts, just so long as the narrowerrule would still support the result reached in the earlier case. It isunclear why lower courts should be given a power to narrow rulings ofhigher courts in this particularly circumscribed manner.

Two ways in which distinguishing can be made less idiosyncratic arethese: (a) to argue that the later court is restricted to making amodification which the earlier court would have made if confrontedwith the current facts (cf. Raz 1979, 187–8), i.e., thatdistinguishing is a form ofreinterpretation of the originalratio; or (b) to argue that there is apresumptionagainst distinguishing (Schauer 1989, 469–71; 1991,174–87). Each of these approaches echo forms of legal reasoningfound in statutory construction. The first, in asking what the earliercourt would have done, assimilates the task of distinguishing to thatof determining the law-maker's intent behind their ruling. Thisis parallel to the practice of interpreting statutes in terms oflegislative intent. The alternative approach of there being apresumption against distinguishing parallels the creation ofexceptions to statutory rules.^[8]

The problem with these two suggestions is that the practice ofdistinguishing does not conform to either of these constraints: whilecourtsdo consider the earlier decision in order to see iftheratio can be reinterpreted, they also introducedistinctions without recourse to the earlier court's views; andthey do not typically approach the task of distinguishing as if thereis 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 theunderstanding ofrationes as creating binding legalrules. (See also Perry 1987, 237–9 ondistinguishing.)

Athird way which purports to deal with the problem ofdistinguishing on the rule model is to argue that the‘rule’ for which the decision is binding is not theprecedent court's ruling, but something narrower—the‘material facts’ that were ‘necessary’ for theresult of the case. (See Goodhart 1930, 1959; and see also Burton1995, 25–58, 60–5 on ‘case-specific facts’ andEisenberg 1988, 51–4 on ‘minimalist’ and‘result-centred’ techniques.) This approach makes use ofthe fact that decisions do not provide canonical formulations of theratio to argue that theratio is not to beidentified with the court'sstated ruling on theissue. The effect of such an approach is to narrow what is regarded asbinding in the case to those facts which were crucial to the actualoutcome, rather than the stated ruling applied to those facts. Thedifficulties with this approach are three-fold:

(1) it goes against general legal practice, which usually doesidentify theratio with the ruling made by the precedentcourt (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 rulingis 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 propertytransferred in breach of trust. A key aspect of the facts is that therecipient did not pay for the property. But why is this‘material’? If the court's own reasoning is put toone side, is it becauseno consideration was given (so had atoken been provided that would have been sufficient); or thatinadequate consideration was provided (so more than a tokenwould be necessary); or that areasonable price was not paid;or that the price was not what the beneficiary would have been willingto accept for the transfer; or that the price is not the best whichthe trustee could have obtained on the open market? All of thepreceding descriptions of the facts are true, but which is‘material’? The requirement for any of them wouldinvalidate the transfer.

(3) Even if there is some way to characterise the‘material’ facts, it does not eliminatedistinguishing. Take later trust case, for example, in which therecipient has paid nothing for the trust property buthasacted detrimentally in reliance on the receipt. The recipient is stilla ‘volunteer’ who has not transferred anything to thetrustee for the property, but therehas been reliance uponthe receipt. This may well lead a later court to distinguish theearlier case, although the facts are otherwise identical to those inthe original case. On the other hand, if the claim is that theprecedent case is only binding whenboth (a) the‘material facts’ are present, and (b) nootherrelevant facts are present, then it is no longer a‘rule-based’ account of precedent—it is simplyreasserting the minimal requirement that the decision in the latercase must not be inconsistent with the result reached in the precedentcase.

2.2 Precedents as the application of underlying principles

A different response to the problem of distinguishing is to relocatethe binding force of precedents in thejustification for theearlier decision, rather than in the ruling itself. (See Perry 1987,esp. 234ff and Moore 1987 for two versions of this view.) Thisapproach has three principal attractions. The first is that itexplains the lengthy expositions of thereasoning for theresult found in many decisions. It is the reasons that contain thegist of the decision, and so it is to this question that mostattention is directed by the courts in justifying theirdecisions. Secondly, this accounts for the fact that courts do notbother (and indeed lack the power) to lay down a precise formulationof theirrationes. Theratio does not lay down arule which must be followed by later courts, but is simply aconvenient short-hand way of referring to the overall effect of theprinciples justifying the result in the case (Perry 1987, 235,239). Thirdly, and most significantly, this approach provides anatural explanation for the practice of distinguishing. A later caseis distinguishable where thejustification for the result inthe precedent does not apply to the different facts of that case, evenif it might seem to fall within theratio of thedecision.

Despite its attractions, the ‘underlying principles’account faces three major difficulties: (i) the scope ofdistinguishing; (ii) accounting for the role played byrationes; and (iii) maintaining the distinction betweenprecedent and analogy. The initial difficulty arises from the factthat distinguishing is not restricted to the application of thejustification provided by the earlier decision. Any good argument canprovide the basis for distinguishing, for example by showing that thenovel facts in the later case provide considerations whichoutweigh the original justification: it is not that theoriginal justification is inapplicable to the novel facts, it issimply that those facts raise additional considerations that are morecompelling. So later courts go beyond what was done in the earlierdecision in determining whether to distinguish the later case.

One possible line of response to these difficulties is to abandon theidea that what is binding is theprecedent court'sjustification for its decision. After all, the standard view is thatlater courts are bound by the ruling in the precedent, not itsreasoning. Instead, it is argued, whether the earlier decision must befollowed in the later case turns on applying thebestjustification for the earlier decision. But not the bestjustification for that decision, taken in isolation. Rather, what isbinding in law is the set of principles which best fit and justify thetotality 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 applyingthe earlier court's justification for its decision, but inapplying the justifications for the doctrine of which that decisionforms a part.^[11]

The second difficulty, however, applies to both versions of thisapproach,viz. accounting for the role played byrationes. The practice of precedent involves latercourts being bound toeither followor distinguishthe earlier decision, butonly if the facts of the later casefall within the terms of theratio. Theratioplays an indispensable role in fixing the scope of the latercourt's duty to follow or distinguish—it is only if thefacts of the later case fall within theratio that thisquestion arises. This role is not appropriately captured byarguing that it is the justifications, and not theratio,which are binding.^[12] (Cf. Moore 1987, 185–7, 211–3). What the approach doeshelp to highlight, on the other hand, is the role played in thepractice of precedent by the justification for decisions. As notedabove, determining theratio is not a mechanical exercise: itinvolves understanding what was decided in a case—by referenceto what was said in the judgment, earlier cases, and the generalunderstanding of that area of the law. Theprecedentcourt's own justification for its decision plays animportant role in determining the level of abstraction of the factorsin theratio, and for providing arguments for a narrower orwider reading of those factors.^[13]

This is related to another point: if the underlying justificationfor a precedent is binding then it undermines the distinction betweenarguments from precedent and those by analogy. Theratioof the precedent sets the outer limit of what isbinding onlater courts—i.e., what a later court is bound to either follow ordistinguish. Analogies (as will be argued below)aregrounded in the underlying rationale for earlier decisions, but they donot bind later courts. If the underlying justificationof precedents were binding, rather than theratio, thenanalogies would be binding and legal reasoning would have a differentshape.

2.3 Precedents as decisions on the balance of reasons

If a precedent is not laying down a rule, nor binding in terms of itsunderlying justification, how should it be regarded? Onealternative is to think of the precedent as representing a decision onthebalance of reasons in the individual case before thecourt that later courts are required to treat as correctly decided(see Lamond 2005). The precedent court took a range of facts intoaccount in reaching its decision. Those facts—facts such as thebreach of trust, the trustee having power to transfer the property,the recipient being a volunteer, and the good faith of therecipient—ground reasons for reaching some particular legalconclusion. On this approach, what theratio provides is astatement of the factors which the court regarded as providing thereasons that were crucial for reaching its result. So theratio represents the view of the court that those facts spokein favour of the outcome, and that they were not defeated by anycombination of the other factors present in the case. For example, thecourt decides that the recipient of trust property must hold theproperty on trust if they are a volunteer even though they acted ingood faith. In reaching its conclusion the court must deliberate onthe competing merits of these two parties and decide which is bettersupported. Both parties were ignorant of the dishonesty orincompetence of the trustee, so neither is favoured on that score; therecipient has acquired property which the trustee did have the legalpower (though not the right) to transfer, so upholding the security ofproperty transactions favours allowing the innocent recipient toobtain the complete title to the property (leaving the beneficiarywith a personal claim for damages against the defaulting trustee); theprinciple that no-one can transfer a greater interest than theypossess favours the beneficiary. Other considerations favour one orother of the parties. In making its ruling, the court concludes thatin the circumstances of the case before it the merits favour thebeneficiary of the trust rather than the recipient.

What is the difference between this approach and that in terms ofprecedents laying down rules? It lies in the fact that instead of theratio representing a rule which presumptively settles thedisposition of later cases whose facts fall within its scope, itprovides apro tanto justification for such a disposition,i.e., other things being equal this is how the later case should bedecided. And it is this that provides a natural explanation for thepractice of distinguishing. The correct statement of the doctrine ofprecedent is that later courts are bound bycases—notsimply byrationes—and bound to either follow ordistinguish them. So later courts whose case-facts fall within thescope of theratio mustconsider the precedent, butdo so in order to consider whether the differences in facts betweenthe later and the precedent cases justify deciding the casesdifferently. What the later court cannot do, on the other hand, is todistinguish on the basis of factors thatwere present in theearlier case (even if they were not part of the decision'sratio), because to do so would be to imply that the earlierdecision had reached the wrong conclusion on the balance of reasons. Alater court cannot treat thecase as wrongly decided, unlessit is able and willing to overrule it

The idea that a precedent is reaching a conclusion on the balance ofreasons in the particular case at hand makes sense of a number ofother features of common law judgments. It explains the practice ofproviding elaborate accounts of thecircumstances of thecase, even though only a small subset of those circumstances matter totheratio, since they were the group of factors that thecourt considered in reaching its decision. It is also consistent withthe lengthy discussions of the reasons for the conclusion, and thelack of interest on the part of courts in providing a carefully wordedformulation of theratio: what matters is the substance ofthe factors considered in reaching the decision, not the particularlanguage in which they are couched.

The main challenge for this account of precedent lies in explainingwhen a later court isbound to follow a precedent which itregards as having beenincorrectly decided. In the case ofthe trust property, the later court may think the precedent courtmistaken to have concluded that the recipient must return the propertyto the beneficiary. May a later court avoid the result of theprecedent by pointing toany general factual differencebetween the cases (e.g. this is real property rather than personalproperty, this is an implied rather than an express trust), anddistinguish the precedent by stating a narrowerratio? Afterall, the balance of reasons never supported the precedent in the firstplace, so shouldn't it be confined to the narrowest possiblestatement of its facts? In which case precedents seem to have verylittle binding force indeed.

One obvious possibility for avoiding this problem would be to ask howtheprecedent court would have assessed the facts in latercase. But although this would be satisfactory in theory (if sometimesdifficult in practice), it again does not reflect legalpractice. Courts sometimes approach the question in this way, butoften they do not, and there is no legalrequirement thatthey do so. A better response is this: the basic common lawrequirement instare decisis is to treat earlier cases ascorrectly decided. A case may be distinguished, but only if thatdistinction does not imply that the precedent was wrongly decided. Soin the later case the court must decide whether the factual difference(real versus personal property, implied versus express trust) providesabetter justification against the earlier decision than thefacts of that case on their own. If it does, then the court maydistinguish (citing that differences with the original case), sincethat does not imply that precedentwas mistaken. Ifnot—because real property or implied trusts raise no specialconsiderations in this context—then the precedent must befollowed. This approach, of course, assumes that itispossible to make these sorts of comparative judgements (for argumentsthat 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 adoctrine ofstare decisis by which later courts are bound tofollow earlier decisions. There is, of course, a prior question of whythe decisions of courts should be regarded asmaking law atall. In some Civilian legal systems, such as the French, the officialview is that court decisions do not make law, they merely involve theapplication of the law. This follows from a straightforwardunderstanding of the separation of powers: the responsibility of thelegislator is to make law, the responsibility of the judiciary is tofaithfully apply the law made by the legislator. For the courts tomake law would be to usurp the legislative function, and to usurp afunction to which the courts have no legitimate claim. One distinctivefeature of Common Law systems is the existence of central areas of lawthat have no legislative foundations—such as contract, tort,trusts, and personal property. All of these areas have seenlegislative intervention, but most Common Law jurisdictions stillleave them on a non-statutory footing. Here the decisions of thecourts are the basis of the law.

In practice no modern legal system has functioned without thedecisions of the courts playing at least an auxiliary role in settlingthe content of the law. To take one well-known example, in France thelaw of civil wrongs (torts, delicts) is based upon five relativelyshort articles of theCode Civil (§§1382–1386). Formally, the law is found in those five articles,and a court decision is legally flawed if it does not cite at leastone of them as the basis for its ruling. But there is a vast body ofcases interpreting and applying those articles, and these cases areregularly cited before the courts to assist them in reaching theirdecisions, even though judgments themselves do not mention earliercases. In substance, then, if not in form, this area is partlyconstituted by judge-made law.

So one question that can be raised about precedent is why it isjustifiable for the decisions of courts to be treated in this way atall, i.e., for them to help constitute the law. There is a morespecialised question, however. In the Common Law at least, thedoctrine ofstare decisis requires later courts to followearlier decisions even if they were wrongly decided. To say that acase was ‘wrongly decided’ is to say that the legallypermissible reasons relevant to the case did not, all thingsconsidered, support the conclusion reached by the court. It should beemphasised that such a conclusion depends upon and is relative to thecontext provided by existing legal doctrine. Take the question ofwhether parents should be able to recover for the cost of raising ahealthy child when it has been born as a result of a negligentlyperformed sterilisation operation on one of the parents. In some legalsystems such costs are recoverable, whereas in others they arenot. Here it is quite possible that these conflicting decisions areboth correct, in the sense that each is correct within its owndoctrinal context. So whether a decision is wrong is not a question ofhow the case ought to be decided without any reference to the law, butwhether it goes against the merits of the legally relevantreasons.

The doctrine of precedent thus raises two justificatory issues: (a)why treat court decisions as partly constituting the law, and (b) whyrequire later courts to followerroneous decisions of earlier courts?^[14] The most influential arguments responding to these issues are basedupon 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 wouldsimply be inconsistent to treat them differently. In the case ofprecedent this argument is said to favour following the earlier case:assuming that one cannot change the earlier decision (because it istoo late to appeal, or the party to the case has reasonably reliedupon it, etc), the only way to ensure consistency is for laterdecision-makers to treat the earlier decision as a precedent. Theclaim of consistency is also sometimes put in terms of‘equality’: to treat the later case differently to thefirst would be to fail to treat the parties before the courtsequally. This argument is made independently of other concerns such asparties' expectations or community perceptions of the courtprocess or the problem of moral disagreement. Arguments of this kindcertainly have weight in some circumstances. If a legal system ismorally legitimate and has authority over those subject to it, then itis inconsistent for one person to be treated less or more favourablyby the law than another person whose situation is legallyindistinguishable. Other things being equal, legal decisions should beconsistent across time and/or decision-makers. A later case shouldonly be treated differently to an earlier case when the law itself hasbeen changed (by the legislator or the courts, including cases wherethe court overrules an earlier decision in reaching a decision on thecase before it) So concerns of consistency provide some justificationfor treating earlier decisions as sources of law, rather thanapproaching each question anew when it arises again.

This fact does not, however, support a doctrine of following earlierdecisions even when they arewrong, i.e., for having a strongpractice ofstare decisis. If the earlier decision was wrongthen the person subject to it may have been treated more or lessfavourably than they should have been treated. If they were treatedmore favourably then clearly that should have been corrected (e.g. onappeal). If it was not corrected then the person had an undeservedslice of good fortune. But that a mistake was made in the earlier caseis not—in itself—an argument for repeating the mistake inthe later case. The first litigant did not deserve their outcome, evenif for reasons of the finality of legal processes they are entitled toretain it. Equality does not demand the repetition of mistakes. On theother hand, if the original litigant was treated less favourably thanthey 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 orby executive action such as pardon orex gratia payments),but it is no reason for treating a later litigant unfavourably aswell. Taken in isolation from other considerations (such asexpectations and predictability), equality does not support thebindingness of incorrect decisions.

By contrast, arguments of equality bite where the court in theoriginal case was confronted with a situation where the correctoutcome was indeterminate, i.e., where more than one outcome waspossible in light of the legally permissible arguments. This may bedue to each outcome being equally well supported by reason, or by theoutcomes being supported by different, incommensurable, values. Insome of these cases the law has closure rules to settle the matter,e.g. in favour of criminal defendants, but in others there are noclosure rules as to the appropriate substantive result to endorse. Apossible illustration of such indeterminacy is the position of aperson who quite innocently buys stolen goods. In some legal systemsthe purchaser acquires good title to those goods, whereas in others(such as the Common Law) she does not. Here, arguably, the merits ofthe two innocent parties (the purchaser and the original owner) are ona par, and all the law can do is choose which one is to prevail. Sowhere an outcome is underdetermined there are arguments of equalityfor later courts following the earlier decision rather than adoptingany of the other possible solutions. None of this, of course, is anargument 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 ofprotecting expectations: if an institution has dealt with an issue inone way in the past, then that creates the expectation that it will doso in the future—an expectation which people use to plan theirlives and enjoy some control over their situations.^[15] So there are good reasons for an institution to follow its previousdecisions (other things being equal), even if it turns out that theywere mistaken.

The fundamental problem with this line of argument in the case ofprecedent is that it suffers from a type of circularity. It is truethat legal systems that follow a practice of precedent createexpectations that earlier decisions will be followed in thefuture. But it is important to bear in mind that it is onlylegitimate expectations which need to be considered indecision-making, not any expectation which someone forms. The merefact that a decision was made in the past provides no reason in itselfto expect that it will be followed in the future, and certainlycreates no entitlement to expect that it will be followed. That acompany orders stationery from a supplier at the start of the year mayraise a hope, and even possibly an expectation, that it will do soagain later in the year, but the supplier does not have a‘legitimate’ expectation that it will do so, and thecompany does not create a precedent for itself. Where thereis an institutional practice of following past decisions, onthe other hand, the reliance of those subject to future decisions mayground legitimate expectations, but it is always open to theinstitution to announce that it will no longer treat past decisions asbinding and will, instead, decide each case on its merits. Equally,it is a common occurrence in some institutional settings where pastdecisionsare followed for a decision to be made subject tothe proviso that it is ‘not setting a precedent’ for thefuture.

Whether a past decision creates legitimate expectations, therefore,depends upon there being good independent reasons for the institutionto follow its earlier decisions, or upon the existence of a practiceof doing so. But the practice itself should only be maintained ifthere are good independent reasons for having it: its mere existencecannot bootstrap a justification for the maintenance of thepractice.

3.3 Replicability

The preceding arguments for precedent presuppose that decision-makerscan correctly ascertain the merits of the cases before them, but lawof course operates under non-ideal conditions where decision-makersmake mistakes and disagree among themselves about the merits ofcases. In practice, the outcome of a case may be uncertain not simplybecause the correct result is rationally indeterminate, but becausethe decision-makers are fallible. Given this, a practice of precedentin law, it can be argued, has a number of advantages due the fact thatit may make institutional decisionsreplicable (see Eisenberg1988, 10–12, 23–4, whose coinage it is; and Schauer 1987,597–8). That a decision is replicable refers to the fact thatit is possible for others to make an informed judgement on thelikelihood of a particular outcome, in the light of the relevant legalmaterials, the canons of reasoning used in a system, and anacquaintance with the general culture from which the decision-makersare drawn. Replicability means that decisions are more predictablethan if they were madede novo each time. This, in turn,allows individuals to make plans that are consistent with the law andto avoid falling foul of it, and hence allows them to be guided by thelaw.

This provides a rationale both for treating earlier cases ascontributing to the law and for the doctrine ofstaredecisis. Other things being equal, it is better if the law ispredictable than if it is unpredictable. It should be noted, however,that such a rationale does not necessarily support as strong adoctrine of precedent as that found in many Common Lawjurisdictions. The concern for predictability needs to be weighedagainst the moral desirability of the law in question. This wouldsuggest that (a) in some circumstances lower courts should be allowedto depart from the decisions of higher courts where their view is thatthe earlier decision was (in the context of the relevant law) clearlymorally undesirable, (b) giving greater freedom to courts to overruletheir own decisions on the basis that there was a morally preferabledecision (in that legal context).

3.4 Law-making

A final justification for the doctrine of precedent is that it isdesirable to give courts the power tomake law. The thoughthere is that it is valuable for the courts to have the power toimprove and supplement the law (Hart 1994, 135–6; Raz 1979,194–201). The assumption underlying this justification is thatthe law is sometimes incomplete and in need of being given greaterspecificity, or that it is erroneous and needs to be corrected. Onthis view the courts are analogous to delegated legislators: they havelimited powers to make law within a broader framework of doctrine.

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

On the other hand, if the argument in favour of courts havinglaw-making power is that they can thereby improve the law, this isreally an argument in favour of having the power to overruleprecedents, rather than an argument in favour of precedent in thefirst place. Indeed, the need for a power to overrule only arises ifearlier decisions are binding even when mistaken, since later courtscould otherwise simply disregard decisions that were erroneous. Sothe argument from law-making, when distinct from arguments fromreplicability and equality, is an argument for the power to overrule,rather than an argument forstare decisis itself.^[16]

In conclusion, both equality and replicability provide arguments infavour of judicial decisions constituting sources of law. And thevalue of replicability also supports a doctrine ofstaredecisis by which later courts are sometimes bound even by theerroneous decisions of earlier courts. This in turn leads to the needfor courts to have the power to overrule existing law, so that thereis scope for incorrect decisions to be reversed.

4. Analogy

An analogical argument in legal reasoning is an argument that a caseshould be treated in a certain way because that is the way asimilar case has been treated. Arguments by analogycomplement arguments from precedent in two ways: (i) they are usedwhen the facts of a case do not fall within theratio of anyprecedent, in order to assimilate the result to that in the analogicalcase; and (ii) they are used when the facts of a casedo fallwithin theratio of a precedent, as a basis for distinguishing thecase at hand from the precedent. Theforce of an argumentfrom analogy is different to that from precedent. An indistinguishableprecedent must be followed unless the court has the power to overrulethe earlier decision and does so. By contrast, arguments from analogyvary 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 aresult. That an analogy is rejected in one case does not precluderaising the analogy in a different case.

Analogies, like precedents, arise within a doctrinal context. Thecase at hand raises a legal issue, e.g. does the impersonation of aboyfriend vitiate the victim's consent in the law of rape, iscross-burning protected ‘speech’ within the FirstAmendment to the US Constitution, does the defence of duress requirethe defendant to have acted as a reasonable person would have done?Other cases dealing with the validity of consent or the scope ofprotected ‘speech’ or reasonableness in defences providepotential analogies. An analogy may either be to another case or toanother legal doctrine, and the analogy rests on there being somecommon characterisation of the facts in both cases or the twodoctrines which is relevant to the issue. So knives may be analogousto guns if the issue concerns weapons, but knives may also beanalogous to teaspoons if the issue concerns cutlery. Duress may beanalogous to provocation if the issue concerns defences, but duressmay also be analogous to incitement if the issue concernscomplicity. Two doctrines or sets of facts are not analogous in theabstract, but in the context of a legal issue.^[17]

Two questions arise about analogical reasoning. Firstly, by whatprocess does a decision-maker identify the ‘commoncharacterisation’ between the case at hand and the analogousone? Secondly, what type of justificatory force does the commoncharacterisation provide? On the first question, just as no two casesare identical in every respect, so no two cases are such that somecommon characterisation of the facts cannot be found. But not everycase is thought to provide an analogy, so what limits or directs theselection of analogies? The answer to this question flows into theissue of the justificatory force of analogies. What sort of reasondoes an analogy provide for deciding the instant case in the sameway?

It is widely agreed that the existence of an analogy dependsultimately upon thejustification for the analogicaldecision. The facts in a case may fall outside theratio ofan existing precedent, and thus the court is not bound by theprecedent. On the other hand thejustification for theearlier decision may apply to the later case, and thus provide anargument from analogy. Take the case of the impersonation of aboyfriend in the law of rape. Assume that there is authority for theproposition that the impersonation of a husband vitiates consent forthe purposes of rape. Whether the impersonation of a boyfriend isanalogous depends upon why such a marital impersonation vitiatesconsent. If it is thought that part of the significance of beingmarried is the sharing of physical intimacy with that particularperson, then the rationale is applicable to other close personalrelationships. If instead the rationale is that consent to animpersonator involves committing an act of adultery, i.e., an actdifferent in kind to that consented to, then although the twosituations are obviously very similar, the analogy will fail.

It is often argued that reasoning by analogy and distinguishingprecedents are mirror images of each other: given the facts of twocases, the question is whether there is a good reason for treatingthem differently (e.g. Eisenberg 1988, 87). In the case ofdistinguishing, a precedent must be followed unless there are goodreasons for treating it differently. In the case of analogy, it issaid, a precedent must be extended unless there are good reasons fortreating the instant case differently. But this is misleading, sincethe symmetry is incomplete. A precedent cannot be distinguished ongrounds that would, in substance, imply that the precedent was wronglydecided: it must be treated as correctly decided. A precedent need notbeextended, however, if later courts regard its rationale asunpersuasive. A longstanding doctrine of the common law was that ahusband could not commit the offence of rape against his wife. By thetwentieth century the rule was increasingly recognised to be archaicand objectionable. Thus, unlike the question of impersonation discussedabove, no one suggested that the rule should beextended to cohabiting couples.^[18] Where a decision is not regarded as misguided, however, it doesprovide an argument for being followed. The later court may stilldecide, however, that it would not be desirable, all thingsconsidered, to do so.

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

4.1 Principles

An influential view on analogy regards it as grounded in theprinciples that underlie existing cases (e.g. MacCormick1978, 152–94; Eisenberg 1988, 83–96; Sunstein 1993). Abody of cases can be examined to determine which principle (or set ofcoherent principles) explains and justifies those decisions, in aprocess akin to reflective equilibrium. The process is only akin toreflective equilibrium because the individual cases (the equivalent ofthe specific judgements about particular situations) are either immunefrom revision, or are highly resistant to revision. So the principles must map the decided cases precisely, or mustdepart from only a small proportion of them. If the principle(s)identified in this process apply to the instant case, then thatprovides a good reason in favour of the result supported by theprinciple.

A number of criticisms question whether this account captures what isnormally going on in analogical reasoning. One criticism focuses onthe fact that the principle must track the existing cases and try tomake the best of them. Unless the decisions are all correct on themerits, any principle based on them must itself be flawed: for if itwere morally correct it would not support the mistaken decisions. Thequestion this raises is whether it can be justifiable to use such aprinciple to decide a novel case, rather than decide the case on itsown merits. Can there be ‘principles’ of this kind, whichare neither conventional parts of a practice nor morally correct?(see further Alexander 1996b, 1998, Alexander and Kress 1995, 1997) Amore common view, however, is that a principle that makes best senseof a series of cases or aspects of legal doctrine can have somejustificatory force even though the cases or doctrines are morallyimperfect. In the case of tort liability, for example, the cases mightbe best explained by the principle that liability will only arisewhere the defendant's conduct has been unreasonable, i.e., thatboth harm to the plaintiff and unreasonable conduct is necessary forliability. This principle may be morally mistaken, i.e., there may besituations where even reasonable conduct should result in legalliability. Nevertheless the principle may still be regarded as havingsome justificatory force in the context of that legal system. A judgemight think that the correct moral principle is thatother thingsbeing equal there should be no liability without unreasonableconduct. But although the law is imperfect in this way, the legalprinciple still has some force because it is a near enough neighbourto the correct principle and it explains the existing cases.^[19]

A separate line of criticism centres on the fact that courts do notoften articulate their use of analogies in terms of some‘principle’ inherent in an earlier case. Where principlesare used as arguments for a result, earlier cases tend to be cited asillustrations of the application of the principle, rather than asanalogies to the facts of the case at hand. If another caseis cited as providing an analogy, the emphasis will be on how‘close’ the analogy is, i.e., on how specific the commoncharacterisation of the facts of the two cases is, and how thatcharacterisation relates to the rationale for the earlierdecision. The more specific an analogy, the stronger; the moreabstract the characterisation, the weaker the argument as ananalogy. The reason for this is that the more specific the analogy,the less room there is for distinguishing the two cases, whereas themore abstract the analogy the more grounds on which the two cases maybe regarded as significantly different. So if it is lawful to consentto 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 sadomasochisticactivities is more remote, although both involve the intentionalinfliction of a certain level of harm.^[21]

This last point relates to the fact that cases are rarely justifiedsolely on the basis of principles: instead there are a range ofconsiderations which are applicable and justify the result. Aprinciple may apply with equal force to two cases with very differentfacts, but those differences may make the cases not veryanalogous. What this suggests is that while principles do providearguments for reaching a certain result, they do not explain thenature of analogical reasoning.

4.2 Reasons

The reasons-based approach to analogical reasoning focuses on thejustifications for the analogical case (for two very differentaccounts see Raz 1979, 201–6 and Brewer 1996). It considers theextent to which the rationale for the decision in the earlier case isapplicable to the case at hand. Take the case of the impersonation ofa boyfriend in the law of rape. Whether this situation is analogous tothe impersonation of a husband depends on the reasons for the lattervitiating consent. There need be no single principle that underliesthe rationale: it may rest on a number of factors that reinforce theconclusion.

One consequence of this approach is that if the rationale for theearlier decision is tied exclusively to the particular category usedin theratio, there will be no scope for analogical extensionto broader categories. In English law duress is not a defence tomurder regardless of the circumstances, due (it is said) to theuniqueness of deliberate killing and the fact that duress is, at best,an excuse. On this rationale there is no room for arguing that duressshould be excluded in cases of physically disabling a victim. On thequestion of whether duress could be apartial defence tomurder, on the other hand, thereis an arguable analogy tothe excuse of provocation, which operates to reduce murder tomanslaughter. Killing may be inexcusable, but that does not mean thatevery deliberate killing warrants a conviction formurder. Ofcourse, duress involves an actual decision to kill, whereasprovocation a temporary loss of self-control. The case for reducingkilling under duress to manslaughter depends upon whether therationale for provocation (e.g. as a concession to human frailty)extends to it. Two factors—the defendant's loss ofself-control and the victim's involvement in thekilling—readily distinguish the two situations, and weaken anyanalogy.

The reasons-based approach helps to explain why individual cases, andindividual doctrines, can ground analogies. It also explains what isaccurate in the principles-based approach, since some of theconsiderations underlying analogical cases will be principles. Butthere are more legal considerations than principles, and these tooplay a role in analogical reasoning.

5. The Justification for Analogical Reasoning

Why does the law make use of arguments by analogy, rather than simplydeciding novel cases on their own merits? In ordinary moraldeliberation, analogies are used to argue that one disputed situationis indistinguishable from another situation where the merits arerelatively clear. They leave three main responses open: (a) that thecase is indeed indistinguishable since the same rationale applies toboth; (b) that the case is distinguishable; or (c) that the case isindistinguishable, but upon reflection the assessment of the originalcase was mistaken. (Reflection on another case might, of course, leadone to conclude that one's original assessment was mistaken, eventhough the two casesare distinguishable.) As a result,analogies are useful heuristic devices for deepening and sharpeningreflection on the merits. It is also the case that people are oftenmore confident in their judgements about various concrete cases thanthey are about abstract theories that attempt to account for theirjudgements, and so regard this is a more profitable way to approach aquestion (see Sunstein 1993, 775–7).

In law, by contrast, analogies carry a weight additional to the meritsof the case. The approach of courts is complex. Some decisions anddoctrines are regarded as mistakes and have no analogicalweight. Other doctrines may be regarded as imperfect—not whollycorrect—but do have analogical weight. Other still may beregarded as simply correct, and their existence provides furthersupport for adopting the view in the novel case. There are a number ofpossible indirect benefits that accrue from the practice of analogicalreasoning, such as exposing judges to a wider variety of factsituations than the particular set before them, making them considerthe views of other judges in previous cases and exerting aconservative pressure on individual decision-makers (see Sherwin1999). But is there any more fundamental rationale to the form ofreasoning?

Like precedent, analogies cannot be justified by recourse toexpectations. Whether there is an expectation of analogies beingfollowed, such expectations will only be justified if there are goodindependent reasons for using analogies in this way. Consistency mayprovide a rationale for a limited exercise of analogy. Where anearlier case has settled some indeterminacy in the application of thelaw, and where the rationale for the earlier decision is equallyapplicable to the later facts, then it would be inconsistent to decidethe later case differently.

The strongest justification for analogical reasoning, however, lies inthe value of replicability. This is often put in terms of theimportance 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 ofcoherence normally emphasise its instrumental value.^[22] This is tied up with the replicability of legaldecision-making. There are two important characteristics of legaldecision-making. The first is thefragmentary nature of legalmaterials. The second is theplurality of decision-makingbodies. Legal materials—precedents, statutes, conventions,principles—are fragmentary in two senses: (a) they are the workof many different hands at different times and with different outlooksand (b) different areas of law owe more to some hands and times thanothers. As a result legal doctrine tends to exhibit only a thin globalcoherence, whereas it may possess a thick local coherence. Thepluralism of decision-makers is also two-fold: (a) there are manyindividuals making decisions using the same body of materials, and (b)these individuals do not share a uniform evaluative outlook. Given thefragmentary nature of legal material and the plurality ofdecision-makers there is considerable scope for disagreement whendecision-makers are faced with novel questions.

Analogical reasoning helps to make the outcome of cases morepredictable by giving weight to existing legal decisions anddoctrines. But it only does so against a certain background, one wheredespite decision-makers not sharing a uniform normative outlook, thereis a large measure of agreement on the existence and importance ofcertain values. A certain level of agreement is required fordecision-makers to see a caseas analogous, since that restson what they judge to be the proper justification for the earlierdecision. It also means that while they may disagree on the resolutionreached in various cases, the disagreement is unlikely to be profound,but reasonable. (For an argument that this requirement can beoverstated, see Sunstein 1993, 769–73).

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

6. Summary

Precedent and analogy are two central and complementary forms of legalargument. What makes them characteristic oflegal reasoningis the circumstances of decision-making in law. The greatest contrastis with individual reasoning, where neither precedent nor analogy havethe same significance. An individual may give weight to what she hasdone in the past, e.g. because she believes the decision was madeunder optimum conditions, or she should not or does not want todisappoint someone's expectations, or there are special reasonsto treat the two situations identically. Similarly, the comparison ofthe problem at hand with another situation may help clarifyone's thinking, but one's judgement on the other case isonly relevant to the extent that it is correct.

In an institutionalised system with many decision-makers and aheterogeneous group of legal materials there is a tension betweendecision-making being relatively predictable for those to whom it willapply and the law being morally improved. In such a context precedentand analogy help to shore up the predictability of decisions whilstleaving room for courts to improve the law. They do this in twodifferent ways. Precedents are distinguishable (and subject tooverruling), while analogies provide non-conclusive reasons forreaching a particular outcome. The success of these compromisesdepends upon there being a fair measure of background agreementbetween decision-makers over the important values served by thelaw—both measures would be too weak in the face of widespreadand deep value disagreement. A range of mechanisms exist in law thathelp maintain such a relative consensus: legal education, the workingenvironment, and the selection of candidates for the bench all tend toproduce more convergence than is found in the general community. Inaddition, there is an internal feedback element—in decidingcases, courts are aware that their decisions can be distinguished (aswell as overruled), and that it is only their ruling that are bindingon later courts. This gives them good reasons to press justificationsthat are based on values widely endorsed by their brethren.

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Acknowledgments

I am grateful to Liam Murphy and Joseph Raz for their very helpfulcomments on a draft of this entry, and to John Stanton-Ife for anumber of valuable discussions of the topic.