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Legal, like natural divisions, however clear in their general outline, will be found on exact scrutiny to end in a penumbra.

Oliver Wendell Holmes, Jr[1]

[It is] a hopeless task to draw a sharp picture corresponding to the blurred [object].

Ludwig Wittgenstein[2]

Introduction

The aim of this article is to show that, taken together, certain torts—which I label “hybrid torts” because they straddle two legal categories—pose a significant problem of fit for leading, explanatory theories of tort law in so far as they set out to explain tort law as a whole. The principal theories falling into this category are those belonging to Robert Stevens, Ernest Weinrib, and John Goldberg and Benjamin Zipursky.[3] It is fairly obvious that any given tort deserves to be explained (or, at least, ought not to be ignored) by a theory which sets out to provide an explanatory account of all of tort law, unless the tort in question can be seen as anomalous, marginal or trivial.[4] A tort will be none of these if it is well-entrenched, its credentials qua tort have never seriously been challenged by either judges or jurists, and it possesses considerable practical significance (on account of its being invoked regularly by litigants). If a putatively explanatory theory of tort law cannot account for well-established, widely recognized and practically significant torts, then that theory may fairly be described as being beset by a significant problem of fit.[5]

What is perhaps less obvious is why the array of hybrid torts upon which this article focuses should also require explanation by such theories and why, when they cannot be so explained, they should be thought of as presenting a significant problem of fit for those theories. The simple reason why they ought to be explained by the theories in view is that the relevant theorists all implicitly commit themselves to providing such explanation.

That Weinrib is committed to explaining all causes of action that are widely recognized as being torts cannot be doubted given the method underpinning his theory. He makes clear that “the point of departure for theorizing about tort law—as well as about anything else—is experience” since, crucially, such “experience allows us to recognize a tort issue.”[6] For him, “[a]n inquiry into the nature of tort law is...a visit to the familiar landmarks of our legal world,”[7] which involves “drawing on what is salient in juristic experience”[8] and, in particular, “the experience of those who are lawyers.”[9] In other words, if a particular action comprises a “familiar landmark” within the world of tort law, this is good reason for it to be treated as an object of theorization.

Stevens is similarly committed. On more than one occasion in Torts and Rights, he makes plain his determination to explain “the law as we find it”[10] and, as we shall see, the law as we find it (whether ideally or not) most certainly treats hybrid torts as part of tort law. They ought therefore to come within the compass of his theory.

Finally, Goldberg and Zipursky are no less tethered to popular conceptions of tort law in developing their theory. They expressly adopt the Hartian position that a legal system (or body of rules) can best be understood from what Hart labelled the “internal point of view” or “internal aspect of rules.”[11] Signing up to this internal point of view, they insist that the “first move in an effort to theorize a subject is to work with, rather than dismiss as empty, the ways in which those acting within a practice make sense of it.”[12] In other words, they defend a strong prima facie case for regarding “tort law to be what it appears to be”[13] and thereby presumptively undertake to explain those actions—including hybrid torts—that are generally taken to constitute part of tort law.

It is perhaps worth spelling out why hybrid torts present a particular problem of fit for explanatory theories. The plausibility of each of my target theories is intimately linked to the idea that tort law has clearly defined and rigid borders. Without such borders, there is an inescapable problem which besets such theories. It is this: if the boundaries between tort law and other legal categories are indistinct, or if they are porous, then the very idea that there exists a discrete body of law to which the theory in question applies, and against which that theory may be tested, is called into question. In short, blurred boundaries carry with them unavoidable ramifications for the explanatory ambitions of the theorists in view given Wittgenstein’s observation (quoted above) that it is impossible to paint a clear picture of a fuzzy object.

Now of course, not all torts are equally well entrenched, and the practical significance of some torts is undoubtedly dwarfed by that of others. From this emerges one ostensibly attractive escape route for tort theorists who find themselves confronted by the problem of fit posed by hybrid torts. The escape route involves showing that the hybrid torts are anomalies, or otherwise insignificant causes of action. Either way, the action in question can be portrayed as something which need not be explained, for there is no need to account for actions that are not proper torts, or actions that are mere trivial exceptions to the norm. As we shall see, however, no such escape route can plausibly be invoked in relation to the hybrid torts considered in this article. They are all too firmly entrenched and/or significant to be sidelined. Any attempt to dismiss the actions in question as something other than torts involves a flagrantly Procrustean approach to theorization. The claim that hybrid torts X, Y, and Z fall outside tort’s clear and rigid borders is an unpersuasive assertion of convenience, contradicted by the conception of these actions held by judges and jurists alike.

The article proceeds as follows. In Part I, I set out three key claims made by all of my target theorists that clash in some profound way with the various hybrid torts I consider. In turn, they are the claims that tort law is (1) necessarily bilaterally structured, (2) exclusively part of private law, and (3) categorically different from other branches of private law. In Part II, I explain fully what I mean by hybrid torts. In particular, I highlight how they come into existence and illustrate the classificatory problems they are apt to cause. In Part III, I address another prefatory issue: the matter of when and why certain types of legal category ought, in theory, to be discrete. The matter is discussed in order to make the important point that not all legal categories are alike, and that only certain types of legal category ought in principle to be distinct from other, neighbouring categories within the same classificatory scheme. I then show that tort law is one such category which should, in theory, be distinct from other legal categories.

In Part IV—having established the theoretical position—I demonstrate how things are very different in practice. I do this by identifying a range of hybrid torts which serve to blur tort law’s boundaries with a number of neighbouring categories. In Part V, I argue that because these actions are routinely treated as torts, they have important ramifications for my target theories. The fact that in practice there are no firm borders between tort law and other legal categories makes it difficult to accept any explanatory theory which proceeds from the assertion or assumption that such rigid borders exist. In Part VI, I consider a superficially compelling objection to this conclusion. The article then ends with a series of concluding remarks.

I. Three Shared Claims

I make the assumption that anyone who has chosen to read this article is likely to be fairly familiar with the main elements of the theories propounded by Weinrib, Stevens, and Goldberg and Zipursky. As such, instead of offering a summary of all their core claims, I limit myself to picking out three major claims that are common to each of the theories in view. I alight upon these claims because they are the key ones that are challenged by one or more of the hybrid torts I consider in this article.

A. Tort Law’s Bipolarity

All of my target theorists subscribe to the view that tort law is characterized in part by its bilateral structure: the idea, that is, that torts link two, and only two, parties (the claimant and the defendant). In each of their hands, though the terminology varies, this two-party characteristic is elevated to the status of structural imperative. For Weinrib, the phenomenon is described in terms of tort law’s bipolarity.[14] Stevens prefers the term “privity”;[15] while Goldberg and Zipursky express the structural imperative in terms of “relational wrongdoing.”[16] But whichever term is used, the core claim is just the same.

There is scarcely a page of chapter 3 of Weinrib’s principal work, The Idea of Private Law, which does not mention his commitment to the notion that corrective justice operates in relation to purely bipolar relationships. And in a subsequent chapter, he goes on to assert that “corrective justice necessarily connects two parties, no more and no less.”[17] Likewise, Stevens is adamant that in tort, “[t]he only person who can enforce a right is the right-holder, and persons who suffer loss because of the infringement of someone else’s right do not have standing to sue.”[18] Finally, Goldberg and Zipursky reveal their attachment to the structural imperative in their treatment of the judgment of Cardozo CJ in Palsgraf v. Long Island Railroad Co.[19] Invoking what was said in that case, they put the matter this way: “a tort plaintiff ‘sues in her own right for a wrong personal to her, and not as the vicarious beneficiary of a breach of duty to another.’”[20] At the heart of this claim is their insistence that the wrongs of tort law must be “personal to” the claimant. Put otherwise, torts involve the breach of a legal duty owed by defendant X to claimant Y. It is not enough that X has in some basic (moral) sense acted wrongfully. Nor is it enough that X has simply caused harm or loss to Y by virtue of his volitional conduct. For an act to be tortious, they insist, it must have been wrongful on the part of X and towards Y (or a class of persons to which Y belongs) given that “[t]he wrongs of tort law spring from relational directives.”[21]

B. Tort Law is Exclusively a Branch of Private Law

A second claim common to all of the theories in view is that tort law belongs exclusively to the private law domain. This conception of tort law is fundamental to the theory advanced in Weinrib’s The Idea of Private Law. In his view, the public/private divide is reflected in two incompatible modes of ordering: corrective justice and distributive justice. Private law is animated by the former, while public law is animated by the latter.[22] Stevens, likewise, believes that “[t]orts belong within private law.”[23] He reinforces the point by reference to the way in which crimes that have tort law counterparts (like battery) can be distinguished from those tortious counterparts. While the former are characterized by “a duty owed to society in general (crimes),” the latter involve the “breach of a duty owed to individual members of society (torts).”[24] And it is because torts are characterized by such private duties (and their correlative rights) that Stevens sees tort law as belonging exclusively to the domain of private law.[25]

Just the same belief can be found in Goldberg and Zipursky’s theory of tort law. They state openly that there is something “distinctively ‘private’ about tort”[26] and that they “conceive of torts as private wrongs.”[27]

C. Tort Law is a Discrete Legal Category

All of the theorists whose work is examined here consider tort law to be a discrete legal category, even though there is considerable disagreement among them as to whether or not the law is unified by a single organizing concept.[28] They all agree that there is a fundamental distinction to be drawn between tort and its nearest neighbour, contract, along the lines that tortious obligations are imposed upon the parties whereas contractual obligations are created by them.[29] Equally, all agree that tort law is categorically distinct, not just from contract, but from other familiar branches of private law, such as unjust enrichment and equity. Stevens, for example, states unequivocally that “the law of torts is...[a] basic category,”[30] and he elaborates upon its separation from other legal categories in these terms:

“Torts” is a catch-all category of “other wrongs”. It is the category of wrongs which are not breaches of contract or equitable wrongs. Breach of contract has conceptual unity. The category of equitable wrongs is unified by their historical provenance in the chancery division of the High Court. Torts has no unity other than that it is what is left after the other two categories of wrongs are excluded.[31]

Although he says no more about the difference between tort and equity, Stevens does reiterate elsewhere in Torts and Rights his commitment to the idea that tort law is categorically separate from contract. He says, “[t]he law of torts is...quite different from the law of contract which [is]...a unity concerned with one primary right arising for one reason: agreement.”[32]

In strikingly similar terms to Stevens, Goldberg and Zipursky also assert that “[t]ort is indeed a basic category of law.”[33] It is one, they say, of just “a handful of fundamental legal categories such as Contracts, Property, and Criminal Law.”[34] They not only see tort as one fundamental part of private law, but also as one that can be distinguished from the other such parts. They assert forthrightly “that torts...[are] different from breaches of contract”[35] and then they move on to explain, more expansively, that tort can also be distinguished from equity in the following way:

Tort law empowers the plaintiff to obtain redress as against the defendant who wrongfully inflicted the “hit,” or injury...Equitable wrongs are a different kettle of fish...The [equity] plaintiff does not take a “hit”; she is not rendered less than intact. Rather, the wrong is a betrayal of trust...Tort’s wrongs lead the state to empower the plaintiff to demand and obtain from the defendant conduct that is responsive to the defendant’s wrongful injuring of the plaintiff. Equity’s wrongs lead the state to empower the plaintiff to demand and obtain from her fiduciary an accounting as to the fiduciary’s handling of the matters with which he has been entrusted...So, we can after all distinguish torts.[36]

Weinrib is just as insistent that tort law is a discrete part of private law. While he eschews the familiar language of ‘legal categories’, he nonetheless maintains that tort law, taken as a whole, is “a mode of legal ordering” such that “before we assess the soundness of any tort decision, we can recognize that it belongs to tort law rather than [for example] to criminal law or administrative regulation.”[37] In other words, for Weinrib, tort law is “a distinct mode of ordering”;[38] one which possesses “features that are constitutive of our conception of tort law.”[39] He states expressly what he perceives to be the key difference between contract and tort at some length:

Both tort law and contact law rectify losses through corrective justice...[However,] [t]he difference between tort law and contract law lies in the origin of the right. In tort law the right exists independently of the defendant’s action; the damage award therefore aims at eliminating the effects on the plaintiff of the defendant’s wrong. In contract law, the parties themselves create the plaintiff’s right to the defendant’s performance of the promised act; the damage award therefore gives the plaintiff the value of that performance.[40]

Relying heavily on the notion of “normative loss” (as opposed to factual loss), Weinrib also explains at some length what he perceives to be the way in which tort law and unjust enrichment come apart.[41] Though he does not specifically address the distinctions between tort law and other areas of private law, it nonetheless seems to follow from his characterization of tort law as “a distinct mode of legal ordering” that he sees tort law as having sharply defined borders.

Taken together, the three claims to which all of my target theorists subscribe make it clear that they all believe tort law to be (i) structured bilaterally, (ii) part of private law, and (iii) within private law, a discrete legal category. Although they do not always spell out in detail the ways in which they perceive tort law to be separate from certain other legal categories, it is nonetheless apparent from what they do say that they think this way. The very fact that they each devote time and space to establishing the divide between tort and its closest neighbour, contract, tends to suggest (though it does not strictly entail) that they also believe there to be a rigid divide between tort law and its more remote neighbours (such as unjust enrichment and equity) with which it has a much less obvious connection or affinity.

II. Hybrid Torts

When a novel case comes before the courts, judges sometimes create a new cause of action by drawing upon an array of interconnected legal principles. These principles may be taken from cases that belong to different legal categories; yet, despite its mongrel heritage, the resulting cause of action is very often labelled a tort.[42] Over time, it gets treated by practitioners, students, and teachers of the law alike as though it were an entirely quotidian member of the ‘tort law’ family. But whether such actions deserve to be treated in this way—as though they were ‘thoroughbred’ torts—is a question that is seldom asked. As we will see, however, it is an important question for the purposes of assessing the merits of explanatory theories of tort law. To be clear, the critical matter is not whether tort law is capable of providing a home for such actions. It plainly is. Rather, the critical question is about how such hybrid torts ramify for explanatory theories.

The problems that these actions cause for such theories arise because—in a metaphor to rival the idea that tort law can be seen as the common law’s Swiss army knife[43]—it can also be seen as the common law’s vacuum cleaner. The metaphor is apt because it is generally tort—as opposed to contract, equity, unjust enrichment or any other legal category—that is called upon to house hybrid actions that are constructed from an array of principles found in cases that belong to different legal categories. Examples are in no short supply.[44]

I can conveniently start with Lumley v. Gye.[45] This is nowadays almost invariably regarded as a tort case. Indeed, it is the very case in which the tort of inducing breach of contract was first properly launched.[46] But a little reflection soon reveals that the case could just as plausibly have been classified as part of the law of contract: as a rule of accessory liability within contract law according to which the duty to make reparation for loss arising from a breach of contract is extended beyond the immediate contract breaker to the person who procured that breach.[47]

Tort law contains several rules of accessory liability.[48] Why should contract law not do likewise? Certainly, Erle J came very close to saying that it should when he declared in Lumley that “he who procures the wrong...may be sued, either alone or jointly with the agent, in the appropriate action for the wrong complained of.”[49] Critical here are the words, “jointly...in the appropriate action for the wrong complained of,” for this suggests a rule of ‘contract law’ which mirrors tort law’s rules on concurrent tortfeasance. Paul Davies appears to adopt this understanding. He contends that, “[l]liability under Lumley should not be crammed under the umbrella of the economic torts,” and that it is better seen as a particular instance of accessory liability belonging “[i]n the contractual context.”[50] So why does this classificatory difficulty matter from the perspective of contemporary tort theory? It matters for at least three reasons.

First, Lumley helps illuminate the fact that tort law as it presents itself is not the sharply defined body of law that explanatory theories proclaim it to be. More specifically, Lumley casts doubt on the idea that tort law has discrete and non-porous boundaries by virtue of the fact that the relevant wrong in that case was a breach of contract, while the action as a whole lay in tort.[51] It cannot plausibly be argued that the relevant wrong was the breach of a free-standing duty not to induce the breach of contract, for the reasons that follow.

One possible source of such a duty would be the contract itself. The making of a contract by X and Y might be thought to generate an obligation that binds Z not to induce breach thereof. But this cannot be right, for any such duty created by the contract would be contractual in nature and, as such, an action for breach thereof would lie in contract, not tort. Furthermore, and more fundamentally, it is trite to state that the privity of contract principle stands in the way of X and Y generating rights and duties that apply to parties other than themselves.

Another, subtler way of establishing a direct duty owed by D to C relies on the idea that the contract’s formation generates a secondary, tortious (not contractual) duty not to induce a breach of the contract. Indeed, it is exactly this view that Stevens holds. He writes: “all contract rights carry with them a right good against everyone else that they do not induce the infringement of the contractual right.”[52] However, this understanding—the nub of which is that there exists a freestanding tortious duty not to induce a breach of contract—is contradicted by authority. In the leading case of OBG Ltd v. Allan[53] their Lordships repeatedly stated that liability under Lumley is accessory, not primary. Yet, liability would be primary if there were any direct duty owed by D to C along the lines that he suggests.[54] Given such weighty countervailing authority, and bearing in mind the fact that no reported decision has ever lent support to the existence of such a duty owed by D to C, the inescapable truth remains that what is key in a case of inducing breach of contract is that quintessential element of contractual liability: the breach of a contractual duty. The action is therefore hybrid in the sense that it mixes tortious and contractual touchstones of liability: it combines the tort law requirement of intention with the need for a contractual duty that gets broken.[55]

The second reason why Lumley is problematic for my target theorists is that it confounds the shared claim sketched earlier that torts are centered upon duties imposed by virtue of a rule of law. The only relevant duty for the purposes of the Lumley tort[56] is, as we have just seen, the contractual duty in play. Since this duty is plainly generated by the parties’ agreement, it must follow that the tort cannot be explained in terms of the breach of a duty imposed by law. Only if one dismisses what the courts have repeatedly said about liability being secondary rather than primary in this area can one begin to argue that Lumley liability is based on a duty imposed by law. But that, of course, involves an obvious departure from explaining the law as we find it.[57]

The third reason why Lumley poses explanatory problems for the theorists in view is this: inducing breach of contract breaks the structural imperative to which they all subscribe. That, recall, is that torts are bilaterally structured around private law rights held directly by C against D. As already noted, the language used to describe this feature varies. There is talk of bipolarity, relational wrongdoing, and the privity of torts. But the core claim is always the same: torts involve wrongs committed by D against C where the wrong in question entails the breach of a duty owed directly by D to C. The Lumley tort cannot be made to fit the structural imperative because the House of Lords was perfectly clear in explaining the three-party nature of the action in OBG.[58]

Of course, the blushes of all my target theorists could be spared if, somehow, it could be shown that inducing breach of contract were somehow an exceptional, anomalous or unprincipled action precisely because it obfuscates (or violates) the putative boundary between contract and tort. If the Lumley tort could be sidelined in this way, then my target theorists need not concern themselves with the fact that it clashes with core tenets of their theories. So, can it be dismissed as anomalous or sui generis? I suggest that it cannot.

The mere fact that the action is rooted partly in the soil of contract law (since the relevant duty is contractual) and partly in that of tort law (since C must show intention) does not per se render it an anomaly. Many other actions have (or have had) affinities with both branches of the law. As long ago as the fourteenth century, there was a class of cases that sounded in the tort of trespass that today would be regarded as cases of contractual misperformance.[59] And, in the modern era, an action under section 2(1) of the Misrepresentation Act 1967 (UK) equally centres on mixed touchstones of liability. In terms that bear an obvious affinity with the reasonableness standard in the law of negligence, the Act requires the defendant to have made a false representation to the claimant in the absence of reasonable grounds for believing that what he said was true. At the same time, with an obvious link to contract law, the claimant must also have been induced to enter into a contract and suffered loss as a result thereof. Lumley, in other words, is by no means alone in having mixed affinities.

If we cannot plausibly regard Lumley as anomalous, we have little choice but to take seriously the idea that inducing breach of contract is best thought of as a hybrid tort, whose touchstones of liability are connected both to contract and to tort. But a single, mongrel common law action is not nearly enough to pose a substantial challenge for the theories in view. Were it the sole example, the relevant theorists could well seek to argue that tort law is sufficiently distinct from other legal categories for their theories to remain credible. We must, therefore, explore in some depth the question of whether legal categories can and do overlap to a significant degree (somewhat like the different sectors in a Venn diagram). As we shall see, many other well-established common law actions also serve to blur tort law’s boundaries in this way even though a respectable theoretical case can be made against their being able to do so.

But before turning to those matters, it is necessary to head off one possible objection to my using the concept of a ‘hybrid tort’ to test the explanatory power of the theories I have chosen to examine. The objection runs as follows. There is a logical flaw in seeking to establish the existence of hybrid torts since the concept of a hybrid tort presupposes the existence of distinct legal categories. Without a clear ex ante conception of, say, tort and equity, so the argument goes, it is meaningless to say that action X is a hybrid of tort and equity.

Despite ostensible appeal, the objection is unfounded. This is because it is perfectly possible to speak of a hybrid of X and Y without settling quite what the difference is between X and Y. Biologists, for example, uniformly accept that it is possible to breed a hybrid of the domesticated horse (equus ferus caballus) and the nearly extinct Asian wild horse (equus ferus przewalskii). Yet, what they cannot do is rely on this hybrid to prove the distinctiveness of the two parent species in the usual biological way, namely, the sterility of any offspring produced by inter-breeding.[60] By analogy, I think it is possible to speak meaningfully of hybrid torts without such torts being necessarily suggestive of the distinctiveness of the two legal categories.

We must now turn to the matter of porous boundaries between legal categories: first in theoretical terms, and then as a matter of practical reality.

III. Tort Law as a Discrete Legal Category: Theory

The enterprise of dividing the law into categories is by no means novel. Blackstone made what is probably the most famous early attempt to classify English common law.[61] For him, the aim of so doing was “to render the whole intelligible to the uninformed minds of beginners.”[62] He saw the provision of “a general map of the law, marking out the shape of the country, its connections and boundaries, its greater divisions and principal cities” as a means by which the work of “an academical expounder of the laws” could be facilitated.[63] In short, he attributed an expository function to the enterprise of legal cartography (as did late nineteenth century treatise writers who were concerned by the “disorderly condition of the law,” and felt the need “to tidy it up, to systematise it”[64]).

Interestingly, Blackstone devised a scheme for carving up the law that has long since lapsed into desuetude (using categories like “the rights of persons” and “the rights of things”). However, the fact that his scheme is no longer in use does not necessarily imply that it was flawed in some way. It is simply that he classified branches of the law in a way that is no longer popular. This alerts us to two key points: the fact that there is no a priori right or wrong way to carve up the law, and the fact that any given case or rule of law could, in theory, be housed in more than one legal category so long as the categories in question do not belong to the same classificatory scheme.

This is possible because not all classificatory schemes share the same ambition. One might, for example, with very limited ambition, seek simply to distinguish statutory law from the common law, or domestic law from supra-national law, or public law from private law. With divisions of this kind, there is no reason why a particular tort case cannot form part of the common law category, the domestic law category, and the private law category. However, this observation does not assist us with the question of whether legal categories belonging to the same classificatory scheme may overlap. Take, for example, the classificatory scheme frequently used in relation to the law of obligations. Here we encounter the familiar categories of contract, torts, equity and unjust enrichment.[65] These legal categories have a markedly different relationship to one another than exists between categories like private law and statutory law. Whereas private law and statutory law belong to different classificatory schemes and are not mutually exclusive, the same cannot be said of contract, torts, equity and unjust enrichment. In theory, these represent distinct subsets of the higher-level legal category: the law of obligations. They are distinct from, yet complement, one another in the same way that private law is distinct from, yet complements, public law, and statutory law comes apart from, yet complements, the common law.

The subdivisions within a particular classificatory scheme are easily understood: they are each constructed according to, and therefore reflect, some or other principle or criterion that is particular to that sub-category. For example, we might take as our starting category, the statutory laws of the last three centuries. We may then seek to divide these laws into three separate sub-categories. The first might comprise the statutory laws of the nineteenth century; the second, the statutory laws of the twentieth century; and the third, the statutory laws of the twenty-first century. No single statute could conceivably be housed in more than one of the subcategories.

More pertinently, we could start with the law of obligations and attempt to subdivide this into the aforementioned subcategories of contract, torts, equity and unjust enrichment. In each case, the question of where to place a given case or rule would be answered not, as under the previous scheme, by reference to the century in which it was decided, but by reference to some central juridical criterion that forms the hallmark of one or other of the subcategories. The criterion of mistaken payments, for example, is widely treated as the organizing principle behind the category of unjust enrichment.

Importantly, one consequence of treating certain juridical features as definitive in this way is that a given case ought, in theory, to belong to just one of the four named subcategories.[66] If the case is characterized by a mistaken payment, then it belongs in the box labelled ‘unjust enrichment’ and not the box labelled ‘contract’ or the one labelled ‘torts’. In order to appreciate why this is so, it is necessary to make an important observation concerning the nature of the four sub-categories within the law of obligations. It is this: unlike the major categories within the Blackstonian scheme, the subcategories of contract, torts, equity and unjust enrichment fulfil important dispositive functions and are, for this reason, appropriately described as dispositive legal categories.[67]

At the heart of a dispositive legal category is a core juridical feature (or set of features). It is this core feature (or set of features) that gives the category both its conceptual unity and its practical utility.[68] Thus, when practitioners treat a case as belonging to a particular legal category, they do so because they think that it bears particular juridical attributes.[69] In turn, their presentation of the case in this way—as belonging to category X—will determine the way in which it is handled by the courts. As Charlie Webb puts it, “the classification of a case must tell us something about how the law should respond to it: what set of rules and principles we apply to it, what questions we ask and what tests we use.”[70] So, for example, if a case of inducing breach of contract with an international dimension is presented as a tort case rather than a contract case, it will attract the application of the choice of law rules applicable to torts rather than those applicable to contract.[71] Similarly, a purely domestic case of inducing breach of contract will necessitate the application of the tort (not the contract) rules on limitation.[72]

The crucial point is this: since the subcategories within the law of obligations fulfil this dispositive function, they will in theory derive conceptual unity from a particular juridical core.[73] Peter Birks thought that he had identified such a core within tort law when he wrote (using the term “wrongs” in preference to that of “tort”[74]) that, “the only definitively essential feature of a wrong is that it is conduct which attracts its legal consequences by virtue of its character as a breach of a primary duty.”[75] Notice that this conception of what belongs in the category ‘wrongs’ is a juridical one.[76] It looks to the specific, narrow question of whether a primary duty has been breached.

Much as Birks thought that wrongs comprised “a distinct category of obligation-creating event,”[77] it is doubtful whether matters are quite that simple. In common law jurisdictions where there exists a multiplicity of different torts (as opposed to the simple idea of tortious wrongdoing that one finds in continental legal systems),[78] tort law lacks the kind of conceptual unity that Birks and some of my target theorists would have us believe.[79] There is no simple juridical core that can be identified. Not only are torts notoriously heterogeneous in this respect,[80] but there are also many well-established mongrel actions that, regardless of the fact that they are uniformly treated as torts, call into play touchstones of liability more readily associated with more than one legal category. These hybrid torts militate against the idea that there exists a body of law that can be sharply defined in juridical terms in the way suggested by the theorists in view. In so doing, they undermine the very foundations of those theories.

IV. Tort Law as Discrete Legal Category: Reality

A. Introduction

As observed earlier, dispositive legal categories which belong to the same classificatory scheme should, in theory, be discrete. At the heart of any such legal category is an organizing juridical principle (or set of such principles) and it is the application of this principle (or set of principles) to all cases within the category that ensures, in line with the rule of law, that like cases are treated alike. As was also noted above, when such organizing principles are used in order to classify cases, any given case ought to belong to just one such category. Webb, making much the same observation, explains the matter this way: “if cases within different classes will fall to be dealt with differently,” that is, according to a particular organizing principle or set of such principles, “then it makes no sense to say that a case can fall within or straddle more than one category.”[81]

The logic behind Webb’s claim is impeccable, but the observation pays no regard to the fact that theory and practice often come apart. So, whatever we might say in theoretical terms about legal categories and the cases they house, we would be naïve to expect reality to be a perfect reflection of what theory dictates. Classificatory schemes, like the judgments to which they are applied, are human constructs. Like most such constructs, they frequently fall short of the ideal. So, from time to time we come across cases that, whether by design or by accident, cannot be slotted comfortably within the various conceptions of tort law proffered by my target theorists. These actions—though widely recognized as torts—bear obvious mongrel traits.

I have noted already the way in which inducing breach of contract has an equally strong juridical affinity with contract as it does with tort, but it is by no means alone in blurring the boundary between contract and tort. And nor is this boundary the only one that gets blurred. As we shall see, many of tort law’s boundaries with neighbouring legal categories[82] are affected in this way by hybrid torts. So the point is inevitably reached where it becomes irresistible to conclude that tort law is not a discrete, sharply defined legal category with a sufficiently distinctive juridical core to support a neat and tidy theory of the same.

B. The Prevalence of Hybrid Torts

Sometimes, the way in which certain causes of action get classified seems to be attributable to the way in which influential jurists have interpreted key cases. For example, F.H. Newark elaborated a well-known account of the supposedly close relationship between the rule in Rylands v. Fletcher and the law of private nuisance. This account played a major role in causing the judiciary to treat the former, many years later, as nothing more than a sub-branch of the latter.[83] In Cambridge Water Co v. Eastern Counties Leather plc, Lord Goff quoted with approval a lengthy passage from Newark’s article in which the latter had asserted that “Rylands v. Fletcher [is] a simple case of nuisance.”[84] Some years later, in Transco plc v. Stockport MBC, Lord Hoffmann acknowledged that Lord Goff had merely been “[a]dopting the opinion of Professor Newark...that the novel feature of Rylands v. Fletcher was to create liability for an ‘isolated’ (i.e., unforeseeable) escape,” but that Rylands v. Fletcher “was nevertheless founded on the principles of nuisance.”[85] So, although some jurists contend that the rule does not, because of certain important peculiarities, form part of tort law,[86] the orthodox view is clear. The rule is formally not just part of tort law but, more specifically, part of the law of private nuisance.[87] Ultimately, it is Newark’s treatment of the case all those years ago that seems to be responsible for this conception.[88]

Jurists are not alone, however, in making controversial classificatory decisions that have this effect. Occasionally, it is the courts themselves that must shoulder the responsibility. As Stephen Smith has observed, it is sometimes the case that “legal decisions themselves tell us how they ought to be classified and categorized—whether they are tort cases, contract cases, or whatever.”[89] All that is required is that the relevant court declares a certain case to be part of tort law and, hey presto, thus is born a new ‘tort’ even if, in truth, the decision is only partly (or minimally) explicable in terms of familiar touchstones of tortious liability.[90] We can once again invoke Lumley as an example.

Although the question that arose in Lumley was a novel one involving accessory (not primary) liability, Erle J did at one point in his judgment say that “[i]t was undoubtedly prima facie an unlawful act on the part of Miss Wagner to break her contract, and therefore a tortious act of the defendant maliciously to procure her to do so.”[91] Of course, his having said this is hard to square with that part of his dictum (considered in Part II, above) in which he suggested that the defendant might somehow be jointly liable in contract for the breach that occurred.[92] Equally, it is less than obvious why it necessarily follows from the fact that X has broken a contract with Z that Y (who procured that breach) should be considered a tortfeasor. But that is not the point. What is important is the fact that, ultimately, Erle J declared that the defendant was a tortfeasor. And in so saying, he provided a clear steer as to how cases of inducing breach of contract should be treated in the future. Ever since that landmark decision, Lumley has almost universally been regarded as establishing a form of tortious liability; and this is despite the fact that its hybrid nature has by no means gone unnoticed.

For example, in his discussion of Lumley in OBG, Lord Hoffmann acknowledged the mongrel nature of inducing breach of contract. He traced the tort’s origins to an “old action on the case for enticing away someone else’s servant” and noted that, in such cases, the only means by which a claimant could be granted a remedy against the person who induced the servant’s breach of contract was by recourse to a certain “mixing and matching of the forms of action.”[93] Even so, Lord Hoffmann was ultimately content to continue to treat inducing breach of contract as part of tort law. A sizeable section of his leading judgment in OBG was headed “Inducing breach of contract: elements of the Lumley v Gye tort”[94] and the phrase “Lumley v Gye tort” was used no fewer than twelve times in his speech as a whole.

The remainder of this section considers numerous other causes of action that are almost always regarded as part of tort law but which, in truth, have hybrid rather than pedigree characteristics. They are addressed according to the various boundaries that they tend to obfuscate.

1. Tort and Contract

A relatively modern development within tort law has been the preparedness of the courts to ascribe a duty of care in negligence on the basis of an assumption of responsibility by the defendant. This branch of the law of negligence has its origins in the principle first enunciated in Hedley Byrne & Co Ltd v. Heller & Partners Ltd.[95] As a subspecies of negligence, one might suppose that these assumption of responsibility cases would occupy a position at the heart of ‘tort law’. It would be a mistake, however, to think of them in this way. In Hedley Byrne itself, Lord Devlin was keenly aware of the juridical propinquity of the case to contract law in which, of course, duties arising from a voluntary assumption of responsibility find their natural home. He specifically referred to the fact that the case before him was almost contractual in nature.[96]

The proximity of the Hedley Byrne principle to the law of contract was also noted in the later case of White v. Jones[97] where a solicitor negligently delayed carrying out a testator’s instructions to amend his will. This delay resulted in financial disappointment for the intended legatees in whose favour the will should have been (but never was) amended prior to the testator’s death. Ultimately, the case was treated as a further extension to the law of negligence. But notably, the Law Lords (some of whom explored this possibility at length) were acutely aware that the case might conceivably have been resolved by way of an extension to the law of contract. In particular, they made mention of the following juridical affinities with contract: the fact that the duty in question was (1) affirmative, not negative, in nature (2) founded upon an assumed responsibility, and (3) designed to protect an expectation interest.[98]

As noted already, all of my target theorists concede that it is in the sphere of contract, not tort, that one finds duties that are voluntarily assumed. They could, of course, point to the fact that in some (but by no means all) of the assumed responsibility cases the relevant duty was merely deemed to have been assumed, rather than consciously shouldered.[99] Yet, this only provides a partial response since it only accounts for some of the cases. And, even then, it is only a response available to non-Kantians (which is not to say that all non-Kantians consider White to be unproblematic).[100]

The reason why Kantians cannot invoke the response just mentioned stems from the fact that, even if the relevant duty was in fact deemed to have been assumed, it remains inexplicable by virtue of being affirmative in nature. To explain: affirmative duties are regarded as being incompatible with the principle of Kantian right insofar as they instantiate an obligation to promote another’s welfare (rather than merely protect an equal right of independence in that person). In this regard, Weinrib is adamant that “private law deems no aspect of [the claimant’s] welfare important enough to ground a positive obligation to forward it.”[101] It is for this reason that he denies the existence of liability for nonfeasance in tort law.

Allan Beever is in agreement with Weinrib on this score[102] and, in an attempt to head off the challenge for his theory presented by the assumption of responsibility cases, he argues that it is preferable to treat cases like White as belonging to a category of law best labelled “consents”.[103] He does not believe that they can be slotted into the law of contract because of the absence of consideration, but he argues strenuously that they have been wrongly pigeonholed as part of the law of negligence. He contends that this mischaracterization is due to the fact that there is a widely-held, yet ultimately mistaken, belief that “it is acceptable to inflict upheaval on the law of negligence but not on the law of contract.”[104] Even so, it is clear that he sees these “consents” cases as being closer to contract law than tort. He takes the view that the doctrine of consideration—a mere “idiosyncrasy of the common law”[105]—is all that stands in the way of treating such cases as quotidian contract cases.

Beever is assuredly right that there is a general preference to use tort rather than contract in order to accommodate hybrid actions. And he may well be right, too, that the doctrine of consideration has relatively little going for it in theoretical terms. But neither point is relevant here. What matters for present purposes is that the assumption of responsibility cases blur the boundary between contract and tort in a way that many tort theorists either overlook or choose not to acknowledge.[106] They blur this boundary by virtue of the fact that some of the relevant touchstones of liability have an obvious affinity with contract while others seem more naturally aligned with tort. So, for all that we may say that the solicitor in White v. Jones owed a duty of care and that this duty was broken by virtue of the defendant’s negligence (classic ‘tort-speak’), we may equally well advert to the fact that the duty in play was voluntarily assumed and that the damages awarded were granted in order to repair a pure economic loss in the form of the claimants’ dashed expectations (classic ‘contract-speak’).

The significance of looking forward in order to gauge expectation losses is not to be underestimated. Both corrective justice theorists and rights theorists look backwards, to what went wrong, when it comes to gauging tort damages.[107] The rights theorist is principally concerned to address the rights infringement that has occurred,[108] while the corrective justice theorist—as the name suggests—regards tort damages as the means by which the injustice suffered by the claimant is corrected. Expectation losses, by contrast, do not aim to restore the claimant to the position occupied before the wrong in question was committed. They seek to place the claimant in the position that he expected to occupy at some point in the future.[109]

In addition, it is vital to note that White v. Jones cannot be explained away on the basis of what Birks called “alternative analysis” (i.e., affording salience to different aspects of any given case so as to enable it to be dealt with either as a tort case (drawing on facets A, B, and C) or as a contract case (drawing on facets X, Y, and Z)).[110] It cannot be so analysed because the factors that were treated as salient in White v. Jones were the self-same factors that would have animated a contract action: the voluntary assumption of responsibility, the omission to fulfil the duty thereby created, and the need to repair the claimants’ damaged expectations. Put bluntly, White v. Jones had but one set of liability touchstones.

Another example of a cause of action that is typically regarded as part of the law of torts, but which might just as well be seen through the lens of contract law, is the ‘tort’ of two-party intimidation.[111] In Kolmar Group AG v. Traxpo Enterprises Pvt Ltd,[112] the defendant coerced the claimant (with whom it had a contract) into paying a higher price for various goods than had originally been agreed. At one point in his judgment Clarke J observed: “I am quite satisfied...that Kolmar agreed to amend the letters of credit to increase the price...as a result of illegitimate pressure amounting to economic duress on the part of Traxpo.”[113] He went on:

[t]he tort of intimidation is established where (i) the defendant makes a demand backed by a coercive and unlawful threat; (ii) the plaintiff complies with that demand because of the coercive and unlawful threat; (iii) the defendant knows or should have known that compliance with its demand will cause loss and damage to the claimant and (iv) the defendant intends its demand to cause loss and damage to the [claimant]...Those requirements are, as it seems to me, satisfied...[and] [a]ccordingly, Kolmar is entitled to $1,405,566.61 as damages for intimidation.[114]

It seems a matter of mere fortuity that the judge ultimately preferred to anchor his judgment to the tort of intimidation rather than, more simply, the juridical fact of economic duress (which he treated as the basis of the tort). The centrality of economic duress to the decision he reached suggests that the case could equally well have been dealt with according to a familiar set of contract law rules. Indeed, at one point in his judgment Clarke J even indicated as much.[115] In fact, perhaps the oddest facet of the case is that the judge ultimately plumped for imposing tortious liability. After all, the continued vitality of two-party intimidation had been specifically called into question just a few years earlier by the House of Lords in OBG.[116] As it stands, however, Kolmar provides a further example of a cause of action that is treated as tortious, but which draws heavily upon juridical ideas more typically associated with a different legal category. And in common with the assumed responsibility cases, Kolmar is not susceptible to Birksian “alternative analysis”.[117] Whether addressed from a tort or a contract perspective, it is the self-same juridical feature—namely, “illegitimate pressure amounting to economic duress”—that is ultimately pivotal.

The preceding paragraphs advert to just a few instances in which it is impossible to disentangle fully contract and tort. There is, however, nothing very new or isolated about these examples.[118] Nor, apart from a desire for theoretical neatness, is there any basis for regarding them as anomalous. Tortious assumed responsibility cases have consistently been endorsed at the highest judicial level,[119] while the tort of two-party intimidation seems also to have survived the questions raised about its vitality in OBG.[120] There is, consequently, no doubt that the border between tort and contract is blurred in the law as we find it. And however much we may think that tort and contract should come apart neatly (in accordance with theory), it is at least noteworthy that Lord Goff cautioned his fellow judges against the “temptation of elegance” in Henderson v. Merrett Syndicates Ltd (No 1).[121]

2. Tort and Equity

A prime example of the overlap that exists between tort and equity can be seen in the developing law on the misuse of private information. This body of law is hard to place in any single legal category since it has a pretty firm foothold in both tort and equity. On the one hand, the modern action in England for misuse of private information has its origins in the equitable wrong of breach of confidence.[122] Yet, on the other, it is nowadays often treated as part of the law of torts. This latter characterization of the action owes a great deal to the speech of Lord Nicholls in Campbell v. MGN Ltd.[123] For there, after noting the way in which the action had “shaken off the limiting constraint of the need for an initial confidential relationship”[124]—which was a key touchstone of the equitable action for breach of confidence—his Lordship went on to state that “the tort is better encapsulated now as misuse of private information.”[125] Although Lord Nicholls was admittedly in a minority of one in describing the action in this way, there has since been considerable judicial endorsement of the view that a new kind of tort action has materialized which is based on the misuse of private information.[126]

Such endorsement does much to settle the question of whether this action is rightly called a tort; but it is also important to notice its hybrid qualities. The fact that textbooks and treatises on both the law of torts and equity now fully discuss this form of civil liability is of course suggestive, but not definitive.[127] Much more telling is the fact that senior judges have revealed their willingness to treat the action as one within tort law while continuing to rely on touchstones of liability that include the quintessentially equitable consideration of whether the claimant behaved in an iniquitous way so as to deny her the reasonable expectation of privacy.[128]

Further areas of overlap between tort law and equity arise in the context of the common law action for passing off as well as in relation to the various statutory causes of action for infringement of intellectual property rights (such as breach of copyright and patent infringement). While all such actions are, again, habitually regarded as torts,[129] it is notable that the first choice of remedy in such cases will often be an account of profits and/or an injunction to restrain further infringements of the claimant’s rights. These remedies are, of course, equitable ones, and this only adds to the suggestion that these actions have as close an affinity with equity as they do with tort. Nor are they alone or anomalous in this respect. The liability imposed upon an accessory for knowing assistance in the breach of a fiduciary obligation (which obligation lies in equity) has also been judicially described as an “equitable tort”,[130] and the decision in A-G v. Blake[131] suggested a fairly sizeable range of circumstances in which an account of profits might be available in tort law.[132]

3. Tort and Property Law[133]

One important overlap between tort and property law exists in the shape of the action for conversion. The problems presented by this tort for those who seek to theorize gain-based damages and the limits of restitution are fairly well known. But, for present purposes, it is only the way in which it blurs the boundary between tort and property law that warrants attention.[134]

Where D1 steals C’s coat and sells it to D2, one remedial option open to C is to sue for re-delivery of the coat. This claim is founded upon C’s possessory rights over the coat. It is a claim made directly against D2. It can be distinguished from the alternative remedy of damages, which attends to the fact that C has suffered a loss by virtue of D1’s wrongdoing. Where C elects to claim re-delivery of the coat, the tort of conversion acts, according to Andrew Tettenborn, “as a kind of surrogate vindicatio, allowing owners to get back their property...from a wrongful possessor.”[135] Putting it this way illuminates the fact that—when re-delivery is sought—conversion is capable of being seen as a proprietary cause of action. In Tettenborn’s view:

[i]t is not really tort but personal property law; it affords not so much reparation for wrongful dealing, as machinery for an owner to get his property back. The law of obligations simply does...what in other systems is achieved by a separate proprietary cause of action.[136]

The point is a fair one. However, when a claimant invokes the fact that he has suffered a loss and sues for damages, conversion operates in a typically tortious way. The truth about conversion, then, is that it comprises another hybrid tort. The key touchstone of possession is a characteristically proprietary one. Furthermore, in line with the other hybrid actions considered above, the material events in a case of conversion are incapable of being explained away according to Birksian “alternative analysis”. This is because the very same element—the non-consensual using, taking, retention or delivery to a third party of the chattel in question—is juridically significant whether what is sought is re-delivery or compensatory damages.

4. Tort and Unjust Enrichment

The tort of conversion also blurs the dividing line between tort law and unjust enrichment. It is uncontroversial that if D hands over to X goods belonging to C in respect of which C has a right to immediate possession, D will commit the tort of conversion.[137] It is equally trite to state that a failure to hand over goods to someone who has an immediate right to possess them also commits conversion.[138] Therefore, one would have thought that a case like Chesworth v. Farrar[139]—in which the executors of an estate of a deceased antique dealer who had both lost and sold certain goods belonging to the claimants—ought to have been resolved squarely on the basis of the tort of conversion. However, Edmund-Davies J remarked as follows:

[a] person upon whom a tort has been committed has at times a choice of alternative remedies, even though it is a sine qua non regarding each that he must establish that a tort has been committed. He may sue to recover damages for the tort, or he may waive the tort and sue in quasi-contract to recover the benefits received by the wrongdoer.[140]

In so saying, the learned judge made clear his belief that the facts in Chesworth were capable of grounding either an action in tort or one in quasi-contract. This was important in the case itself since an action in tort was time-barred. But it was also important more generally, since granting the claimant a choice as to the cause of action is qualitatively different from seeing conversion as something that is purely a tort that makes available different types of remedy. More simply, on Edmund-Davies J’s understanding, Chesworth need not necessarily be treated as a tort case.[141] He could scarcely have been clearer when he said that a claimant in such circumstances is free to “waive the tort and sue in quasi-contract.”[142] So long as the claimant adverts to the fact that the defendant has been unjustly enriched, the case, he said, could proceed along the lines of quasi-contract (a category of law that broadly equates with what would now be called unjust enrichment).

There is, however, a possible snag here, for it might still be said that Chesworth does not really blur the boundary between tort law and unjust enrichment. It might merely be a case of concurrent liability that is susceptible to alternative analysis: one, in other words, in which highlighting two different juridical aspects of the case (Birks used the language of causative events) would support two different types of action.[143] But are there really two different juridical aspects to Chesworth such that there is no genuine threat to the idea that tort and unjust enrichment are quite separate legal categories? I don’t think that there are.

It is true that, for the purposes of the tort of conversion, the claimant must point to the commission of a wrong. It is equally true that the commission of a wrong does not formally animate a claim in unjust enrichment. However, it is difficult to see how one could establish an unjust enrichment in a case like Chesworth without adverting to, and relying on, the very same events/juridical features that illuminate the commission of a wrong. The event that grounds the wrong—the non-consensual transfer—is also what renders intelligible the claim that the transfer was a mistaken one, and thus one in which an action for unjust enrichment could be pursued. As Birks himself conceded, it is “the absence of [C’s] consent [which] supplies the unjust factor.”[144] So whether it is viewed through the lens of tort law or that of unjust enrichment, it is the absence of consent in Chesworth which is key. It supplies both the wrongfulness demanded by tort, and the mistaken payment that is central to unjust enrichment.

Accordingly, even if one accepts that, in theory, different aspects of the same case may support alternative forms of analysis (and thereby ground different causes of action), it is nonetheless true that in Chesworth a single, common juridical feature was in play.[145] And that being so, it is hard to see Chesworth as anything other than a hybrid tort case.[146]

Nor is Chesworth unique in this regard, for much the same can be said in relation to cases of deceit.[147] It is precisely because D (acting wrongfully) manages to deceive C into handing over his money that C can be said to have been mistaken in handing over that money. And it is not just the causative event that may be viewed through the lens of unjust enrichment in a deceit case. The same is true also of the damages payable. As Lord Wright once put it: “in the case of fraud the court will exercise its jurisdiction...to prevent the defendant from enjoying the benefit of his fraud.”[148] In other words, despite the tort law norm of attending to what C has lost, the damages in such cases will be computed with an eye on the fact that D stands to be unjustly enriched.

5. Tort and Public Law

As noted already, there is no a priori right way to categorize the law, and divisions drawn along very broad lines—such as domestic law and international law, or private law and public law—are certainly possible. That said, the legal categories associated with such broad divisions are often too large to be useful for expository purposes. Accordingly, they are usually further broken down into a series of subcategories. Tort is often regarded as one such subcategory within private law, and its status as such is something to which my target theorists subscribe, as we saw above.

Conceived in this way, tort law ought not, in theory, to overlap with any other category within the classificatory scheme to which private law belongs. More concretely, tort law ought not to overlap with public law since private law and public law are separate (but complementary) parts of a single classificatory scheme. Yet, in practice, there are several hybrid torts which confound this dichotomy.

One such hybrid tort is misfeasance in a public office. Unusually for a tort, this cause of action is animated by the infringement of a public, not a private, right. In the famous case of Roncarelli v. Duplessis,[149] for example, the defendant sought to deprive the claimant of something that the claimant only had by virtue of public law: a liquor licence. In recognition of this public law dimension to the tort, several scholars have been hazy in the way they describe it. R.C. Evans, for example, in recognition of its hybrid qualities, has dubbed it “an administrative tort”,[150] while Mads Andenas and Duncan Fairgrieve describe it is as “the only specifically ‘public law’ tort in English law.”[151] Peter Cane and Donal Nolan also label it a “public-law tort,”[152] while for Simon Dench, “[t]he tort of misfeasance...is a solely public law remedy.”[153] If ever there were a hybrid tort, then this is surely it. It is certainly the case that it conflicts with the claim made by all of my target theorists that tort law is exclusively a part of private law and concerned solely with private rights.

A second overlap between tort and public law occurs in certain common law jurisdictions where the breach of a particular constitutional and/or human rights guarantee is treated as a “constitutional tort.”[154] Just as with misfeasance in a public office, the difficulty with classifying such actions as thoroughbred torts, at least from the perspective of the theories in view, inheres in the fact that they have nothing to do with the infringement of private law rights. Actions of this kind ground awards of “vindicatory damages” in several common law jurisdictions. Damages for such actions are designed to reflect the fact that “the right violated was a constitutional right.”[155]

V. Implications of Hybrid Torts for Explanatory Theories

All of the hybrid torts outlined above present a significant problem of fit for at least one of the major explanatory theories of tort law under consideration. Some are even incompatible with all of these theories. The problem they present is that, together, they make it almost impossible to pin down exactly where the frontiers of tort law lie. In this regard, Wittgenstein’s aphorism, set out at the head of this article, becomes salient for it is plainly the case that the more indistinct an object is, the more difficult it is to provide a clear and definitive theory of it. The more amorphous and juridically mixed tort law appears, the less it is amenable to reductive theorization (in the sense that a single norm, principle, or other core juridical feature can be said to animate it).

As we have seen, hybrid torts are characterized by their mixed touchstones of liability. Amongst typically tortious considerations, we find interlopers like the proprietary concept of possession in the tort of conversion, the breach of contract requirement in the Lumley tort, and the relevance of a claimant’s iniquitous behaviour in a case of misuse of private information. None of these chimes with Weinrib’s claim that torts can be characterized by a simple set of familiar concepts, namely, “duty, proximate cause, factual cause, and the standard of reasonable care.”[156]

VI. Irrelevance

It is one thing to point out that hybrid torts raise doubts about the widely held belief that tort law is a discrete legal category. It is quite another, however, to show that these doubts should be considered serious ones. If the extent of the boundary blurring for which they are responsible can be dismissed as trivial, or if the actions in question can be considered anomalous, then the plausibility of those theories which insist (and require) that tort law be a discrete body of law may nonetheless emerge relatively unscathed from the challenge posed by hybrid torts. Perhaps unsurprisingly, then, these irrelevance claims are frequently made.

Sometimes the irrelevance claim takes the form of a contention that a particular case was wrongly decided and that, as a consequence, the legal principle emanating from it should be regarded as a mistake. Such thinking seems to underpin Weinrib’s assertion that “[i]nternal to the process of law is the incremental transformation or reinterpretation or even the repudiation of specific decisions so as to make them conform to a wider pattern of coherence.”[157] Yet, there are limits to how readily this escape route—based on sidelining inconvenient decisions—can be invoked. For one thing, the common law can only “work itself pure”[158] within the accepted confines of the stare decisis principle.[159] Also, even if there is something to be said for now and again dismissing ‘particular holdings’ as wrong-headed, the sheer durability of certain cases and rules speaks powerfully against their plausibly being regarded as anomalies. Take, for example, the tort of misfeasance in a public office, which has its roots in the ancient case of Ashby v. White.[160] This has often been said to be an anomalous tort. It was even singled out for possible abolition by the English Law Commission in fairly recent times. However, mindful of its longevity and the fact that numerous consultees defended its existence (on the basis that it “played a necessary role as a marker for particularly opprobrious action by public officials”),[161] the Law Commission abandoned any suggestion that it should be abolished.

Equally, we ought to bear in mind here the communis error facit jus principle, which has been endorsed by the courts on many occasions.[162] This principle, it will be recalled, operates to confer juridical legitimacy on rules of law that have been invoked and applied many times even though, when first minted, they may have been considered misguided. Any legal system which purports to take seriously both precedent and stability in the law must find room for the communis error facit jus principle.[163] And it is just this principle which belies Beever’s claim that “it is impossible to support the existence of a tort of inducing breach of contract.”[164] The action has been around for a great many years, and it has become firmly embedded as a legitimate part of the law by virtue of its repeated usage.

A second version of the irrelevance claim posits not that a certain case is wrong, but that a whole segment of the law has been created in error. Recall Weinrib’s claim that even an “extensive and ramified jurisprudence”[165] can be sidelined as anomalous in order to allow the law to work itself pure. The problem with any such claim is that it invites us to consider a large number of cases as erroneous in one fell swoop. Yet the very fact that the number of cases is large speaks powerfully against doing this (at least if the objection is based on the fact that the area of law is inconsistent with a particular theory). Of course, a given line of authority may clash with a grand explanatory theory. But when this happens—where, in other words, there is a very considerable gap between the explanandum and the explanans—it seems more appropriate to question not the correctness of the line of authority, but whether the theory was ever very satisfactory in terms of explaining all of the law.

When a theorist suggests that an entire cause of action (rather than just an odd case) be abandoned, or suggests that it should be regarded as something other than a tort, their theory ceases to be explanatory and becomes prescriptive in nature.[166] This transition into prescriptive writing can be seen at work in connection with the tort of public nuisance, described by certain rights theorists as an anomalous cause of action. Stevens, for example, makes exactly this claim when he asserts “that public nuisance is sui generis.”[167] In so saying, he seems happy to ignore the fact that public nuisance has been specifically endorsed as an extant tort at the very highest level,[168] not just in one common law jurisdiction, but in many. So much, then, for his repeatedly saying that he aims to explain the law as we find it. Nor can it help him that certain writers suggest that public nuisance is not even a tort of any kind,[169] let alone one that is an anomaly. Their doing so is equally countered by the fact that the courts have specifically labelled it a tort[170] and applied to it the tort rules on the limitation of actions.[171]

As noted already, Beever engages in a similarly Procrustean manoeuvre in relation to negligence cases predicated upon an assumed responsibility. His preferred approach is to repackage them as part of what he wants to call the “law of consents.”[172] He adopts this position in spite of the numerous judicial endorsements of such cases as part of the law of negligence and it is consequently hard to consider his approach a genuine exercise in interpretive theory. Interpretative theory involves evincing the best interpretation possible of what the courts have said. But when the courts are crystal clear on a matter—as they have been in relation to the category into which we must place assumed responsibility cases—it is hard to see how Beever can find conceptual space for the suggestion that they should be seen as part of a putative law of consents. The difficulty he faces on this front is only augmented once one recalls that he commits himself, in the construction of his theory, “to observ[ing] the way in which the judges developed their understandings of the case law...in order to produce a general account of the law.”[173] A much more plausible understanding of his approach to these cases is that he simply resorts to prescriptive writing in order to avert their clashing with his theory.

The third and final form in which an irrelevance claim may be made relies upon the idea of triviality. In this guise, the irrelevance claim asserts not that a rule of law is wrong, but that it is so inconsequential in either practical or theoretical terms that it may legitimately be treated as causing no (or only de minimis) embarrassment to the main tenets of a theory. Stevens’ rights-based account of tort law again furnishes a good example. In Torts and Rights, he attempts to trivialize the tort of misfeasance in a public office in two stages. He begins by making the point that it is a tort “of narrow scope”, a “public tort...of narrow compass”, “an exception...quite different from other torts.”[174] Then, instead of acknowledging the significant revitalization of the tort in two fairly recent House of Lords’ decisions,[175] he prefers to portray these modern cases in negative terms. He asserts that “[u]ntil relatively recently it [i.e., misfeasance in a public office] could be treated as of mainly historical interest.”[176] Beyond such simple affirmations, however, he does not stray. Yet if he hopes to make good his triviality claim, he must do more than affirm. Blunt and largely undefended assertions of this kind are a long way short of compelling, rigorously constructed arguments in favour of sidelining a tort.

Conclusion

When theorizing category X, no necessary difficulty will be encountered by the fact that this category can be neatly disaggregated into a series of subcategories such as X1, X2, and X3. So long as X1, X2, and X3 are all (1) discrete sub-categories of the broader category X, yet (2) related to one another in a particular way, and (3) demonstrably distinct from any other category of law from which category X is distinct, then the carving up of category X in this way ought to be uncontroversial. If, however, any of the conditions just described does not obtain, things will be very different. If subcategory X1, for example, in fact lies somewhere on the border between category X and category Y, such that it becomes hard or impossible to pin down where category X stops and category Y begins, then successfully theorizing category X in a way that claims or presupposes a clear distinction between categories X and Y will be rendered much more difficult (perhaps even impossible).

If we now jettison the abstract idea of subcategory X1 and replace it with the various hybrid torts considered in this article, it becomes obvious that tort law (the equivalent of category X), cannot simply be said to be distinct from other familiar categories such as contract, unjust enrichment and equity. Consequently, explanatory theories of tort which rely for plausibility on the foundational idea that tort law comprises a discrete body of law can be seen to founder. Not only do they fail to account satisfactorily for the sizeable range of significant hybrid torts that exist, they also fail clearly to set the four corners of their theory.

A final thought is this: though I doubt whether tort law can ever be entirely disentangled from neighbouring categories of law, I do not in so saying imply that the category ‘tort law’ is either meaningless or useless. I acknowledge that the courts frequently refer to ‘tort law’ or ‘the law of torts’, and that doing so serves a number of useful practical purposes. I can also see how a rough-edged conception of tort law is helpful to those engaged in teaching and learning the law. My claim is simply that the fuzziness of tort law’s borders significantly undermines the plausibility of my target theories. They are all explanatory theories purporting to offer a clear account of tort law’s nature and domain. They all treat tort law as though it were a discrete body of law with sharply-defined edges. Yet such treatment is unwarranted given the prevalence and effects of hybrid torts.