01. common law

The question

The preceding unit established that judicial decision carries a different weight in the two great legal traditions, and that this difference is the principal structural division among the legal systems of the world. The present module examines those traditions in turn, and it begins with the common law, the tradition that descends from the law of medieval England and prevails today across much of the English-speaking world, including the United States, Canada, Australia, India, and many states of Africa and the Caribbean. The question this sub-unit answers is what distinguishes the common law as a method of making and applying law, and by what features a lawyer recognises a system as belonging to the tradition. The answer lies in the central place the tradition gives to the decided case.

The origin of the common law in judicial decision

The defining characteristic of the common law is that its foundational rules were made by judges deciding cases, rather than by a legislature enacting a code, and this characteristic is explained by the tradition's origin. Following the Norman conquest of England, the kings established royal courts whose judges travelled the realm and applied a single body of law common to the whole kingdom, displacing the varied local customs that had governed before. Because there was no comprehensive enacted code, the judges developed the law incrementally, decision by decision, each case settling a point that later cases would build upon.

This origin connects directly to the doctrine of sources examined in the previous unit. In a common law system, judicial decision is a primary source of law, standing alongside legislation rather than beneath it, and a vast body of legal rules, termed case law, exists only in the decisions of the courts and in no enacted text. The method is inductive: the law is drawn out of the accumulated decisions on particular facts, and the general rule is found by discerning what the cases, taken together, establish.

Consider the law governing the duty to take care not to injure one's neighbour, which in the common law world was for long not stated in any statute. A person seeking to know the content of that duty consults the leading decisions of the senior courts, extracts from them the principle the courts have applied, and predicts how the principle will govern a new situation. The rule exists in the cases, and the lawyer's task is to read the cases as the source of the rule.

The common law is therefore, at its foundation, a system in which the decided case is the primary material of the law, a feature that follows directly from its development by judges in the absence of a comprehensive code.

The doctrine of precedent

The decided case becomes a source of binding law through the doctrine of precedent, the principle, expressed in the maxim stare decisis, that a court is bound by the relevant decisions of courts above it in the same hierarchy and, in many systems, by its own past decisions. The doctrine converts the accumulated decisions from a mere record of past disputes into a body of authority that governs future cases, and it gives the common law its characteristic stability and its capacity for ordered growth.

The doctrine operates upon a precise distinction within any judgment, and this distinction is the connecting idea of the whole tradition. The ratio decidendi, the reason for the decision, is the principle of law essential to the result on the facts, and it alone binds later courts. The obiter dictum, a thing said by the way, is an observation the judge makes that is not essential to the decision, and it carries only persuasive weight. A later court bound by a precedent is bound by its ratio, and the art of common law reasoning consists in identifying the ratio of a past case and in determining whether the facts of the present case fall within it or may be distinguished from it.

Suppose a senior court decides that a manufacturer owes a duty of care to the ultimate consumer of its product, on facts involving a contaminated beverage, and the judge remarks in passing that a similar duty would arise for the supplier of a defective tool. A later court faced with an injury caused by a defective tool is bound by the ratio concerning the manufacturer's duty only so far as that ratio extends; the remark about tools is obiter and persuasive, and the later court must reason whether the established principle should be extended to the new facts. The example shows the doctrine operating as a disciplined method of growth, in which the law extends to new situations through reasoned analogy from binding rationes.

The doctrine of precedent is thus the engine of the common law, binding later courts to the essential reasoning of earlier ones while leaving room, through the distinction of ratio from obiter and the technique of distinguishing, for the law to develop as new facts arise.

Common law and equity

A common law system is marked by a second feature of historical origin, the dual body of rules known as common law and equity, which developed as two distinct streams and now operate together within a single system of courts. The common law, in this narrower sense, is the body of rules developed by the old royal courts, while equity is the body of rules developed by the separate Court of Chancery to soften the rigour of the common law where its strict application would work injustice.

Equity introduced remedies and doctrines the common law lacked, including the injunction, which orders a party to do or refrain from an act, and the trust, by which one person holds property for the benefit of another. The relation between the two streams is settled by the principle that where the rules of common law and equity conflict, equity prevails. Although the separate courts were long ago fused, so that a single court now administers both, the distinction between legal and equitable rules and remedies persists and remains essential to the analysis of many commercial questions.

Imagine a buyer who has contracted to purchase a unique commercial property and whom the seller then refuses to complete. The common law would award the buyer damages, a sum of money to compensate the loss, yet money may be an inadequate substitute for a unique asset. Equity supplies the remedy of specific performance, an order compelling the seller to complete the sale, available precisely because the common law remedy is inadequate. The example shows the two streams operating together, the equitable remedy supplementing the legal one where justice requires.

The coexistence of common law and equity is therefore a structural feature of the tradition, supplying it with a richer set of remedies and doctrines than a single undifferentiated body of rules would provide.

Adversarial procedure

The common law tradition is associated, finally, with a characteristic mode of procedure, the adversarial system, in which the parties and their representatives control the gathering and presentation of evidence and argument, and the judge presides as a neutral arbiter who decides the matter on what the parties put before the court. The judge does not investigate the facts or direct the inquiry; the contest is driven by the parties, each advancing its own case and testing the case of its opponent through cross-examination.

This mode of procedure connects to the tradition's broader character. Just as the substantive law is developed through the concrete contest of decided cases, so the resolution of each dispute proceeds through the concrete contest of opposing parties, and the law of evidence and procedure that governs the contest is itself elaborate and largely judge-made. The adversarial system contrasts with the inquisitorial procedure of the civil law tradition, examined in the following sub-unit, in which the court takes a more active role in investigating the facts.

In a commercial dispute over an alleged breach of a supply contract, the adversarial system places upon each party the burden of assembling and presenting the documents, witnesses, and arguments that support its position, and the judge decides between the competing cases without conducting an independent inquiry. The procedure mirrors at the level of the individual trial the party-driven, case-by-case character that marks the common law as a whole.

Adversarial procedure is thus the procedural counterpart of the common law method, completing the picture of a tradition in which law is made, found, and applied through the concrete contest of particular cases.