Common law, also known as case law or precedent, is law developed by judges through decisions of courts and similar tribunals rather than through legislative statutes or executive branch action. A “common law system” is a legal system that gives great precedential weight to common law, on the principle that it is unfair to treat similar facts differently on different occasions.  The body of precedent is called “common law” and it binds future decisions. In cases where the parties disagree on what the law is, an idealized common law court looks to past precedential decisions of relevant courts.
If a similar dispute has been resolved in the past, the court is bound to follow the reasoning used in the prior decision (this principle is known as stare decisis). If, however, the court finds that the current dispute is fundamentally distinct from all previous cases (called a “matter of first impression”), judges have the authority and duty to make law by creating precedent.  Thereafter, the new decision becomes precedent, and will bind future courts. In practice, common law systems are considerably more complicated than the idealized system described above.
The decisions of a court are binding only in a particular jurisdiction, and even within a given jurisdiction, some courts have more power than others. For example, in most jurisdictions, decisions by appellate courts are binding on lower courts in the same jurisdiction and on future decisions of the same appellate court, but decisions of lower courts are only non-binding persuasive authority. Interactions between common law, constitutional law, statutory law and regulatory law also give rise to considerable complexity.
However stare decisis, the principle that similar cases should be decided according to consistent principled rules so that they will reach similar results, lies at the heart of all common law systems. Common law legal systems are in widespread use, particularly in England where it originated in the Middle Ages, and in nations that trace their legal heritage to England as former colonies of the British Empire, including the United States, Malaysia, Singapore, Pakistan, Sri Lanka, India, Ghana, Cameroon, Canada, Ireland, New Zealand, South Africa, Hong Kong and Australia. 
Primary connotations The term common law has three main connotations and several historical meanings worth mentioning: 1. Common law as opposed to statutory law and regulatory law This connotation distinguishes the authority that promulgated a law. For example, most areas of law in most Anglo-American jurisdictions include “statutory law” enacted by a legislature, “regulatory law” promulgated by executive branch agencies pursuant to delegation of rule-making authority from the legislature, and common law or “case law”, i. e. , decisions issued by courts (or quasi-judicial tribunals within agencies).
  This first connotation can be further differentiated into (a) pure common law arising from the traditional and inherent authority of courts to define what the law is, even in absence of an underlying statute, e. g. , most criminal law and procedural law before the 20th century, and even today, most of contract law and the law of torts, and (b) court decisions that decide the fine boundaries and distinctions in law promulgated by other bodies, such as judicial interpretations of the Constitution, of statutes, and of regulations.  2.
Common law legal systems as opposed to civil law legal systems This connotation differentiates “common law” jurisdictions and legal systems from “civil law” or “code” jurisdictions.  Common law systems place great weight on court decisions, which are considered “law” with the same force of law as statutes. By contrast, in civil law jurisdictions (the legal tradition that prevails in, or is combined with common law in, Europe and most non-Islamic, non-common law countries), judicial precedent is given less weight (which means that a judge deciding a given case has more freedom to interpret the text of a statute
Common law independently, and less predictably), and scholarly literature is given more. For example, the Napoleonic code expressly forbade French judges from pronouncing general principles of law.  As a rough rule of thumb, common law systems trace their history to England, while civil law systems trace their history to Roman law and the Napoleonic Code. The contrast between common law and civil law systems is elaborated in Alternatives to common law systems, below. 2 3. Law as opposed to equity This connotation differentiates “common law” (or just “law”) from “equity”.
  Before 1873, England had two parallel court systems: courts of “law” that could only award money damages and recognized only the legal owner of property, and courts of “equity” (courts of chancery) that could issue injunctive relief (that is, a court order to a party to do something, give something to someone, or stop doing something) and recognized trusts of property. This split propagated to many of the colonies, including the United States (see “Reception Statutes”, below). For most purposes, most jurisdictions, including the U. S. federal system and most states, have merged the two courts.
  Additionally, even before the separate courts were merged together, most courts were permitted to apply both law and equity, though under potentially different procedural law. Nonetheless, the historical distinction between “law” and “equity” remains important today when the case involves issues such as the following: • categorizing and prioritizing rights to property—for example, the same article of property often has a “legal title” and an “equitable title,” and these two groups of ownership rights may be held by different people.
• in the United States, determining whether the Seventh Amendment’s right to a jury trial applies (a determination of a fact necessary to resolution of a “common law” claim) or whether the issue will be decided by a judge (issues of what the law is, and all issues relating to equity). • the standard of review and degree of deference given by an appellate tribunal to the decision of the lower tribunal under review (issues of law are reviewed de novo, that is, “as if new” from scratch by the appellate tribunal, while most issues of equity are reviewed for “abuse of discretion,” that is, with great deference to the tribunal below).
• the remedies available and rules of procedure to be applied. 4. Historical uses In addition, there are several historical uses of the term that provide some background as to its meaning. The English Court of Common Pleas dealt with lawsuits in which the King had no interest, i. e. between commoners. Additionally, from at least the 11th century and continuing for several centuries after that, there were several different circuits in the royal court system, served by itinerant judges who would travel from town to town dispensing the King’s justice.
The term “common law” was used to describe the law held in common between the circuits and the different stops in each circuit. The more widely a particular law was recognized, the more weight it held, whereas purely local customs were generally subordinate to law recognized in a plurality of jurisdictions. These definitions are archaic, their relevance having dissipated with the development of the English legal system over the centuries, but they do explain the origin of the term. Basic principles of common law Common law adjudication.
In a common law jurisdiction several stages of research and analysis are required to determine “what the law is” in a given situation. First, one must ascertain the facts. Then, one must locate any relevant statutes and cases. Then one must extract the principles, analogies and statements by various courts of what they consider important to determine how the next court is likely to rule on the facts of the present case. Later decisions, and decisions of higher courts or legislatures carry more weight than earlier cases and those of lower courts.
 Finally, one integrates all the lines Common law drawn and reasons given, and determines what “the law is”. Then, one applies that law to the facts. 3 The common law evolves to meet changing social needs and improved understanding The common law is more malleable than statutory law. First, common law courts are not absolutely bound by precedent, but can (when extraordinarily good reason is shown) reinterpret and revise the law, without legislative intervention, to adapt to new trends in political, legal and social philosophy.
Second, the common law evolves through a series of gradual steps, that gradually works out all the details, so that over a decade or more, the law can change substantially but without a sharp break, thereby reducing disruptive effects.  In contrast to common law incrementalism, the legislative process is very difficult to get started, as legislatures tend to delay action until a situation is totally intolerable. For these reasons, legislative changes tend to be large, jarring and disruptive (sometimes positively, sometimes negatively, and sometimes with unintended consequences).
One example of the gradual change that typifies the common law is the gradual change in liability for negligence. For example, the traditional common law rule through most of the 19th century was that a plaintiff could not recover for a defendant’s negligence unless the two were in privity of contract. Thus, only the immediate purchaser could recover for a product defect, and if a part was built up out of parts from parts manufacturers, the ultimate buyer could not recover for injury caused by a defect in the part. Winterbottom v.
Wright, 10 M&W 109, 152 Eng. Rep. 402, 1842 WL 5519 (Exchequer of pleas 1842). In Winterbottom, the postal service had contracted with Wright to maintain its coaches. Winterbottom was a driver for the post. When the coach failed and injured Winterbottom, he sued Wright. The Winterbottom court recognized that there would be “absurd and outrageous consequences” if an injured person could sue any person peripherally involved, and knew it had to draw a line somewhere, a limit on the causal connection between the negligent conduct and the injury.
The court looked to the contractual relationships, and held that liability would only flow as far as the person in immediate contract (“privity”) with the negligent party. A first exception to this rule arose in Thomas v. Winchester , 6 N. Y. 397 (N. Y. 1852), which held that mislabeling a poison as an innocuous herb, and then selling the mislabeled poison through a dealer who would be expected to resell it, put “human life in imminent danger. ” Thomas used this as a reason to create an exception to the “privity” rule.
In Statler v. Ray Mfg. Co. , 195 N. Y. 478, 480 (N. Y. 1909) held that a coffee urn manufacturer was liable to a person injured when the urn exploded, because the urn “was of such a character inherently that, when applied to the purposes for which it was designed, it was liable to become a source of great danger to many people if not carefully and properly constructed. ” Yet the privity rule survived. In Cadillac Motor Car Co. v. Johnson, 221 F. 801 (2nd Cir.
1915) (decided by the federal appeals court for New York and several neighboring states), the court held that a car owner could not recover for injuries from a defective wheel, when the automobile owner had a contract only with the automobile dealer and not with the manufacturer, even though there was “no question that the wheel was made of dead and ‘dozy‘ wood, quite insufficient for its purposes. ” The Cadillac court was willing to acknowledge that the case law supported exceptions for “an article dangerous in its nature or likely to become so in the course of the ordinary usage to be contemplated by the vendor.
” However, held the Cadillac court, “one who manufactures articles dangerous only if defectively made, or installed, e. g. , tables, chairs, pictures or mirrors hung on the walls, carriages, automobiles, and so on, is not liable to third parties for injuries caused by them, except in case of willful injury or fraud,” Finally, in the famous case of MacPherson v. Buick Motor Co. , 217 N. Y. 382, 111 N. E. 1050 (N. Y. 1916), Judge Benjamin Cardozo pulled a broader principle out of these predecessor cases.
The facts were almost identical to Cadillac a year earlier: a wheel from a wheel manufacturer was sold to Buick, to a dealer, to MacPherson, and the wheel failed, injuring MacPherson. Judge Cardozo held: It may be that Statler v. Ray Mfg. Co. have extended the rule of Thomas v. Winchester. If so, this court is committed to the extension. The defendant argues that things imminently dangerous to life are poisons, explosives, deadly weapons—things whose normal function it is to injure or destroy. But whatever the rule in Thomas v.
Winchester may once have been, it has no longer that restricted meaning. A scaffold (Devlin v.Common law Smith, supra) is not inherently a destructive instrument. It becomes destructive only if imperfectly constructed. A large coffee urn (Statler v. Ray Mfg. Co. , supra) may have within itself, if negligently made, the potency of danger, yet no one thinks of it as an implement whose normal function is destruction. What is true of the coffee urn is equally true of bottles of aerated water (Torgeson v. Schultz, 192 N. Y. 156). We have mentioned only cases in this court. But the rule has received a like extension in our courts of intermediate appeal. In Burke v. Ireland (26 App. Div. 487), in an opinion by CULLEN, J.
, it was applied to a builder who constructed a defective building; in Kahner v. Otis Elevator Co. (96 App. Div. 169) to the manufacturer of an elevator; in Davies v. Pelham Hod Elevating Co. (65 Hun, 573; affirmed in this court without opinion, 146 N. Y. 363) to a contractor who furnished a defective rope with knowledge of the purpose for which the rope was to be used. We are not required at this time either to approve or to disapprove the application of the rule that was made in these cases. It is enough that they help to characterize the trend of judicial thought. We hold, then, that the principle of Thomas v.
Winchester is not limited to poisons, explosives, and things of like nature, to things which in their normal operation are implements of destruction. If the nature of a thing is such that it is reasonably certain to place life and limb in peril when negligently made, it is then a thing of danger. Its nature gives warning of the consequences to be expected. If to the element of danger there is added knowledge that the thing will be used by persons other than the purchaser, and used without new tests then, irrespective of contract, the manufacturer of this thing of danger is under a duty to make it carefully.
… There must be knowledge of a danger, not merely possible, but probable. Note that Cardozo’s new “rule” exists in no prior case, but is inferrable as a synthesis of the “thing of danger” principle stated in them, merely extending it to “foreseeable danger” even if “the purposes for which it was designed” were not themselves “a source of great danger. ” MacPherson takes some care to present itself as foreseeable progression, not a wild departure.
Note that Judge Cardozo continues to adhere to the original principle of Winterbottom, that “absurd and outrageous consequences” must be avoided, and he does so by drawing a new line in the last sentence quoted above: “There must be knowledge of a danger, not merely possible, but probable. ” But while adhering to the underlying principle that some boundary is necessary, MacPherson overruled the prior common law by rendering the formerly dominant factor in the boundary, that is, the privity formality arising out of a contractual relationship between persons, totally irrelevant.
Rather, the most important factor in the boundary would be the nature of the thing sold and the foreseeable uses that downstream purchasers would make of the thing. This illustrates two crucial principles that are often not well understood by non-lawyers. (a) The law evolves, this evolution is in the hands of judges, and judges have “made law” for hundreds of years. (b) The reasons given for a decision are often more important in the long run than the outcome in a particular case.
This is the reason that judicial opinions are usually quite long, and give rationales and policies that can be balanced with judgment in future cases, rather than the bright-line rules usually embodied in statutes. 4 Interaction of constitutional, statutory and common law In common law legal systems (connotation 2), the common law (connotation 1) is crucial to understanding almost all important areas of law. For example, in England and Wales and in most states of the United States, the basic law of contracts, torts and property do not exist in statute, but only in common law (though there may be isolated modifications enacted by statute).
In almost all areas of the law (even those where there is a statutory framework, such as contracts for the sale of goods, or the criminal law), legislature-enacted statutes generally give only terse statements of general principle, and the fine boundaries and definitions exist only in the common law (connotation 1). To find out what the precise law is that applies to a particular set of facts, one has to locate precedential decisions on the topic, and reason from those decisions by analogy.
To consider but one example, the First Amendment to the United States Constitution states “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof”—but interpretation (that is, determining the fine boundaries, and resolving the tension between the “establishment” and “free exercise” clauses) of each of the important terms was Common law delegated by Article III of the Constitution to the judicial branch, so that the current legal boundaries of the Constitutional text can only be determined by consulting the common law.
 In common law jurisdictions, legislatures operate under the assumption that statutes will be interpreted against the backdrop of the pre-existing common law and custom. For example, in most U. S. states, the criminal statutes are primarily codification of pre-existing common law. (Codification is the process of enacting a statute that collects and restates pre-existing law in a single document—when that pre-existing law is common law, the common law remains relevant to the interpretation of these statutes.)
In reliance on this assumption, modern statutes often leave a number of terms and fine distinctions unstated—for example, a statute might be very brief, leaving the precise definition of terms unstated, under the assumption that these fine distinctions will be inherited from pre-existing common law. (For this reason, many modern American law schools teach the common law of crime as it stood in England in 1789, because that centuries-old English common law is a necessary foundation to interpreting modern criminal statutes.)
With the transition from English law, which had common law crimes, to the new legal system under the U. S. Constitution, which prohibited ex post facto laws at both the federal and state level, the question was raised whether there could be common law crimes in the United States. It was settled in the case of United States v. Hudson and Goodwin, 11 U. S. 32  (1812), which decided that federal courts had no jurisdiction to define new common law crimes, and that there must always be a (constitutional) statute defining the offense and the penalty for it.
Still, many states retain selected common law crimes. For example, in Virginia, the definition of the conduct that constitutes the crime of robbery exists only in the common law, and the robbery statute only sets the punishment.  Virginia Code section 1-200 establishes the continued existence and vitality of common law principles and provides that “The common law of England, insofar as it is not repugnant to the principles of the Bill of Rights and Constitution of this Commonwealth, shall continue in full force within the same, and be the rule of decision, except as altered by the General Assembly.
” By contrast to statutory codification of common law, some statutes displace common law, for example to create a new cause of action that did not exist in the common law, or to legislatively overrule the common law. An example is the tort of wrongful death, which allows certain persons, usually a spouse, child or estate, to sue for damages on behalf of the deceased. There is no such tort in English common law; thus, any jurisdiction that lacks a wrongful death statute will not allow a lawsuit for the wrongful death of a loved one.
Where a wrongful death statute exists, the compensation or other remedy available is limited to the remedy specified in the statute (typically, an upper limit on the amount of damages). Courts generally interpret statutes that create new causes of action narrowly – that is, limited to their precise terms—because the courts generally recognize the legislature as being supreme in deciding the reach of judge-made law unless such statute should violate some “second order” constitutional law provision (cf. judicial activism).
Where a tort is rooted in common law, all traditionally recognized damages for that tort may be sued for, whether or not there is mention of those damages in the current statutory law. For instance, a person who sustains bodily injury through the negligence of another may sue for medical costs, pain, suffering, loss of earnings or earning capacity, mental and/or emotional distress, loss of quality of life, disfigurement and more. These damages need not be set forth in statute as they already exist in the tradition of common law.
However, without a wrongful death statute, most of them are extinguished upon death. In the United States, the power of the federal judiciary to review and invalidate unconstitutional acts of the federal executive branch is stated in the constitution, Article III sections 1 and 2: “The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish. …
The judicial Power shall extend to all Cases, in Law and Equity, arising under this Constitution, the Laws of the United States, and Treaties made, or which shall be made, under their Authority… ” The first famous statement of “the judicial power” was Marbury v. Madison, 5 U. S. (1 Cranch) 137  (1803). Later cases interpreted the “judicial power” of Article III to establish the power of federal courts to consider or overturn any action of congress or of any state that conflicts with the constitution. 5 Common law 6.
Overruling precedent—the limits of stare decisis Most of the U. S. federal courts of appeal have adopted a rule under which, in the event of any conflict in decisions of panels (most of the courts of appeal almost always sit in panels of three), the earlier panel decision is controlling, and a panel decision may only be overruled by the court of appeals sitting en banc (that is, all active judges of the court) or by a higher court.  In these courts, the older decision remains controlling when an issue comes up the third time.
Other courts, for example, the Court of Customs and Patent Appeals and the Supreme Court, always sit en banc, and thus the later decision controls. These courts essentially overrule all previous cases in each new case, and older cases survive only to the extent they do not conflict with newer cases. The interpretations of these courts – for example, Supreme Court interpretations of the constitution or federal statutes – are stable only so long as the older interpretation maintains the support of a majority of the court.
The majority may persist through some combination of belief that the old decision is right, and that it is not sufficiently wrong to be overruled. In the UK, since 2009, the Supreme Court of the United Kingdom has the authority to overrule and unify decisions of lower courts. From 1966 to 2009, this power lay with the House of Lords, granted by the Practice Statement of 1966.  Common law as a foundation for commercial economies The reliance on judicial opinion is a strength of common law systems, and is a significant contributor to the robust commercial systems in the United Kingdom and United States.
Because there is common law to give reasonably precise guidance on almost every issue, parties (especially commercial parties) can predict whether a proposed course of action is likely to be lawful or unlawful. This ability to predict gives more freedom to come close to the boundaries of the law.  For example, many commercial contracts are more economically efficient, and create greater wealth, because the parties know ahead of time that the proposed arrangement, though perhaps close to the line, is almost certainly legal.
Newspapers, taxpayer-funded entities with some religious affiliation, and political parties can obtain fairly clear guidance on the boundaries within which their freedom of expression rights apply. In contrast, in non-common-law countries, and jurisdictions with very weak respect for precedent (example, the U. S. Patent Office), fine questions of law are redetermined anew each time they arise, making consistency and prediction more difficult, and procedures far more protracted than necessary because parties cannot rely on written statements of law as reliable guides.
In jurisdictions that do not have a strong allegiance to a large body of precedent, parties have less a priori guidance and must often leave a bigger “safety margin” of unexploited opportunities, and final determinations are reached only after far larger expenditures on legal fees by the parties. This is the reason for the frequent choice of the law of the State of New York in commercial contracts.  Commercial contracts almost always include a “choice of law clause” to reduce uncertainty.
Somewhat surprisingly, contracts throughout the world (for example, contracts involving parties in Japan, France and Germany, and from most of the other states of the United States) often choose the law of New York, even where the relationship of the parties and transaction to New York is quite attenuated. Because of its history as the nation’s commercial center, New York common law has a depth and predictability not (yet) available in any other jurisdiction.
Similarly, corporations are often formed under Delaware corporate law, and contracts relating to corporate law issues (merger and acquisitions of companies, rights of shareholders, etc. ) include a Delaware choice of law clause, because of the deep body of law in Delaware on these issues.  On the other hand, some other jurisdictions have sufficiently developed bodies of law so that parties have no real motivation to choose the law of a foreign jurisdiction (e. g. , England and Wales, and the state of California), but not yet so fully developed that parties with no relationship to the jurisdiction choose that law.
The common theme in each case is that commercial parties seek predictability and simplicity in their contractual relations, and frequently choose the law of a common law jurisdiction with a well-developed body of common law to achieve that result. Likewise, for litigation of commercial disputes arising out of unpredictable torts (as opposed to the prospective choice of law clauses in contracts discussed in the previous paragraph), certain jurisdictions attract an unusually high Common law fraction of cases, because of the predictability afforded by the depth of decided cases.
For example, London is considered the pre-eminent centre for litigation of admiralty cases.  This is not to say that common law is better in every situation. For example, civil law can be clearer than case law when the legislature has had the foresight and diligence to address the precise set of facts applicable to a particular situation. For that reason, civil law statutes tend to be somewhat more detailed than statutes written by common law legislatures – but, conversely, that tends to make the statute more difficult to read (the United States tax code is an example).
 Nonetheless, as a practical matter, no civil law legislature can ever address the full spectrum of factual possibilities in the breadth, depth and detail of the case law of the common law courts of even a smaller jurisdiction, and that deeper, more complete body of law provides additional predictability that promotes commerce. 7 History The term “common law” originally derives from after the Norman Conquest. The “common law” was the law that emerged as “common” throughout the realm, as the king’s judges imposed a unified common law throughout England.
The doctrine of precedent developed under the inquisitorial system in England during the 12th and 13th centuries, as the collective judicial decisions that were based in tradition, custom and precedent. Such forms of legal institutions and culture bear resemblance to those that existed historically in societies where precedent and custom played a role in the legal process, including Germanic law.  The form of reasoning used in common law is known as casuistry or case-based reasoning.
The common law, as applied in civil cases (as distinct from criminal cases), was devised as a means of compensating someone for wrongful acts known as torts, including both intentional torts and torts caused by negligence, and as developing the body of law recognizing and regulating contracts. The type of procedure practiced in common law courts is known as the adversarial system; this is also a development of the common law. Medieval English common law Before the Norman conquest in 1066, justice was administered primarily by county courts, presided by the diocesan bishop and the sheriff, exercising both ecclesiastical and civil jurisdiction.
 Trial by jury began in these courts.  In 1154, Henry II became the first Plantagenet king. Among many achievements, Henry institutionalized common law by creating a unified system of law “common” to the country through incorporating and elevating local custom to the national, ending local control and peculiarities, eliminating arbitrary remedies and reinstating a jury system – citizens sworn on oath to investigate reliable criminal accusations and civil claims.
The jury reached its verdict through evaluating common local knowledge, not necessarily through t