Analogy in law is a method of resolving issues on which there is no previous authority by using argument from analogy. Analogy in general involves an inference drawn from one particular situation to another based on similarity, but legal analogy is distinguished by the need to use a legally relevant basis for drawing an analogy between two situations. It may be applied to various forms of legal authority, including statutory law and case law.
In the civil law and common law traditions, the basis of legal relevance that allows drawing a legally valid analogy is described by different terms depending on the source of law involved: for precedent, for statutory law, and for unwritten legal principles. The use of analogy in both traditions is broadly described by the traditional maxim (where the reason is the same, the law is the same).
Although all legal systems use analogy in some fashion, different jurisdictions and legal traditions apply or limit analogy in many different ways. The civil law and common law traditions differ most prominently in the subject matter to which analogy is typically applied: in civil law courts, analogy is most typically employed to fill in gaps in a statute, while in common law courts it is most commonly used to apply and extend precedent. In addition, these legal systems have developed elaborate typologies of analogy, although these are often disputed.
The analogical extension of criminal penalties ("punishment by analogy") and tax liability is prohibited in many modern jurisdictions, under the various legal principles that safeguard legal certainty. Historically, however, punishment by analogy has been part of many legal systems, including those of imperial China, the early USSR, and the People's Republic of China prior to 1998. A few countries have retained legal provisions that at least nominally allow for punishment by analogy.
Related concepts
Legal analogy is usually considered distinct from extensive interpretation, which stays within the words of existing law. However, some authorities argue that the distinction between the two is unclear or untenable, as both approaches extending the effect of a statute beyond its literal words based on the purpose or intent of the legislature. Some authorities do not distinguish between the two at all.
The use of inductive reasoning to derive a general rule from multiple legal norms or precedents and apply it to a new case is sometimes regarded as a form of analogy, for example , but is sometimes considered a distinct form of legal argument since it does not involve a direct analogy from an established case to a new one.
Legal analogy is also distinguished from related forms of legal argument that also turn on the underlying reason for a legal norm, such as argumentum e contrario and argumentum a fortiori.
The analogical interpretation of statutes may also be distinguished from interpretation by implication, although this distinction is not commonly drawn in the civil law tradition.
Method
In broad terms, the use of analogy in law arises from the presumption that similar principles should apply to similar cases. In this broad sense, some legal scholars have argued that all legal reasoning is analogical.
More particularly, the general method of legal analogy has been described as having four steps: An existing legal norm governs a known case. No legal norm governs the current case (in other words, this case represents a legal gap or case of first impression). These two cases are relevantly similar, and are not relevantly dissimilar. Therefore, a new norm is created by applying the existing norm analogously in the current case.
The question of what makes the analogized case relevant generally turns on the reason for the existing norm (for example, the of a statute or the of a judicial precedent).
The detailed application of this method varies by the source of law. Within a legal system, the permitted use of analogy may vary greatly for example between statutory law and case law.
In case law
In case law, which is most prominently associated with the common law legal tradition, analogies are drawn from precedential cases. In the strongest case, a judge who decides a case at hand may find that the facts of the case are so similar to the facts of a prior case that the outcomes of these cases should be the same: stare decisis. Reasoning from the absence of analogy is also done, when a judge distinguishes a precedent and declines to apply it to the case at hand.
In one formulation, the method of analogy in applying precedent has the following steps: An existing case has certain factual characteristics. The current case also has these characteristics. A particular legal characteristic applies to the existing case. The factual similarities between the current case and the existing case are also relevant to the legal characteristic. Therefore, unless there are countervailing considerations of equal or greater weight, the new case also shares the legal characteristic. There are no countervailing considerations of equal or greater weight. Therefore, the new case also shares the legal characteristic.
An often-cited example of analogical reasoning in case law is Adams v. New Jersey Steamboat Co., in which the New York Court of Appeals was called upon to decide whether a steamboat line was liable for money being stolen from a passenger's stateroom, even if neither the passenger nor the crew had been negligent. There was no settled rule of precedent for steamboat liability. If the same event had occurred at an inn, the innkeeper would have been liable. In deciding the case, judge Denis O'Brien wrote that a steamboat passenger "procures and pays for his room for the same reasons that a guest at an inn does" and that a "steamer carrying passengers upon the water, and furnishing them with rooms and entertainment, is, for all practical purposes, a floating inn". He therefore concluded that "the duties which the proprietors owe to the passengers in their charge ought to be the same" and that "no good reason is apparent" for departing from the strict liability that applied to innkeepers. Therefore, because the cases were analogous in relevant respects and there were no countervailing considerations, the steamboat company was also liable.
In a more recent example, in Popov v. Hayashi, a valuable baseball was caught by two different people, confronting the California Superior Court with a fact pattern not governed by established legal standards for possession. The court reasoned by analogy with a New Jersey case involving children tossing an abandoned sock that turned out to contain money in determining that possession required both physical control and intent, and that under the circumstances it was appropriate to order an equitable division among the two people who caught the baseball. The court's decision in Popov has been analogized to the civil law practice of to fill in gaps in existing legal norms.
In statutory law
In statutory interpretation, analogy is used chiefly in civil law legal systems to extend a statute to cover new situations that are outside the actual language of the statute but within its underlying justification. This kind of statutory interpretation by analogy is formally recognized in the civil codes of most civil law jurisdictions, in both and forms. In practice, however, such analogies come into play in only a small minority of cases. A 1978 survey of approximately 1,000 German civil cases found that only 1/20 of them involved statutory analogies.
In addition, a form of analogy also used by the courts in common law jurisdictions to interpret statutes is analogous interpretation: if there are two similar statutes and one has already been construed, the court may construe the second statute by analogy to the construction of the first. This has been referred to as "analogical extensive interpretation".
Some statutes expressly provide for their provisions to be applied analogously. This statutory mandate to analogize gives the resulting analogies greater legal weight. One form of statutorily-mandated analogy is application, often translated as "analogous application". For example, the Dutch euthanasia statute provides for the provisions regarding an informed decision by the patient to be applied where the patient is incapable of making such decisions.
A more unusual example of mandated analogy is found in the Dutch civil code of 1992, where certain provisions governing liability for animals and dangerous objects call on the judge to analogize the case to a counterfactual. For example, Article 6:179 provides that the possessor of an animal is liable for damage unless the possessor would not have been liable, even if the animal was under his control, under the limitations of liability in the preceding section.
In constitutional law
Even in jurisdictions that do not widely practice statutory analogy, analogical methods may be used for interpreting constitutional law. For example, in Canada, the Section 15 Charter right to be free of discrimination covers not only the specific grounds for discrimination listed in the Charter, but also "analogous" grounds such as sexual orientation and marital status. The analogous prohibition in Section 9 of the Constitution of South Africa has also been similarly extended to protect against forms of discrimination analogous to those listed in the constitution.
In United States constitutional law, rights implied by analogy are often referred to as being in the penumbra of the Bill of Rights. This terminology was used by Oliver Wendell Holmes Jr. to describe rights developed by analogy to the Fourth and Fifth Amendments of the US Constitution, and also later by William O. Douglas to describe rights implied by various constitutional amendments, which he regarded as protected by the Ninth Amendment.
In 2022, in NYSRPA v. Bruen, the United States Supreme Court adopted a doctrine that requires courts to use historical analogies to determine whether a statute violates the Second Amendment to the United States Constitution.
The theory of penumbral rights developed by analogy with those articulated in the constitution has also been adopted in other countries. For example, courts in Bangladesh and India have used penumbral theory to extend a constitutional guarantee of the right to life to a right to a healthy environment.
In treaty law Teleological interpretation is commonly practiced by international tribunals. It is particularly associated with the jurisprudence of the European Court of Justice in interpreting the Treaties of the European Union. A teleological approach entails the frequent use of analogy to ensure that the purpose of a treaty's drafters is adequately served.
In addition, some treaties expressly call for their provisions to be interpreted analogously in certain situations. For example, the First Geneva Convention directly addresses the actions of belligerents, but in Article 6 also calls for neutral powers to apply its provisions by analogy.
Classification
Various classifications of legal analogy have been proposed. One typology that has been influential in the civil law tradition classifies legal analogies as intra legem or extra legem based on the legal gaps that they fill:
Extra legem (outside the law) refers to an analogy used to close a gap due to an issue not being clearly dealt with in existing law. Intra legem (within the law) refers to an analogy that closes a gap in which a law-controlled provision regulates the case at hand, but is unclear or ambiguous. In such circumstances, to decide the case at hand, one may try to find out what this provision means by relying on law-controlled provisions which address cases that are similar to the case at hand or other cases that are regulated by this unclear/ambiguous provision for help.
Other terms are also used: