Comparative law is the study of differences and similarities between the law (legal systems) of different countries. More specifically, it involves the study of the different legal "systems" (or "families") in existence in the world, including the common law, the civil law, socialist law, Canon law, Jewish Law, Islamic law, Hindu law, and Chinese law. It includes the description and analysis of foreign legal systems, even where no explicit comparison is undertaken. The importance of comparative law has increased enormously in the present age of internationalism, economic globalization, and democratization.
The origins of modern Comparative Law can be traced back to Gottfried Wilhelm Leibniz in 1667 in his Latin-language book Nova Methodus Discendae Docendaeque Iurisprudentiae (New Methods of Studying and Teaching Jurisprudence). Chapter 7 (Presentation of Law as the Project for all Nations, Lands and Times) introduces the idea of classifying Legal Systems into several families. Notably, a few years later, Leibniz introduced an idea of Language families.
Although every Legal System is unique, Comparative Law through studies of their similarities and differences allows for classification of Legal Systems, wherein Law Families is the basic level of the classification. The main differences between Law Families are found in the source(s) of Law, the role of court precedents, the origin and development of the Legal System. Montesquieu is generally regarded as an early founding figure of comparative law. His comparative approach is obvious in the following excerpt from Chapter III of Book I of his masterpiece, De l'esprit des lois (1748; first translated by Thomas Nugent, 1750):
[T]he political and civil laws of each nation ... should be adapted in such a manner to the people for whom they are framed that it should be a great chance if those of one nation suit another.
They should be in relation to the nature and principle of each government: whether they form it, as may be said of politic laws; or whether they support it, as in the case of civil institutions.
They should be in relation to the climate of each country, to the quality of its soil, to its situation and extent, to the principal occupation of the natives, whether husbandmen, huntsmen, or shepherds: they should have relation to the degree of liberty which the constitution will bear; to the religion of the inhabitants, to their inclinations, riches, numbers, commerce, manners, and customs.
Also, in Chapter XI (entitled 'How to compare two different Systems of Laws') of Book XXIX, discussing the French and English systems for punishment of false witnesses, he advises that "to determine which of those systems is most agreeable to reason, we must take them each as a whole and compare them in their entirety." Yet another place where Montesquieu's comparative approach is evident is the following, from Chapter XIII of Book XXIX:
As the civil laws depend on the political institutions, because they are made for the same society, whenever there is a design of adopting the civil law of another nation, it would be proper to examine beforehand whether they have both the same institutions and the same political law.
The modern founding figure of comparative and anthropological jurisprudence was Sir Henry Maine, a British jurist and legal historian. In his 1861 work Ancient Law: Its Connection with the Early History of Society, and Its Relation to Modern Ideas, he set out his views on the development of legal institutions in primitive societies and engaged in a comparative discussion of Eastern and Western legal traditions. This work placed comparative law in its historical context and was widely read and influential.
The first university course on the subject was established at the University of Oxford in 1869, with Maine taking up the position of professor.
Comparative law in the US was brought by a legal scholar fleeing persecution in Germany, Rudolf Schlesinger. Schlesinger eventually became professor of comparative law at Cornell Law School helping to spread the discipline throughout the US.
Comparative law is an academic discipline that involves the study of legal systems, including their constitutive elements and how they differ, and how their elements combine into a system.
Several disciplines have developed as separate branches of comparative law, including comparative constitutional law, comparative administrative law, comparative civil law (in the sense of the law of torts, contracts, property and obligations), comparative commercial law (in the sense of business organisations and trade), and comparative criminal law. Studies of these specific areas may be viewed as micro- or macro-comparative legal analysis, i.e. detailed comparisons of two countries, or broad-ranging studies of several countries. Comparative civil law studies, for instance, show how the law of private relations is organised, interpreted and used in different systems or countries. The purposes of comparative law are:
Comparative law is different from general jurisprudence (i.e. legal theory) and from public and private international law. However, it helps inform all of these areas of normativity.
For example, comparative law can help international legal institutions, such as those of the United Nations System, in analyzing the laws of different countries regarding their treaty obligations. Comparative law would be applicable to private international law when developing an approach to interpretation in a conflicts analysis. Comparative law may contribute to legal theory by creating categories and concepts of general application. Comparative law may also provide insights into the question of legal transplants, i.e. the transplanting of law and legal institutions from one system to another. The notion of legal transplants was coined by Alan Watson, one of the world's renowned legal scholars specializing in comparative law.
Also, the usefulness of comparative law for sociology of law and law and economics (and vice versa) is very large. The comparative study of the various legal systems may show how different legal regulations for the same problem function in practice. Conversely, sociology of law and law & economics may help comparative law answer questions, such as:
René David proposed the classification of legal systems, according to the different ideology inspiring each one, into five groups or families:
Especially with respect to the aggregating by David of the Civil and Common laws into a single family, David argued that the antithesis between the Common law and Civil law systems, is of a technical rather than of an ideological nature. Of a different kind is, for instance, the antithesis between, say, Italian and American laws, and of a different kind than between the Soviet, Muslim, Hindu, or Chinese laws. According to David, the Civil law legal systems included those countries where legal science was formulated according to Roman law, whereas Common law countries are those dominated by judge-made law. The characteristics that he believed uniquely differentiate the Western legal family from the other four are:
Arminjon, Nolde, and Wolff believed that, for purposes of classifying the (then) contemporary legal systems of the world, it was required that those systems per se get studied, irrespective of external factors, such as geographical ones. They proposed the classification of legal system into seven groups, or so-called 'families', in particular the:
Konrad Zweigert and Hein Kötz propose a different, multidimensional methodology for categorizing laws, i.e. for ordering families of laws. They maintain that, to determine such families, five criteria should be taken into account, in particular: the historical background, the characteristic way of thought, the different institutions, the recognized sources of law, and the dominant ideology. Using the aforementioned criteria, they classify the legal systems of the world into six families:
Up to the second German edition of their introduction to comparative law, Zweigert and Kötz also used to mention Soviet or socialist law as another family of laws.
H. Patrick Glenn proposed the classification of legal systems places national laws in the broader context of major legal tradition: