In ancient society, the most systematic, comprehensive and developed law and jurisprudence belonged to Roman law, so that the later legal research was mostly based on the recovery and development of Roman law; Secondly, the divine law of the medieval church. Roman law and divine law provide endless material and imagination space for the development of modern law. The emergence and development of Roman law and divine law were based on the historical situation at that time and served the social, political, economic and cultural conditions at that time. On the one hand, the systematicness and completeness of Roman law benefited from the prosperity of the Roman Empire. On the other hand, the emergence and development of Roman law promoted this prosperity. As for church law, many legal concepts, terms and legislative techniques still affect modern legal activities.
However, in earlier Greece, law was not a prominent science, and the debate between Plato and Aristotle on the rule of law was also subordinate to their philosophical thoughts, only a department in their research field, and the main direction was still political science. The main reason is that ancient Greece did not face complicated and diverse social governance problems like ancient Rome, and the research approach was still limited to the polis. Compared with the vast territory of ancient Rome and the multi-ethnic and multi-cultural social structure, the production mode, lifestyle and organizational form of the city-state are much simpler. Based on the constraints of historical and social conditions, it is impossible for ancient Greece to develop a set of systematic and complete legal systems and theories like Rome. Therefore, the development of law and jurisprudence is essentially subject to the social structure conditions in a specific historical situation.
So from the perspective of discipline. The main theoretical sources of ancient Roman jurisprudence are ancient Greek philosophy and political science. Early Roman jurists, such as Cicero, analyzed social problems with obvious colors of ancient Greek philosophy and political science, and used the concepts, terms, concepts, basic theories and ways of thinking of philosophy and political science to analyze and understand social (legal) problems. However, with the emergence of new social (legal) problems and the emergence of new specialized legal talents-jurist class, law gradually got rid of the shackles of philosophy and politics, became an independent discipline, and formed its own set of concepts and terms. But we can still say that the matrix of law is philosophy and political science. Since then, Kant, Hegel and others have restored the tradition of ancient Greek ancestors and reconstructed jurisprudence from the perspective of new classical philosophy, which is another story.
Montesquieu's On the Spirit of Law successfully introduced historiography into legal research. Understanding the law by means of history and textual research, replacing transcendental philosophy with historical materials, the representative figure of Britain is Main's Ancient Law; German jurists, represented by savigny, developed Montesquieu's research methods and eventually formed a famous school of historical law. Since then, law has been evolving with the development of society, and emerging jurists have been using other disciplines to understand and analyze legal issues, thus giving birth to a series of legal schools. These schools of law have their own unique theoretical origins and their own systems. For example, natural law school (whose theoretical origin continues ancient Greek philosophy, middle-earth theology, classical philosophy and enlightenment thought); Normative analysis school (Austin and Hart borrowed the theories of logic, rhetoric and semantic analysis); School of Sociology of Law (drawing extensively on the sociological theories founded by Marx and Weber) and so on. Under these schools, it can be divided into smaller schools according to different theoretical foundations (for example, although both belong to the school of law, Hart's semantic analysis is different from kelsen's pure law; Although they all belong to social law, Yelin's purpose law, Heck's interest law and Digi's social joint law are different. As for the schools of modern law, it is even more varied: McCormick and Vajnberger's institutional law; Holmes' pragmatic jurisprudence; American legal realism; Hayek's neo-liberal jurisprudence; Marxist jurisprudence; Existentialist law and so on, the most famous of which is of course the economic analysis law represented by Posner, which uses the principles of modern economics to understand and analyze legal issues. Standing in different theoretical origins and backgrounds, these schools understand and analyze legal issues from different angles. There are differences between them, but they also learn from each other and communicate with each other.
It can be seen that in the history of legal development, applying the theories of other disciplines to study legal issues may lead to the birth of a new discipline from a big perspective, which is a very important landmark event; Look small, at least the birth and formation of a genre, a new perspective. This conclusion, I think, is valid in all fields of society and humanities, which is a very important research idea. At present, the mainstream of legal research methods is still advocated by three major law schools, namely, the value of natural law school, the normative analysis of normative law school and the facts of social law school.
How to treat the subject to which the new conclusion finally belongs? Using the theories of other disciplines to analyze legal issues has both theoretical and legal colors, and its conclusions can be attributed to legal disciplines because they study legal issues; But from the perspective of other disciplines, it can be regarded as the application and practice of knowledge, theory and method in this discipline, and can also be included in the fields of other disciplines in a broad sense. This is really an interesting phenomenon. But as law learners and researchers, we still count them as new achievements in the field of law and classify them as law subjects, which is no problem.
Finally, although the theoretical origins are consistent, due to the different knowledge, interests and personal experiences of researchers, different perspectives of research may also lead to different understanding and analysis of legal issues. Like Hugue and Heck, who belong to the same school of social law, there is a continuation and inheritance relationship between them, but Hugue's law of purpose reconstructs the understanding of legal issues from the perspective of law-making purpose (subjective); Heck's interest law is more about analyzing legal issues from the perspective of interests that the law tries to adjust (biased towards objectivity). Although their conclusions are similar, they are quite different.