The basic principles of social law fall into three: fairness of contract, the social nature of ownership and no-fault liability. First, fairness of contract: labor law emerged as social law to secure fair contracts by modifying the principle of freedom of contract, which had deepened inequality between capital and labor. Second, the social nature of ownership modifies civil law's principle of absolute ownership and means that the exercise of ownership is not an absolute freedom but must be subject to necessary limits and restraints from a social and national standpoint. Third, no-fault liability reflects a shift from the employer's fault-based liability to collective liability as the structural contradictions of capitalism and the resulting social problems deepened. Social law, which seeks to modify the principle of individual responsibility into a principle of collective responsibility, has developed mainly around social security law and social welfare services law. With the appearance of industrial accident compensation insurance law, collective liability in which employers jointly bear the burden of industrial accidents was recognized. Such collective liability means that the causes of accidents and illness lie not in individual failings but in the structure of society itself, so society must bear responsibility jointly.

In short, social law emerged by modifying the principles of civil law. One can debate whether social law is a continuation of civil law or an entirely new form of law that breaks with it. This is directly connected to the issue of how capitalist market relations and social policy relate to each other. People gradually realized that human beings who were formally equal before the law were in reality not equal at all. A capitalist who owns the means of production and a worker who has nothing but labor power can never be equal. Social law thus emerged as a modification and supplement of civil law principles. Civil law was made for freedom and equality, but with the passage of time it did not work out as its ideals intended.

To add: Bismarck's social insurance legislation in Germany in the 1880s is regarded as a leading starting point of social law modifying civil law principles, and the 1919 Weimar Constitution was the first to put social rights into a constitution. In Korea, the Labor Standards Act was enacted in 1953 and the Industrial Accident Compensation Insurance Act in 1963, and the Framework Act on Social Security set the basic principles of the social security system in 1995. Besides industrial accident insurance, no-fault liability appears in the Product Liability Act, in force since 2002, and in the operator's liability under the Compulsory Motor Vehicle Liability Security Act. The principles of good faith and prohibition of abuse of rights in Article 2 of the Civil Act also reflect the social nature of ownership.