The relevance of determining the theoretical and methodological determinants of the Robert von Moll’s concept of the social state is due to the need to determine the patterns of evolution of ideas about the state and law, as well as the need to assess the ability to use the potential of the Robert von Moll’s theoretical and legal heritage, his predecessors and contemporaries to identify the optimal model of the social state. Modern Russia attempts to build such state. The proclamation and consolidation of Russia as a social state governed by the rule of law at the constitutional level requires attention both to the experiments carried out in social and legal development, and to the practices of social reform, and also to those ideas that have not yet been embodied. The ideas of European scholars regarding the evolution of the state-legal organization of society in the early modern period, based on which Robert von Mohl (1799–1875) developed original concepts of a social state and a state governed by the rule of law are discussed in the article. An analysis of the state of European political and legal thought and identification of the factors that have a significant impact on the development of Robert von Mohl’s doctrine of a social state governed by the rule of law are the purposes of the scientific article. The methodological basis of the study was the dialectical-materialistic, general scientific (historical, systemic) and special (historical-legal, comparativelegal) methods of legal research. The method of reconstruction and interpretation of legal ideas had great importance. As a result of the study, it was concluded that in the first half of the 19th century in European political and legal thought various approaches was formed to consider the problems of social protection and how to resolve them. The development trend of European political science became the transition from ideas and principles formed in the conditions of police states and enlightened absolutism to the ideas of a state governed by the rule of law (constitutional) that protects the rights and freedoms of a citizen. At the same time, it was a question of the rights and freedoms of only a part of the population: the proletariat growing in number and significance was not always evaluated as an independent social stratum. The axiological principles of state justification have also changed. Rights and utility principle became dominant principles. In the first half of the 19th century the social issue as an independent scientific problem of the European political and legal thought was not posed and not systematically developed. Questions about the social essence of the state, the specifics of the implementation of the state social function, the features of public administration in the new stage of socio-economic development of society predetermined the emergence of the idea of a social state. This idea was comprehensively characterized in the Robert von Mohl’s works. He went down in the history of political and legal thought as founder of the concepts of social and governed by the rule of law state.