The article is devoted to the problem of the social state as one of the fundamental constitutional principles of the state structure of modern developed countries. The course of historical development of philosophical and legal thought on this problem is considered. The idea of a close connection between the concept of the social state and the ideas of utopian socialism of Thomas More and Henri Saint-Simon is put forward. Liberals also made a significant contribution to the development of the idea of the social state, they argued that the ratio of equality and freedom is a key problem for the classical liberal doctrine. It is concluded that the emergence of the theory of the social state for objective reasons was inevitable, since it is due to the historical development of society.