The article is devoted to reasoning of postmodernist paradigm of the nature of law. It is substantiated that from the anthroposociocultural approach law is nothing else but the foundational means of cobeing of individuals in society for satisfaction of their common needs. The authors analyzed the understanding of the spontaneity of law by L. Petrazycki, E. Ehrlich, A. Reinach, F. Hayek, representatives of the second wave of German practical philosophy, shown through their research that spontaneity of law is not its attributive property, which independently explains the nature of law, but presents it as the means of spawn, being, regression and renewal of law. It is resumed in the article, that just as law does not exist out of the individual, so there is no law out of spontaneous means of its manifestation; law makes the cobeing of individuals possible, it is the condition of existence for the latter as the self-regulating processual system of social cooperation of individuals; in its turn, cobeing of individuals in society causes and creates their law for the assurance of transcendental exchange of public benefits between them; such is the dialectics of spontaneous cobeing of individual through his spontaneous law with other individuals.