In his paper, the author proves that market failure theory does not explain the subject of the public sector. The rule of social inclusion and availability of goods needs normative justification, which is the need for cohesion and solidarity. What groups a society together are institutions which determine realization of individual and common interests. Internalized institutions create modus operandi in all aspects of social life. Reproduction of social solidarity is determined by rules of social justice. Implementation of these rules imposes on a state the responsibility to make social primary goods accessible (according to J. Rawls' theory) or to strengthen the ability to participate in social life (A. Sen).