public goods

In economics, a public good is a good that is both non-excludable and non-rivalrous in that individuals cannot be effectively excluded from use and where use by one individual does not reduce availability to others. Gravelle and Rees: "The defining characteristic of a public good is that consumption of it by one individual does not actually or potentially reduce the amount available to be consumed by another individual". Public goods include fresh air, knowledge, public infrastructure,  national security, education, common language(s), widespread and high public literacy levels, flood control systems, lighthouses, and street lighting. Public goods that are available everywhere are sometimes referred to as global public goods. There is an important conceptual difference between the sense of 'a' public good, or public 'goods' in economics, and the more generalized idea of 'the public good' (or common good, or public interest),"‘the’ public good is a shorthand signal for shared benefit at a societal level [this] (philosophical/political) sense should not be reduced to the established specific (economic) sense of ‘a’ public good."