Rivalry (economics) in the context of "Sharing"

In philosophy, economics, and political science, the common good (also commonwealth, common weal, general welfare, or public benefit) is either what is shared and beneficial for all or most members of a given community, or alternatively, what is achieved by citizenship, collective action, and active participation in the realm of politics and public service. The concept of the common good differs significantly among philosophical doctrines. Early conceptions of the common good were set out by Ancient Greek philosophers, including Aristotle and Plato. One understanding of the common good rooted in Aristotle's philosophy remains in common usage today, referring to what one contemporary scholar calls the "good proper to, and attainable only by, the community, yet individually shared by its members."

The concept of common good developed through the work of political theorists, moral philosophers, and public economists, including Thomas Aquinas, Niccolò Machiavelli, John Locke, Jean-Jacques Rousseau, James Madison, Adam Smith, Karl Marx, John Stuart Mill, John Maynard Keynes, John Rawls, and many other thinkers. In contemporary economic theory, a common good is any good which is rivalrous yet non-excludable, while the common good, by contrast, arises in the subfield of welfare economics and refers to the outcome of a social welfare function. Such a social welfare function, in turn, would be rooted in a moral theory of the good (such as utilitarianism). Social choice theory aims to understand processes by which the common good may or may not be realized in societies through the study of collective decision rules. Public choice theory applies microeconomic methodology to the study of political science in order to explain how private interests affect political activities and outcomes.

In economics, a public good (also referred to as a social good or collective good) is a commodity, product or service that is both non-excludable and non-rivalrous and which is typically provided by a government and paid for through taxation. Use by one person neither prevents access by other people, nor does it reduce availability to others, so the good can be used simultaneously by more than one person. This is in contrast to a common good, such as wild fish stocks in the ocean, which is non-excludable but rivalrous to a certain degree. If too many fish were harvested, the stocks would deplete, limiting the access of fish for others. A public good must be valuable to more than one user, otherwise, its simultaneous availability to more than one person would be economically irrelevant.

Capital goods may be used to produce public goods or services that are "...typically provided on a large scale to many consumers." Similarly, using capital goods to produce public goods may result in the creation of new capital goods. In some cases, public goods or services are considered "...insufficiently profitable to be provided by the private sector.... (and), in the absence of government provision, these goods or services would be produced in relatively small quantities or, perhaps, not at all."

Common goods (also called common-pool resources) are defined in economics as goods that are rivalrous and non-excludable. Thus, they constitute one of the four main types based on the criteria:

• whether the consumption of a good by one person precludes its consumption by another person (rivalrousness)
• whether it is possible to prevent people (consumers) who have not paid for it from having access to it (excludability)

As common goods are accessible by everybody, they are at risk of being subject to overexploitation which leads to diminished availability if people act to serve their own self-interests.

In economics, excludability is the degree to which a good, service or resource can be limited to only paying customers, or conversely, the degree to which a supplier, producer or other managing body (e.g. a government) can prevent consumption of a good. In economics, a good, service or resource is broadly assigned two fundamental characteristics; a degree of excludability and a degree of rivalry.

Excludability was originally proposed in 1954 by American economist Paul Samuelson where he formalised the concept now known as public goods, i.e. goods that are both non-rivalrous and non-excludable. Samuelson additionally highlighted the market failure of the free-rider problem that can occur with non-excludable goods. Samuelson's theory of good classification was then further expanded upon by Richard Musgrave in 1959, Garrett Hardin in 1968 who expanded upon another key market inefficiency of non-excludable goods; the tragedy of the commons.

In economics, the free-rider problem is a type of market failure that occurs when those who benefit from resources, public goods and common pool resources do not pay for them or under-pay. Free riders may overuse common pool resources by not paying for them, neither directly through fees or tolls, nor indirectly through taxes. Consequently, the common pool resource may be under-produced, overused, or degraded. Additionally, despite evidence that people tend to be cooperative by nature (a prosocial behaviour), the presence of free-riders has been shown to cause cooperation to deteriorate, perpetuating the free-rider problem.

In social science, the free-rider problem is the question of how to limit free riding and its negative effects in these situations, such as the free-rider problem of when property rights are not clearly defined and imposed. The free-rider problem is common with public goods which are non-excludable and non-rivalrous. The non-excludability and non-rivalry of public goods results in there being little incentive for consumers to contribute to a collective resource as they enjoy its benefits.