Adam Smith in the context of "Barter"

Comparative history is the comparison of different societies which existed during the same time period or shared similar cultural conditions.

The comparative history of societies emerged as an important specialty among intellectuals in the Enlightenment in the 18th century, as typified by Montesquieu, Voltaire, Adam Smith, and others. Sociologists and economists in the 19th century often explored comparative history, as exemplified by Alexis de Tocqueville, Karl Marx, and Max Weber.

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 microeconomics, economies of scale are the cost advantages that enterprises obtain due to their scale of operation, and are typically measured by the amount of output produced per unit of cost (production cost). A decrease in cost per unit of output enables an increase in scale that is, increased production with lowered cost. At the basis of economies of scale, there may be technical, statistical, organizational or related factors to the degree of market control.

Economies of scale arise in a variety of organizational and business situations and at various levels, such as a production, plant or an entire enterprise. When average costs start falling as output increases, then economies of scale occur. Some economies of scale, such as capital cost of manufacturing facilities and friction loss of transportation and industrial equipment, have a physical or engineering basis. The economic concept dates back to Adam Smith and the idea of obtaining larger production returns through the use of division of labor. Diseconomies of scale are the opposite.

Classical economics, also known as the classical school of economics, or classical political economy, is a school of thought in political economy that flourished, primarily in Britain, in the late 18th and early-to-mid 19th century. It includes both the Smithian and Ricardian schools. Its main thinkers are held to be Adam Smith, Jean-Baptiste Say, David Ricardo, Thomas Robert Malthus, and John Stuart Mill. These economists produced a theory of market economies as largely self-regulating systems, governed by natural laws of production and exchange (famously captured by Adam Smith's metaphor of the invisible hand).

Adam Smith's The Wealth of Nations in 1776 is usually considered to mark the beginning of classical economics. The fundamental message in Smith's book was that the wealth of any nation was determined not by the gold in the monarch's coffers, but by its national income. This income was in turn based on the labor of its inhabitants, organized efficiently by the division of labour and the use of accumulated capital, which became one of classical economics' central concepts.

In the history of economic thought, a school of economic thought is a group of economic thinkers who share or shared a mutual perspective on the way economies function. While economists do not always fit within particular schools, particularly in the modern era, classifying economists into schools of thought is common. Economic thought may be roughly divided into three phases: premodern (Greco-Roman, Indian, Persian, Islamic, and Imperial Chinese), early modern (mercantilist, physiocrats) and modern (beginning with Adam Smith and classical economics in the late 18th century, and Karl Marx and Friedrich Engels' Marxian economics in the mid 19th century). Systematic economic theory has been developed primarily since the beginning of what is termed the modern era.

Currently, the great majority of economists follow an approach referred to as mainstream economics (sometimes called 'orthodox economics'). Economists generally specialize into either macroeconomics, broadly on the general scope of the economy as a whole, or microeconomics, on specific markets or actors.

In the Marxist theory of historical materialism, a mode of production (German: Produktionsweise, "the way of producing") is a specific combination of the:

• Productive forces: these include human labour power and means of production (tools, machinery, factory buildings, infrastructure, technical knowledge, raw materials, plants, animals, exploitable land).
• Social and technical relations of production: these include the property, power and control relations (legal code) governing the means of production of society, cooperative work associations, relations between people and the objects of their work, and the relations among the social classes.

Marx said that a person's productive ability and participation in social relations are two essential characteristics of social reproduction, and that the particular modality of those social relations in the capitalist mode of production is inherently in conflict with the progressive development of the productive capabilities of human beings. A precursor concept was Adam Smith's mode of subsistence, which delineated a progression of types of society based upon how the citizens of a society provided for their material needs.

Labour power (German: Arbeitskraft; French: force de travail) is the capacity to work, a key concept used by Karl Marx in his critique of capitalist political economy. Marx distinguished between the capacity to do the work, i.e. labour power, and the physical act of working, i.e. labour. Human labour power exists in any kind of society, but on what terms it is traded or combined with means of production to produce goods and services has historically varied greatly.

The general idea of labour-power had existed previously in classical political economy. Adam Smith's The Wealth of Nations and David Ricardo's On the Principles of Political Economy and Taxation already referred to the "productive powers of labour". However, Marx made the concept much more precise, critically examining the functions of labour-power in production, how labour-power is used, organized and exploited, and how it is typically valued and priced in bourgeois society.