The law of value is a central concept with Karl Marx’s judge of political economy, first expounded with his polemic The actual Poverty of School of thought (1847) against Pierre-Joseph Proudhon, with reference to David Ricardo’s economics. Many generally, it is the term for a regulative principle of the economic exchange of the products of man work: the relative exchange-values of the products in buy and sell, expressed by means of money-prices, are proportional to the average amounts involving human labor-time that happen to be currently socially necessary to produce them.