Cournot on the Communication of Markets: The Principle of Compensation of Demands and the Effects of International Trade on Social Income

Abstract Cournot's views on the effects of international trade on social income have received little attention. Drawing upon a comprehensive analysis of Cournot's writings, this article shows that Cournot distinguished between variations in nominal income and variations in real income. He introduced the principle of compensation of demands: if the price of a commodity changes, the value of the total demand for other commodities remains unchanged. He relied on this principle to demonstrate that a unilateral removal of trade restrictions can cause real income to fall. Under specific circumstances, protective tariffs may be warranted. Cournot thus endorsed the infant-industry argument without being a die-hard protectionist. The article discusses the arguments of his critics and concludes that many commentators have misrepresented his thinking.