William Stanley Jevons Born Sept. 1, 1835 in Liverpool, England. Died Aug. 13, 1882 in Hastings, England. Education: Studied Chemistry, Metallurgy, Botany at University College, London. Earned BA and MA at University College, London. In 1854, Jevons went to Australia to be the Assayer at the Mint in Sydney. He returned in 1859 and studied Logic in London. He later became Professor of Logic and Moral Philosophy at the Univ. of Manchester, England in 1866. In 1876, he became a Professor of Political Economy at University College, London. He retired from that position in 1880, and died while swimming in 1882 at Hastings, England. His works : • General Mathematical Theory of Political Economy (1862) − Outlined the theory of marginal utility • Investigations in Currency and Finance (1863−1864) • The Coal Question (1865) − Argued coal was England's greatest industrial resource and was exhaustible • The Theory of Political Economy (1871) − Argued that economics should be based on mathematics, because it deals with mathematical quantities. This book provided much of the basis for microeconomics. • Principles of Science (1874) − Treaty on Logic • The State in Relation to Labour (Posthumous, 1888) • Investigations (Posthumous Collection of Essays) − Dealt mainly with the fluctuations of markets. • The Solar Period and the Price of Corn (Pub. Posthumously) − Describes a 30−year study attempting to relate fluctuations in the business cycle to abnormal solar activity, such as solar flares Other Info: He was greatly influenced by Utilitarianism, a theory that states questions of morality should be answered by calculating the consequences of actions. This is demonstrated by his "equation of exchange" which states that for a consumer to maximize his or her utility, "the ratio of the marginal utility of each item consumed to its price must be equal." This basically states that people should pay for what something is worth. His description of Marginal Utility in 1862 did not draw much attention, but with common discoveries by economists Carl Menger and Leon Walrus, and the publication of Theory of Political Economy in 1871, the discovery was publicized. He developed the "logical piano", an adding machine that had 21 keys for logical operations. Many features were introduced into modern day computers. He also contributed greatly in studies towards probability. Jevons was mainly concerned with Microecononomics, price changes, utility, opportunity cost and certain 1

goods. Economics WILLIAM STANLEY JEVONS 11th Grade Februrary 29, 1999. Mathematical Theory of Political Economy −Marginal Utility− William Jevons In his theory of marginal utility, Jevons expresses that an object is useful when the consequences of consuming it will lead to pleasure, either at the present time, or in the future. The quantity of pleasure is proportional to the amount of utility. He said that the more quantity received of an object, the less pleasure the next application will provide. In other words, the utility of that good will decrease in proportion with every extra unit consumed. Each good has a unique function that describes its behavior. The means through which individuals can acquire pleasure always come with a certain drawback, this is, in order to obtain a pleasurable feeling one must work to get it. This is called labor or work. From the theory of marginal utility comes the theory of exchange which states that if two people have designated goods and if both think that the good of the other person would provide more utility than the good they already posses, then an exchange will occur between them. It is neccesary that both sides will, if not gain, at least not lose with the exchange. The objective of the exchange is the gain of utility, and, by nature of the exchange, at least one side will gain.

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