William Stanley Jevons – The Father of Marginal Utility Analysis
William Stanley Jevons (1835-1882) was a pioneering British economist and logician whose work revolutionized economic theory in the late 19th century. Often considered one of the founders of neoclassical economics, Jevons helped transition the field towards becoming a more scientific and mathematical discipline grounded in theory and logic.
In this comprehensive guide, we explore Jevons’ extraordinary life along with his seminal contributions across economics, philosophy, logic and beyond.
Early Life and Education
Born in Liverpool on September 1st 1835, Jevons was the son of an iron merchant and writer, Thomas Jevons, and Mary Anne Roscoe, whose father William Roscoe was a noted historian and abolitionist.
Showing early promise as a scholar, Jevons was sent to London at age 15 to attend University College School studying a range of science and arts subjects. But his education was interrupted when his father’s business went bankrupt in 1847, forcing Jevons to leave school and take up a role as an assayer at the new Sydney Mint in Australia.
Jevons disliked the idea of leaving England, but secured the post thanks to his skills in chemistry and metallurgy. He would spent the next five years working at the Mint, honing his interests in economics and philosophy during his spare time.
According to his letters, Jevons felt isolated being so far from the intellectual company he craved. But the role did provide financial security, and Jevons was able to resume his formal studies in 1853, returning to London’s University College to complete a B.A. in 1856 and M.A. in logic and moral philosophy in 1857.
The Theory of Utility
Jevons is most renowned in economics for his Theory of Utility, first outlined in a brief 1860 paper ‘A General Mathematical Theory of Political Economy’.
Building on earlier utility concepts suggested by the likes of Daniel Bernoulli, Jevons asserted that economic value and decision-making were based on the underlying utility or usefulness provided by a product or service. Moreover, utility could be quantified mathematically with precision.
Specifically, Jevons proposed utility as a declining function relative to quantity consumed. In other words, the more units of a good someone consumes, the lower the additional satisfaction derived from each extra unit. This principle of marginal utility contrasted classical ideas that utility was dictated by cost of production or labor.
According to Jevons, the price a consumer is willing to pay depends on the utility at the margin. A product has higher marginal utility when it provides more additional satisfaction per unit relative to substitutes. This drives consumer preference and demand. Firms likewise allocate resources based on comparing marginal returns.
Jevons demonstrated how supply and demand intersect by equating relative marginal utilities to relative prices, a core model now known as partial equilibrium analysis. This breakthrough enabled a far more scientific examination of microeconomic behavior grounded in psychology and math.
Though marginal utility concepts had earlier precedents, historians widely credit Jevons with popularizing their formal application in economic theory. His work inspired kindred perspectives developed in the 1870s by Carl Menger in Austria and Leon Walras in Switzerland, together marking the advent of the ‘marginal revolution’.
Appointment at Owens College & The Coal Question
In 1866, one year after publishing an expanded treatise on ‘The Coal Question’, Jevons was appointed professor of logic and political economy at Owens College, Manchester (later absorbed into the Victoria University of Manchester).
His first major book length work, The Coal Question; An Inquiry Concerning the Progress of the Nation, and the Probable Exhaustion of Our Coal Mines analyzed coal reserves data to argue that Britain’s industrial supremacy would wane as domestic coal – integral for steam engines and manufacturing – became increasingly scarce.
Though the imminent decline predicted by Jevons did not quite eventuate, his volume brought the finite nature of industrial resources into stark focus and proved influential in the burgeoning conservation movement. The Coal Question also displayed Jevons’ ability to apply rigorous logic and empirical evidence to investigate real-world economic issues.
Logic Piano
In addition to economics, Jevons had a profound interest in formal logic stemming from his studies under the renowned logician Augustus De Morgan.
In 1869 he outlined an innovative ‘Logical Piano’ built to mechanically test syllogistic reasoning. Syllogisms comprise three propositions where the conclusion necessarily follows from the preceding premises based on logical deduction.
Jevons’ piano had a keyboard where pressing certain keys denoted allocation of terms in one of the four standard proposition structures. Mechanical rods would then remove invalid conclusions, leaving only logically coherent combinations on a statement display grid. This allowed the user to quickly filter viable syllogistic inferences.
Though Jevons saw practical use cases in education, contemporaries like John Venn argued the piano’s functionality was quite limited given people rarely needed to manually iterate through syllogisms. Nonetheless it represented an impressive attempt to computationally model the syllogistic process.
The Logical Piano built on Jevons’ earlier work devising aLogical Slate and Logical Abacus board game to manually enumerate term combinations. He similarly explored a Logical Calculator and Expression Evaluator capable of solving Boolean algebraic formula.
In his lifetime Jevons authored several logic textbooks in addition to published papers on computer science topics like complexity theory and cryptography – anticipating key developments in those fields decades later. Colleagues praised his drive to mechanically simulate logical reasoning well before the advent of computers.
Later Career & Death
Jevons continued expanding on his utility theory after joining Owens College while also writing on logic, philosophy and political economy more broadly.
His team taught the UK’s first course dedicated to economics in 1871, and Jevons helped found both the Manchester Statistical Society and the British Association‘s economics section where he regularly presented papers.
His stature as one of Britain’s leading scholars saw Jevons awarded a professorship for political economy at University College London in 1876. However continuing health issues forced his return to Australia two years later, and he resumed academic work back at Manchester upon his 1880 homecoming.
Tragically Jevons died at just 46 years old in 1882 after drowning accidentally while swimming near Hastings. The previous year he had penned his last major book The State in Relation to Labour, arguing against government intervention in labor markets.
Jevons was subsequently buried in Hampstead Cemetery. His son Herbert later became an economics professor as well, furthering the family’s academic legacy.
Legacy & Impact
Despite his premature death, Jevons’ work left an indelible mark on the discipline of economics. By mathematically modeling the mechanics of supply, demand and utility maximization, his theories provided microeconomics a theoretical backbone it had hitherto lacked.
Jevons bridged classical and neoclassical schools of thought, directly influencing seminal economists like Alfred Marshall and Irving Fisher while laying foundations later built upon by 20th century thinkers.
It is hard to overstate how revolutionary marginal utility was to the field’s development. As Joseph Schumpeter later wrote, “Jevons, Menger and Walras are the three greatest economists of the nineteenth century.”
Today Jevons remains a pivotal figure in economic history, while marginal analysis constitutes a core component of mainstream micro and macro models. Fittingly the British Economists Society named its main award after Jevons, which has been conferred upon 11 Nobel Laureates among other eminent scholars since 1965.
Outside economics, Jevons also left his mark across philosophy, sustainable development and formal symbolic logic – playing an important role popularizing Boolean approaches in Britain. Few academics can claim such wide and lasting influence across so many domains. Though many of his economic predictions were inaccurate, Jevons’ legacy as one of the chief pioneers of neoclassical theory persists well over a century later.
Frequently Asked Questions
Who was William Stanley Jevons?
William Stanley Jevons (1835–1882) was a pioneering British philosopher and economist who helped develop the marginal utility theory of value and advance economics as a mathematical science.
What is Jevons best known for?
Jevons is best known for proposing the influential Theory of Utility which states that as more of a good is consumed, overall utility declines at the margin (i.e. marginal utility). This explained economic decision making and demand in terms of underlying quantified utility or satisfaction.
What was Jevons’ Logic Piano?
The Logic Piano was a mechanical device built to calculate viable conclusions from logical syllogisms as denoted by presses on a keyboard. It aimed to simulate and reduce the labor of deducing syllogisms manually.
What is the Jevons Number?
In his 1874 book The Principles of Science, Jevons proposed the number 8,616,460,799 and cryptically asked if readers could factor it, suggesting only he knew the two prime components. The large semiprime became known as ‘Jevons’ Number’ and was factored 15 years later.
When did Jevons die and what was the cause?
Jevons died suddenly in 1882 at just 46 years old after accidentally drowning during a swim at Hastings beach on the south coast of England. Prior bouts of ill health and insomnia likely contributed to his drowning.
