William Stanley Jevons warned that efficient engines make Britain burn more coal
In 1865 a young Manchester tutor argued that squeezing more work from each lump of coal would not save Britain's reserves but drain them faster. That counterintuitive idea now bears his name, the Jevons paradox, and its author also helped make economics mathematical and built a wooden logic machine shaped like a piano.
Jevons was born in Liverpool in 1835, the son of an iron merchant whose firm collapsed in 1847. Money troubles pushed him to abandon chemistry and botany at University College London and, in 1854, sail to Sydney as an assayer at the new mint. There he photographed the city, drew a social map of it and first grew curious about political economy. Five years later he came home by way of America and went back to his studies.
His breakthrough in pure theory was the idea that the value a consumer gets from one more unit of something falls as he owns more of it. He had sketched this by 1860 and set it out in a paper for the British Association in 1862, which attracted little notice. Only with The Theory of Political Economy in 1871 did it land. Carl Menger in Vienna and Léon Walras in Switzerland reached similar conclusions around the same time, and together they opened what became the marginal revolution, though the German H. H. Gossen had got there first.
Fame actually came from practical work. His 1863 pamphlet on the falling value of gold, followed by The Coal Question, put him among the leading applied economists, and the second earned him a reputation as an early ecological thinker. He also drew mockery for linking sunspots to corn prices and trade crises, reasoning that solar cycles shaped weather and so harvests; the press coined the word sunspottery.
Logic ran alongside economics. Building on Boole, he distilled reasoning into one rule, that whatever holds for a thing holds for its like, and had a mechanical device built in 1869 to perform simple inferences. Nicknamed the Logic Piano for its upright shape, it was shown to the Royal Society in 1870. He died in 1882, leaving an unfinished treatise on economics.
Source: William Stanley Jevons
