**Stanley Jevons** was an English mathematician, economist and logician.

- Thomas Jevons was an iron merchant but showed lots of talent both as an inventor of iron boats and as a writer on various legal and economic topics.
- There is very clear evidence in Jevons later writings of the Unitarian influence.
- Stanley was sent to London to became a boarder at University College School in 1850.
- This involved determining the characteristics such as weight, measure, or quality of the coinage, and Jevons was offered the post because of his already impressive abilities at chemistry.
- Now, filled with the feelings of mission he described, Jevons gave up his lucrative job and returned to England in 1859 to complete his education.
- An important influence on Jevons while he was studying in London was De Morgan, not in terms of Jevons thoughts on economics but certainly in terms of his thoughts on logic and probability.
- Jevons' developing thoughts on economics are evident in his correspondence.
- After being awarded his Master's Degree, Jevons was appointed as a tutor at Owens College, which went on to become the University of Manchester.
- Jevons remained in Manchester until he moved to University College, London in 1876.
- Jevons's main contributions outside economics are in mathematical logic.
- It was Boole, particularly with his book The Laws of Thought (1854), who strongly influenced Jevons' ideas on mathematical logic.
- On the one hand Jevons can be seen as a strong supporter of Boole's ideas, and someone who both worked on improving them and bringing them to a wider audience.
- Jevons was fond of syllogistic methods.
- In many ways this showed one weakness that Jevons had, namely that although he was advocating a mathematical approach to many problems, his lack of understanding of Boole's mathematics in particular shows that he could not fully appreciate it.
- The 'logical piano', a machine designed by Jevons and constructed by a Salford watchmaker, had 21 keys for operations in equational logic.
- Jevons claims in this work that absolute precision in observations is impossible, as is a complete correspondence between a theory and the physical situation that it models.
- Jevons, writing in 1873, knew 64 chemical elements had been discovered of which 50 are metals.
- We have already noted that Jevons left Manchester in 1876 when he moved to University College, London.
- Jevons' work is very highly regarded by most.
- Jevons was not a precursor of logical positivism despite his attempt to build up a unified science.
- His mechanical reductionism was directed towards this project, and Jevons tried to found mathematics on logic through the development of a theory of number.
- Although Jevons did not succeed in establishing a unified science, his flawed methodology resulted in one of the first applications of statistics to the social sciences.

Born 1 September 1835, Liverpool, England. Died 13 August 1882, Hastings, England.

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Origin England, Statistics

**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive