Sir Harold Jeffreys (22 April 1891 – 18 March 1989) was a mathematician, statistician, geophysicist, and astronomer. April 22 is the 112th day of the year in the Gregorian calendar (113th in leap years). ... 1891 (MDCCCXCI) was a common year starting on Thursday (see link for calendar). ... March 18 is the 77th day of the year in the Gregorian calendar (78th in leap years). ... 1989 (MCMLXXXIX) was a common year starting on Sunday of the Gregorian calendar. ...

He was born in Fatfield, County Durham, England. He studied at Armstrong College in Newcastle upon Tyne, then part of the University of Durham but later to become the University of Newcastle. He then went to St John's College, Cambridge and became a fellow in 1914. At Cambridge University he taught mathematics, then geophysics and finally became the Plumian Professor of Astronomy. County Durham is a county in north-east England. ... Royal motto (French): Dieu et mon droit (Translated: God and my right) Englands location (dark green) within the United Kingdom (light green), with the Republic of Ireland (blue) to its west Languages None official English de facto Capital None official London de facto Largest city London Area – Total Ranked... This article is about a city in the United Kingdom. ... Durham University is a university in England. ... The University of Newcastle upon Tyne is a British university located in Newcastle upon Tyne in the north of England. ... Full name The College of Saint John the Evangelist of the University of Cambridge Motto Souvent me Souvient I Often Remember Named after The Hospital of Saint John the Evangelist, Cambridge, named after John the Evangelist Previous names Incorporates part of what was Merton Hall which no longer exists Established... 1914 (MCMXIV) was a common year starting on Thursday. ... The University of Cambridge (often called Cambridge University), located in Cambridge, England, is the second-oldest university in the English-speaking world. ... Euclid, detail from The School of Athens by Raphael. ... Geophysics, the study of the earth by quantitative physical methods, especially by seismic reflection and refraction, geodesy, gravity, magnetic, electrical, electromagnetic, and radioactivity methods. ... The Plumian chair of Astronomy and Experimental Philosophy is one of the two major Professorships in Astronomy at Cambridge University, alongside the Lowndean Professorship. ...

He married another mathematician and physicist, Bertha Swirles (1903-1999), in 1940 and together they wrote Methods of Mathematical Physics. Bertha Swirles (Lady Jeffreys), (22 May 1903 - 18 December 1999) carried out research on quantum theory, particularly in its early days. ... 1903 (MCMIII) was a common year starting on Thursday (see link for calendar). ... 1999 (MCMXCIX) was a common year starting on Friday, and was designated the International Year of Older Persons by the United Nations. ... 1940 (MCMXL) was a leap year starting on Monday (the link is to a full 1940 calendar). ...

Among his other contributions was a Bayesian approach to probability (also see Jeffreys prior), and the idea that the Earth's planetary core was liquid. He was knighted in 1953. Bayesian refers to probability and statistics -- either methods associated with the Reverend Thomas Bayes (ca. ... The word probability derives from the Latin probare (to prove, or to test). ... In Bayesian probability, the Jeffreys prior is a noninformative prior distribution proportional to the square root of the Fisher information: and is invariant under reparameterization of . ... The planetary core consists of the innermost layers of a planet. ... The silver Anglia knight, commissioned as a trophy in 1850, intended to represent the Black Prince. ... 1953 (MCMLIII) was a common year starting on Thursday (link is to a full 1953 calendar). ...

Jeffreys received the Gold Medal of the Royal Astronomical Society in 1937. Gold Medal awarded to Asaph Hall The Gold Medal is the highest award of the Royal Astronomical Society. ... 1937 (MCMXXXVII) was a common year starting on Friday (link will take you to calendar). ...

He should not be confused with William H. Jefferys, also both an astronomer and a Bayesian. William H. (Bill) Jefferys (1940- ) is a U.S. astronomer and a professor emeritus of astronomy at the University of Texas at Austin. ...

References

• David Howie, "Interpreting Probability: Controversies and Developments in the Early Twentieth Century" (Cambridge University Press, 2002)

• Maria Carla Galavotti. "Harold Jeffreys' Probabilistic Epistemology: Between Logicism And Subjectivism". British Journal for the Philosophy of Science, 54(1):43-57 (March 2003). (A review of Jeffreys' approach to probability; includes remarks on R.A. Fisher, Frank P. Ramsey, and Bruno de Finetti. Also online: [1])

Sir Ronald Fisher Sir Ronald Aylmer Fisher, FRS (February 17, 1890–July 29, 1962) was an extraordinarily talented evolutionary biologist, geneticist and statistician. ... Frank Plumpton Ramsey (February 22, 1903 – January 19, 1930) was a British mathematician, philosopher and economist. ... Bruno de Finetti (Innsbruck, June 13, 1906 - Rome, July 20, 1985) was an Italian probabilist and statistician, noted for the operational subjective conception of probability. ...

External links

• John J. O'Connor and Edmund F. Robertson. Harold Jeffreys at the MacTutor History of Mathematics archive.
• Biography of Vetlesen Prize Winner - Sir Harold Jeffreys
• Harold Jeffreys as a Statistician