Sir Harold Jeffreys, FRS (22 April 1891 – 18 March 1989) was a British mathematician, statistician,

geophysicist Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' som ...

, and

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

. His book, ''Theory of Probability'', which was first published in 1939, played an important role in the revival of the objective Bayesian view of probability.

Education

Jeffreys was born in Fatfield, County Durham, England, the son of Robert Hal Jeffreys, headmaster of Fatfield Church School, and his wife, Elizabeth Mary Sharpe, a school teacher. He was educated at his father's school then studied at Armstrong College in

Newcastle upon Tyne Newcastle upon Tyne ( RP: , ), or simply Newcastle, is a city and metropolitan borough in Tyne and Wear, England. The city is located on the River Tyne's northern bank and forms the largest part of the Tyneside built-up area. Newcastle is ...

, then part of the

University of Durham , mottoeng = Her foundations are upon the holy hills ( Psalm 87:1) , established = (university status) , type = Public , academic_staff = 1,830 (2020) , administrative_staff = 2,640 (2018/19) , chancellor = Sir Thomas Allen , vice_cha ...

, and with the

University of London External Programme The University of London Worldwide (previously called the University of London International Academy) is the central academic body that manages external study programmes within the collegiate university, federal University of London. All courses ...

Career

Jeffreys became a fellow of

St John's College, Cambridge St John's College is a constituent college of the University of Cambridge founded by the Tudor matriarch Lady Margaret Beaufort. In constitutional terms, the college is a charitable corporation established by a charter dated 9 April 1511. The ...

in 1914. At the

University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...

he taught mathematics, then

geophysics Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' so ...

and finally became the Plumian Professor of Astronomy. In 1940 he married fellow mathematician and physicist, Bertha Swirles (1903–1999), and together they wrote ''Methods of Mathematical Physics''. One of his major contributions was on the Bayesian approach to

probability Probability is the branch of mathematics concerning numerical descriptions of how likely an event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and 1, where, roughly speaking, ...

(also see Jeffreys prior), as well as the idea that the Earth's

planetary core A planetary core consists of the innermost layers of a planet. Cores may be entirely solid or entirely liquid, or a mixture of solid and liquid layers as is the case in the Earth. In the Solar System, core sizes range from about 20% (the Moon ...

was liquid. By 1924 Jeffreys had developed a general method of approximating solutions to linear, second-order differential equations, including the

Schrödinger equation The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. It is a key result in quantum mechanics, and its discovery was a significant landmark in the development of th ...

. Although the Schrödinger equation was developed two years later, Wentzel, Kramers, and Brillouin were apparently unaware of this earlier work, so Jeffreys is often neglected when credit is given for the WKB approximation. Jeffreys received the

Gold Medal of the Royal Astronomical Society The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...

in 1937, the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

Copley Medal The Copley Medal is an award given by the Royal Society, for "outstanding achievements in research in any branch of science". It alternates between the physical sciences or mathematics and the biological sciences. Given every year, the medal is t ...

in 1960, and the

Royal Statistical Society The Royal Statistical Society (RSS) is an established statistical society. It has three main roles: a British learned society for statistics, a professional body for statisticians and a charity which promotes statistics for the public good. ...

Guy Medal The Guy Medals are awarded by the Royal Statistical Society in three categories; Gold, Silver and Bronze. The Silver and Bronze medals are awarded annually. The Gold Medal was awarded every three years between 1987 and 2011, but is awarded biennia ...

in Gold in 1962. In 1948, he received the Charles Lagrange Prize from the

Académie royale des Sciences, des Lettres et des Beaux-Arts de Belgique The Royal Academy of Science, Letters and Fine Arts of Belgium (french: Académie royale des sciences, des lettres et des beaux-arts de Belgique, sometimes referred to as ') is the independent learned society of science and arts of the French Comm ...

. He was

knighted A knight is a person granted an honorary title of knighthood by a head of state (including the Pope) or representative for service to the monarch, the church or the country, especially in a military capacity. Knighthood finds origins in the G ...

in 1953. From 1939 to 1952 he was established as Director of the International Seismological Summary further known as

International Seismological Centre The International Seismological Centre (ISC) is a non-governmental, nonprofit organisation charged with the final collection, definitive analysis and publication of global seismicity. The ISC was formed in 1964 as an international organisation ...

. The textbook ''Probability Theory: The Logic of Science,'' written by the physicist and probability theorist

Edwin T. Jaynes Edwin Thompson Jaynes (July 5, 1922 – April 30, 1998) was the Wayman Crow Distinguished Professor of Physics at Washington University in St. Louis. He wrote extensively on statistical mechanics and on foundations of probability and statist ...

, is dedicated to Jeffreys. The dedication reads, "Dedicated to the memory of Sir Harold Jeffreys, who saw the truth and preserved it." It is only through an appendix to the third edition of Jeffreys' book ''Scientific Inference'' that we know about Mary Cartwright's method of proving that the number is

irrational Irrationality is cognition, thinking, talking, or acting without inclusion of rationality. It is more specifically described as an action or opinion given through inadequate use of reason, or through emotional distress or cognitive deficiency. T ...

Opposition to continental drift and plate tectonics

Like most of his contemporaries, Jeffreys was a strong opponent of

continental drift Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed. The idea of continental drift has been subsumed into the science of pl ...

as proposed by Alfred Wegener,

Arthur Holmes Arthur Holmes (14 January 1890 – 20 September 1965) was an English geologist who made two major contributions to the understanding of geology. He pioneered the use of radiometric dating of minerals, and was the first earth scientist to grasp ...

, and even into the 1960s his Cambridge contemporaries. For him, continental drift was "out of the question" because no force even remotely strong enough to move the continents across the Earth's surface was evident. As geological and geophysical evidence for continental drift and

plate tectonics Plate tectonics (from the la, label= Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of larg ...

mounted in the 1960s and after, to the point where it became the unifying concept of modern geology, Jeffreys remained a stubborn opponent of the theory to his death.

Honours and awards

* Fellow, Royal Society, 1925 * Adams Prize, 1927 (Constitution of the Earth) * Gold Medal, Royal Astronomical Society, 1937 * Buchan Prize, Royal Meteorological Society, 1929 *

Murchison Medal The Murchison Medal is an academic award established by Roderick Murchison, who died in 1871. First awarded in 1873, it is normally given to people who have made a significant contribution to geology by means of a substantial body of research and ...

of Geological Society (Great Britain) 1939 * Victoria Medal, Royal Geographical Society, 1941 * Charles Lagrange Prize, Brussels Academy, 1948 * Royal Medal, 1948 *

William Bowie Medal The William Bowie Medal is awarded annually by the American Geophysical Union for "outstanding contributions to fundamental geophysics and for unselfish cooperation in research". The award is the highest honor given by the AGU and is named in honor ...

, American Geophysical Union, 1952 * Knighted, 1953 * Copley Medal, Royal Society, 1961 * Vetlesen Prize, 1962

Bibliography

* 1924: ''The Earth, Its Origin, History and Physical Constitution'',

Cambridge University Press Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by King Henry VIII in 1534, it is the oldest university press in the world. It is also the King's Printer. Cambridge University Pr ...

; 5th edn. 1970; 6th edn. 1976 * 1927
Operational Methods in Mathematical Physics

via

Internet Archive The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including websites, software applications/games, music, ...

, Review: * 1929: ''The Future of the Earth'',

Norton & Company W. W. Norton & Company is an American publishing company based in New York City. Established in 1923, it has been owned wholly by its employees since the early 1960s. The company is known for its Norton Anthologies (particularly ''The Norton A ...

* 1931: ''Scientific Inference'',

Macmillan Publishers Macmillan Publishers (occasionally known as the Macmillan Group; formally Macmillan Publishers Ltd and Macmillan Publishing Group, LLC) is a British publishing company traditionally considered to be one of the 'Big Five' English language publi ...

; 2nd edn. 1937; 3rd edn. 1973 * 1931: ''Cartesian Tensors''. Cambridge University Press; 2nd edn. 1961 * 1934: ''Ocean Waves and Kindred Geophysical Phenomena'', with Vaughan Cornish, Cambridge University Press * 1935: ''Earthquakes and Mountains'',

Methuen Publishing Methuen Publishing Ltd is an English publishing house. It was founded in 1889 by Sir Algernon Methuen (1856–1924) and began publishing in London in 1892. Initially Methuen mainly published non-fiction academic works, eventually diversifying t ...

; 2nd edn. 1950 * 1939: ''Theory of Probability'',

Clarendon Press Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books ...

, Oxford; 2nd edn. 1948; 3rd edn. 1961 * 1946: ''Methods of Mathematical Physics'', with Bertha S. Jeffreys. Cambridge University Press; 2nd edn. 1950; 3rd edn. 1956; corrected 3rd edn. 1966 * 1962: ''Asymptotic Approximations'',

, Oxford * 1963: ''Nutation and Forced Motion of the Earth's Pole from the Data of Latitude Observations'', Macmillan * 1971–77: ''Collected Papers of Sir Harold Jeffreys on Geophysics and Other Sciences'',

Gordon and Breach Taylor & Francis Group is an international company originating in England that publishes books and academic journals. Its parts include Taylor & Francis, Routledge, F1000 Research or Dovepress. It is a division of Informa plc, a United Ki ...

References

External links

*
Photographs of Harold Jeffreys at Emilio Segrè Visual Archives, American Institute of Physics

{{DEFAULTSORT:Jeffreys, Harold 1891 births 1989 deaths Alumni of University of London Worldwide Alumni of the University of London Bayesian statisticians 20th-century British astronomers 20th-century English mathematicians English statisticians Fellows of St John's College, Cambridge Fellows of the Royal Society Foreign associates of the National Academy of Sciences Knights Bachelor People from Fatfield Recipients of the Copley Medal Recipients of the Gold Medal of the Royal Astronomical Society Royal Medal winners British seismologists Wollaston Medal winners Analysands of Ernest Jones Presidents of the Royal Astronomical Society Victoria Medal recipients Alumni of Armstrong College, Durham Plumian Professors of Astronomy and Experimental Philosophy