Harold Jeffreys
Encyclopedia
Sir Harold Jeffreys, FRS (22 April 1891 – 18 March 1989) was a mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
, statistician
Statistician
A statistician is someone who works with theoretical or applied statistics. The profession exists in both the private and public sectors. The core of that work is to measure, interpret, and describe the world and human activity patterns within it...
, geophysicist
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
, and astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
. His seminal book Theory of Probability, which first appeared in 1939, played an important role in the revival of the Bayesian view of probability
Bayesian probability
Bayesian probability is one of the different interpretations of the concept of probability and belongs to the category of evidential probabilities. The Bayesian interpretation of probability can be seen as an extension of logic that enables reasoning with propositions, whose truth or falsity is...
.
Biography
Jeffreys was born in FatfieldFatfield
Fatfield is a village in Tyne and Wear, located in the City of Sunderland metropolitan borough, England. It formed part of the Washington new town....
, Washington
Washington, Tyne and Wear
Washington is a town in the City of Sunderland in Tyne and Wear, England. Historically part of County Durham, it joined a new county in 1974 with the creation of Tyne and Wear...
, County Durham
County Durham
County Durham is a ceremonial county and unitary district in north east England. The county town is Durham. The largest settlement in the ceremonial county is the town of Darlington...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. He studied at Armstrong College
Armstrong College
Armstrong College may refer to:* Armstrong Atlantic State University, formerly known as Armstrong College* Armstrong College, a former college of Durham University* Armstrong College, a former college in Berkeley, California...
in Newcastle upon Tyne
Newcastle upon Tyne
Newcastle upon Tyne is a city and metropolitan borough of Tyne and Wear, in North East England. Historically a part of Northumberland, it is situated on the north bank of the River Tyne...
, then part of the University of Durham
Durham University
The University of Durham, commonly known as Durham University, is a university in Durham, England. It was founded by Act of Parliament in 1832 and granted a Royal Charter in 1837...
, and with the University of London External Programme
University of London External Programme
The University of London International Programmes is a division of the University of London that manages external study programmes.Several colleges and institutes of the University of London offer degrees through the programme, including Birkbeck, Goldsmiths, Heythrop College, Institute of...
. He then went to St John's College, Cambridge
St John's College, Cambridge
St John's College is a constituent college of the University of Cambridge. The college's alumni include nine Nobel Prize winners, six Prime Ministers, three archbishops, at least two princes, and three Saints....
and became a fellow in 1914. At Cambridge University
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
he taught mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
, then geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
and finally became the Plumian Professor of Astronomy.
He married another mathematician and physicist, Bertha Swirles
Bertha Swirles
Bertha Swirles, Lady Jeffreys , carried out research on quantum theory, particularly in its early days. She was associated with Girton College, University of Cambridge, as student and Fellow, for over 70 years....
(1903–1999), in 1940 and together they wrote Methods of Mathematical Physics.
One of his major contributions was on the Bayesian
Bayesian probability
Bayesian probability is one of the different interpretations of the concept of probability and belongs to the category of evidential probabilities. The Bayesian interpretation of probability can be seen as an extension of logic that enables reasoning with propositions, whose truth or falsity is...
approach to probability
Probability
Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
(also see Jeffreys prior
Jeffreys prior
In Bayesian probability, the Jeffreys prior, named after Harold Jeffreys, is a non-informative prior distribution on parameter space that is proportional to the square root of the determinant of the Fisher information:...
), as well as the idea that the Earth's planetary core
Planetary core
The planetary core consists of the innermost layer of a planet.The core may be composed of solid and liquid layers, while the cores of Mars and Venus are thought to be completely solid as they lack an internally generated magnetic field. In our solar system, core size can range from about 20% to...
was liquid. He was knighted
Knight Bachelor
The rank of Knight Bachelor is a part of the British honours system. It is the most basic rank of a man who has been knighted by the monarch but not as a member of one of the organised Orders of Chivalry...
in 1953.
By 1924 Jeffreys had developed a general method of approximating solutions to linear, second-order differential equations, including the Schrödinger equation
Schrödinger equation
The Schrödinger equation was formulated in 1926 by Austrian physicist Erwin Schrödinger. Used in physics , it is an equation that describes how the quantum state of a physical system changes in time....
. 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 credit for the WKB approximation
WKB approximation
In mathematical physics, the WKB approximation or WKB method is a method for finding approximate solutions to linear partial differential equations with spatially varying coefficients...
.
Jeffreys received the Gold Medal of the Royal Astronomical Society
Gold Medal of the Royal Astronomical Society
-History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...
in 1937, the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
's Copley Medal
Copley Medal
The Copley Medal is an award given by the Royal Society of London for "outstanding achievements in research in any branch of science, and alternates between the physical sciences and the biological sciences"...
in 1960, and the Royal Statistical Society
Royal Statistical Society
The Royal Statistical Society is a learned society for statistics and a professional body for statisticians in the UK.-History:It was founded in 1834 as the Statistical Society of London , though a perhaps unrelated London Statistical Society was in existence at least as early as 1824...
's Guy Medal
Guy Medal
The Guy Medals are awarded by the Royal Statistical Society in three categories; Gold, Silver and Bronze. The Gold Medal is awarded triennially, the other two are awarded annually...
in Gold in 1962. In 1948, Jeffreys received the Prix Charles Lagrange from the Académie royale des Sciences, des Lettres et des Beaux-Arts de Belgique.
From 1939 to 1952 he was established as Director of the International Seismological Summary further known as International Seismological Centre
International Seismological Centre
The International Seismological Centre is a non-governmental, non-profit making organization charged with the final collection, analysis and publication of standard earthquake information from all over the world.-History:...
.
Opposition to continental drift
Jeffreys was a strong opponent of continental driftContinental drift
Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912...
. 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.
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 of Geological Society (Great Britain) 1939
- Victoria Medal, Royal Geographical Society, 1941
- LaGrange Prize, Brussels Academy, 1948
- Royal Medal, 1948
- William Bowie Medal, American Geophysical Union, 1952
- Knighted, 1953
- Copley Medal, Royal Society, 1961
- Vetlesen PrizeVetlesen PrizeThe Vetlesen Prize is awarded from Columbia University's Lamont-Doherty Earth Observatory and the G. Unger Vetlesen Foundation.-Background:The Vetlesen Prize has been described as an attempt to establish an equivalent of a Nobel award for geophysics or geology...
, 1962
Further reading
- 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. RamseyFrank P. RamseyFrank Plumpton Ramsey was a British mathematician who, in addition to mathematics, made significant and precocious contributions in philosophy and economics before his death at the age of 26...
, and Bruno de FinettiBruno de FinettiBruno de Finetti was an Italian probabilist, statistician and actuary, noted for the "operational subjective" conception of probability...
. Also online: http://dx.doi.org/10.1093/bjps/54.1.43) - Bertha Swirles, Reminiscences and Discoveries: Harold Jeffreys from 1891 to 1940, Notes and Records of the Royal Society of London, Vol. 46, No. 2, pp. 301–308 (1992). http://www.jstor.org/view/00359149/ap020080/02a00080/0