In mathematical logic, more specifically in the proof theory of first-order theories, extensions by definitions formalize the introduction of new symbols by means of a definition.
 For example, it is common in naive set theory to introduce a symbol formula_1 for the set which has no member.
 In the formal setting of first-order theories, this can be done by adding to the theory a new constant formula_1 and the new axiom formula_3, meaning 'for all "x", "x" is not a member of formula_1'.
 It can then be proved that doing so adds essentially nothing to the old theory, as should be expected from a definition.
 More precisely, the new theory is a conservative extension of the old one.
Francis Watson (born 1956) is an English theologian and New Testament scholar.
 He commenced his career at King's College London before being appointed to the Kirby Laing Chair of New Testament Exegesis at the University of Aberdeen in 1999.
 In 2007 he took up his current position as Professor in the Department of Theology and Religion at the Durham University.
A New Theory of the Earth was a book written by William Whiston, in which he presented a description of the divine creation of the Earth and a posited global flood.
 He also postulated that the earth originated from the atmosphere of a comet and that all major changes in earth's history could be attributed to the action of comets.
 It was published in 1696 and was well received by intellectuals of the day such as Isaac Newton and John Locke.
Remarks on Certain Passages in the Thirty-Nine Articles, better known as Tract 90, was a theological pamphlet written by the English theologian and churchman John Henry Newman and published in 1841.
 It is the most famous and the most controversial of the "Tracts for the Times" produced by the first generation of the Anglo-Catholic Oxford Movement.
William George Ward (21 March 1812 – 6 July 1882) was an English theologian and mathematician.
 A Roman Catholic convert, his career illustrates the development of religious opinion at a time of crisis in the history of English religious thought.
William Whiston (9 December 1667 – 22 August 1752) was an English theologian, historian, and mathematician, a leading figure in the popularisation of the ideas of Isaac Newton.
 He is now probably best known for helping to instigate the Longitude Act in 1714 (and his attempts to win the rewards that it promised) and his important translations of the "Antiquities of the Jews" and other works by Josephus (which are still in print).
 He was a prominent exponent of Arianism and wrote "A New Theory of the Earth".
Ibtina Theory is a new theory in the field of “Logic of Understanding Religion” and has direct influence on the issues of Philosophy of Religion.
 The "Ibtina Theory" is a theory for explaining the process and mechanism of "religious knowledge" formation.
Joseph Priestley FRS ( ; 24 March [O.S. 13 March] 1733 – 6 February 1804) was an 18th-century English theologian, English Dissenters clergyman, natural philosopher, chemist, innovative grammarian, multi-subject educator, and liberal political theorist who published over 150 works.
Theory of International Politics is a 1979 international relations (IR) theory by Kenneth Waltz that offers a new theory, the neorealist theory of international relations.
 Taking into account the influence of neoclassical economic theory, Waltz argued that the fundamental "ordering principle" (p. 88) of the international political system is anarchy, which is defined by the presence of "functionally undifferentiated" (p. 97) individual state actors lacking "relations of super- and subordination" (p. 88) that are distinguished only by their varying capabilities.
 Theory of International Politics is arguably the most influential book in international relations, causing a fundamental discursive transformation and bringing the concept of anarchy to the forefront.
Don Lynn Anderson (March 5, 1933 – December 2, 2014) was an American geophysicist who made significant contributions to the understanding of the origin, evolution, structure, and composition of Earth and other planets.
 An expert in numerous scientific disciplines, Anderson’s work combined seismology, solid state physics, geochemistry and petrology to explain how the Earth works.
 Anderson was best known for his contributions to the understanding of the Earth’s deep interior, and more recently , for the hypothesis that hotspots are the product of plate tectonics rather than narrow plumes emanating from the deep Earth.
 Anderson was Professor (Emeritus) of Geophysics in the Division of Geological and Planetary Sciences at the California Institute of Technology (Caltech).
 He received numerous awards from geophysical, geological and astronomical societies.
 In 1998 he was awarded the prestigious Crafoord Prize by the Royal Swedish Academy of Sciences along with Adam Dziewonski.
 Later that year, Anderson received the National Medal of Science.
 He held honorary doctorates from Rensselaer Polytechnic Institute (where he did his undergraduate work in geology and geophysics) and the University of Paris (Sorbonne), and served on numerous university advisory committees, including those at Harvard, Princeton, Yale, University of Chicago, Stanford, University of Paris, Purdue University, and Rice University.
 Anderson’s wide-ranging research resulted in hundreds of published papers in the fields of planetary science, seismology, mineral physics, petrology, geochemistry, tectonics and the philosophy of science.
 He continued to work and publish until his death.
 His widely known textbooks, Theory of the Earth, and New Theory of the Earth are regarded by colleagues as compelling syntheses of the origins of the Earth and its inner workings by one of the great geophysical authorities of our time.

Question: A New Theory of the Earth was written by what English theologian?
Answer: William Whiston