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Thomas Bradwardine

Thomas Bradwardine (c. 1290-1349), English archbishop, called "the Profound Doctor," was born either at Hartfield in Sussex or at Chichester.

He was educated at Merton College, Oxford, where he took the degree of doctor of divinity, and acquired the reputation of a profound scholar, a skilful mathematician and an able divine. He was afterwards raised to the high offices of chancellor of the university and professor of divinity.

From being chancellor of the diocese of London, he became chaplain and confessor to Edward III, whom he attended during his wars in France. On his return to England, he was successively appointed prebendary of Lincoln, archdeacon of Lincoln (1347), and in 1349 archbishop of Canterbury. He died of the plague at Lambeth on August 26 1349, forty days after his consecration.

Chaucer in his Nun's Priest's Tale ranks Bradwardine with St Augustine. His great work is a treatise against the Pelagians, entitled De causa Dei contra Pelagium et de virtute causarum, edited by Sir Henry Savile (London, 1618). He wrote also De Geometria speculativa (Paris, 5530); De A rithmetica practica (Paris, 1502); De Proportionibus (Paris, 495; Venice, 1505); De Quadratura Circuli (Paris, 1495); and an Ars Memorative, Sloane manuscripts. No. 3974 in the British Museum.

Bradwardine was one of the Oxford Calculators, of Merton College, Oxford University, studying mechanics with William Heytesbury, Richard Swineshead, and John Dumbleton. The Oxford Calculators distinguished kinematics from dynamics, emphasizing kinematics, and investigating instantaneous velocity. They first formulated the mean speed theorem: a body moving with constant velocity travels distance and time equal to an accelerated body whose velocity is half the final speed of the accelerated body. They also demonstrated this theorem -- essence of "The Law of Falling Bodies" -- long before Galileo is credited with this.

The mathematical physicist and historian of science Clifford Truesdell, wrote, "The now published sources prove to us, beyond contention, that the main kinematical properties of uniformly accelerated motions, still attributed to Galileo by the physics texts, were discovered and proved by scholars of Merton college .... In principle, the qualities of Greek physics wre replaced, at least for motions, by the numerical quantities that have ruled Western science ever since. The work was quickly diffused into France, Italy, and other parts of Europe. Almost immediately, Antonio da Casale and Nicole Oreme found how to represent the results by geometrical graphs, introducing the conection between geometry and the physical world that became a second characteristic habit of Western thought ..."

In Tractatus de proportionibus (1328), Thomas Bradwardine extended the theory of proportions of Eudoxus to anticipate the concept of exponential growth, later developed by the Bernoullis and Euler, with compound interest as a special case. Arguments for the mean speed theorem (above) require the modern concept of limit, so Bradwardine had to use arguments of his day. Mathematician and mathematical historian Carl O. Boyer writes, "Bradwardine developed the Boethian theory of double or triple or, more generally, what we would call 'n-tple' proportion".

Boyer also writes that "the works of Bradwardine had contained some fundementals of trigonometry gleaned from Muslim sources".


A History of Mathematics (288, 302), Carl O. Boyer, Princeton Univsity Press, Princeton, 1984.

The Science of Mechanics in the Middle Ages, Marshall Claggett, U. of Wisconsin Press, Madison, 1960.

Tractatus de Proportionibus, Its Significance for the Development of Mathematical Physics, H. L. Crosby, University of Wisconsin Press, Madison, 1955.

Essays in The History of Mechanics, Clifford Truesdell, Springer-Verlag, New York, 1968, QC122.T7.

See Quétif-Echard, Script. Praedic. (1719), i. 744; WF Hook, Lives of the Archbishops of Canterbury, vol. iv.