Dictionary of National Biography, 1885-1900/Craig, John (d.1731)
CRAIG, JOHN (d. 1731), mathematician, said to have been a Scotsman who settled in Cambridge, was a distinguished mathematician and a friend of Newton. He wrote several papers in the ‘Philosophical Transactions,’ and published two mathematical treatises, ‘Methodus Figurarum … Quadraturas determinandi,’ 1685, and ‘Tractatus … de Figurarum Curvilinearum Quadraturis et locis Geometricis,’ 1693. These writings were of some importance in the development of the theory of fluxions, and involved him in a controversy with James Bernoulli. In 1699 he published his curious tract, ‘Theologiæ Christianæ Principia Mathematica.’ He applies the theory of probabilities to show how the evidence is gradually weakened by transmission through successive hands. He argues that in 1699 the evidence in favour of the truth of the gospel narrative was equal to that represented by the statement of twenty-eight contemporary disciples; but that in the year 3144 it will diminish to zero. He infers that the second coming (at which period it is doubtful whether faith will be found on the earth) must take place not later than the last epoch. He afterwards calculates the ratio of the happiness promised in another world to that obtainable in this, and proves it to be infinite. In spite of his vagaries Craig was in 1708 collated by his countryman Bishop Burnet to the prebend of Durnford in the cathedral of Salisbury, which in 1726 he exchanged for the prebend of Gillingham Major. This had been held from 1698 to 1720 by a William Craig, who may probably have been a connection. He is said to have been ‘an inoffensive, virtuous man,’ and he showed his simplicity by living in London in his later years in hopes of being noticed for his mathematical abilities. The hope was disappointed, and he died in London 11 Oct. 1731. Besides the above he published ‘De Calculo Fluentium libri duo,’ 1718.
[Hutchins's Dorsetshire, iii. 218, 220, iv. 420; General Biographical Dictionary, 1761; Le Neve's Fasti, ii. 665, 668, 669; Hutton's Math. Dict.; Montucla's Histoire, iii. 127–8, 130; De Morgan's Budget of Paradoxes, pp. 77–8.]