HARTLEY, David, an ingenious physician and philosopher, was the son of a clergyman at Armley, in Yorkshire, and born on the 30th of August 1705. After spending some time at a private school, he was admitted of Jesus College, Cambridge, in 1720, became afterwards a fellow of that college, and took his master’s degree in 1729. He was originally intended for the church; but having some scruples about subscribing the thirty-nine articles, he directed hisstudies to the medical profession, and having completed his professional education, commenced practice at Newark, whence he removed to Bury St Edmund’s, and afterwards settled for some time in London, but eventually established himself at Bath. Dr Hartley was indefatigable in the pursuit of all collateraPbranches of knowledge, and he lived in personal intimacy with some of the most learned men of his age, including Law, Butler, Warburton, Jortin, Hales, Young, Hooke the Roman historian, and others. From early youth he was devoted to the sciences, particularly logic and mathematics; he studied mathematics and experimental philosophy under Professor Saunderson; he was an ardent admirer of Newton, even where Newton was not in his strength, we mean, on the subjects of chronology and religion; and from Locke he derived the first principles of logic and metaphysics, as appears from the work by which he is now principally known. The doctrine of vibrations, as instrumental to sensation and motion, he obtained from Newton; and the principle of association he derived originally from Locke. This work he commenced about the age of twenty-five, and published it in 1749, under the title of Observations on Man, his Frame, his Duty, and his Expectations, in two vols. 8vo. He did not expect that it would meet with any general or immediate reception in the philosophical world; nor did it happen otherwise than he had expected; but he entertained a hope that, at some future period, his system would be adopted by philosophers; and in this he appears to have been mistaken. Dr Priestley, indeed, published, in 1775, a work on Hartley’s theory; but all that he has done in this production is to convince us of his own materialism, and his earnest desire to prove Hartley a materialist, although the latter dreaded nothing so much. It must be confessed, however, that his doctrines have an apparent tendency towards that principle, and that other philosophers, who had not the same views or object with Priestley, have arrived at the same conclusion with him. Nor is this all. Although Hartley’s mind was active and penetrating, his industry indefatigable, and his philosophical observations unremitting, he has built upon a gratuitous assumption the doctrine by which he attempts to explain the origin and propagation of sensation; for Haller has shown that he attributes properties to the medullary substance of the brain and nerves which are incompatible with their nature; and that, consequently, he has assumed, as the basis of his system, what neither does nor can exist. (See, on the subject of Hartley’s philosophical doctrines, Sir James Mackintosh’s continuation of Dissertation Second, p. 362.) Hartley was the author of several medical tracts relative to the operation of Mrs Stephens’ medicine for the stone, a disease with which he was himself afflicted; and he is also said to have written a defence of inoculation for smallpox, against Dr Warren and others. He died at Bath, on the 28th of August 1757, in the fifty-second year of his age. The philosophical character of Hartley is delineated in his works, which are alike remarkable for modesty and originality, though disfigured by an affectation of mathematical forms of reasoning in treating a subject to which they can never be made to apply. In private life he was gay, cheerful, and social; his hours of recreation were devoted to music, poetry, and history; and the virtuous principles which he instilled in his works formed the invariable guides of his life and doctrine. (a.)