HARTLEY, DAVID English philosopher, and founder of the Associationist school of psychologists, was born on Aug. 3o, 1705. He was educated at Bradford grammar school and Jesus College, Cambridge, later practising as a physician at Newark, Bury St. Edmunds, London, and lastly at Bath, where he died on Aug. 28, Hartley's Observations on Man was the first systematic attempt to interpret the phenomena of mind by the theory of association; its two main theories are the doctrine of vibrations and the doctrine of associations. His physical theory, he tells us, was drawn from Newton's Principia. His psychological theory was suggested by the Rev. John Gray's Dissertation concerning the Fundamental Principles of Virtue or Morality, which was prefixed to Bishop Law's translation of Archbishop King's Origin of Evil.
With Locke, Hartley asserted that, prior to sensation, the .mind is a blank. From simple sensations, however, originate all states of consciousness, the law of growth being the law of contiguity, synchronous and successive. By this law he explained not only memory, as others had done, but also emotion (which he analyses with skill), reasoning, and voluntary and involuntary action (see ASSOCIATION OF IDEAS). He held that sensation is the result of a vibration of the minute particles of the medullary substance of the nerves made possible by New ton's subtle elastic ether.
BIBLIOGRAPHY.--The 18o1 ed. of the Observations contains a life by Bibliography.--The 18o1 ed. of the Observations contains a life by his son. See also Sir L. Stephen, Hist. of Eng. Thought in the r8th Century; G. S. Bower, Hartley and James Mill (1881) ; B. Schonlank, Hartley and Priestley die Begriinder des Assoziationismus in England (1882) ; Th. Ribot, English Psychology (Eng. trs., 1873) ; E. Albee, Hist. of Eng. Utilitarianism (1902).