HARTLEY, DAVID (1705-1757), English philosopher, and founder of the Associationist school of psychologists, was born on the 30th of August 1705. He was educated at Bradford grammar school and Jesus College, Cambridge, of which society he became a fellow in 1727. Originally intended for the Church, he was deterred from taking orders by certain scruples as to signing the Thirty-nine Articles, and took up the study of medicine. Nevertheless, he remained in the communion of the English Church, living on intimate terms with the most distinguished churchmen of his day. Indeed he asserted it to be a duty to obey ecclesiastical as well as civil authorities. The doctrine to which he most strongly objected was that of eternal punishment. Hartley practised as a physician at Newark, Bury St Edmunds, London, and lastly at Bath, where he died on the 28th of August 1757. His Observations on Man was published in 1749, three years after Condillac's Essai sur l'origine des connaissances humaines, in which theories essentially similar to his were expounded. It is in two parts—the first dealing with the frame of the human body and mind, and their mutual connexions and influences, the second with the duty and expectations of mankind. His two main theories are the doctrine of vibrations and the doctrine of associations. His physical theory, he tells us, was drawn from certain speculations as to nervous action which Newton had published in his Principia. His psychological theory was suggested by the Dissertation concerning the Fundamental Principles of Virtue or Morality, which was written by a clergyman named John Gay (1699-1745), and prefixed by Bishop Law to his translation of Archbishop King's Latin work on the Origin of Evil, its chief object being to show that sympathy and conscience are developments by means of association from the selfish feelings.
The outlines of Hartley's theory are as follows. With Locke he asserted that, prior to sensation, the human mind is a blank. By a growth from simple sensations those states of consciousness which appear most remote from sensation come into being. And the one law of growth of which Hartley took account was the law of contiguity, synchronous and successive. By this law he sought to explain, not only the phenomena of memory, which others had similarly explained before him, but also the phenomena of emotion, of reasoning, and of voluntary and involuntary action (see Association of Ideas).
By his physical theory Hartley gave the first strong impulse to the modern study of the intimate connexion of physiological and psychical facts which has proved so fruitful, though his physical theory in itself is inadequate, and has not been largely adopted. He held that sensation is the result of a vibration of the minute particles of the medullary substance of the nerves, to account for which he postulated, with Newton, a subtle elastic ether, rare in the interstices of solid bodies and in their close neighbourhood, and denser as it recedes from them. Pleasure is the result of moderate vibrations, pain of vibrations so violent as to break the continuity of the nerves. These vibrations leave behind them in the brain a tendency to fainter vibrations or "vibratiuncles" of a similar kind, which correspond to "ideas of sensation." Thus memory is accounted for. The course of reminiscence and of the thoughts generally, when not immediately dependent upon external sensation, is accounted for on the ground that there are always vibrations in the brain on account of its heat and the pulsation of its arteries. What these vibrations shall be is determined by the nature of each man's past experience, and by the influence of the circumstances of the moment, which causes now one now another tendency to prevail over the rest. Sensations which are often associated together become each associated with the ideas corresponding to the others; and the ideas corresponding to the associated sensations become associated together, sometimes so intimately that they form what appears to be a new simple idea, not without careful analysis resolvable into its component parts.
Starting, like the modern Associationists, from a detailed account of the phenomena of the senses, Hartley tries to show how, by the above laws, all the emotions, which he analyses with considerable skill, may be explained. Locke's phrase "association of ideas" is employed throughout, "idea" being taken as including every mental state but sensation. He emphatically asserts the existence of pure disinterested sentiment, while declaring it to be a growth from the self-regarding feelings. Voluntary action is explained as the result of a firm connexion between a motion and a sensation or "idea," and, on the physical side, between an "ideal" and a motory vibration. Therefore in the Freewill controversy Hartley took his place as a determinist. It is singular that, as he tells us, it was only with reluctance, and when his speculations were nearly complete, that he came to a conclusion on this subject in accordance with his theory.
See life of Hartley by his son in the 1801 edition of the Observations, which also contains notes and additions translated from the German of H. A. Pistorius; Sir Leslie Stephen, History of English Thought in the Eighteenth Century (3rd ed., 1902), and article in the Dictionary of National Biography; G. S. Bower, Hartley and James Mill (1881); B. Schönlank, Hartley und Priestley die Begründer des Assoziationismus in England (1882). See also the histories of philosophy and bibliography in J. M. Baldwin's Dictionary of Philosophy and Psychology (1905), vol. iii.
↑Anonymously in the 1731 ed., with acknowledgment in the 1758 ed.