Hartley, David an English practitioner of medicine, and a philosopher of considerable, but transitory reputation. The Scotch school of metaphysics borrowed much from his conclusions; and the long-prevalent theory of Beauty, which was elaborated in Alison's Principles of Taste, derived from them its cardinal doctrines. Dr. Hartley occupies a notable position in the history of speculation on other grounds. He presented a curious example of the partial conciliation of Des Cartes, Newton, and Locke; he inaugurated the impulse which transmuted the system of the last of these great men into the materialism of the French Encyclopedia; he preceded Bonnet, of Geneva, in applying physiological observation to psychological discussion, and thus became the precursor of Cabanis and Broussais, of Moleschott and Huxley. He was contemporary with Collier, and Berkeley, and Hume, and Reid. While the two first were undermining the philosophy of Locke by questioning the credibility of the senses, and Hume was achieving a similar result by impugning the evidences of consciousness, to be imperfectly refuted by Reid's exaggeration of the reliability of external perception, Hartley was still further invalidating the authority of Locke by proposing a purely mechanical explanation of the processes of thought. He is thus even more noteworthy for his relations to the revolutions of opinion in the 18th century than for the positive additions he is supposed to have made to the science of the human mind. He was one of the dominant spirits of that agitation of the intellectual waters, which heralded and produced the political convulsions of the last century. At the same time, he is the link between widely separated dogmas: furnishing a bond between Des Cartes and Stewart; connecting Locke with Condillac and French sensationalism; reviving neglected positions of Aristotle, and prefiguring many of the latest manifestations of scientific materialism.
Life. — The biography of Dr. Hartley is singularly devoid of salient incidents and of general interest. He belonged to that numerous class of very worthy men who run their eminently useful career without experiencing or occasioning violent excitement of any kind. But for his philosophical productions, his epitaph might have been Vivens moriensque fefellit. He was the son of a respectable clergyman, and was born Aug. 30,1705, at Armley, Yorkshire, of which parish his father was vicar. He completed his education at Jesus College, Cambridge, and was designed for the paternal vocation. But he was induced to divert his attention to medicine, in consequence of scruples about subscribing the XXXIX Articles, for religious opinion within the bosom of the Anglican Church was much divided at the time by the recent issues of the "Bangorian Controversy." His experience was frequently repeated in other cases in the ensuing years. He retained, however, the fervent but simple piety appropriate to his meditated profession, and never withdrew his interest from the subjects which attract the intelligent theologian. He informs us that the seeds of his own doctrine began to germinate when he was twenty- five years of age, though their elaboration was not completed till he was more than forty. His views were given to the world in 1749, in a work entitled Observations on Man, his Frame, his Duties, his Expectations. He survived its publication about eight years, and died at Bath Aug. 28, 1757, when within a fortnight of completing his fifty-third year. His life had been expended in the diligent and kindly pursuit of his calling at Newark, Bury St. Edmund's, London, and Bath.
Mackintosh and Coleridge, while presenting diverse views of Hartley's doctrine, are lavish of encomiums upon his virtues and purity of character. A very brief and very dry biography was composed by his son, with filial regard and quaint delineation. A few fragments from this recondite production will present the philosopher "in the habit and manner as he lived." "His person was of middle size and well proportioned. His complexion fair, his features regular and handsome. His countenance open, ingenuous and animated. He was peculiarly neat in person and attire. He lived in personal intimacy with the learned men of his age," among whom are enumerated Law, bishop of Carlisle; Butler, bishop of Durham; Warburton, bishop of Gloucester; Hoadley, successively bishop of Bangor, Hereford, and Winchester; Pope and Young; Dr. Jortin and Dr. Byrom; Hawkins, Browne, and Hooke, the forgotten historian of Rome. The list is sufficiently heterogeneous. "His mind was formed to benevolence and universal philanthropy. His genius was penetrating and active, his industry indefatigable, his philosophical observations and attentions unremitting. His natural temper was gay, cheerful, and sociable. He was addicted to no vice in any part of his life, neither to pride, nor to sensuality, nor intemperance, nor ostentation, nor envy, nor to any sordid self-interest; but his heart was replete with every contrary virtue."
Philosophy. — Hartley neither proclaimed nor produced any scheme of speculation, nor did he pretend that his views were characterized by any marked degree of originality. He investigated and endeavored to explain certain phenomena of the human mind, and to discover the machinery of thought. He has bequeathed a doctrine which has been in part generally adopted, and which has been frequently exaggerated by admirers who have repudiated, ignored, or been ignorant of the characteristic groundwork on which it had been erected. The source and filiations of his tenets have been indicated by him with what Sir James Mackintosh conceives to have been extravagant generosity. Hartley's acknowledgments are, however, made in ignorance of his much larger, but more remote obligations to Aristotle. "About eighteen years ago," says he, in 'the preface of his work, "I was informed that the Rev. Mr. Gay, then living, asserted the possibility of deducing all our intellectual pleasures and pains from association. This put me upon considering the power of association. By degrees many disquisitions foreign to the doctrine of association, or, at least, not immediately connected with it, intermixed themselves." "I think, however, that I cannot be called a system maker, since I did not first form a system, and then suit the facts to it, but was carried on by a train of thoughts from one thing to another, frequently without any express design, or even any previous suspicion of the consequences that might arise." Assuredly this is neither a systematic nor a philosophical method of procedure. But this easy divagation of thought explains the instability, want of consistency, and partial incoherence of Hartley's speculations. It also explains the facility and unsuspected inconsequence with which a portion of the doctrine has been separated from its accompaniments for special acceptance and development.
The characteristic tenets of Hartley have been very clearly and concisely stated by Morell. "The objects of the external world affect in some manner the extreme ends of the nerves, which spread from the brain as a center to every part of the body. This affection produces a vibration, which is continued along the nerve by the agency of an elastic ether until it reaches the brain, where it produces the phenomenon we term sensation. When a sensation has been experienced several times, the vibratory movement from which it arises acquires the tendency to repeat itself spontaneously, even when the external object is not present. These repetitions, or relics of sensation, are ideas, which in their turn possess the property of recalling each other by virtue of mutual association among themselves… The subordinate effects of these principles are easy to be imagined. If all our ideas are but relics of sensations, and all excited spontaneously by the laws of association, it is abundantly evident that the power of the will must be a nonentity, that man can really have no control of his own mind, that he is the creature of irresistible necessity. Hartley was accordingly a firm necessarian. Another natural effect of the theory of vibrations is materialism." The pernicious consequences of their dogmas are perspicaciously displayed by Coleridge, who had at one time been so devoted to their teachings that he bestowed the name of their author upon his son; Hartley Coleridge.
In this speculation there are three distinct but intimately connected doctrines.
1. The theory of the association of ideas.
2. The physiological and physical mode of accounting for this association and for perception by the vibrations of an elastic ether through the medullary substance of the nerves.
3. The assertion of the necessity of human actions. The last of these connects itself with the optimism of Leibnitz and the fatalism of Spinoza, through King's Origin of Evil. The second dogma was early abandoned, at least in the form in which it was presented by this author. It was not entirely novel, but it was the most original portion of Hartley's labors, and through it he mainly influenced the development of the French philosophy. It was suggested-by one of the queries in Newton's Optics, and may be traced through the animal spirits of Locke and Des Cartes, and the vortices and elastic ether of Des Cartes to the earlier philosophers, and up to Epicurus and Leucippus. It may merit renewed consideration if the physiological psychology now in prospect should gain acceptance. The doctrine of Association is regarded as being peculiarly Hartley's own. It was not altogether novel: he himself ascribes its first suggestion to Gay. It is presupposed in many suggestions of Locke, and is descended from a more remote and illustrious ancestry, which runs back to the Stagyrite —
the reputed fountain of so much error, the father of so much wisdom. It received, however, such an ingenious and extensive development from Hartley that Sir James Mackintosh rightly disregards the claims of Gay, but wrongly neglects earlier obligations.' It is largely incorporated into recent schemes of metaphysics, ethics, and aesthetics, but severed from the mechanical hypothesis which gave it its chief originality and its distinctive complexion. In this mutilated form it possesses unquestionable truth; but still it is only an imperfect explanation of a limited class of mental and moral phenomena, and is easily pressed, as it has often been pushed, to absurd and hazardous conclusions. Coleridge has. forcibly signalized its dangers, and has declared that, wherever it deviates from the simpler exposition of Aristotle, it declines into error and immoral courses.
Literature. — Hartley, Observations on Man, his Framer his Duty, his Expectations, with Notes and Additions by Herman Andrew Pistorius (Lond. 1791, 3 vols. 8vo). Al. abridgment of the original edition had been published by Dr. Priestley (Lond. 1775), with the omission of the doctrine of vibrations and vibratiuncules. It is from this mutilated presentment that the theory of Association has been principally derived. Hume, Inquiry concerning the Human Understanding, sec. 2-7; Reid, On the Intellectual Powers, Essay 2, ch. 3, ed. Hamilton — unfortunately, Sir William never supplied the notes to Reid, which he indicates by numbers: Mackintosh, On the Progress of Ethical Philosophy; Dugald Stewart, On the Progress of Metaphysical, Ethical, and Political Philosophy (Philosophical Essays, Works, edit. Sir W. Hamilton); Coleridge, Biographia Literaria. ch. 5-7 Morell, History of Modern Philosophy. (G. F. H.)