that great man, than to enter into the general spirit of his metaphysical philosophy.

To this translation, Dr. Law prefixed a Dissertation concerning the Fundamental Principle of Virtue, by the Reverend Mr. Gay; a performance of considerable ingenuity, but which would now be entitled to little notice, were it not for the influence it appears to have had in suggesting to Dr. Hartley the possibility of accounting for all our intellectual pleasures and pains, by the single principle of the Association of Ideas. We are informed by Dr. Hartley himself, that it was in consequence of hearing some account of the contents of this dissertation, he was first led to engage in those inquiries which produced his celebrated Theory of Human Nature.

The other principle on which this theory proceeds (that of the vibrations and vibratiuncles in the medullary substance of the brain) is also of Cambridge origin. It occurs in the form of a query in Sir Isaac Newton's Optics; and a distinct allusion to it, as a principle likely to throw new light on the phenomena of mind, is to be found in the concluding sentence of Smith's Harmonics.

Very nearly about the time when Hartley's Theory appeared, Charles Bonnet of Geneva published some speculations of his own, proceeding almost exactly on the same assumptions. Both writers speak of vibrations (ébranlemens) in the nerves; and both of them have recourse to a subtile and elastic ether, co-operating with the nerves in carrying on the communication between soul and body.* This fluid Bonnet conceived to be contained in the nerves, in a manner analogous to that in which the electric fluid is contained in the solid bodies which conduct it; differing in this respect from the Cartesians as well as from the ancient physiologists, who considered the nerves as hollow tubes, or pipes, within which the animal spirits were included. It is to this elastic ether that Bonnet ascribes the vibrations of which he supposes the nerves to be susceptible; for the nerves themselves (he justly observes) have no resemblance to

* Essai Analytique de l'Ame, Chap. v. See also the additional notes on the first chapter of the seventh part of the Contemplation de la Nature.

the stretched cords of a musical instrument.* Hartley's Theory differs in one respect from this, as he speaks of vibrations and vibratiuncles in the medullary substance of the brain and nerves. He agrees, however, with Bonnet in thinking, that to these vibrations in the nerves the cooperation of the ether is essentially necessary; and, therefore, at bottom the two hypotheses may be regarded as in substance the same. As to the trifling shade of difference between them, the advantage seems to me to be in favor of Bonnet.

Nor was it only in their Physiological Theories concerning the nature of the union between soul and body, that these two philosophers agreed. On all the great articles of metaphysical theology, the coincidence between their conclusions is truly astonishing. Both held the doctrine of Necessity in its fullest extent; and both combined with it a vein of mystical devotion, setting at defiance the creeds of all established churches. The intentions of both are allowed, by those who best knew

* "Mais les nerfs sont mols, ils ne sont point tendus comme les cordes d'un instrument; les objets y exciteroient-ils donc les vibrations analogues à celles d'un corde pincée ? Ces vibrations se communiqueroient-elles à l'instant au siège de l'âme La chose paroit difficile à concevoir. Mais si l'on admet dans les nerfs un fluide dont la subtilité et l'élasticité approche de celle de la lumière ou de l'éther, on expliquera facilement par le secours de ce fluide, et la célérité avec laquelle les impressions se communiquent à l'âme, et celles avec laquelle l'âme éxécute tant d'opé rations différentes." (Essai Anal. Chap. v.)

"Au reste, les physiologistes qui avoient cru que les filets nerveux étoient solides, avoient cédé à des apparences trompeuses. Ils vouloient d'ailleurs faire osciller les nerfs, pour rendre raison des sensations, et les nerfs ne peuvent osciller. Ils sont mous, et nullement élastiques. Un nerf coupé ne se retire point. C'est le fluide invisible que les nerfs renferment, qui est doué de cette élasticité qu'on leur attribuoit, et d'une plus grand élasticité encore." (Contemp. de la Nature, VII Partie, Chap. i. Notes at the end of the chapter.)

M. Quesnai, the celebrated author of the Economical System, has expressed himself to the same purpose concerning the supposed vibrations of the nerves: "Plusieurs physiciens ont pensé que le seul ébranlement des nerfs, causé par les objets qui touchent les organes des corps, suffit pour occasioner le mouvement et le sentiment dans les parties où les nerfs sont ébranlés. Ils se représentent les nerfs comme des cordes fort tendus, qu'un léger contact met en vibration dans toute leur étendue. Des philosophes, peu instruits en anatomie, ont pu se former une telle idée. Mais cette tension qu'on suppose dans les nerfs, et qui les rend si susceptibles d'ébranlement et de vibration, est si grossièrement imaginée qu'il seroit ridicule de s'occuper sérieusement à la réfuter. (Econ. Animale, sect. c. 13.)

As this passage from Quesnai is quoted by Condillac, and sanctioned by his authority (Traité des Animaux, Chap. iii.), it would appear that the hypothesis which supposes the nerves to perform their functions by means of vibrations was going fast into discredit, both among the metaphysicians and the physiologists of France, at the very time when it was beginning to attract notice in England, in consequence of the vis¡onary speculations of Hartley.

them, to have been eminently pure and worthy; but it cannot be said of either, that his metaphysical writings have contributed much to the instruction or to the improvement of the public. On the contrary, they have been instrumental in spreading a set of speculative tenets very nearly allied to that sentimental and fanatical modification of Spinozism, which, for many years past, has prevailed so much, and produced such mischievous effects in some parts of Germany.

But it is chiefly by his application of the associating principle to account for all the mental phenomena that Hartley is known to the world; and upon this I have nothing to add to what I have already stated in another work. (Phil. Essays, Essay IV.) His Theory seems to be already fast passing into oblivion; the temporary popularity which it enjoyed in this country having, in a great measure, ceased with the life of its zealous and indefatigable apostle, Dr. Priestley.*

It would be unfair, however, to the translator of Archbishop King, to identify his opinions with those of Hartley and Priestley. The zeal with which he contends for man's free agency is sufficient, of itself, to draw a strong line of distinction between his Ethical System and theirs. (See his Notes on King, passim.) But I must be allowed to say of him, that the general scope of his writings tends, in common with that of the two other metaphysicians, to depreciate the evidences of Natural Religion, and more especially to depreciate the evidences which the light of nature affords of a life to come; "a doctrine equally necessary to comfort the weakness, and to support our lofty ideas of the grandeur of human nature;" and of which it seems hard to confine exclusively the knowledge to that portion of mankind

Dr. Priestley's opinion of the merits of Hartley's work is thus stated by himself: "Something was done in this field of knowledge by Descartes, very much by Mr. Locke, but most of all by Dr. Hartley, who has thrown more useful light upon the theory of the mind, than Newton did upon the theory of the natural world."(Remarks on Reid, Beattie, and Oswald, p. 2. Lond. 1774.)

Smith's Theory of Moral Sentiments, 6th Ed. Vol. I. pp. 325, 326.

Dr. Law's doctrine of the sleep of the soul, to which his high station in the church could not fail to add much weight in the judgment of many, is, I believe, now universally adopted by the followers of Hartley and Priestley; the theory of vibrations being evidently inconsistent with the supposition of the soul's being able to exercise her powers in a separate state from the body.

who have been favored with the light of Revelation. The influence of the same fundamental error, arising, too, from the same mistaken idea, of thus strengthening the cause of Christianity, may be traced in various passages of the posthumous work of the late Bishop of Llandaff. It is wonderful that the reasonings of Clarke and of Butler did not teach these eminent men a sounder and more consistent logic; or, at least, open their eyes to the inevitable consequences of the rash concessions which they made to their adversaries.*

Among the disciples of Law, one illustrious exception to these remarks occurs in Dr. Paley, whose treatise on Natural Theology is unquestionably the most instructive as well as interesting publication on that subject which has appeared in our times. As the book was intended for popular use, the author has wisely avoided, as much as possible, all metaphysical discussions; but I do not know that there exists any other work where the argument from final causes is placed in so great a variety of pleasing and striking points of view.

Without entering at all into the argument with Dr. Law or his followers, it is sufficient here to mention, as an historical fact, their wide departure from the older lights of the English church, from Hooker downwards. "All religion," says Archbishop Tillotson, whom I select as an unexceptionable organ of their common sentiments, "is founded on right notions of God and his perfections, insomuch that Divine Revelation itself does suppose these for its foundations; and can signify nothing to us unless they be first known and believed; so that the principles of natural religion are the foundation of that which is revealed." (Sermon 41.) "There is an intrinsical good and evil in things, and the reasons and respects of moral good and evil are fixed and immutable, eternal and indispensable. Nor do they speak safely, who make the Divine will the rule of moral good and evil, as if there were nothing good or evil in its own nature antecedently to the will of God; but, that all things are therefore good and evil because God wills them to be so." (Sermon 88.) "Natural religion is obedience to the natural law, and the performance of such duties as natural light, without any express and supernatural revelation, doth dictate to men. These lie at the bottom of all religion, and are the great fundamental duties which God requires of all mankind. These are the surest and most sacred of all other laws; those which God hath rivetted in our souls and written upon our hearts; and these are what we call moral duties, and most valued by God, which are of eternal and perpetual obligation because they do naturally oblige, without any particular and express revelation from God; and these are the foundation of revealed and instituted religion; and all revealed religion does suppose them and build upon them." (Sermons 48, 49.)

SECTION VI.

Condillac, and other French Metaphysicians of a later date.

WHILE Hartley and Bonnet were indulging their imagination in theorizing concerning the nature of the union between soul and body, Condillac was attempting to draw the attention of his countrymen to the method of studying the phenomena of Mind recommended and exemplified by Locke.* Of the vanity of expecting to illustrate, by physiological conjectures, the manner in which the intercourse between the thinking principle and the external world is carried on, no philosopher seems ever to have been more completely aware; and, accordingly, he confines himself strictly, in all his researches concerning this intercourse, to an examination of the general laws by which it is regulated. There is, at the same time, a remarkable coincidence between some of his views and those of the other two writers. All of the three, while they profess the highest veneration for Locke,

* It may appear to some unaccountable, that no notice should have been taken, in this Dissertation, of any French metaphysician during the long interval between Malebranche and Condillac. As an apology for this apparent omission, I beg leave to quote the words of an author intimately acquainted with the history of French literature and philosophy, and eminently qualified to appreciate the merits of those who have contributed to their progress. 66 If we except," says Mr. Adam Smith, in a Memoir published in 1755, "the Meditations of Descartes, I know of nothing in the works of French writers which aspires at originality in morals or metaphysics; for the philosophy of Regius and that of Malebranche are nothing more than the meditations of Descartes unfolded with more art and refinement. But Hobbes, Locke, Dr. Mandeville, Lord Shaftesbury, Dr. Butler, Dr. Clarke, and Mr. Hutche son, each in his own system, all different and all incompatible, have tried to be original, at least in some points. They have attempted to add something to the fund of observations collected by their predecessors, and already the common property of mankind. This branch of science, which the English themselves neglect at present, appears to have been recently transported into France. I discover some traces of it not only in the Encyclopédie, but in the Theory of Agreeable Sensations, by M. de Pouilly; and much more in the late discourse of M. Rousseau, On the Origin and Foundation of the Inequality of Ranks among Men."

Although I perfectly agree with Mr. Smith in his general remark on the sterility of invention among the French metaphysicians posterior to Descartes, when compared to those of England, I cannot pass over the foregoing quotation without expressing my surprise, 1. To find the name of Malebranche (one of the highest in modern philosophy) degraded to a level with that of Regius; and, 2. To observe Mr. Smith's silence with respect to Buffier and Condillac, while he mentions the author of the Theory of Agreeable Sensations as a metaphysician of original genius. Of the merits of Condillac, whose most important works were published several years before this paper of Mr. Smith's, I am about to speak in the text; and those of Buffier I shall have occasion to mention in a subsequent part of this discourse. In the mean time, I shall only say of him, that I regard him as one of the most original as well as sound philosophers of whom the eighteenth century has to boast.