Hartley's Theory of Vibrations, he confesses explicitly, that "we cannot absolutely ascertain, what that affection of the brain is, which, by the constitution of human nature, causes memory;" and that, "the theory of Vibrations, though more probable than some others, is still but an hypothesis." Secondly, that Mr. Belsham, after making this explicit acknowledgment is nevertheless pleased to insinuate, that all who presume to object to this particular hypothesis, are bound by their own principles to assert, that memory has no dependence whatever on the state of the brain. Where the inconsistency lies in Dr. Reid's admission, that a certain constitution or state of the brain is necessary to memory, after he had stated some objections against the commonly received theories, I am at a loss to discover. Indeed, I should be glad to know, what philosopher, ancient or modern, has ever yet asserted, that memory is not liable to be injured by such affections of the brain as are produced by intemperance, disease, old age, and other circumstances which disturb the bodily mechanism. The philosophical inference, however, from this concession is not that the hypothesis of Dr. Hartley, or the hypothesis of Mr. Belsham must necessarily be true, but that, laying aside all hypotheses, we should apply ourselves to collect such facts as may lead us, in due time, to the only satisfactory conclusions we have much chance of ever forming concerning the connexion between mind and body-the discovery of some of the general laws by which this connexion is regulated.

In offering these strictures on the physiological metaphysics of the present day, it is proper for me at the same time, to observe that I object to it merely as an idle waste of labor and ingenuity, on questions to which the human faculties are altogether incompetent; and not because I consider any of the theories, to which it has given birth, as standing in the way of my own doctrines. The facts which I wish to ascertain rest on their own proper evidence ;-an evidence which would remain entire and unshaken, although a demonstration should be produced in favor of the animal spirits of Descartes, or of the Vibrations of Hartley; and which

would not gain the slightest accession of strength, if both these hypotheses were to fall into the contempt they deserve. The circumstance which peculiarly characterizes the inductive Science of the Mind is, that it professes to abstain from all speculations concerning its nature and essence; confining the attention entirely to phenomena, which every individual has it in his power to examine for himself, who chooses to exercise the powers of his understanding. In this respect, it differs equally in its scope, from the pneumatological discussions concerning the seat of the Soul, and the possibility or the impossibility of its bearing any relation to Space or to Time, which so long gave employment to the subtilty of the schoolmen;-and from the physiological hypotheses which have made so much noise at a later period, concerning the mechanical causes on which its operations depend. Compared with the first, it differs, as the inquiries of Galileo concerning the laws of moving bodies differ from the disputes of the ancient sophists concerning the existence and the nature of motion. Compared with the other, the difference is analogous to what exists between the conclusions of Newton about the law of gravitation, and his query concerning the invisible ether, of which he supposed it might possibly be the effect.— It may be worth while to add, in passing, that the diversity of opinion among Newton's followers, with respect to the verisimilitude of this query, while they have unanimously acquiesced in the physical conclusions of their master, affords an instructive proof, how little the researches of inductive science are liable to be influenced by the wanderings of Imagination, in those regions which human reason is not permitted to explore. Whatever our opinion concerning the unknown physical or metaphysical cause of gravitation may be, our reasonings concerning the system of nature will be equally just, provided only we admit the general fact that bodies tend to approach each other with a force varying with their mutual distances, according to a certain law. The case is precisely similar with respect to those conclusions concerning the mind, to which we are fairly led by the method of Induction. They rest upon a firm and

indisputable basis of their own; and (as I have elsewhere remarked) are equally compatible with the metaphysical creeds of the Materialist and of the Berkeleian.*

II. Intimately connected with the physiological hypothesis of the Hartleian school, is their metaphysical theory of Association, from which single principle they boast to have explained synthetically all the phenomena of the mind. In Dr. Priestley's Remarks on Reid's Inquiry, there is an attempt to turn into ridicule, by what the author calls a Table of Dr. Reid's Instinctive Principles, the application of the Inductive Logic to these phenomena. How far this Table is faithfully extracted from Dr. Reid's book, it is unnecessary for me to consider at present.† Supposing, for the sake of argument, that the Twelve Principles enumerated by Priestley had been actually stated by his antagonist as instinctive principles or as general laws of our nature, it is difficult to see for what reason the enumeration should be regarded as absurd, or even as unphilosophical, after the explanation given by Reid himself of the sense in which he wished his conclusions to be understood.

"The most general phenomena we can reach, are what we call Laws of Nature. So that the laws of na

*The hypothesis which assumes the existence of a subtle fluid in the nerves, propagated by their means from the brain to the different parts of the body, is of great antiquity; and is certainly less repugnant to the general analogy of our frame, than that by which it has been supplanted. How very generally it once prevailed, may be inferred from the adoption into common speech of the phrase animal spirits, to denote that unknown cause which "gives vigor or cheerfulness to the mind;' a phrase for which our language does not, at this day, afford a convenient substitute. The late Dr. Alexander Monro (one of the most cautious and judicious of medical inquirers) speaks of it as a fact which appeared to him to be almost indisputable. "The existence of a liquid in the cavities of the nerves, is supported by little short of demonstrative evidence." (See some observations of his, published by Cheselden in his Anatomy.)

The hypothesis of Vibrations first attracted public notice in the writings of Dr. William Briggs. It was from. him that Sir Isaac Newton derived his anatomical knowledge; along with which he appears plainly, from his Queries, to have imbibed also some of the physiological theories of his preceptor.

In the Monthly Review for 1808, I observe the following passage: "For the partiality which he (Dr. Cogan) shews to Dr. Reid, we may easily account, as being a just tribute to the ingenuity and industry of that writer, and to the numerous valuable observations which enrich his works, unconnected with his crude hypothesis on the subject of the Human Mind." In what part of Dr. Reid's writings is this crude hypothesis proposed?

†The reader will be enabled to form a judgment on this point, by the Note (**) at the end of this Volume.

ture are nothing else but the most general facts relating to the operations of nature, which include, a great many particular facts under them. And, if, in any case, we should give the name of a law of nature to a general phenomenon, which human industry shall afterwards trace to one more general, there is no great harm done. The most general assumes the name of a law of nature when it is discovered; and the less general is contained and comprehended in it." *

In another part of his work, he has introduced the same remark. "The labyrinth may be too intricate, and the thread too fine, to be traced through all its windings; but if we stop where we can trace it no farther, and secure the ground we have gained, there is no harm done; a quicker eye may in time trace it farther." t

In reply to these passages, Priestley observes, that "the suspicion that we are got to ultimate principles, necessarily checks all farther inquiry, and is therefore of great disservice in philosophy. Let Dr. Reid," he continues, "lay his hand upon his breast, and say, whether, after what he has written, he would not be exceedingly mortified to find it clearly proved, to the satisfaction of all the world, that all the instinctive principles in the preceding Table were really acquired; and that all of them were nothing more than so many different cases of the old and well known principle of Association of Ideas."

With respect to the probability of this supposition, I have nothing to add to what I have stated on the same head, in the Philosophy of the Human Mind; "that, in all the other sciences, the progress of discovery has been gradual, from the less general to the more general laws of nature; and that it would be singular indeed, if, in this science, which but a few years ago was confessedly in its infancy, and which certainly labors under many disadvantages peculiar to itself, a step should all at once be made to a single principle, comprehending all the particular phenomena which we know."

* Reid's Inquiry, p. 232, 3d ed.

† Page 9.

Elements, &c. vol. i. p. 398 (3d edition), where I have enlarged on this point at some length.

As the order established in the intellectual world seems to be regulated by laws perfectly analogous to those which we trace among the phenomena of the material system; and as, in all our philosophical inquiries (to whatever subject they may relate) the progress of the mind is liable to be affected by the same tendency to a premature generalization, the following extract from an eminent chemical writer may contribute to illustrate the scope, and to confirm the justness of some of the foregoing reflections.

"Within the last fifteen or twenty years, several new metals, and new earths, have been made known to the world. The names that support these discoveries are respectable, and the experiments decisive. If we do not give our assent to them, no single proposition in chemistry can for a moment stand. But whether all these are really simple substances, or compounds not yet resolved into their elements, is what the authors themselves cannot possibly assert; nor would it, in the least diminish the merit of their observations, if future experiments should prove them to have been mistaken, as to the simplicity of these substances. This remark should not be confined to later discoveries; it may as justly be applied to those earths and metals with which we have been long acquainted."-" In the dark ages of chemistry, the object was to rival nature; and the substance which the adepts of those days were busied to create, was universally allowed to be simple. In a more enlightened period, we have extended our inquiries, and multiplied the number of the elements. The last task will be to simplify; and, by a closer observation of nature, to learn from what a small store of primitive materials, all that we behold and wonder at was created."*

This analogy between the history of chemistry and that of the philosophy of the human mind, which has often struck myself in contrasting the views of the Alchemists with those of Lavoisier and his followers, has acquired much additional value and importance in my

Inquiries concerning the nature of a metallic substance, lately sold in London as a new Metal, under the title of Palladium. By Rich. Chenevix, Esq.