speculations, than from the examples of sound investigation exhibited by a few eminent men, who professed to follow him as their guide, that the practical spirit of his writings has been caught by the multitude of physical experimentalists over Europe; truth and good sense descending gradually, in this as in other instances, by the force of imitation and of early habit, from the higher orders of intellect to the lower. In some parts of the continent, more especially, the circulation of Bacon's philosophical works has been surprisingly slow. It is doubtful whether Descartes himself ever perused them; and as late as the year 1759, if we may credit Montucla, they were very little known in France. The introductory discourse prefixed by D'Alembert to the Encyclopédie, first recommended them, in that country, to gen

eral attention.

The change which has taken place during the two last centuries in the plan of physical research, and the success which has so remarkably attended it, could not fail to suggest an idea, that something analogous might probably be accomplished at a future period, with respect to the phenomena of the intellectual world. And accordingly, various hints of this kind may be traced in different authors, since the era of Newton's discoveries. A memorable instance occurs in the prediction with which that great man concludes his Optics; "That if natural philosophy, in all its parts, by pursuing the inductive method, shall at length be perfected, the bounds of moral philosophy will also be enlarged." Similar remarks may be found in other publications; particularly in Mr. Hume's Treatise of Human Nature, where the subject is enlarged on with much ingenuity. As far, however, as I am able to judge, Dr. Reid was the first who conceived justly and clearly the analogy between these two different branches of human knowledge; defining with precision the distinct provinces of observation and of reflection, in furnishing the data of all our reasonings concerning matter and mind; and demonstrating the necessity of a careful separation between the phenomena which they respectively exhibit, while we adhere to the same mode of philosophizing in investigating the laws of both.

That so many philosophers should have thus missed their aim, in prosecuting the study of the human mind, will appear the less surprising, when we consider, in how many difficulties, peculiar to itself, this science is involved. It is sufficient at present to mention those which arise, from the metaphorical origin of all the words which express the intellectual phenomena; from the subtle and fugitive nature of the objects of our reasonings; from the habits of inattention we acquire, in early life, to the subjects of our consciousness; and from the prejudices which early impressions and associations create to warp our opinions. It must be remembered, too, that in the science of mind; so imperfectly are its logical rules as yet understood! we have not the same checks on the abuses of our reasoning powers, which serve to guard us against error in our other researches. In physics, a speculative mistake is abandoned, when contradicted by facts which strike the senses. In mathematics, an absurd or inconsistent conclusion is admitted as a demonstrative proof of a faulty hypothesis. But, in those inquiries which relate to the principles of human nature, the absurdities and inconsistencies to which we are led by almost all the systems hitherto proposed, instead of suggesting corrections and improvements on these systems, have too frequently had the effect of producing scepticism with respect to all of them alike. How melancholy is the confession of Hume! "The intense view of these manifold contradictions and imperfections in human reason, has so wrought upon me, and heated my brain, that I am ready to reject all belief and reasoning, and can look upon no opinion even as more probable or likely than another."

Under these discouragements to this branch of study, it affords some comfort to reflect on the great number of important facts with respect to the mind, which are scattered in the writings of philosophers. As the subject of our inquiry here lies within our own breast, a considerable mixture of truth may be expected even in those systems which are most erroneous; not only because a number of men can scarcely be long imposed on by an hypothesis which is perfectly

groundless, concerning the objects of their own consciousness; but because it is generally by an alliance with truth and with the original principles of human nature, that prejudices and associations produce their effects. Perhaps it may even be affirmed, that our progress in this research depends less on the degree of our industry and invention, than on our sagacity and good sense in separating old discoveries from the errors which have been blended with them; and on that candid and dispassionate temper that may prevent us from being led astray by the love of novelty, or the affectation of singularity. In this respect, the science of mind possesses a very important advantage over that which relates to the laws of the material world. The former has been cultivated with more or less success in all ages and countries: the facts which serve as the basis of the latter have, with a very few exceptions, been collected during the course of the two last centuries. An observation similar to this is applied to systems of Ethics by Mr. Smith, in his account of the theory of Mandeville; and the illustration he gives of it may be extended with equal propriety to the science of mind in general. "A system of Natural Philosophy," he remarks, "may appear very plausible, and be, for a long time, very generally received in the world, and yet have no foundation in nature, nor any sort of resemblance to the truth. But it is otherwise with systems of Moral Philosophy. When a traveller gives an account of some distant country, he may impose upon our credulity the most groundless and absurd fictions as the most certain matters of fact; but when a person pretends to inform us of what passes in our neighbourhood, and of the affairs of the very parish we live in, though here too, if we are so careless as not to examine things with our own eyes, he may deceive us in many respects; yet the greatest falsehoods which he imposes on us must bear some resemblance to the truth, and must even have a considerable mixture of truth in them.”

These considerations demonstrate the essential importance, in this branch of study, of forming, at the commencement of our inquiries, just notions of the

criteria of true and false science, and of the rules of philosophical investigation. They demonstrate, at the same time, that an attention to the rules of philosophizing, as they are exemplified in the physical researches of Newton and his followers, although the best of all preparations for an examination of the mental phenomena, is but one of the steps necessary to ensure our success. On an accurate comparison of the two subjects, it might probably appear, that after this preliminary step has been gained, the most arduous part of the process still remains. One thing is certain, that it is not from any defect in the power of ratiocination or deduction, that our speculative errors chiefly arise; a fact of which we have a decisive proof in the facility with which most students may be taught the mathematical and physical sciences, when compared with the difficulty of leading their minds to the truth on questions of morals and politics.

The logical rules which lay the foundation of sound and useful conclusions concerning the laws of this internal world, although not altogether overlooked by Lord Bacon, were plainly not the principal object of his work; and what he has written on the subject, consists chiefly of detached hints dropped casually in the course of other speculations. A comprehensive view of the sciences and arts dependent on the philosophy of the human mind, exhibiting the relations which they bear to each other, and to the general system of human knowledge, would form a natural and useful introduction to the study of these logical principles; but such a view remains still a desideratum, after all the advances made toward it by Bacon and D'Alembert. Indeed, in the present improved state of things, much is wanting to complete and perfect that more simple part of their intellectual map which relates to the material universe. Of the inconsiderable progress hitherto made toward a just delineation of the method to be pursued in studying the mental phenomena, no other evidence is necessary than this; that the sources of error and false judgment so peculiarly connected, in consequence of the association of ideas, with studies in which our best interests are immediately and deeply concerned,

have never yet been investigated with such accuracy, as to afford effectual aid to the student, in his attempts to counteract their influence. One of these sources alone, that which arises from the imperfections of language, furnishes an exception to the general remark. It attracted, fortunately, the particular notice of Locke, whose observations with respect to it, compose, perhaps, the most valuable part of his philosophical writings; and, since the time of Condillac, the subject has been still more deeply analyzed by others. Even on this article, much yet remains to be done; but enough has been already accomplished to justify the profound aphorism in which Bacon pointed it out to the attention of his followers: "Credunt homines rationem suam verbis imperare; sed fit etiam ut verba vim suam super rationem retorqueant." *

Into these logical discussions concerning the means of advancing the philosophy of human nature, Dr. Reid has seldom entered; and still more rarely has he indulged himself in tracing the numerous relations, by which this philosophy is connected with the practical business of life. But he has done what was still more essential at the time he wrote: he has exemplified, with the happiest success, that method of investigation by which alone any solid progress can be made; directing his inquiries to a subject which forms a necessary groundwork for the labors of his successors; an analysis of the various powers and principles belonging to our constitution. Of the importance of this undertaking, it is sufficient to observe, that it stands somewhat, although I confess not altogether, in the same relation to the different branches of intellectual and moral science, such as grammar, rhetoric, logic, ethics, natural theology, and politics, in which the anatomy of the human body stands to the different branches of physiology and pathology. And as a course of medical education naturally, or rather necessarily, begins with a general survey of man's animal frame; so, I apprehend, that the proper, or rather the

*This passage of Bacon forms the motto to a very ingenious and philosophical dissertation, lately published by M. Prévost of Geneva, entitled, "Des Signes envisagés relativement à leur Influence sur la Formation des Idées." Paris, an 8.