The Collected Works of Dugald Stewart/Volume 1/Preface

by Dugald Stewart

PREFACE.

CONTAINING SOME CRITICAL REMARKS ON THE DISCOURSE
PREFIXED TO THE FRENCH ENCYCLOPÉDIE.

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When I ventured to undertake the task of contributing a Preliminary Dissertation to these Supplemental Volumes of the Encyclopædia Britannica, my original intention was, after the example of D'Alembert, to have begun with a general survey of the various departments of human knowledge. The outline of such a survey, sketched by the comprehensive genius of Bacon, together with the corrections and improvements suggested by his illustrious disciple, would, I thought, have rendered it comparatively easy to adapt their intellectual map to the present advanced state of the sciences; while the unrivalled authority which their united work has long maintained in the republic of letters, would, I flattered myself, have softened those criticisms which might be expected to be incurred by any similar attempt of a more modern hand. On a closer examination, however, of their labours, I found myself under the necessity of abandoning this design. Doubts immediately occurred to me with respect to the justness of their logical views, and soon terminated in a conviction, that these views are radically and essentially erroneous. Instead, therefore, of endeavouring to give additional currency to speculations which I conceived to be fundamentally unsound, I resolved to avail myself of the present opportunity to point out their most important defects,—defects which, I am nevertheless very ready to acknowledge, it is much more easy to remark than to supply. The critical strictures which, in the course of this discussion, I shall have occasion to offer on my predecessors, will, at the same time, account for my forbearing to substitute a new map of my own, instead of that to which the names of Bacon and D'Alembert have lent so great and so well-merited a celebrity; and may perhaps suggest a doubt, whether the period be yet arrived for hazarding again, with any reasonable prospect of success, a repetition of their bold experiment. For the length to which these strictures are likely to extend, the only apology I have to offer is the peculiar importance of the questions to which they relate, and the high authority of the writers whose opinions I presume to controvert.

Before entering on the main subject, D'Alembert is at pains to explain a distinction, which he represents as of considerable importance, between the Genealogy of the sciences, and the Encyclopedical arrangement of the objects of human knowledge.^[1] "In examining the former," he observes, "our aim is, by remounting to the origin and genesis of our ideas, to trace the causes to which the sciences owe their birth; and to mark the characteristics by which they are distinguished from each other. In order to ascertain the latter, it is necessary to comprehend, in one general scheme, all the various departments of study; to arrange them into proper classes; and to point out their mutual relations and dependencies." Such a scheme is sometimes likened by D'Alembert to a map or chart of the intellectual world; sometimes to a genealogical^[2] or encyclopedical tree, indicating the manifold and complicated affinities of those studies, which, however apparently remote and unconnected, are all the common offspring of the human understanding. For executing successfully this chart or tree, a philosophical delineation of the natural progress of the mind may (according to him) furnish very useful lights; although he acknowledges that the results of the two undertakings cannot fail to differ widely in many instances the laws which regulate the generation of our ideas often interfering with that systematical order in the relative arrangement of scientific pursuits, which it is the purpose of the Encyclopedical Tree to exhibit.^[3]

In treating of the first of these subjects, it cannot be denied that D'Alembert has displayed much ingenuity and invention; but the depth and solidity of his general train of thought may be questioned. On various occasions, he has evidently suffered himself to be misled by a spirit of false refinement; and on others, where probably he was fully aware of his inability to render the theoretical chain complete, he seems to have aimed at concealing from his readers the faulty links, by availing himself of those epigrammatic points, and other artifices of style, with which the genius of the French language enables a skilful writer to smooth and varnish over his most illogical transitions.

The most essential imperfections, however, of this historical sketch, may be fairly ascribed to a certain vagueness and indecision in the author's idea, with regard to the scope of his inquiries. What he has in general pointed at is to trace, from the theory of the Mind, and from the order followed by nature in the development of its powers, the successive steps by which the curiosity may be conceived to have been gradually conducted from one intellectual pursuit to another; but, in the execution of this design, (which in itself is highly philosophical and interesting,) he does not appear to have paid due attention to the essential difference between the history of the human species, and that of the civilized and inquisitive individual. The former was undoubtedly that which principally figured in his conceptions; and to which, I apprehend, he ought to have confined himself exclusively; whereas, in fact, he has so completely blended the two subjects together, that it is often impossible to say which of them was uppermost in his thoughts. The consequence is, that instead of throwing upon either those strong and steady lights which might have been expected from his powers, he has involved both in additional obscurity. This indistinctness is more peculiarly remarkable in the beginning of his Discourse, where he represents men in the earliest infancy of science, before they had time to take any precautions for securing the means of their subsistence, or of their safety,—as philosophizing on their sensations,—on the existence of their own bodies,—and on that of the material world. His Discourse, accordingly, sets out with a series of Meditations, precisely analogous to those which form the introduction to the philosophy of Descartes; meditations which, in the order of time, have been uniformly posterior to the study of external nature; and which, even in such an age as the present, are confined to a comparatively small number of recluse metaphysicians.

Of this sort of conjectural or theoretical history, the most unexceptionable specimens which have yet appeared, are indisputably the fragments in Mr. Smith's posthumous work on the History of Astronomy, and on that of the Ancient Systems of Physics and Metaphysics. That, in the latter of these, he may have occasionally accommodated his details to his own peculiar opinions concerning the object of Philosophy, may perhaps, with some truth, be alleged; but he must at least be allowed the merit of completely avoiding the error by which D'Alembert was misled; and even in those instances where he himself seems to wander a little from the right path, of furnishing his successors with a thread, leading by easy and almost insensible steps, from the first gross perceptions of sense, to the most abstract refinements of the Grecian schools. Nor is this the only praise to which these fragments are entitled. By seizing on the different points of view from whence the same object was contemplated by different sects, they often bestow a certain degree of unity and of interest on what before seemed calculated merely to bewilder and to confound; and render the apparent aberrations and caprices of the understanding subservient to the study of its operations and laws.

To the foregoing strictures on D'Alembert's view of the origin of the sciences, it may be added, that this introductory part of his Discourse does not seem to have any immediate connexion with the sequel. We are led, indeed, to expect, that it is to prepare the way for the study of the Encylopedical Tree afterwards to be exhibited; but in this expectation we are completely disappointed;—no reference to it whatever being made by the author in the farther prosecution of his subject. It forms, accordingly, a portion of his Discourse altogether foreign to the general design; while, from the metaphysical obscurity which pervades it, the generality of readers are likely to receive an impression, either unfavourable to the perspicuity of the writer, or to their own powers of comprehension and of reasoning. It were to be wished, therefore, that instead of occupying the first pages of the Encyclopédie, it had been reserved for a separate article in the body of that work. There it might have been read by the logical student, with no small interest and advantage; for, with all its imperfections, it bears numerous and precious marks of its author's hand.

In delineating his Encyclopedical Tree, D'Alembert has, in my opinion, been still more unsuccessful than in the speculations which have been hitherto under our review. His veneration for Bacon seems, on this occasion, to have prevented him from giving due scope to his own powerful and fertile genius, and has engaged him in the fruitless task of attempting, by means of arbitrary definitions, to draw a veil over incurable defects and blemishes. In this part of Bacon's logic, it must, at the same time, be owned, that there is something peculiarly captivating to the fancy; and, accordingly, it has united in its favour the suffrages of almost all the succeeding authors who have treated of the same subject. It will be necessary for me, therefore, to explain fully the grounds of that censure, which, in opposition to so many illustrious names, I have presumed to bestow on it.

Of the leading ideas to which I more particularly object, the following statement is given by D'Alembert. I quote it in preference to the corresponding passage in Bacon, as it contains various explanatory clauses and glosses, for which we are indebted to the ingenuity of the commentator.

"The objects about which our minds are occupied, are either spiritual or material, and the media employed for this purpose are our ideas, either directly received, or derived from reflection. The system of our direct knowledge consists entirely in the passive and mechanical accumulation of the particulars it comprehends; an accumulation which belongs exclusively to the province of Memory. Reflection is of two kinds, according as it is employed in reasoning on the objects of our direct ideas, or in studying them as models for imitation.

"Thus, Memory, Reason, strictly so called, and Imagination, are the three modes in which the mind operates on the subjects of its thoughts. By Imagination, however, is here to be understood, not the faculty of conceiving or representing to ourselves what we have formerly perceived, a faculty which differs in nothing from the memory of these perceptions, and which, if it were not relieved by the invention of signs, would be in a state of continual exercise. The power which we denote by this name has a nobler province allotted to it, that of rendering imitation subservient to the creations of genius.

"These three faculties suggest a corresponding division of human knowledge into three branches:—1. History, which derives its materials from Memory; 2. Philosophy, which is the product of Reason; and 3. Poetry (comprehending under this title all the Fine Arts,) which is the offspring of Imagination.^[4] If we place Reason before Imagination, it is because this order appears to us conformable to the natural progress of our intellectual operations.^[5] The Imagination is a creative faculty, and the mind, before it attempts to create, begins by reasoning upon what it sees and knows. Nor is this all. In the faculty of Imagination, both Reason and Memory are, to a certain extent, combined—the mind never imagining or creating objects but such as are analogous to those whereof it has had previous experience. Where this analogy is wanting, the combinations are extravagant and displeasing; and, consequently, in that agreeable imitation of nature, at which the fine arts aim in common, invention is necessarily subjected to the control of rules which it is the business of the philosopher to investigate.

"In farther justification of this arrangement, it may be remarked, that Reason, in the course of its successive operations on the subjects of thought, by creating abstract and general ideas, remote from the perceptions of sense, leads to the exercise of Imagination as the last step of the process. Thus metaphysics and geometry are, of all the sciences belonging to Reason, those in which Imagination has the greatest share. I ask pardon for this observation from those men of taste, who, little aware of the near affinity of geometry to their own pursuits, and still less suspecting that the only intermediate step between them is formed by metaphysics, are disposed to employ their wit in depreciating its value. The truth is, that, to the geometer who invents, Imagination is not less essential than to the poet who creates. They operate, indeed, differently on their object, the former abstracting and analyzing, where the latter combines and adorns;—two processes of the mind, it must, at the same time, be confessed, which seem from experience to be so little congenial, that it may be doubted if the talents of a great geometer and of a great poet will ever be united in the same person. But whether these talents be, or be not mutually exclusive, certain it is, that they who possess the one, have no right to despise those who cultivate the other. Of all the great men of antiquity, Archimedes is perhaps he who is the best entitled to be placed by the side of Homer."

D'Alembert afterwards proceeds to observe, that of these three general branches of the Encyclopedical Tree, a natural and convenient subdivision is afforded by the metaphysical distribution of things into Material and Spiritual. "With these two classes of existences," he observes farther," history and philosophy are equally conversant; but as for the Imaginagination, her imitations are entirely confined to the material world;—a circumstance," he adds, "which conspires with the other arguments above stated, in justifying Bacon for assigning to her the last place in his enumeration of our intellectual faculties."^[6] Upon this subdivision he enlarges at some length, and with considerable ingenuity; but on the present occasion it would be quite superfluous to follow him any farther, as more than enough has been already quoted to enable my readers to judge, whether the objections which I am now to state to the foregoing extracts be as sound and decisive as I apprehend them to be.

Of these objections a very obvious one is suggested by a consideration, of which D'Alembert himself has taken notice,—that the three faculties to which he refers the whole operations of the understanding are perpetually blended together in their actual exercise, insomuch that there is scarcely a branch of human knowledge which does not, in a greater or less degree, furnish employment to them all. It may be said, indeed, that some pursuits exercise and invigorate particular faculties more than others; that the study of History, for example, although it may occasionally require the aid both of Reason and of Imagination, yet chiefly furnishes occupation to the Memory; and that this is sufficient to justify the logical division of our mental powers as the ground-work of a corresponding Encyclopedical classification.^[7] This, however, will be found more specious than solid. In what respects is the faculty of Memory more essentially necessary to the student of history than to the philosopher or to the poet; and, on the other hand, of what value, in the circle of the sciences, would be a collection of historical details, accumulated without discrimination, without a scrupulous examination of evidence, or without any attempt to compare and to generalize? For the cultivation of that species of history, in particular, which alone deserves a place in the Encyclopedical Tree, it may be justly affirmed, that the rarest and most comprehensive combination of all our mental gifts is indispensably requisite.

Another, and a still more formidable objection to Bacon's classification, may be derived from the very imperfect and partial analysis of the mind which it assumes as its basis. Why were the powers of Abstraction and Generalization passed over in silence?—powers which, according as they are cultivated or neglected, constitute the most essential of all distinctions between the intellectual characters of individuals. A corresponding distinction, too, not less important, may be remarked among the objects of human study, according as our aim is to treasure up particular facts, or to establish general conclusions. Does not this distinction mark out, with greater precision, the limits which separate philosophy from mere historical narrative, than that which turns upon the different provinces of Reason and of Memory?

I shall only add one other criticism on this celebrated enumeration, and that is, its want of distinctness, in confounding together the Sciences and the Arts under the same general titles. Hence a variety of those capricious arrangements, which must immediately strike every reader who follows Bacon through his details; the reference, for instance, of the mechanical arts to the department of History; and, consequently, according to his own analysis of the mind, the ultimate reference of these arts to the faculty of Memory: while, at the same time, in his tripartite division of the whole field of human knowledge, the art of Poetry has one entire province allotted to itself.

These objections apply in common to Bacon and to D'Alembert. That which follows has a particular reference to a passage already cited from the latter, where, by some false refinements concerning the nature and functions of Imagination, he has rendered the classification of his predecessor incomparably more indistinct and illogical than it seemed to be before.

That all the creations, or new combinations of Imagination, imply the previous process of decomposition or analysis, is abundantly manifest; and, therefore, without departing from the common and popular use of language, it may undoubtedly be said, that the faculty of abstraction is not less essential to the Poet, than to the Geometer and the Metaphysician.^[8] But this is not the doctrine of D'Alembert. On the contrary, he affirms, that Metaphysics and Geometry are, of all the sciences connected with Reason, those in which Imagination has the greatest share; an assertion which, it will not be disputed, has at first sight somewhat of the air of a paradox; and which, on closer examination, will, I apprehend, be found altogether inconsistent with fact. If indeed D'Alembert had, in this instance, used (as some writers have done) the word Imagination as synonymous with Invention, I should not have thought it worth while (at least so far as the geometer is concerned) to dispute his proposition. But that this was not the meaning annexed to it by the author, appears from a subsequent clause, where he tells us, that the most refined operations of reason, consisting in the creation of generals which do not fall under the cognizance of our senses, naturally lead to the exercise of Imagination. His doctrine, therefore, goes to the identification of Imagination with Abstraction; two faculties so very different in the direction which they give to our thoughts, that (according to his own acknowledgment) the man who is habitually occupied in exerting the one, seldom fails to impair both his capacity and his relish for the exercise of the other.

This identification of two faculties, so strongly contrasted in their characteristical features, was least of all to be expected from a logician, who had previously limited the province of Imagination to the imitation of material objects; a limitation, it may be remarked in passing, which is neither sanctioned by common use, nor by just views of the philosophy of the Mind. Upon what ground can it be alleged that Milton's portrait of Satan's intellectual and moral character was not the offspring of the same creative faculty which gave birth to his Garden of Eden? After such a definition, however, it is difficult to conceive how so very acute a writer should have referred to Imagination the abstractions of the geometer and of the metaphysician; and still more, that he should have attempted to justify this reference, by observing, that these abstractions do not fall under the cognizance of the senses. My own opinion is, that in the composition of the whole passage he had a view to the unexpected parallel between Homer and Archimedes, with which he meant, at the close, to surprise his readers.

If the foregoing strictures be well founded, it seems to follow, not only that the attempt of Bacon and of D'Alembert to classify the sciences and arts according to a logical division of our faculties, is altogether unsatisfactory, but that every future attempt of the same kind may be expected to be liable to similar objections. In studying, indeed, the Theory of the Mind, it is necessary to push our analysis as far as the nature of the subject admits of; and, wherever the thing is possible, to examine its constituent principles separately and apart from each other: but this consideration itself, when combined with what was before stated on the endless variety of forms in which they may be blended together in our various intellectual pursuits, is sufficient to shew how ill adapted such an analysis must for ever remain to serve as the basis of an Encyclopedical distribution.^[9]

The circumstance to which this part of Bacon's philosophy is chiefly indebted for its popularity, is the specious simplicity and comprehensiveness of the distribution itself—not the soundness of the logical views by which it was suggested. That all our intellectual pursuits may be referred to one or other of these three heads—History, Philosophy, and Poetry, may undoubtedly be said with considerable plausibility; the word history being understood to comprehend all our knowledge of particular facts and particular events; the word philosophy, all the general conclusions or laws inferred from these particulars by induction; and the word poetry, all the arts addressed to the imagination. Not that the enumeration, even with the help of this comment, can be considered as complete, for (to pass over entirely the other objections already stated) under which of these three heads shall we arrange the various branches of pure mathematics?

Are we therefore to conclude, that the magnificent design conceived by Bacon, of enumerating, defining, and classifying the multifarious objects of human knowledge—(a design, on the successful accomplishment of which he himself believed that the advancement of the sciences essentially depended)—are we to conclude that this design was nothing more than the abortive offspring of a warm imagination, unsusceptible of any useful application to enlighten the mind, or to accelerate its progress? My own idea is widely different. The design was, in every respect, worthy of the sublime genius by which it was formed. Nor does it follow, because the execution was imperfect, that the attempt has been attended with no advantage. At the period when Bacon wrote, it was of much more consequence to exhibit to the learned a comprehensive sketch, than an accurate survey of the intellectual world; such a sketch as, by pointing out to those whose views had been hitherto confined within the limits of particular regions, the relative positions and bearings of their respective districts, as parts of one great whole, might invite them all, for the common benefit, to a reciprocal exchange of their local riches. The societies or academies which, soon after, sprung up in different countries of Europe, for the avowed purpose of contributing to the general mass of information, by the collection of insulated facts, conjectures, and queries, afford sufficient proof that the anticipations of Bacon were not, in this instance, altogether chimerical.

In examining the details of Bacon's survey, it is impossible not to be struck (more especially when we reflect on the state of learning two hundred years ago) with the minuteness of his information, as well as with the extent of his views; or to forbear admiring his sagacity in pointing out, to future adventurers, the unknown tracts still left to be explored by human curiosity. If his classifications be sometimes artificial and arbitrary, they have at least the merit of including, under one head or another, every particular of importance; and of exhibiting these particulars with a degree of method and of apparent connexion, which, if it does not always satisfy the judgment, never fails to interest the fancy, and to lay hold of the memory. Nor must it be forgotten, to the glory of his genius, that what lie failed to accomplish remains to this day a desideratum in science,—that the intellectual chart delineated by him is, with all its imperfections, the only one of which modern philosophy has yet to boast;—and that the united talents of D'Alembert and of Diderot, aided by all the lights of the eighteenth century, have been able to add but little to what Bacon performed.

After the foregoing observations, it will not be expected that an attempt is to be made, in the following essay, to solve a problem which has so recently baffled the powers of these eminent writers; and which will probably long continue to exercise the ingenuity of our successors. How much remains to be previously done for the improvement of that part of logic, whose province it is to fix the limits by winch contiguous departments of study are defined and separated! And how many unsuspected affinities may be reasonably presumed to exist among sciences, which, to our circumscribed views, appear at present the most alien from each other! The abstract geometry of Apollonius and Archimedes was found, after an interval of two thousand years, to furnish a torch to the physical inquiries of Newton; while, in the farther progress of knowledge, the Etymology of Languages has been happily employed to fill up the chasms of Ancient History; and the conclusions of Comparative Anatomy, to illustrate the Theory of the Earth. For my own part, even if the task were executed with the most complete success, I should be strongly inclined to think, that its appropriate place in an Encyclopædia would be as a branch of the article on Logic;—certainly not as an exordium to the Preliminary Discourse; the enlarged and refined views which it necessarily presupposes being peculiarly unsuitable to that part of the work which may be expected, in the first instance, to attract the curiosity of every reader. As, upon this point, however, there may be some diversity of opinion, I have prevailed on the Editor to add to these introductory Essays a translation of D'Alembert's Discourse, and of Diderot's Prospectus. No English version of either has, as far as I know, been hitherto published; and the result of their joint ingenuity, exerted on Bacon's ground-work, must for ever fix no inconsiderable era in the history of learning.

Before concluding this preface, I shall subjoin a few slight strictures on a very concise and comprehensive division of the objects of Human Knowledge, proposed by Mr. Locke, as the basis of a new classification of the sciences. Although I do not know that any attempt has ever been made to follow out in detail the general idea, yet the repeated approbation which has been lately bestowed on a division essentially the same, by several writers of the highest rank, renders it in some measure necessary, on the present occasion, to consider how far it is founded on just principles; more especially as it is completely at variance, not only with the language and arrangement adopted in these preliminary essays, but with the whole of that plan on which the original projectors, as well as the continuators, of the Encyclopædia Britannica appear to have proceeded. These strictures will, at the same tune, afford an additional proof of the difficulty, or rather of the impossibility, in the actual state of logical science, of solving this great problem, in a manner calculated to unite the general suffrages of philosophers.

"All that can fall," says Mr. Locke," within the compass of Human Understanding being either, first, The nature of things as they are in themselves, their relations, and their manner of operation; or, secondly, That which man himself ought to do, as a rational and voluntary agent, for the attainment of any end, especially happiness; or, thirdly, The ways and means whereby the knowledge of both the one and the other of these is attained and communicated: I think science may be divided properly into these three sorts:—

1. Φυσικκὴ, or Natural Philosophy. The end of this is bare speculative truth; and whatsoever can afford the mind of man any such falls under this branch, whether it be God himself, angels, spirits, bodies, or any of their affections, as number and figure, &c.
2. Πρακτικὴ, The skill of right applying our own powers and actions for the attainment of things good and useful. The most considerable under this head is Ethics, which is the seeking out those rules and measures of human actions which lead to happiness, and the means to practise them. The end of this is not bare speculation, but right, and a conduct suitable to it.^[10]
3. Σημειωτικὴ, or the doctrine of signs, the most usual whereof being words, it is aptly enough termed also Λογικὴ'', Logic. The business of this is to consider the nature of signs the mind makes use of for the understanding of things, or conveying its knowledge to others.

"This seems to me," continues Mr. Locke, "the first and most general, as well as natural, division of the objects of our understanding; for a man can employ his thoughts about nothing but either the contemplation of things themselves, for the discovery of truth, or about the things in his own power, which are his own actions, for the attainment of his own ends; or the signs the mind makes use of, both in one and the other, and the right ordering of them for its clearer information. All which three, viz., things as they are in themselves knowable; actions as they depend on us, in order to happiness; and the right use of signs, in order to knowledge; being toto cœlo different, they seemed to me to be the three great provinces of the intellectual world, wholly separate and distinct one from another."^[11]

From the manner in which Mr. Locke expresses himself in the above quotation, he appears evidently to have considered the division proposed in it as an original idea of his own; and yet the truth is, that it coincides exactly with what was generally adopted by the philosophers of ancient Greece. "The ancient Greek Philosophy," says Mr. Smith, "was divided into three great branches, Physics, or Natural Philosophy; Ethics, or Moral Philosophy; and Logic. This general division," he adds, "seems perfectly agreeable to the nature of things." Mr. Smith afterwards observes, in strict conformity to Locke's definitions, (of which, however, he seems to have had no recollection when he wrote this passage,) "That, as the human mind and the Deity, in whatever their essence may be supposed to consist, are parts of the great system of the universe, and parts, too, productive of the most important effects, whatever was taught in the ancient schools of Greece concerning their nature, made a part of the system of physics."^[12]

Dr. Campbell, in his Philosophy of Rhetoric, has borrowed from the Grecian schools the same very extensive use of the words physics and physiology, which he employs as synonymous terms; comprehending under this title "not merely Natural History. Astronomy, Geography, Mechanics, Optics, Hydrostatics, Meteorology, Medicine, Chemistry, but also Natural Theology

and Psychology, which," he observes, "have been, in his opinion, most unnaturally disjoined from Physiology by philosophers." "Spirit," he adds, "which here comprises only the Supreme Being and the human soul, is surely as much included under the notion of natural object as body is; and is knowable to the philosopher purely in the same way, by observation and experience."^[13]

A similar train of thinking led the late celebrated M. Turgot to comprehend under the name of Physics, not only Natural Philosophy, (as that phrase is understood by the Newtonians,) but Metaphysics, Logic, and even History.^[14]

Notwithstanding all this weight of authority, it is difficult to reconcile one's self to an arrangement which, while it classes with Astronomy, with Mechanics, with Optics, and with Hydrostatics, the strikingly contrasted studies of Natural Theology and of the Philosophy of the Human Mind, disunites from the two last the far more congenial sciences of Ethics and of Logic. The human mind, it is true, as well as the material world which surrounds it, forms a part of the great system of the Universe; but is it possible to conceive two parts of the same whole more completely dissimilar, or rather more diametrically opposite, in all their characteristical attributes? Is not the one the appropriate field and province of observation,—a power habitually awake to all the perceptions and impressions of the bodily organs? and does not the other fall exclusively under the cognizance of reflection,—an operation which inverts all the ordinary habits of the understanding, abstracting the thoughts from every sensible object, and even striving to abstract them from every sensible image? What abuse of language can be greater than to apply a common name to departments of knowledge which invite the curiosity in directions precisely contrary, and which tend to form intellectual talents, which, if not altogether incompatible, are certainly not often found united in the same individual? The word Physics, in particular, which, in our language, long and constant use has restricted to the phenomena of Matter, cannot fail to strike every ear as anomalously, and therefore illogically, applied, when extended to those of Thought and of Consciousness.

Nor let it be imagined that these observations assume any particular theory about the nature or essence of Mind. Whether we adopt, on this point, the language of the Materialists, or that of their opponents, it is a proposition equally certain and equally indisputable, that the phenomena of Mind and those of Matter, as far as they come under the cognizance of our faculties, appear to be more completely heterogeneous than any other classes of facts within the circle of our knowledge; and that the sources of our information concerning them are in every respect so radically different, that nothing is more carefully to be avoided, in the study of either, than an attempt to assimilate them, by means of analogical or metaphorical terms, applied to both in common. In those inquiries, above all, where we have occasion to consider Matter and Mind as conspiring to produce the same joint effects, (in the constitution, for example, of our own compounded frame,) it becomes more peculiarly necessary to keep constantly in view the distinct province of each, and to remember, that the business of philosophy is not to resolve the phenomena of the one into those of the other, but merely to ascertain the general laws which regulate their mutual connexion. Matter and Mind, therefore, it should seem, are the two most general heads which ought to form the ground-work of an Encyclopedical classification of the sciences and arts. No branch of human knowledge, no work of human skill, can be mentioned, which does not obviously fall under the former head or the latter.

Agreeably to this twofold classification of the sciences and arts, it is proposed, in the following introductory Essays, to exhibit a rapid sketch of the progress made since the revival of letters—First, in those branches of knowledge which relate to mind; and, secondly, in those which relate to matter. D'Alembert, in his Preliminary Discourse, has boldly attempted to embrace both subjects in one magnificent design; and never, certainly, was there a single mind more equal to such an undertaking. The historical outline which he has there traced forms by far the most valuable portion of that performance, and will for ever remain a proud monument to the depth, to the comprehensiveness, and to the singular versatility of his genius. In the present state of science, however, it has been apprehended that, by dividing so great a work among different hands, something might perhaps be gained, if not in point of reputation to the authors, at least in point of instruction to their readers. This division of labour was, indeed, in some measure rendered necessary (independently of all other considerations) by the important accessions which mathematics and physics have received since D'Alembert's time; by the innumerable improvements which the spirit of mercantile speculation, and the rivalship of commercial nations, have introduced into the mechanical arts; and, above all, by the rapid succession of chemical discoveries which commences with the researches of Black and of Lavoisier. The part of this task which has fallen to my share is certainly, upon the whole, the least splendid in the results which it has to record; but I am not without hopes that this disadvantage may be partly compensated by its closer connexion with (what ought to be the ultimate end of all our pursuits) the intellectual and moral improvement of the species.

I am, at the same time, well aware that, in proportion as this last consideration increases the importance, it adds to the difficulty of my undertaking. It is chiefly in judging of questions "coming home to their business and bosoms," that casual associations lead mankind astray; and of such associations how incalculable is the number arising from false systems of religion, oppressive forms of government, and absurd plans of education! The consequence is, that while the physical and mathematical discoveries of former ages present themselves to the hand of the historian like masses of pure and native gold, the truths which we are here in quest of may be compared to iron, which, although at once the most necessary and the most widely diffused of all the metals, commonly requires a discriminating eye to detect its existence, and a tedious, as well as nice process, to extract it from the ore.

To the same circumstance it is owing, that improvements in moral and in political science do not strike the imagination with nearly so great force as the discoveries of the mathematician or of the chemist. When an inveterate prejudice is destroyed by extirpating the casual associations on which it was grafted, how powerful is the new impulse given to the intellectual faculties of man! Yet how slow and silent the process by which the effect is accomplished! Were it not, indeed, for a certain class of learned authors, who from time to time heave the log into the deep, we should hardly believe that the reason of the species is progressive. In this respect, the religious and academical establishments in some parts of Europe are not without their use to the historian of the human mind. Immovably moored to the same station by the strength of their cables and the weight of their anchors, they enable him to measure the rapidity of the current by which the rest of the world are borne along.

This, too, is remarkable in the history of our prejudices, that as soon as the film falls from the intellectual eye, we are apt to lose all recollection of our former blindness. Like the fantastic and giant shapes which, in a thick fog, the imagination lends to a block of stone or to the stump of a tree, they produce, while the illusion lasts, the same effect with truths and realities; but the moment the eye has caught the exact form and dimensions of its object, the spell is broken for ever, nor can any effort of thought again conjure up the spectres which have vanished.

As to the subdivisions of which the sciences of matter and of mind are susceptible, I have already said that this is not the proper place for entering into any discussion concerning them. The passages above quoted from D'Alembert, from Locke, and from Smith, are sufficient to shew how little probability there is, in the actual state of logical science, of uniting the opinions of the learned in favour of any one scheme of partition. To prefix, therefore, such a scheme to a work which is professedly to be carried on by a set of unconnected writers, would be equally presumptuous and useless; and, on the most favourable supposition, could tend only to fetter, by means of dubious definitions, the subsequent freedom of thought and of expression. The example of the French Encyclopédie cannot be here justly alleged as a precedent. The preliminary pages by which it is introduced were written by the two persons who projected the whole plan, and who considered themselves as responsible, not only for their own admirable articles, but for the general conduct of the execution; whereas, on the present occasion, a porch was to be adapted to an irregular edifice, reared at different periods by different architects. It seemed, accordingly, most advisable to avoid as much as possible, in these introductory Essays, all innovations in language, and, in describing the different arts and sciences, to follow scrupulously the prevailing and most intelligible phraseology. The task of defining them with a greater degree of precision properly devolves upon those to whose province it belongs, in the progress of the work, to unfold in detail their elementary principles.

The Sciences to which I mean to confine my observations are Metaphysics, Ethics, and Political Philosophy; understanding, by Metaphysics, not the Ontology and Pneumatology of the schools, but the inductive Philosophy of the Human Mind; and limiting the phrase Political Philosophy almost exclusively to the modern science of Political Economy; or (to express myself in terms at once more comprehensive and more precise) to thatbranch of the theory of legislation which, according to Bacon's definition, aims to ascertain those "Leges legum, ex quibus informatio peti potest quid in singulis legibus bene aut perperam positum aut constitutum sit." The close affinity between these three departments of knowledge, and the easy transitions by which the curiosity is invited from the study of any one of them to that of the other two, will sufficiently appear from the following Historical Review.

1. Il ne faut pas confondre l'orde Podre Encyclopédique des connoissances bumaines avec la Généalogie des Sciences."—Avertissement, p.7.
2. It is to be regretted that the epithet geneaological should have been employed on this occassion, where the author's wish was to contradistinguish the idea denoted by it, from that historical view of the sciences to which the word genealogy had been previously applied.
3. The true reason of this might perhaps have been assigned in simpler terms, by remarking that the order of invention is, in most cases, the reverse of that fitted for didactic communication. This observation applies not only to the analytical and synthetical processes of the individual, but the the progressive improvements of the species, when compared with the arrangements prescribed by logical method for conveying a knowledge of them to students. In an enlightened age, the sciences are justly considered as the basis of the arts; and, in a course of liberal education, the former are always taught prior to the latter. But, in the order of invention and discovery, the arts preceeded the sciences. Men measured land before they studied speculative geometry; and governments were established before politics were studied as a science. A remark somewhat similar is made by Celsus concerning the history of medicine: "Non medicinam rationi essec posteriorem, sed post medicinam inventam, rationon essc quæsitam."
4. The latitude given by D'Alembert to the meaning of the word Poetry is as real and very important improvement on Bacon, who restricts it to fictitious History or Fables.—(De Aug. Scient. lib. ii. cap. i.) D' Alembert, on the other hand, employs it in its natural signification, as synonymous with invention or creation. "La peinture, la Sculpture, l'Architecture, La Poésie, la Musique, et leurs différentes divisions, composent la troisième distribution générale qui nait de l'Imagination, et dont les parties sont comprises sous le nom de Beaux-Arts. On peut les rapporter tous à la Poésie en prenant ce mot dans sa signification naturelle, qui n'est autre chose qu'invention on création."
5. In placing Reason before Imagination, D'Alembert departs from these faculties arranged by Bacon. "Si nous n'avons pas placé, comme lui, la Raison après l'Imagination, c'est que nous avons suivi, dans le système Encyclopédique, l'ordre métaphysique des opérations de l'espirit, plutôt que l'ordre historique de ses progrès depuis la renaissance des lettres."—(Disc Prélim) How far the motive here assigned for the change is valid, the reader will be enabled to judge from the sequel of the above notation.
6. In this exclusive linitations of the province of Imagination to things material and sensible, D'Alembert has followed the definition given by Descarts in his second Meditation:—Imaginari nihil aliud est quam rei corporeœ figuram seu imaginem contemplari;"—a power of the mind, which (as I have elsewhere observed) appears to me to be most precisely expressed in our language by the word Conception. The province assigned to Imagination by D'Alembert is more extensive than this, for he ascribes to her also a creative and combining power; but still his definition agrees with that of Descartes, inasmuch as it excludes entirely from her dominion both the intellectual and the moral worlds.
7. I allude here to the following apology for Bacon, suggested by a very learned and judicious writer:—
   "On a fait cependant à Bacon quelques reproches assez fondés. On a observé que sa classification des sciences repose sur une distinction qui n'est pas rigoureuse, puisque la mémoire, la raison, et l'Imagination concourent nécessairement dans chaque art, comme dans chaque science. Mais on peut répronde, que l'une ou l'autre de ces trois facultés, quoique secondée par les deux autres, peut cependant jouer le rôle principal. En prenant la distinction de Bacon dans ce sans, sa classification reste exacte, et devient très utile."—Degerando, Hist-Comp, tome i. p. 298.
8. This assertion must, however, be understood with some qualifications; for, although the poet, as well as the geometer and the metaphysician, be perpetually called upon to decompose, by means of abstraction, the complicated objects of perception, it must not be concluded that the abstractions of all the three are exactly of the same kind. Those of the poet amount to nothing more than to a separation into parts of the realities presented to his senses; which separation is is only a preliminary step to a subsequent recomposition into new and ideal forms of the things abstracted; whereas the abstractions of the metaphysician and of the geometer form the very objects of their respective sciences.
9. In justice to the authors of the Encyclopedical Tree prefixed to the French Dictionary, it ought to be observed, that it is spoken of by D'Alembert, in his Preliminary Discourse, with the utmost modesty and diffidence; and that he has expressed not only his own conviction, but that of his colleague, but that of his colleague, of the impossibility of executing such a task in a manner likely to satisfy the public. "Nous sommes trop convaincus de l'arbitraire qui régenera toujours dans une pareille division, pour croire que notre système soit l'unique ou le meilleur; il nous suffira que notre travail ne soit pas entièrement désapprouvé par les bons espirits." And, some pages afterwards—"Si le public éclairé donne son approbation à ces changemens, elle sera la récompense pas, nous n'en serons que plus convaincus de l'impossibilité de former un arbre encyclopédique qui soit un gré de tout le monde."
10. From this definition it appears, that as Locke included under the title of Physics, not only Natural Philosophy, properly so called, but Natural Theology, and the Philosophy of the Human Mind, so he meant to refer to the head of Practics, not only Ethics, but all the various Arts of life, both mechanical and liberal.
11. See the concluding chapter of the Essay on the Human Understanding, entitled, "Of the Division of the Sciences."
12. Wealth of Nations, Book V. chap. i.
13. Philosophy of Rhetoric, Book I. chap. v. Part iii. § 1.
14. "Sous le nom de sciences physique je comprends la logique, qui est la connoissauce des opérations de notre esprit et de la génération de nos idées, la métaphysique, qui s'occupe de la nature et de l'origine des êtres, en enfin la physique, proprement dite, qui observe l'action mutuel des corps les uns sur les autres, et les causes at l'enchainement des phénomènes sensibles, On pourrait y ajouter l'histoire."—Œuvres de Turgot, tome ii. pp. 284, 285.
    In the year 1795, a quarto volume was published at bath, entitled Intellectual Physics. It consists entirely of speculations concerning the human mind, and is by far no means destitute of merit. The publication was anonymous; but I have reason to believe that the author was the late well-known Governer Pownall.