Lectures on the Philosophy of the Human Mind (Vol. 1 of 3)

by Thomas Brown

Footnote

[92] On the Intellectual Powers, Essay II. c. 17.

[LECTURE XXVI.]

ON DR REID'S SUPPOSED CONFUTATION OF THE IDEAL SYSTEM; HYPOTHESIS OF THE PERIPATETICS REGARDING PERCEPTION; AND OPINIONS OF VARIOUS PHILOSOPHERS ON THE SAME SUBJECT.

The remarks which I offered, in my last Lecture, in illustration of what have been termed the primary and secondary qualities of matter, were intended chiefly to obviate that false view of them, in which the one set of these qualities is distinguished, as affording us a knowledge that is direct, and the other set, a knowledge that is relative only;—as if any qualities of matter could become known to the mind, but as they are capable of affecting the mind with certain feelings, and as relative, therefore, to the feelings which they excite. What matter is, but as the cause of those various states of mind, which we denominate our sensations or perceptions, it is surely impossible for us, by perception, to discover. The physical universe, amid which we are placed, may have innumerable qualities that have no relation to our percipient mind,—and qualities, which, if our mind were endowed with other capacities of sensation, we might discover as readily as those which we know at present; but the qualities that have no relation to the present state of the mind, cannot to the mind, in its present state, be elements of its knowledge. From the very constitution of our nature, indeed, it is impossible for us not to believe, that our sensations have external causes, which correspond with them, and which have a permanence, that is independent of our transient feelings,—a permanence, that enables us to predict in certain circumstances, the feelings which they are again to excite in our percipient mind; and to the union of all these permanent external causes, in one great system, we give the name of the material world. But the material world, in the sense in which alone we are entitled to speak of it, is still only a name for a multitude of external causes of our feelings,—of causes which are, recognized by us as permanent and uniform in their nature; but are so recognized by us, only because, in similar circumstances, they excite uniformly in the mind the same perceptions, or, at least, are supposed by us to be uniform in their own nature, when the perceptions which they excite in us are uniform. It is according to their mode of affecting the mind, then, with various sensations, that we know them,—and not according to their own absolute nature, which it is impossible for us to know,—whether we give the name of primary or secondary to the qualities which affect us. If our sensations were different, our perceptions of the qualities of things, which induce these sensations in us, would instantly have a corresponding difference. All the external existences, which we term matter,—and all the phenomena of their motion or their rest,—if known to us at all, are known to us only by exciting in us, the percipients of them, certain feelings:—and qualities, which are not more or less directly relative to our feelings, as sentient or percipient beings, are, therefore, qualities which we must be forever incapable even of divining.

This, and some other discussions which have of late engaged us, were in part intended as preparatory to the inquiry on which we entered in the close of my Lecture,—the inquiry into the justness of the praise which has been claimed and received by Dr Reid, as the confuter of a very absurd theory of perception, till then universally prevalent:—and if, indeed, the theory, which he is said to have confuted, had been the general belief of philosophers till confuted by him, there can be no question, that he would have had a just claim to be considered as one of the chief benefactors of the Philosophy of Mind. At any rate, since this glory has been ascribed to him, and his supposed confutation of the theory of perception, by little images of objects conveyed to the mind, has been considered as forming one of the most important eras in intellectual science, it has acquired, from this universality of mistake with respect to it, an interest which, from its own merits, it would certainly be far from possessing.

In the Philosophy of the Peripatetics, and in all the dark ages of the scholastic followers of that system, ideas were truly considered as little images derived from objects without; and, as the word idea still continued to be used after this original meaning had been abandoned, (as it continues still, in all the works that treat of perception,) it is not wonderful that many of the accustomed forms of expression, which were retained together with it, should have been of a kind that, in their strict etymological meaning, might have seemed to harmonize more with the theory of ideas as images, which prevailed when these particular forms of expression originally became habitual, than with that of ideas as mere states of the mind itself; since this is only what has happened with respect to innumerable other words, in the transmutations of meaning which they have received during the long progress of scientific inquiry. The idea, in the old philosophy, had been that, of which the presence immediately preceded the mental perception,—the direct external cause of perception; and accordingly, it may well be supposed, that when the direct cause of perception was believed to be, not a foreign phantasm, but a peculiar affection of the sensorial organ, that word, which had formerly been applied to the supposed object, would still imply some reference to the organic state, which was believed to supply the place of the shadowy film, or phantasm, in being, what it had been supposed to be, the immediate antecedent of perception. Idea, in short, in the old writers, like the synonymous word perception at present, was expressive, not of one part of a process, but of two parts of it. It included, with a certain vague comprehensiveness, the organic change as well as the mental,—in the same way as perception now implies a certain change produced in our organs of sense, and a consequent change in the state of the mind; and hence it is surely not very astonishing, that while many expressions are found in the works of these older writers, which, in treating of ideas, have a reference to the mental part of the process of perception, other expressions are occasionally employed which relate only to the material part of the process,—since both parts of the process, as I have said, were, to a certain degree, denoted by that single word. All this might very naturally take place, though nothing more was meant to be expressed by it than these two parts of the process,—the organic change, whatever it might be, and the subsequent mental change, without the necessary intervention of something distinct from both, such as Dr Reid supposes to have been meant by the term Idea.

It is this application, to the bodily part of the process, of expressions, which he considered as intended to be applied to the mental part of perception, that has sometimes misled him in the views which he has given of the opinions of former philosophers. But still more frequently has he been misled, by understanding in a literal sense phrases which were intended in a metaphorical sense, and which seem so obviously metaphorical, that it is truly difficult to account for the misapprehension. Indeed, the same metaphors, on the mere use of which Dr Reid founds so much, continue still to be used in the same manner as before he wrote. We speak of impressions on the mind,—of ideas bright or obscure, permanent or fading,—of senses, that are the inlets to our knowledge of external things,—and of memory, in which this knowledge is stored,—precisely as the writers and speakers before us used these phrases; without meaning any thing more, than that certain organic changes, necessary to perception, are produced by external objects,—and that certain feelings, similar to those originally excited in this manner, are afterwards renewed, with more or less permanence and vivacity, without the recurrence of the objects that originally produced them;—and to arrange all the moods and figures of logic in confutation of mere metaphors, such as I cannot but think the images in the mind to have been, which Dr Reid so powerfully assailed, seems an undertaking not very different from that of exposing, syllogistically and seriously, all the follies of Grecian Paganism as a system of theological belief, in the hope of converting some unfortunate poetaster or poet, who still talks, in his rhymings to his mistress, of Cupid and the Graces.

There is, however, one very important practical inference to be drawn from this misapprehension,—the necessity of avoiding, as much as possible, in philosophic disquisition, the language of metaphor, especially when the precise meaning has not before been pointed out, so as to render any misconception of the intended meaning, when a metaphor is used, as nearly impossible as the condition of our intellectual nature will allow. In calculating the possibility of this future misconception, we should never estimate our own perspicuity very highly; for there is always in man a redundant facility of mistake, beyond our most liberal allowance. As Pope truly says,—

“The difference is as great between

The optics seeing, as the objects seen;”

and, unfortunately, it is the object only which is in our power. The fallible optics, that are to view it, are beyond our controul; and whatever opinion, therefore, the most cautious philosopher may assert, he ought never to flatter himself with the absolute certainty, that, in the course of a few years, he may not be exhibited, and confuted, as the assertor of a doctrine, not merely different from that which he has professed, but exactly opposite to it.

The true nature of the opinions really held by philosophers is, however, to be determined by reference to their works. To this then let us proceed.

The language of Mr Locke,—to begin with one of the most eminent of these,—is unfortunately, so very figurative, when he speaks of the intellectual phenomena,(though I have no doubt that he would have avoided these figures, if he could have foreseen the possibility of their being interpreted literally,) that it is not easy to show, by any single quotation, how very different his opinions as to perception were, from those which Dr Reid has represented them to be. The great question is, whether he believed the existence of ideas, as things in the mind, separate from perception, and intermediate between, the organic affection, whatever it might be, and the mental affection; or whether the idea and the perception were considered by him as the same. “In the perception of external objects,” says Dr Reid, “all languages distinguish three things,—the mind that perceives,—the operation of that mind, which is called perception,—and the object perceived. Philosophers have introduced a fourth thing, in this process, which they call the idea of the object.”[93] It is the merit of shewing the nullity of this supposed fourth thing, which Dr Reid claims, and which has been granted to him, without examination. The perception itself, as a state of the mind, or, as he chooses to call it, an operation of the mind, he admits, and he admits also the organic change which precedes it. Did Mr Locke then contend for any thing more, for that fourth thing, the idea, distinct from the perception,—over which Dr Reid supposes himself to have triumphed? That he did not contend for any thing more, nor conceive the idea to be any thing different from the perception itself, is sufficiently apparent from innumerable passages both of his Essay itself, and of his admirable defence of the great doctrines of his Essay, in his controversy with Bishop Stillingfleet. He repeatedly states, that he uses the word idea, as synonymous with conception or notion, in the common use of those terms; his only reason for preferring it to notion, (which assuredly Dr Reid could not suppose to mean any thing, distinct from the mind) being, that the term notion seems to him better limited to a particular class of ideas, those which he technically terms mixed modes. That ideas are not different from perceptions is clearly expressed by him. “To ask at what time a man has first any ideas,” he says, “is to ask when he begins to perceive; having ideas and perception being the same thing.”[94] If he speaks of our senses, as the inlets to our ideas, the metaphor is surely a very obvious one; or, if any one will still contend, that what is said metaphorically must have been intended really, it must be remembered, that he uses precisely the same metaphor, in cases in which the real application of it is absolutely impossible, as, for example, with respect to our perceptions or sensations, and that, if we are to understand, from his use of such metaphors, that he believed the ideas, thus introduced, to be distinct from the mind, we must understand, in like manner, that he believed our sensations and perceptions, introduced, in like manner, to be also things self-existing, and capable of being admitted, at certain inlets, into the mind as their recipient. “Our senses, conversant about particular sensible objects, do convey,” he says, “into the mind, several distinct perceptions of things, according to those various ways wherein those objects do affect them.”[95] “The senses are avenues provided by nature for the reception of sensations.”[96] I cannot but think, that these, and the similar passages that occur in the Essay, ought, of themselves, to have convinced Dr Reid, that he who thus spoke of PERCEPTIONS, conveyed into the mind, and of avenues provided for the reception of SENSATIONS, might also, when he spoke of the conveyance of ideas into the mind, and of avenues for the reception of ideas, have meant nothing more than the simple external origin of those notions, or conceptions, or feelings, or affections of mind, to which he gave the name of ideas; especially when there is not a single argument in his Essay, or in any of his works, that is founded on the substantial reality of our ideas, as separate and distinct things in the mind. I shall refer only to one additional passage, which I purposely select, because it is, at the same time, very full of the particular figures, that have misled Dr Reid, and shews, therefore, what the true meaning of the author was at the time at which he used these figures.

“The other way of retention, is the power to revive again in our minds those ideas, which after imprinting have disappeared, or have been as it were laid aside out of sight; and thus we do, when we conceive heat or light, yellow or sweet, the object being removed. This is memory, which is, as it were the storehouse of our ideas. For the narrow mind of man not being capable of having many ideas under view and consideration at once, it was necessary to have a repository to lay up those ideas, which at another time it might have use of. But our ideas being nothing but actual perceptions in the mind, which cease to be any thing, when there is no perception of them, this laying up of our ideas in the repository of the memory, signifies no more but this, that the mind has a power in many cases to revive perceptions, which it has once had, with this additional perception annexed to them, that it has had them before. And in this sense it is, that our ideas are said to be in our memories, when indeed they are actually no where, but only there is an ability in the mind when it will to revive them again, and as it were paint them a-new on itself, though some with more, some with less difficulty; some more lively, and others more obscurely.”[97]

The doctrine of this truly eminent philosopher, therefore, is, that the presence of the external object, and the consequent organic change, are followed by an idea, “which is nothing but the actual perception;” and that the laying up of these ideas in the memory, signifies nothing more, than that the mind has, in many cases, a power to revive perceptions which it has once had. All this, I conceive, is the very doctrine of Dr Reid on the subject; and to have confuted Mr Locke, therefore, if it had been possible for him, must have been a very unfortunate confutation, as it would have been also to have confuted as completely the very opinions on the subject, which he was disposed himself to maintain.

I may now proceed further back, to another philosopher of great eminence, whose name, unfortunately for its reputation, is associated more with his political and religious errors, than with his analytical investigations of the nature of the phenomena of thought. The author to whom I allude is Hobbes, without all question one of the most acute intellectual inquirers of the country and age in which he lived. As the physiology of the mind, in Britain at least seemed at that time to be almost a new science, he was very generally complimented by his contemporary poets, as the discoverer of a new land. Some very beautiful Latin verses, addressed to him, I quoted to you, in a former Lecture, in which it was said, on occasion of his work on Human Nature, that the mind, which had before known all things, was now for the first time made known to itself.

“Omnia hactenus

Quæ nosse potuit, nota jam primum est sibi.”

And in which he was said, in revealing the mind, to have performed a work, next in divinity to that of creating it.

“Divinum est opus

Animum creare, proximum huic ostendere.”

By Cowley, who styles him “the discoverer of the golden lands of new philosophy,” he is compared to Columbus, with this difference, that the world, which that great navigator found, was left by him, rude and neglected, to the culture of future industry; while that which Hobbes discovered might be said to have been at once explored by him and civilized. The eloquence of his strong and perspicuous style, I may remark by the way, seems to have met with equal commendation, from his poetical panegyrists, with whom, certainly not from the excellence of his own verses, he appears to have been in singular favour. His style is thus described, in some verses of Sheffield, Duke of Buckingham:

“Clear as a beautiful transparent skin,

Which never hides the blood, yet holds it in;

Like a delicious stream it ever ran

As smooth as woman, and as strong as man.”[98]

The opinions of Hobbes, on the subject which we are considering, are stated at length, in that part of his Elements of Philosophy, which he has entitled Physica; and, far from justifying Dr Reid's assertion, with respect to the general ideal system of philosophers, may be considered, in this important respect, as far, at least, as relates to the unity of the idea, and the perception itself, as similar to his own. Sensation or perception, he traces to the impulse of external objects, producing a motion along the nerves towards the brain, and a consequent reaction outwards, which he seems to think, very falsely indeed, may account for the reference to the object as external. This hypothesis, however, is of no consequence. The only important point in reference to the supposed universality of the system of ideas, is whether this philosopher of another age, asserted the existence of ideas, as intermediate things, distinct from the mere perception; and, on this subject, he is as explicit as Dr Reid himself could be. The idea or phantasma, as he terms it, is the very perception or actus sentiendi. “Phantasma enim est sentiendi actus; neque differt a sensione, aliter quam fieri differt a factum esse.”[99] The same doctrine, and I may add also, the same expression of the unity of the actus sentiendi and the phantasma, are to be found in various other parts of his works.

I may, however, proceed still further back, to an author of yet wider and more varied genius, one of those extraordinary men whom nature gives to the world, for her mightiest purposes, when she wishes to change the aspect, not of a single science merely, but of all that can be known by man; that illustrious rebel, who, in overthrowing the authority of Aristotle, seemed to have acquired, as it were by right of conquest, a sway in philosophy, as absolute, though not so lasting, as that of the Grecian despot. “Time,” says one of the most eloquent of his countrymen, “has destroyed the opinions of Des Cartes. But his glory subsists still. He appears like one of those dethroned monarchs, who, on the very ruins of their empire, still seem born for the sovereignty of mankind.”

On the opinions of Des Cartes, with respect to perception, Dr Reid has dwelt at great length, and has not merely represented him as joining in that belief of ideas, distinct from perception, which he represents as the universal belief of philosophers, but has even expressed astonishment, that Des Cartes, whose general opinions might have led him to a different conclusion, should yet have joined in the common one. “The system of Des Cartes,” he says, “is with great perspicuity and acuteness explained by himself, in his writings, which ought to be consulted by those who would understand it.”[100] He probably was not aware, when he wrote these few lines, how important was the reference which he made, especially to those whom he was addressing; since, the more they studied the view which he has given of the opinions of Des Cartes, the more necessary would it become for them to consult the original author.

“It is to be observed,” he says, “that Des Cartes rejected a part only of the ancient theory, concerning the perception of external objects by the senses, and that he adopted the other part. That theory may be divided into two parts,—the first, that images, species, or forms of external objects, come from the object, and enter by the avenues of the senses to the mind; the second part is, that the external object itself is not perceived, but only the species or image of it in the mind. The first part Des Cartes and his followers rejected, and refuted by solid arguments; but the second part, neither he nor his followers have thought of calling in question; being persuaded that it is only a representative image, in the mind, of the external object that we perceive, and not the object itself. And this image, which the Peripatetics called a species, he calls an idea, changing the name only, while he admits the thing.”[101]—“Des Cartes, according to the spirit of his own philosophy, ought to have doubted of both parts of the Peripatetic hypothesis, or to have given his reasons, why he adopted one part, as well as why he rejected the other part; especially since the unlearned, who have the faculty of perceiving objects by their senses, in no less perfection than philosophers, and should therefore know, as well as they, what it is they perceive, have been unanimous in this, that the objects they perceive are not ideas in their own minds, but things external. It might have been expected, that a philosopher, who was so cautious as not to take his own existence for granted, without proof, would not have taken it for granted, without proof, that every thing he perceived was only ideas in his own mind.”[102]

All this might certainly have been expected, as Dr Reid says, if the truth had not been, that the opinions of Des Cartes are precisely opposite to the representation which he has given of them,—that, far from believing in the existence of images of external objects, as the immediate causes or antecedents of perception, he strenuously contends against them. The presence of the external body,—the organic change, which he conceives to be a sort of motion of the small febrils of the nerves and brain,—and the affection of the mind, which he expressly asserts to have no resemblance whatever to the motion that gave occasion to it,—these are all which he conceives to constitute the process of perception, without any idea, as a thing distinct,—a fourth thing intervening between the organic and the mental change. And this process is exactly the process which Dr Reid himself supposes, with this only difference,—an unimportant one for the present argument,—that Dr Reid, though he admits some intervening organic change, does not state, positively, what he conceives to be its nature, while the French philosopher supposes it to consist in a motion of the nervous fibrils. The doctrine of Des Cartes is to be found, very fully stated, in his Principia Philosophiæ, in his Dioptrics, and in many passages of his small controversial works. He not merely rejects the Peripatetic notion, of images or shadowy films, the resemblance of external things, received by the senses,—contending, that the mere organic affection—the motion of the nervous fibril—is sufficient, without any such images, “diversos motus tenuium uniuscujusque nervi capillamentorum sufficere ad diversos sensus producendum;” and proving this by a very apposite case, to which he frequently recurs, of a blind man determining the dimensions of bodies by comprehending them within two crossed sticks,—in which case, he says, it cannot be supposed, that the sticks transmit, through themselves, any images of the body; but he even proceeds to account for the common prejudice, with respect to the use of images of perception, ascribing it to the well-known effect of pictures in exciting notions of the objects pictured. “Such is the nature of the mind,” he says, “that, by its very constitution, when certain bodily motions take place, certain thoughts immediately arise, that have no resemblance whatever, as images, to the motions in consequence of which they arise. The thoughts which words, written or spoken, excite, have surely no resemblance to the words themselves. A slight change in the motion of a pen may produce, in the reader, affections of mind the most opposite; nor is it any reply to this to say, that the characters traced by the pen are only occasions, that excite the mind itself to form opposite images,—for the case is equally striking, when no such image can be formed, and the feeling is the immediate result of the application of the external body. When a sword has pierced any part, is not the feeling excited as different altogether from the mere motion of the sword, as colour, or sound, or smell, or taste; and since we are sure, in the case of the mere pain from the sword, that no image of the sword is necessary, ought we not to extend the same inference, by analogy, to all the other affections of our senses, and to believe these also to depend, not on any images, or things transmitted to the brain, but on the mere constitution of our nature, by which certain thoughts are made to arise, in consequence of certain corporeal motions?” The passage is long, indeed, but it is so clear, and so decisive, as to the misrepresentation by Dr Reid of the opinion which he strangely considered himself as confuting, that I cannot refrain from quoting the original, that you may judge for yourselves, of the real meaning, which a translation might be supposed to have erred in conveying.

“Probatur deinde, talem esse nostræ mentis naturam, ut ex eo solo quod quidam motus in corpore fiant ad quaslibet cogitationes, nullam istorum motuum imaginem referentes, possit impelli; et speciatim ad illas confusas, quæ sensus, sive sensationes dicuntur. Nam videmus, verba, sive ore prolata, sive tantum scripta, quaslibet in animis nostris cogitationes et commotiones excitare. In eadem charta, cum eodem calamo et atramento, si tantum calami extremitas certo modo supra chartam ducatur, literas exarabit, quæ cogitationes præliorum, tempestatum, furiarum, affectusque indignationis et tristitiæ in lectorum animis concitabunt; si vero alio modo fere simili calamus moveatur, cogitationes valde diversas, tranquillitatis, pacis, amœnitatis, affectusque plane contrarios amoris et lætitiæ efficiet. Respondebitur fortasse, scripturam vel loquelam nullos affectus, nullasque rerum a se diversarum imaginationes immediate in mente excitare, sed tantummodo, diversas intellectiones; quarum deinde occasione anima ipsa variarum rerum imagines in se efformat. Quid autem dicetur de sensu doloris et titillationis? Gladius corpori nostro admovetur; illud scindit; ex hoc solo sequitur dolor; qui sane non minus diversus est a gladii, vel corporis quod scinditur locali motu, quam color, vel sonus, vel odor, vel sapor. Atque ideo cum clare videamus, doloris sensum in nobis excitari ab eo solo, quod aliquae corporis nostri partes contactu alicujus alterius corporis localiter moveantur, concludere licet, mentem nostram esse talis naturæ, ut ab aliquibus etiam motibus localibus omnium aliorum sensuum affectiones pati possit.

“Præterea non deprehendimus ullam differentiam inter nervos, ex qua liceat judicare, aliud quid per unos, quam alios, ab organis sensuum externorum ad cerebrum pervenire, vel omnino quidquam eo pervenire præter ipsorum nervorum motum localem.”[103]

It is scarcely possible to express more strongly, or illustrate more clearly, an opinion so exactly the reverse of that doctrine of perception, by the medium of representative ideas or images, ascribed by Dr Reid to its illustrious author. It would not be more unjust, even after all his laborious writings on the subject, to rank the supposed confuter of the ideal system, as himself one of its most strenuous champions, than to make this charge against Des Cartes, and to say of him, in Dr Reid's words, that “the image which the Peripatetics called a species, he calls an idea, changing the name only, while he admits the thing.”[104]

To these authors, whose opinions, on the subject of perception, Dr Reid has misconceived, I may add one, whom even he himself allows, to have shaken off the ideal system, and to have considered the idea and the perception, as not distinct, but the same, a modification of the mind, and nothing more. I allude to the celebrated Jansenist writer, Arnauld, who maintains this doctrine as expressly as Dr Reid himself, and makes it the foundation of his argument in his controversy with Malebranche. But, if I were to quote to you every less important writer, who disbelieved the reality of ideas or images, as things existing separately and independently, I might quote to you almost every writer, British and foreign, who, for the last century, and for many years preceding it, has treated of the mind. The narrow limits of a Lecture have forced me to confine my notice to the most illustrious.

Of all evidence, however, with respect to the prevalence of opinions, the most decisive is that which is found, not in treatises read only by a few, but in the popular elementary works of science of the time, the general text-books of schools and colleges. I shall conclude this long discussion, therefore, with short quotations from two of the most distinguished and popular authors, of this very useful class.

The first is from the logic or rather the pneumatology, of Le Clerc, the Friend of Locke. In his chapter, on the nature of ideas, he gives the history of the opinions of philosophers on this subject, and states among them the very doctrine which is most forcibly and accurately opposed to the ideal system of perception. “Others,” he says, “held that ideas and the perception of ideas are absolutely the same in themselves, and differ merely in our relative application of them; that same feeling of the mind, which is termed an idea, in reference to the object which the mind considers, is termed a perception, when we speak of it relatively to the percipient mind; but it is only of one modification of the mind that we speak in both cases.” According to these philosophers, therefore, there are, in strictness of language, no ideas distinct from the mind itself. “Alii putant ideas et perceptiones idearum easdem esse, licet relationibus differant. Idea, uti censent, proprie ad objectum refertur, quod mens considerat;—perceptio, vero, ad mentem ipsam quæ percipit; sed duplex illa relatio ad unam modificationem mentis pertinet. Itaque secundum hosce philosophos, nullæ sunt proprie loquendo ideæ a mente nostra distinctæ.”[105] What is it, I may ask, which Dr Reid considers himself as having added to this very philosophic view of perception? and, if he added nothing, it is surely too much to ascribe to him the merit of detecting errors, the counter statement to which had long formed a part of the elementary works of the schools.

In addition to these quotations,—the number of which may perhaps already have produced at least as much weariness as conviction,—I shall content myself with a single paragraph, from a work of De Crousaz, the author, not of one merely, but of many very popular elementary works of logic, and unquestionably one of the most acute thinkers of his time. His works abound with many sagacious remarks, on the sources of the prejudice involved in that ideal system, which Dr Reid conceived himself the first to have overthrown; and he states, in the strongest language, that our ideas are nothing more than states or affections of our mind itself. “Cogitandi modi—quibus cogitatio nostra modificatur, quos induit alios post alios, sufficiunt, ut per eos ad rerum cognitionem veniat; nec sunt fingendæ ideæ, ab illis modificationibus diversæ.”[106] I may remark by the way, that precisely the same distinction of sensations and perceptions, on which Dr Reid founds so much, is stated and enforced in the different works of this ingenious writer. Indeed so very similar are his opinions, that if he had lived after Dr Reid, and had intended to give a view of that very system of perception which we have been examining, I do not think that he could have varied in the slightest respect, from that view of the process which he has given in his own original writings.

It appears then, that, so far is Dr Reid from having the merit of confuting the universal, or even general illusion of philosophers, with respect to ideas in the mind, as images or separate things, distinct from the perception itself; that his own opinions as to perception on this point at least, are precisely the same, as those which generally prevailed before. From the time of the decay of the Peripatetic Philosophy, the process of perception was generally considered, as involving nothing more, than the presence of an external object—an organic change or series of changes—and an affection of the mind immediately subsequent,—without the intervention of any idea as a fourth separate thing between the organic and the mental affection. I have no doubt, that,—with the exception of Berkeley and Malebranche,—who had peculiar and very erroneous notions on the subject, all the philosophers whom Dr Reid considered himself as opposing, would, if they had been questioned by him, have admitted, before they heard a single argument on his part, that their opinions, with respect to ideas were precisely the same as his own;—and what then would have remained for him to confute? He might, indeed, still have said, that it was absurd, in those who considered perception as a mere state or modification of the mind, to speak of ideas in their mind: but the very language, used by him for this purpose, would probably have contained some metaphor as little philosophic. We must still allow men to speak of ideas in their mind, if they will only consent to believe that the ideas are truly the mind itself variously affected;—as we must still allow men to talk of the rising and setting of the sun, if they will only admit that the motion which produces those appearances is not in that majestic and tranquil orb, but in our little globe of earth, which, carrying along with it, in its daily revolution, all our busy wisdom and still busier folly, is itself as restless as its restless inhabitants.

That a mind, so vigorous as that of Dr Reid, should have been capable of the series of misconceptions which we have traced, may seem wonderful, and truly is so; and equally, or rather, still more wonderful, is the general admission of his merit in this respect. I trust it will impress you with one important lesson,—which could not be taught more forcibly than by errors of so great a mind,—that it will always be necessary for you to consult the opinions of authors,—when their opinions are of sufficient importance to deserve to be accurately studied—in their own works and not in the works of those who profess to give a faithful account of them. From my own experience, I can most truly assure you, that there is scarcely an instance, in which, on examining the works of those authors whom it is the custom more to cite than to read, I have found the view which I had received of them to be faithful. There is usually something more or something less, which modifies the general result,—some mere conjecture represented as an absolute affirmation, or some limited affirmation extended to analogous cases, which it was not meant to comprehend. And, by the various additions or subtractions, thus made, in passing from mind to mind, so much of the spirit of the original doctrine is lost, that it may, in some cases, be considered as having made a fortunate escape, if it be not at last represented, as directly opposite to what it is. It is like those engraved portraits of the eminent men of former ages,—the copies of mere copies,—from which every new artist, in the succession, has taken something, or to which he has added something, till not a lineament remains the same. If we are truly desirous of a faithful likeness, we must have recourse once more to the original painting.