Chapter XIX: Part 19

These praises are certainly not higher than his merits. But, at the same time, while by philosophers in one part of the island, his merits seem to have been unjustly undervalued, I cannot but think also, that, in his own country, there has been an equal or rather a far greater tendency to over-rate them,--a tendency arising in part from the influence of his academic situation, and his amiable personal character--partly, and in a very high degree, from the general regard for the moral and religious objects which he uniformly had in view, as contrasted with the consequences that are supposed to flow from some of the principles of the philosopher, whose opinions he particularly combated--and partly also, I may add, from the eloquence of his Illustrious Pupil, and Friend, and Biographer, whose understanding, so little liable to be biassed by any prejudices but those of virtue and affectionate friendship, has yet, perhaps, been influenced in some degree by those happy and noble prejudices of the heart, and who, by the persuasive charms both of his Lectures and of his Writings, could not fail to cast, on any system of opinions which he might adopt and exhibit, some splendour of reflection from the brilliancy of his own mind.

The genius of Dr Reid does not appear to me to have been very inventive, nor to have possessed much of that refined and subtile acuteness, which,--capable as it is of being abused,--is yet absolutely necessary to the perfection of metaphysical analysis.

It is chiefly on his opinions, in relation to the subject at present under our view, that his reputation as an _original thinker_ rests. Indeed, it is on these that he has inclined himself to rest it. In a part of a letter to Dr Gregory, preserved in Mr Stewart's Memoir, he considers his confutation of the ideal system of perception, as involving almost every thing which is truly his. “I think there is hardly any thing that can be called mine,” he says, “in the philosophy of mind, which does not follow with ease from the detection of this prejudice.”[107] Yet there are few circumstances, connected with the fortune of modern philosophy, that appear to me more wonderful, than that a mind, like Dr Reid's, so learned in the history of metaphysical science,--and far too honourable to lay claim to praise to which he did not think himself fairly entitled,--should have conceived, that, on the point of which he speaks, any great merit--at least any merit of originality--was justly referable to him particularly. Indeed, the only circumstance, which appears to me more wonderful, is, that the claim thus made by him, should have been so readily and generally admitted.

His supposed confutation of the ideal system is resolvable into two parts--_first_, his attempt to overthrow what he terms “the common theory” of _ideas_ or images of things in the mind, as the immediate objects of thought--and _secondly_, the evidence which the simpler theory of perception may be supposed to yield, of the _reality_ of an external world. The latter of these inquiries would, in order, be more appropriate to our late train of speculation; but we cannot understand it fully, without some previous attention to the former.

That Dr Reid _did_ question the theory of ideas or images, as separate existences in the mind, I readily admit; but I cannot allow, that, in doing this, he questioned the _common_ theory. On the contrary, I conceive, that, at the time at which he wrote, the theory had been universally, or at least almost universally, abandoned; and that, though philosophers might have been in the habit of speaking of ideas or images in the mind,--as we continue to speak of them at this moment,--they meant them to denote nothing more _then_, than we use them to denote _now_. The phraseology of any system of opinions, which has spread widely, and for a length of time, does not perish with the system itself. It is transmitted from the system which expires, to the system which begins to reign,--very nearly as the same crown and sceptre pass, through a long succession, from monarch to monarch. To tear away our very language, as well as our belief, is more than the boldest introducer of new doctrines can hope to be permitted, for it would be to force our ignorance or errors too glaringly on our view. He finds it easier, to seduce our vanity, by leaving us something which we can still call _our own_, and which it is not very difficult for him to accommodate to his own views; so that, while he allows us to pronounce the same words, with the same confidence, we are sensible only of what we have gained, and are not painfully reminded of what we have been forced to discard. By this, too, he has the advantage of adding, in some measure, to his own novelties the weight and importance of ancient authority; since the feelings, associated with the name as formerly used, are transferred, secretly and imperceptibly, with the name itself. There is scarcely a term in popular science, which has not gone through various transmutations of this sort. It is not wonderful, therefore, that the phrase _image in the mind_, which was no metaphor as used by the Peripatetics, should have been retained, in a figurative sense, in metaphysical discussions, long after the authority of Aristotle had ceased, and when one who could maintain, with a square cap on his head, “a thesis on the universal _a parti rei_,” was no longer, as Voltaire says, “considered as a prodigy.” At the time of Dr Reid's publication, the _image in the mind_ was as truly a mere relic of an obsolete theory of perception, as the rising and setting of the sun were relics of that obsolete astronomy, in which this great luminary was supposed to make his daily journey, round the atom which he enlightened.

Before proceeding to the proof of this assertion, however, with respect to the originality and importance of Dr Reid's remarks on this subject, some previous observations will be necessary.

In the discussions, which, as yet, have engaged our attention, you may, perhaps, have remarked that I have made little, if any, use of the word _idea_,--a word of very frequent occurrence, in the speculations of philosophers, with respect to the phenomena of perception, and the intellectual phenomena in general. I have avoided it, partly on account of its general ambiguity, but, more especially, with a view to the question at present before us, that, on examining it, you might be as free as possible, from any prejudice, arising from our former applications of the term.

The term, I conceive, though convenient for its brief expression of a variety of phenomena, which might otherwise require a more paraphrastic expression, might yet be omitted altogether, in the metaphysical vocabulary, without any great inconvenience,--certainly without inconvenience, equal to that which arises from the ambiguous use of it, with different senses, by different authors. But, whatever ambiguity it may have had, the notion of it, as an image in the mind separate and distinct from the mind itself, had certainly been given up, long before Dr Reid had published a single remark on the subject. In its present general use, it is applied to many species of the mental phenomena, to our particular sensations or perceptions, simple or complex, to the remembrances of these, either as simple or complex, and to the various compositions or decompositions of these, which result from certain intellectual processes of the mind itself. The presence of certain rays of light, for example, at the retina, is followed by a certain affection of the sensorial organ, which is immediately followed by a certain affection of the sentient mind. This particular affection, which is more strictly and definitely termed the sensation or perception of redness, is likewise sometimes termed, when we speak more in reference to the external light, which causes the sensation, than to ourselves, as sentient of it, an idea of redness; and when, in some train of internal thought, without the renewed presence of the rays, a certain state of the mind arises, different, indeed, from the former, but having a considerable resemblance to it, we term this state the conception or remembrance of redness, or the idea of redness; or, combining this particular idea with others, which have not co-existed with it as a sensation, we form, what we term the complex idea, of a red tree, or a red mountain, or some other of those shadowy forms, over which Fancy, in the moment of creating them, flings, at pleasure, her changeful colouring. An _idea_, however, in all these applications of the term, whether it be a perception, a remembrance, or one of those complex or abstract varieties of conception, is still nothing more than the mind affected in a certain manner, or, which is the same theory, the mind existing in a certain state. The idea is not distinct from the mind, or separable from it, in any sense, but is truly the mind itself, which in its very belief of external things, is still recognizing one of the many forms of its own existence.

“Qualis Hamadryadum, quondam, si forte sororum
Una novos peragrans saltus et devia rura,
(Atque illam in viridi suadet procumbere ripa
Fontis pura quies et opaci frigoris umbra)
Dum prona in latices speculi de margine pendet,
Mirata est subitam venienti occurrere Nympham;
Mox eosdem quos ipsa artus, eadem ora gerentem
Una inferre gradus, una succedere sylvæ,
Aspicit alludens, seseque agnoscit in undis.
Sic sensu interno rerum simulacra suarum
Mens ciet, et proprios observat conscia vultus.”[108]

In sensation, there is, as we have seen, a certain series,--the presence of the external body, whatever this may be in itself, independently of our perception,--the organic affection, whatever it may be, which attends the presence of this body,--and the affection of mind that is immediately subsequent to the organic affection. I speak only of _one_ organic affection; because, with respect to the mind, it is of no consequence whether there be one only, or a series of these, prior to the new mental state induced. It is enough, that, whenever the immediate sensorial organ has begun to exist in a certain state, whether the change which produces this state be single, or second, third, fourth, or fifth, of a succession of changes, the mind is instantly affected in a certain manner. This new mental state induced is sensation.

But, says Dr Reid, the _sensation_ is accompanied with a _perception_, which is very different from it; and on this difference of sensation and perception is founded the chief part of his system. The distinction thus made by him, has been commonly, though very falsely, considered as original; the radical difference itself, whether accurate or inaccurate, and the minor distinctions founded upon this, being laid down with precision in some of the common elementary works of logic, of a much earlier period.

“When I smell a rose,” he says, “there is in this operation both sensation and perception. The agreeable odour I feel, considered by itself, without relation to any external object, is merely a sensation. It affects the mind in a certain way; and this affection of the mind may be conceived, without a thought of the rose, or any other object. This sensation can be nothing else than it is felt to be. Its very essence consists in being felt; and when it is not felt, it is not. There is no difference between the sensation and the feeling of it; they are one and the same thing. It is for this reason, that we before observed, that, in sensation, there is no object distinct from that act of the mind by which it is felt; and this holds true with regard to all sensations.

“Let us next attend to the perception which we have in smelling a rose. Perception has always an external object; and the object of my perception, in this case, is that quality in the rose which I discern by the sense of smell. Observing that the agreeable sensation is raised when the rose is near, and ceases when it is removed, I am led, by my nature, to conclude some quality to be in the rose, which is the cause of this sensation. This quality in the rose is the object perceived; and that act of my mind, by which I have the conviction and belief of this quality, is what in this case I call perception.”[109]

That the reference to an external object is, in this case, something more than the mere sensation itself, is very evident; the only question is, whether it be necessary to ascribe the reference to a peculiar power termed perception, or whether it be not rather the result of a common and more general principle of the mind.

When I smell a rose, that is to say, when certain odorous particles act on my organ of smell, a certain state of mind is produced, which constitutes the sensation of that particular fragrance; and this is all which can justly be ascribed to the mind as simply _sentient_. But the mind is not sensitive merely, in the strict sense of that term, for there are many states of it, which do not depend on the immediate presence of external objects. Those feelings, of any kind, which have before existed, together, or in trains of succession, arise afterwards, as it were spontaneously, in consequence merely of the existence of some other part of the train. When the fragrance of a rose, therefore, has been frequently accompanied with the sensations of vision, that arise, when a rose is before us, with the muscular and tactual sensations, that arise on handling it, the mere fragrance, of itself, will afterwards suggest these sensations, and this suggestion is all, which, in the case of smell, instanced by Dr Reid, is termed the perception, as distinguished from the mere sensation. We ascribe the fragrance to the unseen external rose, precisely in the same manner as we ascribe smoke and ashes to previous combustion; or, from a portrait, or a pictured landscape, infer the existence of some artist who painted it. Yet, in inferring the artist from the picture, it is surely not to any mere power of sense, that we ascribe the inference, and as little should we trace to any such simple power, what is in this instance termed perception. The perception is a suggestion of memory, combined with the simple sensation. There are not, in ascribing the smell to odorous particles of a rose, as its cause, sensation, perception, and association or suggestion, as three powers or general principles of the mind. But there are sensation and the associate suggestion; and, when these coexist, perception coexists, because perception is the name which we give to the union of the former two. There is, indeed, the belief of some cause of the sensation, as there is a belief of some cause of every feeling of the mind, internal as well as external; but the cause, in the case of smell, is supposed to be external, and corporeal, merely because the presence of an external rose has been previously learned from another source, and is suggested when the sensation of fragrance recurs, in intimate association.

In the case of _taste_, to proceed to our other senses--the perception, as it is termed by Dr Reid, is precisely of the same kind--a mere reference of association. We have previously learned, from other sources, to believe in things without, and these, as sapid bodies acting on our tongue, are suggested by the mere sensation, which, but for the means of this suggestion, would have been a sensation alone, of which the cause would have been as little conceived to be corporeal as the causes of any of the internal affections of the mind. The melody of a flute, if we had had no sense but that of hearing--the redness of a rose, if we had had no sense but that of vision, would as little, as the sensation of smell when considered as a transient state of the mind, have involved, or given occasion to, the notion of corporeal substance. We refer the melody to the external flute, and redness to the external rose, because we have previously acquired the notions of extension and resistance--of a flute and of a rose as external substances--and this reference of mere suggestion is all, which, in these cases, distinguishes the perception from the sensation. Without the suggestions of memory, in short, we could not in these cases have had, in Dr Reid's sense of the term, any perceptions whatever, to distinguish the causes of our sensations as external, more than the causes of any of our other feelings. The great perception, then, in the sense, in which he understands the term, is that by which we primarily form the complex notion of extension and resistance--that which has parts, and that which resists our attempt to grasp it--since all the other perceptions, of which he speaks, in contradistinction from mere sensations, are only these complex notions, _suggested_ by the particular sensations, and combined with them, in consequence of former association, and the general reference to a cause of some sort, which may be supposed to attend our feelings of every kind, internal as well as external, when considered as changes or new phenomena. It is not, however, from any peculiar power, to be distinguished by the name of perception, that this complex notion of extended resistance appears to me to arise, but from the union of our notion of _extension_, acquired by the mere remembrance of various progressive series of feelings, with the notion of _resistance_, when an accustomed series of muscular feelings without any change of circumstances, in the mind itself, is interrupted by that peculiar and very different muscular feeling which arises from impeded effort. Perception, in short, in all our senses, is nothing more than the association of this complex notion with our other sensations--the notion of something extended and resisting, suggested by these sensations, when the sensations themselves have previously arisen; and suggested in the same manner, and on the same principle, as any other associate feeling suggests any other associate feeling.

It is very evident that perception, in Dr Reid's sense, is not the mere reference to a cause of some sort, for it would then be as comprehensive as all the feelings or changes of the mind,--our hope, fear, anger, pity,--which we ascribe to some cause or antecedent, as much as our tastes and smells; it is the reference of certain feelings to a _corporeal_ cause, that is say, to a cause _extended_ and _resisting_. If, for example, without any previous knowledge of external things, on the first sensation of fragrance, or sweetness, or sound, or colour, we could be supposed to be capable of believing that there was some cause of this new state of our being, this would not be _perception_, in the sense in which he uses that term; and yet but for our organ of touch, or at least but for feelings which are commonly ascribed to that organ, it would be manifestly impossible for us to make more than this vague and general inference. When a rose is present, we find, and have uniformly found, that a certain sensation of fragrance arises, which ceases when the rose is removed. The influence of association, therefore, operates in this, as in every other case of ordinary co-existence. We do not merely suppose that the sensation has some cause, as we believe that our joys and sorrows have a cause, but we ascribe the fragrance to the external substance, the presence of which we have found to be so essential to the production of it. Perception in every case, as I have said, in which it is to be distinguished from the prior sensation, is a reference of this prior sensation to a _material cause_;--and this complex notion of a material cause,--that is to say, of something extended and resisting,--mere smell, mere taste, mere hearing, mere vision, never could have afforded. I have already explained how this notion of matter, as it appears to me, is produced, or may be imagined to be produced. A train of muscular feelings has been frequently repeated, so that the series has become familiar to the infant, constituting in its remembrance the notion of a certain progressive length.--When all the known antecedent circumstances have been the same, the well-known series is suddenly broken, so as to excite in the mind of the infant the notion of a cause which is not in itself;--this cause, which is something foreign to itself, is that which excites the particular muscular feeling of resistance,--and it is combined with the notion of a certain length, because it uniformly supplies the place of what has been felt as a certain length, so as at last, by the operation of the common laws of association, to become truly representative of it, or rather to involve it in one complex feeling, in the same manner as colour, in vision, seems to involve whole miles of distance. Such is all that seems to me to constitute what Dr Reid would term perception, even with respect to the feelings commonly termed tactual;--and in all the other classes of sensations it is obviously nothing more than the suggestion of these associate feelings, in the same way as any other feelings, in our trains of thought and emotions, are suggested by those conceptions or other feelings which have frequently accompanied them.--It is sufficient to think of a mind, possessing all the other susceptibilities of sensation, _but those_ which give us the perceptions commonly ascribed to touch, to be sensible how truly what we term perception in the other senses, is the mere suggestion of these. If we were capable only of smelling,--or had no other sensations than those of mere taste, mere sound, mere colour,--what perception could we have had of a material cause of these sensations?--and if it be to the mere suggestion of the object of another sense that we owe what is termed perception in all these sensations,--in what circumstance does the reference of these to a resisting and extended substance, differ from any other of the common references which the principle of association enables us to make?

“Sensation,” says Dr Reid, “can be nothing else than it is felt to be. Its very essence consists in being felt; and when it is not felt, it is not. There is no difference between the sensation and the feeling of it; they are one and the same thing.”[110] But this is surely equally true, of what he terms _perception_, which, as a state of mind, it must be remembered, is, according to his own account of it, as different from the object perceived, as the sensation is. We may say of the mental state of perception too, in his own language, as indeed we must say of all our states of mind, whatever they may be, that it can be nothing else than it is felt to be. Its very essence consists in being felt; and when it is not felt, it is not. There is no difference between the perception and the feeling of it; they are one and the same thing. The sensation, indeed, which is mental, is different from the object exciting it, which we term material; but so also is the state of mind which constitutes perception; for Dr Reid was surely too zealous an opponent of the systems, which ascribe every thing to mind alone, or to matter alone, to consider the perception as itself the object perceived. That in sensation, as contradistinguished from perception, there is no reference made to an external object, is true; because, when the reference is made, we then use the new term of perception; but that in sensation there is no object distinct from that act of the mind by which it is felt; no object independent of the mental feeling, is surely a very strange opinion of this philosopher; since what he terms perception, is nothing but the reference of this very sensation to its external object. The sensation itself he certainly supposes to depend on the presence of an external object, which is all that can be understood, in the case of perception, when we speak of its objects, or, in other words, of those external causes, to which we refer our sensations; for the material object itself, he surely could not consider as forming a part of the perception which is a state of the mind alone. To be the object of perception, is nothing more than to be the foreign cause or occasion, on which this state of the mind directly or indirectly arises; and an object, in this only intelligible sense, as an occasion, or cause of a certain subsequent effect, must on his own principles, be equally allowed to sensation. Though he does not inform us, what he means by the term _object_, as peculiarly applied to perception--(and indeed, if he had explained it, I cannot but think that a great part of his system, which is founded on the confusion of this single word, as something different from a mere external cause of an internal feeling must have fallen to the ground,)--he yet tells us, very explicitly, that to be the object of perception, is something more than to be the external occasion, on which that state of the mind arises which he terms perception; for, in arguing against the opinion of a philosopher, who contends for the existence of certain images or traces in the brain, and yet says, “that we are not to conceive the images or traces in the brain to be perceived, as if there were eyes in the brain; these traces are only occasions, on which, by the laws of the union of soul and body, ideas are excited in the mind; and, therefore, it is not necessary, that there should be an exact resemblance between the traces and the things represented by them, any more than that words or signs should be exactly like the things signified by them:”[111]--He adds, “These two opinions, I think cannot be reconciled. For if the images or traces in the brain are perceived, they must be the _objects_ of perception, and not the occasions of it only. On the other hand, if they are only the _occasions_ of our perceiving, they are not perceived at all.”[112]--Did Dr Reid, then, suppose that the feeling, whatever it may be, which constitutes perception as a state of the mind, or, in short, all of which we are conscious in perception, is not strictly and exclusively mental, as much as all of which we are conscious in remembrance, or in love, or hate;--or did he wish us to believe that matter itself, in any of its forms, is, or can be, a part of the phenomena or states of the mind;--a part therefore of that mental state or feeling which we term a perception? Our sensations like our remembrances or emotions, we refer to some cause or antecedent. The difference is, that in the one case we consider the feeling as having for its cause some previous feeling or state of the mind itself; in the other case we consider it as having for its cause something which is external to ourselves, and independent of our transient feelings,--something which, in consequence of former feelings suggested at the moment, it is impossible for us not to regard as extended and resisting.--But still what we thus regard as extended and resisting, is known to us only by the feelings which it occasions in our mind. What matter, in its relation to the percipient mind, can be, but the cause or occasion, direct or indirect, of that class of feelings which I term sensations or perceptions, it is absolutely impossible for me to conceive.

The percipient mind, in no one of its affections, can be said to be the mass of matter which it perceives, unless the separate existence, either of matter or of mind, be abandoned by us, the existence of which, Dr Reid would have been the last of philosophers to yield. He acknowledges that our perceptions are consequent on the presence of external bodies, not from any necessary connexion subsisting between them, but merely from the arrangement which the Deity, in his wisdom, has chosen to make of their mutual phenomena; which is surely to say, that the Deity has rendered the presence of the external object the occasion of that affection of the mind, which is termed perception; or, if it be not to say this, it is to say nothing. Whatever state of mind perception may be; whether a primary result of a peculiar power, or a mere secondary reference of association that follows the particular sensation, of which the reference is made, it is itself, in either view of it, but a state of the mind; and to be the external occasion or antecedent of this state of mind, since it is to produce, directly or indirectly, all which constitutes perception, is surely, therefore, to be perceived, or there must be something in the mere word _perceived_, different from the physical reality which it expresses.

The confusion of Dr Reid's notions on this subject, seems to have arisen from a cause, which has been the chief source of the general confusion that prevails in intellectual science; and, indeed, it was principally with the view of exhibiting this confusion, and its source, to you _strongly_, that I have dwelt so long on a criticism, which, to those among you who are not acquainted with the extensive and important applications that have been made of this doctrine, may, perhaps, have appeared of very little interest. Dr Reid, it is evident, was not sufficiently in the habit of considering the phenomena of the mind,--its perceptions, as well as its remembrances, judgments, passions, and all its other affections, whatever these may be,--in the light in which I have represented them to you, merely as the mind affected, in a certain manner, according to certain regular laws of succession, but as something more mysterious than the subject of this sequence of feelings; for, but for this notion of something more mysterious, the object of perception, and the external occasion of that state of mind which we term perception, must have conveyed precisely the same notion. To have a clear view of the phenomena of the mind, as mere affections or states of it, existing successively, and in a certain series, which we are able, therefore, to predict, in consequence of our knowledge of the past, is, I conceive, to have made the most important acquisition which the intellectual inquirer can make. To say, merely, that it is to have learned to distinguish that which may be known, from that which never can be known, and which it therefore would be an idle waste of labour to attempt to discover,--would be to say far too little. It is to see the mind, in a great measure, as it is in nature, divested of every thing foreign, passing instantly from thought to thought, from sensation to sensation, in almost endless variety of states, and differing as completely from that cumbrous representation of it, which philosophers are fond of representing to us, as the planets revolving freely in the immense space of our solar system, differ from those mimic orbs, which, without any principle of motion in themselves, are, as it were, dragged along, in the complex mechanism of our orreries.

In objecting, however, to Dr Reid's notion of perception, I am far from wishing to erase the word from our metaphysical vocabulary. On the contrary, I conceive it to be a very convenient one, if the meaning attached to it be sufficiently explained, by an analysis of the complex state of mind, which it denotes, and the use of it confined rigidly to cases in which it has this meaning. Sensation may exist, _without_ any reference to an external cause, in the same manner as we may look at a picture, without thinking of the painter; or read a poem, without thinking of the poet,--or it may exist _with_ reference to an external cause; and it is convenient, therefore, to confine the term _sensation_ to the former of these cases, and _perception_ to the latter. But, then, it must be understood, that the perception is nothing but the suggestion of ideas associated with the simple _sensation_, as it originally took place,--or is only another name for the original simple sensation itself, in the cases, if any there be, in which sensation involves immediately in itself, the belief of some existence external to the sentient mind,--or is only a mere inference, like all our other inferences, if it arise, in the manner in which I have endeavoured to explain to you, how the notions of extension and resistance in an external cause of our feelings, might arise, and be afterwards suggested in association with other feelings that had frequently accompanied it.

To give a brief summary, however, of the argument which I have urged;--in that state of acquired knowledge, long after the first elementary feelings of infancy, in which modified state alone, the phenomena of the mind can become to us objects of reflective analysis, certain feelings are referred by us to an external material cause. The feelings themselves, as primarily excited, are termed _sensations_, and, when followed by the reference to an external cause, receive the name of _perceptions_, which marks nothing more in addition to the primary sensations, than this very reference. But what is the reference itself, in consequence of which the new name is given? It is the suggestion of some extended resisting object, the presence of which had before been found to be attended with that particular sensation, which is now again referred to it. If we had had no sense but that of smell; no sense but that of taste; no sense but that of sound; no sense but that of sight; we could not have known the existence of extended resisting substances, and, therefore, could not have referred the pleasant or painful sensations of those classes to such external causes, more than we refer directly to an external cause, any painful or pleasing emotion, or other internal affection of the mind. In all but _one_ class of our sensations, then, it is evident that what Dr Reid calls _perception_, as the operation of a peculiar mental faculty, is nothing more than a suggestion of memory or association, which differs in no respect from other suggestions arising from other coexistences or successions of feelings, equally uniform or frequent. It is only in a single class of sensations, therefore,--that which Dr Reid ascribes to touch,--that perception, which he regards as a peculiar faculty, extending to all our sensations, can be said to have any primary operation, even though we should agree with him in supposing, that our belief of extended resistance is not reducible by analysis, to any more general principles. If, however, my analysis of the complex notion of matter be just, perception, in its relation to our original sensations of touch, as much as in relation to the immediate feelings which we derive from smell, taste, sight, and hearing, is only one of the many operations of the suggesting or associating principle. But, even on his own principles, I repeat, it must be confined to the single class of feeling, which he considers as tactual, and is not an original principle, coextensive with all the original varieties of sensation. Even in the single class, to which it is thus, on his own principles, to be confined, it is not so much what he would term a faculty, as an intuitive belief, by which we are led irresistibly, on the existence of certain sensations, to ascribe these to causes that are external and corporeal; or, if we give the name of faculty to this peculiar form of intuition, we should give it equally to all our intuitions, and rank among our faculties, the belief of the continued order of Nature, or the belief of our own identity, as much as our belief of external things, if our senses themselves are unable to give us any information of them.

FOOTNOTES:

[107] Account of the Life, &c. p. xci. prefixed to Reid's Works. Edin. 1803.

[108] Gray, de Princip. Cogit. Lib. I. v. 143--153.

[109] On the Intellectual Powers, Essay II. c. 16.

[110] See before, p. 416.

[111] On the Intellectual Powers, Essay II. c. 8.

[112] Ibid.

LECTURE XXVIII.

ON DR REID'S SUPPOSED PROOF OF A MATERIAL WORLD--ON VISION--AND ANALYSIS OF THE FEELINGS ASCRIBED TO IT.

In my Lecture of yesterday, Gentlemen, we were engaged in considering the grounds of Dr Reid's claim to the honour of detecting and exposing the fallacy of the hypothesis of _ideas_ as _images_, or things, in the mind, distinct from the mind itself,--a claim which, though made by one who has many other indubitable titles to our respect and gratitude, we found, in this particular instance, to be inadmissible.

It appeared, on an examination of the original works of the eminent philosophers who preceded him for more than a century, and even of the common elementary treatises of the schools, that, though after the Peripatetic hypothesis of species had been universally or generally abandoned, the language of that hypothesis continued to subsist metaphorically,--as it continues with equal force at this moment,--it was only metaphorically that it did thus continue; and that when Dr Reid, therefore, conceived,--in proving ideas not to be self-existing things, separate and distinct from the percipient mind itself,--that he was confuting what every body believed, he merely assumed as _real_ what was intended as _metaphorical_, and overthrew opinions which the authors, to whom he ascribes them, would themselves have been equally eager to overthrow. But there is yet another point, connected with the theory of perception, on which he is believed to have made an important addition to our metaphysical knowledge. I allude to his supposed proof of the existence of a material world. In this, too, we shall find, that he has truly added nothing to our former knowledge; that he has left us, in short, our belief as originally felt by us, but has not supplied us with the slightest evidence in addition to the force of that original belief itself, nor given any additional strength to that very belief, which before was confessedly irresistible.

The confutation of the scepticism on this subject, it is evident, may be attempted in _two ways_,--by shewing the arguments urged by the sceptic to be _logically false_; or by opposing to them the belief itself, as of evidence either directly intuitive, or the result, at least, of other intuitions, and early and universal associations and inferences, so irresistible after the first acquisitions of infancy, as to have then all the force of intuition itself. As long as Dr Reid confines himself to the latter of these pleas, he proceeds on safe ground; but his footing is not so firm when he assails the mere logic of the sceptic,--for the sceptical argument, as a mere play of reasoning, admits of no reply. It is vain for him to say, that the scepticism proceeding, as he thinks, on the belief of ideas in the mind, as the direct objects of perception, must fall with these ideas; for, though the scepticism may be consistent with the belief of ideas as separate existences in the mind, it does not depend, in the slightest degree, on their existence or non-existence. We have only to change the term _ideas_ into the synonymous phrase _affections or states of the mind_, and the scepticism, if not stronger, is at least in strength exactly what it was before. In the one case the sceptic will say, that we are sensible of ideas only, not of external objects, which may have no resemblance to our ideas; in the other case, that perception is but a state of the mind as much as any of our other feelings, and that we are conscious only of this, and other states or affections of our mind, which have variously succeeded each other, and not of external objects, which themselves can be no parts of that train of mental consciousness. Whatever weight there may be in the former of these sceptical theories, exists, I may say, even with greater force, because with greater simplicity, in the second; and the task, therefore, of proving by logic,--if logical proof were requisite for our belief,--the existence of a material world, would remain as laborious as before, after the fullest confutation of the system, which might suppose perception to be carried on by the medium of little images of bodies in the mind.

So far, indeed, would the confutation of this hypothesis as to perception,--even if Dr Reid had truly overthrown it,--be from lessening the force of the scepticism as to the existence of matter, that, of two sceptics, one believing every thing with respect to ideas which Dr Reid supposed himself to have confuted, and the other believing ideas to be mere states of his mind, there can be no question, that the former would be the more easy to be overcome, since his belief would already involve the existence of SOMETHING separate from the mind; while the other might maintain, that all of which he was conscious, was the mere series of affections of his own mind, and that beyond this consciousness he could know nothing.

Against the argument of one, who founds his very argument on his consciousness merely, and professes to have no knowledge either of little images, or of any thing else beyond his consciousness, it would be as idle to urge, that ideas are not little images in the mind, as it would have been for a Cartesian to attempt to confute the Newtonian system of attraction, by a denial of the Ptolemaic spheres.

All that remains, then, to supply the place of logical demonstration, which would be needless where the belief is as strong as that of demonstration itself, is the paramount force of this universal and irresistible belief; and there is no fear that this can be weakened by any argument, or be less felt by him who denies it, than by him who asserts it. We are conscious, indeed, only of the feelings that are the momentary states of our own mind; but some of these it is absolutely impossible for us not to ascribe to causes that are external, and independent of us; and the belief of a system of external things, is one of these very states of the mind, which itself forms, and will ever form, a part of the train of our consciousness. This Mr Hume himself, the great sceptic whom Dr Reid opposes, admits as readily as Dr Reid himself:--“A Copernican or Ptolemaic, who supports each his different system of astronomy, may hope to produce a conviction, which will remain constant and durable, with his audience. A Stoic or Epicurean displays principles, which may not only be durable, but which have an effect on conduct and behaviour. But a Pyrrhonian cannot expect, that his philosophy will have any constant influence on the mind: or, if it had, that its influence would be beneficial to society. On the contrary, he must acknowledge, if he will acknowledge any thing, that all human life must perish, were his principles universally and steadily to prevail. All discourse, all action, would immediately cease; and men remain in a total lethargy, till the necessities of nature, unsatisfied, put an end to their miserable existence. It is true, so fatal an event is very little to be dreaded. Nature is always too strong for principle; and, though a Pyrrhonian may throw himself, or others, into a momentary amazement and confusion by his profound reasonings, the first and most trivial event in life will put to flight all his doubts and scruples, and leave him the same, in every point of action and speculation, with the philosophers of every other sect, or with those who never concerned themselves in any philosophical researches. When he awakes from his dream, he will be the first to join in the laugh against himself.”[113] In what respect does this differ from the language of Dr Reid himself, when he says, that “the belief of a material world is older, and of more authority, than any principles of philosophy. It declines the tribunal of reason, and laughs at all the artillery of the logician.”[114] Surely, if it decline the tribunal of reason, it is not by reasoning that it is to be supported,--even though the reasoner should have the great talents which Dr Reid unquestionably possessed.

The sceptic, and the orthodox philosopher of Dr Reid's school, thus come precisely to the same conclusion. The creed of each, on this point, is composed of two propositions, and of the same two propositions; the first of which is, that the existence of a system of things, such as we understand when we speak of an external world, cannot be proved by argument; and the second, that the belief of it is of a force, which is paramount to that of argument, and absolutely irresistible. The difference, and the only difference is, that, in asserting the same two propositions, the sceptic pronounces the first in a loud tone of voice, and the second in a whisper,--while his supposed antagonist passes rapidly over the first, and dwells on the second, with a tone of confidence. The negation in the one case, and the affirmation in the other case, are, however, precisely the same. To him, indeed, who considers the _tone_ only, and not the _meaning_, there may seem to be a real strife of sentiment; but, if we neglect the tone, which is of no consequence, and attend to the meaning only of what is affirmed and denied by both, we shall not be able to discover even the slightest discrepancy. There is no argument of mere reasoning that can prove the existence of an external world; it is absolutely impossible for us not to believe in the existence of an external world. We may call these two propositions, then, a summary of the doctrine of Reid, or of the doctrine of Hume, as we please; for it is truly the common and equal doctrine of the two.

Though we have thus seen reason to deny to Dr Reid the merit commonly ascribed to him, on the points which we have been considering, relative to the theory of perception, I trust you will not on that account, be insensible to the merits which he truly possessed. _He_ knows little, indeed, of the human mind, who does not know, how compatible many errors and misconceptions are with the brightest and most active energies of intellect. On this “Isthmus of a middle State,” of which Pope speaks, man, though not “reasoning but to err,” is yet subject to occasional error, even in his proudest reasonings. With all his wisdom, he is still but “darkly wise;” and with all the grandeur of his being, but “rudely great.”

VISION.

Our inquiry into the nature of the sensations of _touch_,--or at least of those sensations, which are truly, and of others which are commonly, though, I think, falsely, ascribed to this organ, has led us into speculations, in the course of which I have been obliged to anticipate many remarks, that more peculiarly belong to the sense which still remains to be considered by us,--the sense of sight, that to which we owe so much of our most valuable information, with respect to nature, and so many of those pleasures, which the bounty of Him, who, has formed us to be happy, as well as to be wise, has so graciously intermingled, with all the primary means of our instruction.

The anticipations, into which I have been led, were necessary for throwing light on the subjects before considered, particularly on the complex feelings ascribed to touch,--the knowledge of which feelings, however, was still more necessary, for understanding fully the complex perceptions of this sense. It is thus scarcely possible, in science, to treat of _one_ subject, without considering it in relation to some other subject, and often to subjects between which, on first view, it would be difficult to trace any relation. Every thing throws light upon every thing,--though the reflection,--which is, in many cases, so bright, as to force itself upon common eyes--may, in other cases, be so faint, as to be perceptible only to eyes of the nicest discernment. It may almost be said, that there is an universal _affinity_ in _truths_,--like that universal attraction, which unites to each other, as one common system, the whole masses which are scattered through the infinity of space, and by which, as I have before remarked, the annihilation of a single particle of matter, in any one of these orbs,--however inconceivably slight its elementary modification might be of the general sum of attraction,--would in that very instant be productive of change throughout the universe. It is not easy to say, what any _one_ science would have been, if any other science had not existed. How different did Astronomy become, in consequence of the accidental burning of a few sea-weeds upon the sand, to which the origin of glass has been ascribed; and, when we think of the universal accessions, which navigation has made to every department of knowledge, what an infinity of truths may be considered as almost starting into existence, at the moment, when the polarity of the magnet was first observed!

“True to the pole, by thee the pilot guides
His steady helm, amid the struggling tides,
Braves with broad sail the unmeasurable sea,
Cleaves the dark air, and asks no star but thee.”[115]

The anticipations, which have been made, in the present instance, will be of advantage, in abridging much of the labour, which would have been necessary in treating of vision simply. I may now safely leave you, to make, for yourselves, the application of many arguments, on which I have dwelt at length, in treating of the other senses.

The organ of sight, as you well know, is the eye,--a machine of such exquisite and obvious adaptation to the effects produced by it, as to be, of itself, in demonstrating the existence of the Divine Being who contrived it, equal in force to many volumes of theology. The atheist, who has seen, and studied, its internal structure, and yet _continues an atheist_, may be fairly considered as beyond the power of mere argument to reclaim. The minute details of its structure, however, belong to the anatomist. It is enough for our purpose to know, that, by an apparatus of great simplicity, all the light, which, from every quarter strikes on the pellucid part of the ball of the eye,--and which if it continued to pass in the same direction, would thus produce one mingled and indistinct expanse of colour,--is so _refracted_, as it is termed, or bent from its former direction to certain focal points, as to be distributed again on the retina, in distinct portions, agreeing with the portions which come from each separate object, so exactly, as to form on it a miniature landscape of the scenery without. Nor is this all. That we may vary, at our pleasure, the field of this landscape, the ball of the eye is furnished with certain muscles, which enable us to direct it more particularly toward the objects which we wish to view; and according as the light which falls from these may be more or less intense, there are parts which minister to the sensibility of the eye, by increasing or diminishing in proportion the transparent aperture at which the light is admitted. There are, then, in this truly wonderful and beautiful process, in the first place, as determining what objects, in the wide scene around us, are to be visible at the moment, _the contraction of certain muscles_, on which the particular field of our vision depends, and which may almost be said to enable us to increase the extent of our field of vision, by enabling us to vary it at will;--in the second place, the _external light_, emitted from all the objects within this radiant field, which, on its arrival at the retina, is itself the direct object of vision; in the third place, the provision for increasing or diminishing the diameter of the pupil, in proportion to the quantity of that incident light;--in the fourth place, the _apparatus_, by which the dispersed rays of light are made to assume within the eye, the focal convergence necessary for distinct vision;--and lastly, the expansion of the optic nerve, as a part of the great sensorial organ, essential to sensation. The difference of the phenomena, produced by the varieties of the external light itself, is exhibited in almost every moment of our waking existence; and the diversities, arising from other parts of the process, are not less striking. There are peculiar diseases which affect the optic nerve, or other parts of the sensorial organ immediately connected with it,--there are other diseases which affect the refracting apparatus,--others which affect the iris, so as to prevent the enlargement or diminution of the pupil, when different quantities of light are poured on it,--others, which affect the muscles that vary the position of the ball,--and, in all these cases, we find, as might be expected, a corresponding difference of the phenomena.