Lecture Xxiv.

THE SAME SUBJECT, CONTINUED.

Gentlemen, having stated, in a former Lecture, the reasons which seem to show, that the origin of our notion of extension, and of the notions, which it involves, of figure, magnitude, divisibility, is not to be found in our sense of touch, I endeavoured, in my last Lecture, to trace these to their real source,--cautioning you at the same time, with respect to the great difficulty of the inquiry, and the very humble reliance, therefore, which we can have any title to put, on the results of our investigation of a subject so very obscure.

In our present circumstances, when we attempt such an investigation, it is impossible for us to derive even the slightest aid, from remembrance of our original feelings; since memory,--which afterwards can look back through so many long and busy years, and comprehend all of life, but the very commencement of it,--sees yet, in this dawn of being, a darkness which it cannot penetrate. We have already formed,--spontaneously, and without the aid of any one,--our little system of physical science, and have, in truth, enriched ourselves with acquisitions, far more important than any which we are afterwards to form, with all the mature vigour of our faculties, and all the splendid aids of traditionary philosophy,--at a time, when we seem scarcely capable of more than of breathing and moving, and taking our aliment, and when the faculties, that leave us so much invaluable knowledge, are to leave us no knowledge of the means, by which we have acquired it.

To the period of our first sensations, therefore, we cannot look back; and, hence, all which remains for us, in an inquiry of this kind, is to consider the circumstances in which the infant is placed, and to guess, as nearly as general analogy will allow us, the nature and the order of the feelings, which, in such circumstances, would arise, in a being possessing the powers and susceptibilities of man, but destitute of all the knowledge which man possesses.

In these first circumstances of life, the infant, of course, cannot know that he has a bodily frame, or a single organ of that frame, more than he can know, that there are other bodies in nature, that act upon his own; and we are not entitled to suppose,--however difficult it may be for us to accommodate our supposition to the true circumstances of the case,--that because we, the inquirers, know, that external bodies are pressing on his organ of touch, the little sensitive being is to have any knowledge, but of the mental affections, which these external bodies excite. How the knowledge of any thing more than his own mind is acquired, is, in truth, the very difficulty, which it is our labour to solve.

In conformity with this view, then,--when we look on the infant,--one of the most remarkable circumstances, which strike us, is its tendency to use its muscles, with almost incessant exercise, particularly the muscles of those parts, which are afterwards its principal organs of measurement. Its little fingers are continually closing and opening, and its little arms extending and contracting. The feelings, therefore,--whatever these may be,--which attend the progressive contraction of those parts,--and some feeling unquestionably attends the contraction in all its stages,--must be continually arising in its mind, beginning and finishing, in regular series, and varying exactly, with the quantity of the contraction.

A succession of feelings, however, when remembered by the mind, which looks back upon them, we found to involve, necessarily, the notion of divisibility into separate parts, and, therefore, of length, which is only another name for continued divisibility. Time, in short, is to our conception, a series in constant onward progress, and cannot be conceived by us, but as a progressive series, of which our separate feelings are parts; the remembrance of the events of our life, whenever we take any distant retrospect of them, being like the remembrance of the space, which we have traversed in a journey,--an indistinct continuity of length, as truly divisible, in our conception, into the separate events which we remember, as the space, which we remember to have traversed, into its separate variety of scenes.

Time, then, or remembered succession, we found to involve, not metaphorically, as is commonly said, but truly and strictly, in its very essence, the notions of length and divisibility,--the great elements of extension; and whatever other feelings may be habitually and uniformly associated with these, will involve, of course, these elementary notions.

The series of muscular feelings, of which the infant is conscious,--in incessantly closing and opening his little hand,--must, on these principles, be accompanied with the notion,--not, indeed, of the existence of his hand, or of any thing external,--but of a certain length of succession; and each stage of the contraction, by frequent renewal, gradually becomes significant of a particular length, corresponding with the portion of the series. When any hard body, therefore, is placed in the infant's hand,--though he cannot, indeed, have any knowledge of the object, or of the hand,--he yet feels, that he can no longer perform the accustomed contraction,--or, to speak more accurately,--since he is unacquainted with any parts that are contracted, he feels, that he can no longer produce his accustomed series of feelings; and he knows the quantity of contraction, which remained to be performed, or rather the length of the series, which remained to be felt. The place of this remaining length is now supplied by a new feeling, partly muscular, and partly the result of the affection of the compressed organ of touch,--and is supplied by the same feeling, at the same point of the series, as often, as he attempts to renew the contraction, while the body remains within his hand. The tactual feeling, therefore,--whatever it may be,--becomes, by this frequent repetition, associated with the notion of that particular progressive series, or length, of which it thus uniformly supplies the place; and at last becomes representative of this particular length, precisely in the same manner, as, in the acquired perceptions of vision, certain shades of colour become representative of distance, to which they have, of themselves, no resemblance or analogy, whatever; and we thus learn to feel length, as we learn to see length,--not directly by the mere affections of our tactual or visual organs, but by the associated notions which they suggest.

If time,--as perceived by us in the continued series of our feelings,--do involve conceptual length and divisibility, it seems, indeed, scarcely possible, that, in the circumstances supposed, the notions supposed should not arise,--that the infant should be conscious of a regular series of feelings, in the contraction of its fingers and arms, and yet that portions of this series should not become significant of various proportional lengths;--and, if the notion of certain proportional lengths do truly accompany certain degrees of progressive contraction, it seems equally impossible, according to the general principles of our mental constitution, that the compound tactual and muscular feeling, which must arise in every case, in which any one of these degrees of contraction is impeded, should not become associated with the notion of that particular length, of which it supplies the place, so as at last to become truly representative of it.

In this manner, I endeavoured to explain to you, how our knowledge of the mere length of bodies may have been acquired, from varieties of length that are recognized as coexisting and proximate, and are felt to unite, as it were, and terminate in our sensation of resistance, which interrupts them equally, and interrupts always a greater number of the coexisting truths, in proportion to the size of the body compressed; and, in a similar manner, our notions of the other dimensions of bodies, which are only these varieties of length in different directions. I cannot conclude this summary, however, without recalling to your attention, a very simple experiment, which I requested you to make for yourselves,--an experiment, that, even in the unfavourable circumstances in which it must now be tried, is yet, I conceive, demonstrative of the influence of mere time, as an element of that complex notion, which we have been examining, when the more rapid measurements of vision,--which are confessedly not original but acquired,--are excluded. If, in passing our finger, with different degrees of slowness or rapidity, along the same surface, with our eyes shut,--even though we should previously know the exact boundaries of the extent of surface,--we feel it almost impossible not to believe,--and but for the contrary evidence of vision, could not have hesitated a single moment in believing,--that this extent is greater or less, according as the time employed in performing exactly the same quantity of motion, with exactly the same force of pressure, on the same quantity of our organ of touch, may have been greater or less,--it must surely be admitted, that the notion of the length, which thus uniformly varies with the time, when all other circumstances are the same, is not absolutely independent of the time,--or it must, in like manner, be believed, that our notion of visual distance, which varies with the distribution of a few rays of light on the small expanse of the optic nerve, is yet independent of those faint shades of colouring, according to the mere varieties of which, it seems at one time to lay open to our view a landscape of many miles, and at another time to present to us, as it were before our very eyes, an object of scarcely an inch in diameter. The greater dimness, and diminished size of a few objects in the back ground of a picture, which is in itself one coloured plane of light, does not more truly seem to increase the line of distance of those objects, than, in the other case, the increased slowness of the motion of our hand along any surface, seems to lengthen the line which separates one of its boundaries from the other.

That we now seem to perceive extension, immediately by touch, cannot be denied; and, in a case so obscure as this,--with our very limited knowledge, and our very limited power of adding to this knowledge,--it may seem the most prudent, and perhaps even the most suitable,--as it is, without all question, by far the easiest part,--to acquiesce in the opinion, that the perception, which now seems immediate, was so originally,--that the belief of the presence of an external figured body, is, by the very constitution of our nature, attached to a certain affection of the mere organ of touch. But, since there are circumstances,--as we have seen,--which show this opinion, when very nicely examined, to be inadmissible, we may, at least, attempt to proceed a little farther, if we do this with a sufficient sense of the very great difficulty of the attempt, in relation to our power and knowledge, and consequently with a very humble assurance, as to the certainty of any opinion which we may be led to form. To know the mind well, is to know its weaknesses as well as its powers; and it is precisely in a case of this sort, that he, whose knowledge is least imperfect, will be the best judge of its imperfection, and, therefore, the least disposed to put complete reliance on it in his own speculations,--or to assert it dogmatically, when he offers it, as all opinions, on so very obscure a subject, should be offered, to the inquiry, rather than to the undoubting assent.

The analysis, I own, is one which must require a considerable effort of attention on your part, because it is truly one of the most subtile on which I could call you to enter. But you must be aware, that this subtlety is in the nature of the very inquiry itself; since it is an inquiry into the elements and progressive growth of feelings, which seem to us, at present, simple and immediate, and that the alternatives, therefore, are not those of greater or less subtlety and refinement of analysis, but of attempting the analysis, or abandoning it altogether.

Before proceeding farther, in our inquiry with respect to the origin of the notion of extension, it may, however, be of advantage, to take a short retrospect of the progress which we have already made; for, if we have found nothing more, we have, at least, as I conceive, found reason to reject a considerable part of our former belief on the subject, which, though a negative acquisition, is yet a very important one. Though we should not be able to discover the true source of the notion which we seek, it is something, at least, to know, that we have little reason to expect to find it, where we have uniformly been accustomed to seek it.

In the first place, then, we have seen the fallacy of the supposition, that our knowledge of extension may be easily accounted for, by the similarity in figure of the compressed part of the organ of touch to the compressing body, since the notion of extension is not a state of the material organ, compressed and figured, which, as mere matter, however exquisitely organized, is as little capable of this notion, as of smell, or taste, love or aversion, but, a state of the mind itself, which is susceptible of shape or pressure, being as little square, when it perceives a square, as when it perceives a circle; and any affection of which, therefore, may be supposed as much to follow any one shape, as any other shape of the mere external organ. If, indeed, as this explanation most strangely seems to assume, we could be supposed to have any previous knowledge of the shape of our organ of touch, nothing more would be necessary, for we should then have a perfect knowledge of extension, though no other extended body but our own organ of touch were in existence. To refer us to the organ is, however, only to bring the very same difficulty one step nearer, since previously to the application of an external body, the mind has as little knowledge of the shape of its organ of touch, as it has of the body compressing it; and it is manifestly most absurd, to ascribe the origin of our knowledge of extension, to our knowledge of the resemblance in figure of an external body to our organ; since this very knowledge of the resemblance must imply the previous knowledge of the figure of both, and consequently of that very extension, which, according to this supposition, must be known to us BEFORE it is known.

In the second place, we have seen, that, if the configuration of the sensorial organ were the only circumstance necessary, to induce, immediately, in mind, the notion of figure, this notion should accompany every sensation of every kind; the smell of a rose, for example, as much as the pressure of a cube or a sphere: for the nervous expansion, in the organ of smell, and in every other organ, is of a certain figure, before sensation, during sensation, and after sensation, as much as the nervous expansion of the organ of touch. And, though we were to confine ourselves wholly to this organ, the nervous matter in it is, at all times, of a certain shape, as much when there is no pressure on it, as when it is exposed to such pressure; yet the mere figure of the organ of touch, is not then accompanied with the mental notion of its figure; nor is this the case, merely when the sense is quiescent, but, in many cases, in which it is affected in the most lively manner; as, for example, when we are exposed to great cold or heat, in which cases, the shape of this very tactual organ, thus strongly affected, is as much unperceived by us, as when there is no affection of it whatever.

Lastly, which is a point of much more importance, because it has relation to the only philosophic view of touch, as the immediate organ of extension; the view, in which the mere configuration of the compressed organ, as similar to that of the compressing body, is laid out of account, and the immediate belief of extension is supposed to depend on the original constitution of the mind, by which its affections have been arranged, so as to correspond with certain affections of the bodily organs; the mental state which constitutes the perception of a square, arising immediately when the organ of touch is affected, in a certain manner, as that mental state which constitutes the sensation of the fragrance of a rose, arises immediately, when the organ of smell is affected, in a certain manner; this opinion too, philosophic as it is, compared with those which we before considered, though, in truth, it only assumes the point in question, without attempting to solve any difficulty, supposed to be connected with it, we have yet found to be as little tenable, as the opinions that suppose the mental notion of figure to depend on the peculiar figure of the compressed material organ. The consideration which, as I stated in my last Lecture, seems to me decisive on this point, is, that, if touch inform us of extension immediately, as smell informs us of fragrance, sight of colour, and hearing of sound; it must do this in every instance, without relation to particular figure, as smell, sight, and hearing, extend to all odours, hues, and sounds; for it would certainly be, as I said, a very strange abuse of the license of supposition, to imagine that we perceive a square immediately by touch, but not a circle; or a circle, but not a square; or any one figure, but not any other figure. In short, if figure be the direct primary object of touch, as sight is of vision, we should feel immediately every form impressed, as we see immediately every colour. It is only when the figures are very simple and regular, however, such as we might be supposed to have easily learned, in the same manner as we learn, visually, to judge of distances, that we are able to discover them, as it were, immediately, by touch; and, even when we are able, in this manner, to determine the species of figure, that is to say, the mere outline of a body, we are rarely able to determine the exact magnitude which that outline comprehends; yet, as our organ must be affected by each part of the compressing surface, by the central parts, as much as by the exterior parts which form its outline, and by these, as much as by the central parts; and as every feeling which the organ directly affords, must be immediate, when there is no change of the position, or other circumstances of the object, that might vary the sensation, we should, if mere touch communicated to us the knowledge supposed, be able to determine, exactly and instantly, the magnitude and figure; or, it is evident, that the determination of magnitude and figure must depend wholly, or in part, on something that is different from touch. The magnitude we are far from being able to discover exactly, even of simple figures; and when the form is very irregular, and we know nothing more, than that a certain body is pressed against our hand,--the magnitude and figure are alike difficult to be discovered; so difficult, that I may safely say, that no one, who makes the experiment, will find, on opening his eyes, that his tactual or intellectual measurement has, in any one case, been exact, or his notion of the figure half so distinct as it now is, after a single glance. Can we then think that it is by mere touch we discover figure, as exactly as by the glance of our mature vision,--that we discover it, in all its varieties, originally by touch, and as accurately at first, as after innumerable trials,--when we discover it, only in a few cases, that are previously familiar to us, and even in these very imperfectly? The determination of the form impressed, in which we are almost conscious of a sort of intellectual measurement, has surely a much greater resemblance to the perceptions, which we term acquired, than to those which are immediate. In vision, for example, when the original power of that sense has been strengthened and enriched, by the acquisitions which it is capable of receiving from other sources, we see a long line of distance before us; and the small distances with which we are familiar, we distinguish with sufficient accuracy; but, in our visual measurement of greater distances, we are almost certain to err, taking often the less for the greater, and the greater for the less. It is precisely the same in touch. When a small body, which we have never seen, is pressed upon our hand, we are able, if its surface be square, or circular, or of any other form, with which we are well acquainted, to determine its figure, without much hesitation; because we have learned, tactually, to distinguish these regular figures. But, in endeavouring to determine, in this manner, by touch alone, the figure of any irregular body, less familiar to us, though, as a direct object of sense, if touch be the sense of figure, it should be equally and as immediately tangible as the most regular form, we feel a hesitation of the same sort, as when we attempt to ascertain by our eye, the exact distance of a remote object. To know extension or figure, is to know, not one point merely in the surface of a body, but many continuous points; and if, when the surface, is circular, we know these continuous points, and their relation to each other, immediately on pressure, we must know, as immediately, the same points and their relations, though the surface comprehending them, instead of being circular, should be of an outline more irregular. We certainly cannot know this irregular surface to have any extension at all, unless we know some parts of it; and, when the pressure is uniform from every point, and the organ of touch uniform, on which the pressure is made, it would be absurd to suppose, that we know fifty, or eighty, of the hundred points which form the impressing surface, but cannot determine its figure, because we are ignorant of the twenty of fifty remaining points; when these remaining points are acting on our organ of touch, in exactly the same manner as the fifty or eighty which we know, and when, if the surface containing merely the same number of points, had been circular, or of any other single form, as familiar to us, the whole hundred points would have been known to us equally and at once.

When our perceptions of form, then, are so various and irregular, and are more or less quick and precise, exactly as the shape which we endeavour to determine, has more or less resemblance to shapes that are familiar to us, it does not seem too bold an inference to conclude, that the knowledge of figure, which, as all extension that is capable of being perceived by us, must have some boundary, is nothing more than the knowledge of extension, is not the state of mind originally and immediately subsequent to affections of our organs of touch, any more than the perception of distance is the state of mind originally and immediately subsequent to affections of our organ of sight; and the very striking analogy of these two cases, it will be of great importance for you to have constantly in view; as it will render it less difficult for you to admit many circumstances, with respect to touch, which you might otherwise have been slower to conceive. That we should seem to perceive extension immediately by touch, though touch originally, and of itself, could not have afforded this perception, will not then appear more wonderful, than the apparently immediate perception of distance by the eye, which, of itself, originally afforded us no perception of that sort; nor the impossibility of feeling a body, without the notion of it, as extended, be more wonderful than the similar impossibility of separating colour from extension, in the case of distant vision. Above all, the analogy is valuable, as shewing the closeness and indissolubleness of the union, which may be formed of feelings that have in themselves no resemblance. What common properties, could we have conceived in vision, and that absolute blindness, which has never had a single sensation from light! and, yet, it is worthy of remark, that the perceptions of the blind, in consequence of this singular power of association, form truly the most important part of those very perceptions of vision, of which, as a whole, they are unfortunately deprived. We do not merely see with our eyes, what we may have felt with our hands; but our eyes, in the act of vision, have borrowed, as it were, those very sensations.

The proof, that our perception of extension by touch, is not an original and immediate perception of that sense, is altogether independent of the success of any endeavour which may be made, to discover the elements of the compound perception. It would not be less true, that touch does not afford it, though we should be incapable of pointing out any other source, from which it can be supposed to be derived. Of the difficulty of the attempt, and the caution with which we should venture to form any conclusion on the subject, I have already spoken. But the analysis, difficult as it is, is too interesting not to be attempted, even at the risk, or perhaps I should rather say, with the very great probability, of failure.

In such an analysis, however, though we are to proceed with the greatest caution, it may be necessary to warn you, that it is a part of this very caution, not to be easily terrified, by the appearance of paradox, which the result of our analysis may present. This appearance we may be certain, that any analysis which is at all accurate must present, because the very object of the analysis is to shew, that sensations, which appear simple and direct, are not simple,--that our senses, in short, are not fitted, of themselves, to convey that information, which they now appear, and through the whole course of our memory have appeared to us instantly to convey. It is very far, indeed from following, as a necessary consequence, that every analysis of our sensations which affords a paradoxical result, is, therefore, a just one--for error may be extravagant in appearance as well as in reality. But it may truly be regarded as a necessary consequence, that every accurate and original analysis of our sensations must afford a result, that, as first stated, will appear paradoxical.

To those who are wholly unacquainted with the theory of vision, nothing certainly can seem, as first stated, more absurd than the assertion, that we see, not with our eyes merely, but chiefly by the medium of another organ, which the blind possess in as great perfection as ourselves, and which, at the moment of vision, may perhaps be absolutely at rest. It must not surprise you, therefore, though the element which seems to me to form the most important constituent of our notion of extension should in like manner, as first stated to you, seem a very unlikely one.

This element is our feeling of succession, or time--a feeling, which necessarily, involves the notion of divisibility or series of parts, that is so essential a constituent of our more complex notion of matter,--and to which notion of continuous divisibility, if the notion of resistance be added, it is scarcely possible for us to imagine, that we should not have acquired, by this union, the very notion of physical extension,--that which has parts, and that which resists our effort to grasp it.

That memory is a part of our mental constitution, and that we are thus capable of thinking of a series of feelings, as successive to each other, the experience of every moment teaches us sufficiently. This succession frequently repeated, suggests immediately, or implies the notion of length, not metaphorically, as is commonly said, but as absolutely as extension itself: and, the greater the number of the successive feelings may have been, the greater does this length appear. It is not possible for us to look back on the years of our life, since they form truly a progressive series, without regarding them as a sort of length, which is more distinct indeed, the nearer the succession of feelings may be to the moment at which we consider them, but which, however remote, is still felt by us as one continued length, in the same manner, as when, after a journey of many hundred miles, we look back, in our memory, on the distance over which we have passed, we see, as it were, a long track of which some parts, particularly the nearer parts, are sufficiently distinct, but of which the rest seems lost in a sort of distant obscurity. The line of our long journeying--or, in other words, that almost immeasurable line of plains, hills, declivities, marshes, bridges, woods,--to endeavour to comprehend which in our thought, seems an effort as fatiguing as the very journey itself--we know well, can be divided into those various parts:--and, in like manner, the progressive line of time--or, in other words, the continued succession, of which the joy, the hope, the fragrance, the regret, the melody, the fear, and innumerable other affections of the mind, were parts, we feel that we can mentally divide into those separate portions of the train. Continuous length and divisibility, those great elementary notions of space, and of all that space contains, are thus found in every succession of our feelings. There is no language in which time is not described as long or short,--not from any metaphor--for no mere arbitrary metaphor can be thus universal, and inevitable, as a form of human thought--but because it is truly impossible for us to consider succession, without this notion of progressive divisibility attached to it: and it appears to us as absurd to suppose, that by adding, to our retrospect of a week, the events of the month preceding, we do not truly lengthen the succession, as it would be to suppose, that we do not lengthen the line of actual distance, by adding, to the few last stages of a long journey, the many stages that preceded it.

It is this spreading out of life into a long expanse, which allows man to create, as it were, his own world. He cannot change, indeed, the scene of external things. But this may be said, in one sense, to be the residence only of his corporeal part. It is the moral scene in which the spirit truly dwells; and this adapts itself, with harmonious loveliness, or with horror as suitable, to the character of its pure or guilty inhabitant. If but a single moment of life,--a physical point, as it were, of the long line--could be reviewed at once, conscience would have little power of retribution. But he who has lived, as man should live, is permitted to enjoy that best happiness which man can enjoy,--to behold, in one continued series, those years of benevolent wishes or of heroic suffering, which are at once his merit and his reward. He is surrounded by his own pure thoughts and actions, which, from the most remote distance, seem to shine upon him wherever his glance can reach; as in some climate of perpetual summer, in which the inhabitant sees nothing but fruits and blossoms, and inhales only fragrance, and sunshine, and delight. It is in a moral climate as serene and cloudless, that the destined inhabitant of a still nobler world moves on, in that glorious track, which has heaven before, and virtue and tranquillity behind;--and in which it is scarcely possible to distinguish, in the immortal career, when the earthly part has ceased, and the heavenly begins.

Is it in metaphor only, that a youth and maturity, and old age of guilt, seem to stretch themselves out in almost endless extent, to that eye which, with all its shuddering reluctance, is still condemned to gaze on them,--when, after the long retrospect seems finished, some fraud, or excess, or oppression, still rises and adds to the dreadful line--and when eternity itself, in all the horrors which it presents, seems only a still longer line of the same dreadful species, that admits of no other measure, than the continued sufferings, and remembrance, and terrors that compose it!

It is a just and beautiful observation of an ancient Stoic, that time which is past is like something consecrated to the gods, over which fortune and mortality have no longer any power, and that, dreadful as it must be to the wicked, to whom their own memory is an object of terror, it still, to the virtuous, offers itself as a consolation or joy--not in single moments like the present hour, but in all that long series of years which rises before us, and remains with us at our bidding. “Ille qui multa ambitiosè cupiit, superbè contempsit, insidiosè decepit, avarè rapuit, prodigè effudit,--necesse est memoriam suam timeat. Atqui hæc est pars temporis nostri sacra ac dedicata, omnes humanos casus supergressa, extra regnum fortunæ subducta; quam non inopia, non metus, non morborum incursus exagitat. Hæc nec turbari nec eripi potest; perpetua ejus et intrepida possessio est. Singuli tantùm dies, et hi per momenta, præsentis sunt: at præteriti temporis omnes, cum jusseris aderunt, ad arbitrium tuum se inspici ac detineri patientur.”

By those, who can look back on years that are long past, and yet say, that the continued progress, or the length and the shortness of time, are only metaphorical expressions, it might be said with equal justness, that the roundness of a sphere, is a metaphor, or the angularity of a cube. We do not more truly consider the one as angular and the other as round, than we consider the time to be continuously progressive, in which we considered, first the one figure, and then the other, and inquired into the properties of each. That which is progressive must have parts. Time, or succession, then involves the very notions of longitudinal extension and divisibility, and involves these, without the notion of any thing external to the mind itself;--for though the mind of man had been susceptible only of joy, grief, fear, hope, and the other varieties of internal feeling, without the possibility of being affected by external things, he would still have been capable of considering these feelings, as successive to each other, in a long continued progression, divisible into separate parts. The notions of length, then, and of divisibility, are not confined to external things, but are involved, in that very memory, by which we consider the series of the past,--not in the memory of distant events only, but in those first successions of feeling, by which the mind originally became conscious of its own permanence and identity. The notion of time, then, is precisely coeval with that of the mind itself; since it is implied in the knowledge of succession, by which alone, in the manner formerly explained to you, the mind acquires the knowledge of its own reality, as something more than the mere sensation of the present moment.

Conceiving the notion of time, therefore, that is to say of feelings past and present, to be thus one of the earliest notions which the infant mind can form, so as to precede its notions of external things, and to involve the notions of length and divisibility, I am inclined to reverse exactly the process commonly supposed; and, instead of deriving the measure of time from extension, to derive the knowledge and original measure of extension from time. That one notion or feeling of the mind may be united indissolubly with other feelings, with which it has frequently coexisted, and to which, but for this coexistence, it would seem to have no common relation, is sufficiently shown by those phenomena of vision to which I have already so frequently alluded.

In what manner, however, is the notion of time peculiarly associated with the simple sensation of touch, so as to form, with it, the perception of extension? We are able, in the theory of vision, to point out the coexistence of sensations which produce the subsequent union; that renders the perception of distance apparently immediate. If a similar coexistence of the original sensations of touch, with the notion of continued and divisible succession, cannot be pointed out in the present case, the opinion which asserts it, must be considered merely as a wild and extravagant conjecture.

The source of such a coexistence is not merely to be found, but is at least as obvious, as that which is universally admitted in the case of vision.

Before I proceed, however, to state to you, in what way I conceive the notion to be acquired, I must again warn you of the necessity of banishing, as much as possible, from your view of the mind of the infant in this early process, all those notions of external things, which we are so apt to regard as almost original in the mind, because we do not remember the time, when they arose in our own. As we know well, that there are external things, of a certain form, acting on our organs, which are also of a certain form, it seems so very simple a process, to perceive extension--that is to say, to know that there exist without us those external forms, which really exist--that to endeavour to discover the mode, in which extension, that now appears so obvious a quality of external things, is perceived by us, seems to be a needless search, at a distance, for what is already before our very eyes. And it will be allowed, that all this would, indeed, be very easy to a mind like ours, after the acquisitions of knowledge which it has made; but the difficulty of the very question is, how the mind of the infant makes these acquisitions, so as to become like ours. You must not think of a mind, that has any knowledge of things external, even of its own bodily organs, but of a mind simply affected with certain feelings, and having nothing but these feelings to lead it to the knowledge of things without.

To proceed, then,--The hand is the great organ of touch. It is composed of various articulations, that are easily moveable, so as to adapt it readily to changes of shape, in accommodation to the shape of the bodies which it grasps. If we shut our hand gradually, or open it gradually, we find a certain series of feelings, varying with each degree of the opening or closing, and giving the notion of succession of a certain length. In like manner, if we gradually extend our arms, in various directions, or bring them nearer to us again, we find that each degree of the motion is accompanied with a feeling that is distinct, so as to render us completely conscious of the progression. The gradual closing of the hand, therefore, must necessarily give a succession of feelings,--a succession, which, of itself, might, or rather must, furnish the notion of length, in the manner before stated, the length being different, according to the degree of the closing; and the gradual stretching out of the arm gives a succession of feelings, which, in like manner, must furnish the notion of length,--the length being different according to the degree of the stretching of the arm. To those who have had opportunities of observing infants, I need not say, how much use, or rather what constant use, the future inquirer makes of his little fingers and arms; by the frequent contraction of which, and the consequent renewal of the series of feelings involved in each gradual contraction, he cannot fail to become so well acquainted with the progress, as to distinguish each degree of contraction, and, at last, after innumerable repetitions, to associate with each degree the notion of a certain length of succession. The particular contraction, therefore, when thus often repeated, becomes the representative of a certain length, in the same manner as shades of colour, in vision become ultimately representative of distance,--the same principle of association, which forms the combination in the one case, operating equally in the other.

In these circumstances of acquired knowledge,--after the series of muscular feelings, in the voluntary closing of the hand, has become so familiar, that the whole series is anticipated and expected, as soon as the motion has begun,--when a ball, or any other substance, is placed for the first time in the infant's hand, he feels that he can no longer perform the usual contraction,--or, in other words, since he does not fancy that he has muscles which are contracted, he feels that the usual series of sensations does not follow his will to renew it,--he knows how much of the accustomed succession is still remaining; and the notion of this particular length, which was expected, and interrupted by a new sensation, is thus associated with the particular tactual feeling excited by the pressure of the ball,--the greater or less magnitude of the ball preventing a greater or less portion of the series of feelings in the accustomed contraction. By the frequent repetition of this tactual feeling, as associated with that feeling, which attends a certain progress of contraction, the two feelings at last flow together, as in the acquired perceptions of vision; and when the process has been repeated with various bodies innumerable times, it becomes, at last, as impossible to separate the mere tactual feeling, from the feeling of length, as to separate the whiteness of a sphere, in vision, from that convexity of the sphere, which the eye, of itself, would have been forever incapable of perceiving.

As yet, however, the only dimension of the knowledge, of which we have traced the origin, is mere length; and it must still be explained, how we acquire the knowledge of the other dimensions. If we had had but one muscle, it seems to me very doubtful, whether it would have been possible for us, to have associated with touch any other notion than that of mere length. But nature has made provision, for giving us a wider knowledge, in the various muscles, which she has distributed over different parts, so as to enable us to perform motions in various directions at the same instant, and thus to have coexisting series of feelings, each of which series was before considered as involving the notion of length. The infant bends one finger gradually on the palm of his hand; the finger, thus brought down, touches one part of the surface of the palm, producing a certain affection of the organ of touch, and a consequent sensation; and he acquires the notion of a certain length, in the remembered succession of the muscular feelings during the contraction:--he bends another finger; it, too, touches a certain part of the surface of the palm, producing a certain feeling of touch, that coexists and combines, in like manner, with the remembrance of a certain succession of muscular feelings. When both fingers move together, the coexistence of the two series of successive feelings, with each of which the mind is familiar, gives the notion of coexisting lengths, which receive a sort of unity, from the proximity in succession of the tactual feelings in the contiguous parts of the palm which they touch,--feelings, which have before been found to be proximate, when the palm has been repeatedly pressed along a surface, and the tactual feelings of these parts, which the closing fingers touch at the same moment, were always immediately successive,--as immediately successive, as any of the muscular feelings in the series of contraction. When a body is placed in the infant's hand, and its little fingers are bent by it as before, sometimes one finger only is impeded in its progress, sometimes two, sometimes three,--and he thus adds to the notion of mere length, which would have been the same, whatever number of fingers had been impeded, the notion of a certain number of proximate and coexisting lengths, which is the very notion of breadth; and with these, according as the body is larger or smaller, is combined always the tactual affection produced by the pressure of the body, on more, or fewer, of the interior parts of the palm, and fingers, which had before become, of themselves, representative of certain lengths, in the manner described; and the concurrence of these three varieties of length, in the single feeling of resistance, in which they all seem to meet, when an incompressible body is placed within the sphere of the closing fingers,--however rude the notions of concurring dimensions may be, or rather must be, as at first formed,--seems at least to afford the rude elements, from which, by the frequent repetition of the feeling of resistance, together with the proximate lengths, of which it has become representative, clearer notions of the kind may gradually arise.

The progressive contractions of the various muscles which move the arms, as affording similar successions of feelings, may be considered in precisely the same light, as sources of the knowledge of extension; and, by their motion in various directions, at the same time with the motion of the fingers, they concur powerfully, in modifying, and correcting, the information received from these. The whole hand is brought, by the motion of the arm, to touch one part of the face or body; it is then moved, so as to touch another part, and, with the frequent succession of the simple feelings of touch, in these parts, is associated the feeling of the intervening length, derived from the sensations that accompanied the progressive contraction of the arm. But the motion is not always the same; and, as the same feeling of touch, in one part, is thus followed by various feelings of touch in different parts, with various series of muscular feelings between, the notion of length in various directions, that is to say, of length in various series commencing from one power, is obtained in another way. That the knowledge of extension, or in other words, the association of the notion of succession with the simple feelings of touch, will be rude and indistinct at first, I have already admitted; but it will gradually become more and more distinct and precise: as we can have no doubt, that the perception of distance by the eye, is, in the first stages of visual association, very indistinct, and becomes clearer after each repeated trial. For many weeks or months, all is confusion in the visual perceptions, as much as in the tactual and muscular. Indeed, we have abundant evidence of this continued progress of vision, even in mature life, when, in certain professions that require nice perceptions of distance, the power of perception itself, by the gradual acquisitions which it obtains from experience, seems to unfold itself more and more, in proportion to the wants that require it.

The theory of the notion of extension, of which I have now given you but a slight outline, might, if the short space of these Lectures allowed sufficient room, be developed with many illustrations, which it is now impossible to give to it. I must leave you, in some measure, to supply these for yourselves.

It may be thought, indeed, that the notion of time, or succession, is, in this instance, a superfluous incumbrance of the theory, and that the same advantage might be obtained, by supposing the muscular feelings themselves, independently of the notion of their succession, to be connected with the notion of particular lengths. But this opinion, it must be remarked, would leave the difficulty precisely as before; and sufficient evidence in confutation of it, may be found in a very simple experiment, which it is in the power of any one to make. The experiment I cannot but consider as of the more value, since it seems to me,--I will not say decisive, for that is too presumptuous a word,--but strongly corroborative of the theory, which I have ventured to propose; for it shows, that, even after all the acquisitions, which our sense of touch has made, the notion of extension is still modified, in a manner the most striking and irresistible, by the mere change of accustomed time. Let any one, with his eyes shut, move his hand, with moderate velocity, along a part of a table, or any other hard smooth surface, the portion, over which he presses, will appear of a certain length; let him move his hand more rapidly, the portion of the surface pressed will appear less; let him move his hand very slowly, and the length, according to the degree of the slowness, will appear increased, in a most wonderful proportion. In this case, there is precisely the same quantity of muscular contraction, and the same quantity of the organ of touch compressed, whether the motion be rapid, moderate, or slow. The only circumstance of difference is the time, occupied in the succession of the feelings; and this difference is sufficient to give complete diversity to the notion of length.

If any one, with his eyes shut, suffer his hand to be guided by another, very slowly along any surface unknown to him, he will find it impossible to form any accurate guess as to its length. But it is not necessary, that we should be previously unacquainted with the extent of surface, along which the motion is performed; for the illusion will be nearly the same, and the experiment, of course, be still more striking, when the motion is along a surface with which we are perfectly familiar, as a book which we hold in our hand, or a desk at which we are accustomed to sit.

I must request you, not to take for granted the result which I have now stated, but to repeat for yourselves an experiment, which it is so very easy to make, and which, I cannot but think is so very important, as to the influence of mere difference of time, in our estimation of longitudinal extent. It is an experiment, tried, unquestionably, in most unfavourable circumstances, when our tactual feelings, representative of extension, are so strongly fixed, by the long experience of our life; and yet, even now, you will find, on moving your hand, slowly and rapidly, along the same extent of surface, though with precisely the same degree of pressure in both cases, that it is as difficult to conceive the extent, thus slowly and rapidly traversed, to be the same, as it is difficult to conceive the extent of visual distance to be exactly the same, when you look alternately through the different ends of an inverted telescope. If when all other circumstances are the same, the different visual feelings, arising from difference of the mere direction of light, be representative of length, in the one case,--the longer or shorter succession of time, when all other circumstances are the same, has surely as much reason to be considered as representative of it, in the other case.

Are we, then, to believe, that the feeling of extension, or, in other words, of the definite figure of bodies, is a simple feeling of touch, immediate, original, and independent of time; or is there not rather reason to think, as I have endeavoured to show, that it is a compound feeling, of which time, that is to say, our notion of succession, is an original element?