SECTION VI.

142

It is necessary to take notice of this term, because the idea which is named by it is apt to present the appearance of something mysterious, though, after the expositions with which we are now familiar, the materials of which it is compounded, will not be difficult to find.

The word Motion, is the abstract of Moving. What we have to investigate, therefore, are the sensations, on account of which, we call a body â€œmoving;â€ motion being merely moving, the connotation dropped.

All motion is in a Line, either a straight line, or some other line. The idea of â€œmoving,â€ therefore, contains, for one ingredient, the idea of a line.

A body â€œmoving,â€ is a body which is successively at every point of a line. Every point of a line, as we have seen, is a particular position. A body â€œmoving,â€ therefore, is a body first in one position, then in another, then in another, through a certain series.

In the idea of a Body moving, then, we can enumerate the following particulars: the idea of a body, the idea of a position, the idea of a line, the idea of succession. These are all complex ideas; some of them highly complex; united into one idea, motion, they compose one of the most complex of all our143ideas. The ingredients, however, being already explained, there can be no great difficulty in understanding the compound.

It is commonly said, that motion includes the idea both of Space, and of Time. As it includes the idea of Succession, it includes the idea of Time, successions in the abstract (otherwise called instants), without end, receiving the name of Time. As it includes the idea of a Line, it includes the idea of extension in one direction. As it includes the idea of Position, which is that of lines, in every direction, it includes the idea of extension in every direction; but extension in every direction, taken abstractly, is Space.

It is important to observe, that, though we receive, and that the most frequently, information of motions by the eye, it is not from the sensations of sight, that the idea of motion is derived. It is by association of ideas alone, that we fancy we see motion, as it is thence we fancy that we see figure, and distance. The classes of sensations, from which we derive the idea of motion, and the idea of extension, are the same; they are the muscular and tactual sensations. The man born blind, is not without the idea of motion, as he is without that of colour; on the contrary, he has the idea probably much more precise, than we who have entangled it inextricably with the perceptions of sight.

To recur to the exposition which we have already given; we may remember, that the sensations (taking the simplest case), on account of which we apply the name Line, are partly sensations of Touch, partly sensations of Muscular Action. If we touch a line at one point with any part of our bodies, say the finger; so long as the finger is still, we have merely the144sensations, on account of which we call the line tangible. As soon as we move the finger along the line, we have the sensations and ideas, on account of which we call it extended. But these new feelings, on account of which we call the line extended, are also the feelings, on account of which we call the finger moved. The sensations, therefore, whence we derive our ideas of extension, and of motion, exist simultaneously. We have a certain compound of feelings, partly sensations, and partly ideas; for we have already seen, that the perception of succession consists in a present sensation, associated with the idea of a past one; and we assign to this compound, not one name, as on other occasions, but two names, after a very peculiar and remarkable manner. These two names are, Line Extended, Finger Moved. The complication of the feelings here, and of course the obscurity of them, is very remarkable; though the naming, as in certain other cases of obscure ideas, is very distinct. We are never misled in the application of the terms, Line Extended, Finger moved; though we may be very much puzzled to shew, of the compound of feelings which are thus named, and which, in the compound, are easily, and infallibly traced, how much is included under the one term, and how much under the other. A certain portion of the sensations in the compound is peculiar to what is called the Line, another portion is peculiar to what is called the Finger. The rest is common to both. The common part, united to what is peculiar to line, is called line extended; the same common part, united with what is peculiar to finger, is called Finger moved.

Our ideas of extension and motion, are, no doubt,145originally derived from the action of our own bodies. I touch something, and have the sensation of resistance. The idea of resistance is the fundamental part in every combination to which I give the name of object. In this case, there is the object touched, and there is the finger touching. A certain action is given to my finger, still touching the object. That action involves certain feelings; these I combine both with the object, and with the finger, and to these two combinations I give the two names, Object Extended, Finger Moved.

If any one shut his eyes, excluding as much as possible, the ideas of sight, and conceiving, without admixture, the feelings in the finger and the arm, while the finger passes along a line, he will get some notion of the series of antecedents and consequents, whence the idea of Motion is derived. They are feelings, which language does not enable us to communicate by words; but it does not seem very difficult for any man to raise the ideas of them in himself.

Let any one suppose, that the line commences opposite to the centre of his body. He begins by touching it at that point with the finger of his right hand; and in this there is one state of feeling. He gives the finger the smallest perceptible motion towards the right: this is another state of feeling. He gives it a further motion, the smallest perceptible, in the same direction: this is another state of feeling; and so on, as far as the arm can reach. The antecedent states are in each instance united with the present by memory, and by the amount of the states, thus united, the amount of the motion is computed.

Conceiving the case of a man born blind, the more146easily to exclude the illusions of association; it is obvious, that such a man can obtain the idea of another body in motion, only by accompanying it with his hand; or by associating the ideas, on account of which he calls the hand, moved, with the body in question. By frequent operations of the hand, such as that described above, he becomes familiar with the idea of the hand moved. The ideas of the sensations, on account of which, he calls it moved, are easily raised, easily form themselves into combination, and easily associate themselves with the object, Hand. The idea of Hand, and the idea of Hand moved, having become very familiar, it is an easy case of association to transfer the termmovedto other things, as the foot moved, the body moved, the stone moved. When he has become familiar with the application of Moved, as a connotative term, to various objects, it is easy, in this, as in other cases, to drop the connotation; and then he has the abstract, MOTION.3132

31The author correctly, in my opinion, refers to our muscular sensibility (aided by Touch), the fundamental notions of Resistance, Motion, Extension, Space. He also remarks properly, that the idea of motion and the idea of extension are the same; they are merely different modes of viewing one experience. In a mutually involved series of properties such as these, the Analysis may proceed in several different arrangements, no one being apparently very decisive. The following mode is suggested as on the whole, the most consecutive.The feeling of Resistance expresses what is probably the most fundamental state of all, the consciousness of muscular energy or expended force. Taking the case of a dead strain, or a pressure without movement, we have mere muscular energy and nothing else. We have an indivisible, unanalysable, mode147of consciousness, distinct from all modes of passive sensation, and from all forms of emotion. It is a kind of consciousness remarkably constant in its character; it varies in degree, but with this peculiarity that because a man is physically weaker than usual, he does not on that account exaggerate or misrepresent the degree of his muscular expenditure; the feeling of lifting two pounds is not made the same as the feeling of lifting four pounds, although in some of the incidents of exertion, as in the organic state of exhaustion, the smaller expenditure in one state is held to be equal to the greater expenditure in another state. The consciousness of putting forth power is the most uniform, the least variable, of all our sensibilities; the same amount of actual force expended is estimated as nearly the same under all circumstances.In being conscious of expended energy, we discriminate its degrees, within certain limits; we know when we increase or diminish the amount; and our sensibility is measured by the smallness of the difference that makes a change in our consciousness. This discrimination is the basis of our estimate of the property termed Force, Resistance, Momentum, in moving bodies. Our idea of force is a muscular idea, an idea of muscular force of a certain amount. Force may be viewed in other ways, or from other aspects, but its direct and simple estimate is muscular energy in the dead strain.2. We are farther conscious of muscular energy as more or less enduring or continuing. Our consciousness varies according as a strain is protracted; a weight supported half a minute gives a feeling different from a weight supported a quarter of a minute.Farther, it is important to remark that increase of continuance is not confounded with increase of force in the same time. Mechanically speaking, it is the same to us, whether we support two pounds one minute, or one pound two minutes; the energy gone out of us, the oxidation, or consumption of material, must be the same for both. But the consciousness is not the same for both; each has a character of its own, and we recognise the distinction in clear consciousness. If we148confounded all modes of expended energy that are dynamically equal, we should be disqualified from attaining the ideas of motion and extension.When energy is accompanied bymovement, there is a new and characteristic mode of consciousness, of vital importance. Energy in the dead strain and energy with motion may be equal as regard expended force, but they are not the same to our feelings. Continuance in the one is a different fact from continuance in the other. The feeling of continuance in moving energy is the fact that we call motion; and also the fundamental property, the starting point, with reference to Extension; although much more is wanted to complete that cognition. Mere dead strain would not amount to extension; and the discriminating of dead strain from moving strain is thus of essential moment. From the sense of this distinction, and the estimate of degree of continuance in movement, we begin at once the experience of motion and the ground-work of extension.The consciousness of continuance whether of dead strain or of movement is also a consciousness of duration, but not the only mode of becoming versed in this property. All our mental states,â€”whether muscular feelings, sensations, emotions, thoughts, volitions,â€”are different as they are more or less continued, and this consciousness of difference is a consciousness of Duration or Time. Hence the usual saying that Time is a property common to the Object and to the subject. The object experiences of motion and extension are the most convenient modes of measuring time, they are the most accurate and discriminative, but they are not the only nor the chief concrete embodiments of it. We often measure time by the duration and succession of our feelings and thoughts.3. Another mode of discrimination inhering in our muscular consciousness is the degree of movement, as slow or quick. We are differently affected according to the rapidity of our movements; an accelerated pace in the arm, or in the whole body, sensibly alters our feelings. Farther, we do not compound this alteration with its dynamical equivalents in the149other modesâ€”with increase in the amount of the dead strain, in the continuance of the dead strain, or in the continuance of movement. A characteristic mode of feeling attends this special form of augmenting or reducing our expenditure of force. The consequence is, a feeling of velocity or speed of movement. But this feeling of speed is not all. We gain another equivalent of degrees of extension; more speed in the same time being equal to more time with the same speed. It is proper to remark, however, that we are premature in speaking of extension, or in regarding it as arrived at, at once by our primary experiences of movement; much has to be gone through before this is fully formed or developed. Motion is the fundamental fact, but motion is a fact of succession, and can do nothing to suggest a group of contemporaneous phenomena, an outspread universe of the co-existing in time. Our primary sensibility is a mere thread of succession, duration, or continuance; we have to acquire by a process of aggregation and association, the highly artificial experience of things permanently situated in a relationship of co-existence in space or extension.It is at this point that Sensation comes to our aid. Passive sensation by itself is incompetent to give us the foundations of extension; through it, we have neither resistance nor movement, nor any fact partaking in what is essential to the extended or object universe. Mere warmth, odour, relish, touch, sound, colour, contain no elements of extension. The co-operation with moving energy is what introduces us to the object world.How then does Sensation aid muscularity in evolving Extension? In various ways, but chiefly thus. Our movements are not performed in vacuo, but in conjunction with sensation. The movements of the hand and arm, are usually conjoined with sensations of touch. We draw the hand across a table; there is an arm sensibility, purely motor or energetic, which is distinct from every mode of passive sensation. There accompanies it, however, a series of tactile sensations, making a united experience, active and passive. If this conjunction150were to happen but once, nothing would be thought of it farther than as a mere experience of succession. Again, in another situation the sweep of the movement ends in a contact or sensation of touch, or begins in the loss of such a contact. So far, these are mere casual conjunctions, unions of moving energy and passive sensibility. But in the course of many trials, there arise uniform conjunctions of movement with passive sensibility: the same movement being associated with the same tactile series, or with the same beginning or ending of tactile sensation. Take the case of the movement of the hand over the surface of our own body. A certain definite start, and definite amount of exertion brings with it a uniform tactile sensation, as in drawing the hand over the face. This uniformity generates an expectation that the same sensation will follow on the same definite energy. Many such conjunctions are formed in this manner. There is an interesting variety of the experience of such concurrences; namely, when we reverse a movement, and find a series of sensations identified as the same in an inverted order. The hand passed along the side of a knife, experiences movement coupled with sensations, as often as the movement is made; the inverted movement inverts the sensations.The supposition, hitherto, has been confined to Touch. When we take in sight, the scope for the operation is greatly enlarged. Almost all our movements are conjoined with optical changesâ€”sensations of colour and of visible form in a certain sequence. We speedily detect a number of uniform occurrences of movement and visible sensation. The same movement gives the same series of appearances at all times; and an inverted movement corresponds with an inverted order. Here too we attain to a number of uniformities of coincidence, with the expectation of future occurrence. A certain movement of the eyes is accompanied with an optical series, as scanning the starry heavens; as often as the movement is repeated from the same stand-point, the optical series is repeated; the inverted movement gives the inverted series. We151contract an expectation, that such a coincidence will occur in the future, and this expectation is our idea of the starry space.Our idea of extended things is thus completed by sensation. It is a series of conjunctions, or associations, of movements and sensations, in a fixed order. We do not in our idea of space, command an entire view at one glance; the successive perception of points or limited portions is what we begin with, and is the character of the mindâ€™s working even after we are educated to the utmost. The co-existing in space, is the mindâ€™s potentiality of finding definite sensations by means of definite movements; and it seems impossible to assign any other meaning or import to the phenomena. The genesis of the idea of space determines our mode of settling the great question of the Perception of a material world.â€”B.

The feeling of Resistance expresses what is probably the most fundamental state of all, the consciousness of muscular energy or expended force. Taking the case of a dead strain, or a pressure without movement, we have mere muscular energy and nothing else. We have an indivisible, unanalysable, mode147of consciousness, distinct from all modes of passive sensation, and from all forms of emotion. It is a kind of consciousness remarkably constant in its character; it varies in degree, but with this peculiarity that because a man is physically weaker than usual, he does not on that account exaggerate or misrepresent the degree of his muscular expenditure; the feeling of lifting two pounds is not made the same as the feeling of lifting four pounds, although in some of the incidents of exertion, as in the organic state of exhaustion, the smaller expenditure in one state is held to be equal to the greater expenditure in another state. The consciousness of putting forth power is the most uniform, the least variable, of all our sensibilities; the same amount of actual force expended is estimated as nearly the same under all circumstances.

In being conscious of expended energy, we discriminate its degrees, within certain limits; we know when we increase or diminish the amount; and our sensibility is measured by the smallness of the difference that makes a change in our consciousness. This discrimination is the basis of our estimate of the property termed Force, Resistance, Momentum, in moving bodies. Our idea of force is a muscular idea, an idea of muscular force of a certain amount. Force may be viewed in other ways, or from other aspects, but its direct and simple estimate is muscular energy in the dead strain.

2. We are farther conscious of muscular energy as more or less enduring or continuing. Our consciousness varies according as a strain is protracted; a weight supported half a minute gives a feeling different from a weight supported a quarter of a minute.

Farther, it is important to remark that increase of continuance is not confounded with increase of force in the same time. Mechanically speaking, it is the same to us, whether we support two pounds one minute, or one pound two minutes; the energy gone out of us, the oxidation, or consumption of material, must be the same for both. But the consciousness is not the same for both; each has a character of its own, and we recognise the distinction in clear consciousness. If we148confounded all modes of expended energy that are dynamically equal, we should be disqualified from attaining the ideas of motion and extension.

When energy is accompanied bymovement, there is a new and characteristic mode of consciousness, of vital importance. Energy in the dead strain and energy with motion may be equal as regard expended force, but they are not the same to our feelings. Continuance in the one is a different fact from continuance in the other. The feeling of continuance in moving energy is the fact that we call motion; and also the fundamental property, the starting point, with reference to Extension; although much more is wanted to complete that cognition. Mere dead strain would not amount to extension; and the discriminating of dead strain from moving strain is thus of essential moment. From the sense of this distinction, and the estimate of degree of continuance in movement, we begin at once the experience of motion and the ground-work of extension.

The consciousness of continuance whether of dead strain or of movement is also a consciousness of duration, but not the only mode of becoming versed in this property. All our mental states,â€”whether muscular feelings, sensations, emotions, thoughts, volitions,â€”are different as they are more or less continued, and this consciousness of difference is a consciousness of Duration or Time. Hence the usual saying that Time is a property common to the Object and to the subject. The object experiences of motion and extension are the most convenient modes of measuring time, they are the most accurate and discriminative, but they are not the only nor the chief concrete embodiments of it. We often measure time by the duration and succession of our feelings and thoughts.

3. Another mode of discrimination inhering in our muscular consciousness is the degree of movement, as slow or quick. We are differently affected according to the rapidity of our movements; an accelerated pace in the arm, or in the whole body, sensibly alters our feelings. Farther, we do not compound this alteration with its dynamical equivalents in the149other modesâ€”with increase in the amount of the dead strain, in the continuance of the dead strain, or in the continuance of movement. A characteristic mode of feeling attends this special form of augmenting or reducing our expenditure of force. The consequence is, a feeling of velocity or speed of movement. But this feeling of speed is not all. We gain another equivalent of degrees of extension; more speed in the same time being equal to more time with the same speed. It is proper to remark, however, that we are premature in speaking of extension, or in regarding it as arrived at, at once by our primary experiences of movement; much has to be gone through before this is fully formed or developed. Motion is the fundamental fact, but motion is a fact of succession, and can do nothing to suggest a group of contemporaneous phenomena, an outspread universe of the co-existing in time. Our primary sensibility is a mere thread of succession, duration, or continuance; we have to acquire by a process of aggregation and association, the highly artificial experience of things permanently situated in a relationship of co-existence in space or extension.

It is at this point that Sensation comes to our aid. Passive sensation by itself is incompetent to give us the foundations of extension; through it, we have neither resistance nor movement, nor any fact partaking in what is essential to the extended or object universe. Mere warmth, odour, relish, touch, sound, colour, contain no elements of extension. The co-operation with moving energy is what introduces us to the object world.

How then does Sensation aid muscularity in evolving Extension? In various ways, but chiefly thus. Our movements are not performed in vacuo, but in conjunction with sensation. The movements of the hand and arm, are usually conjoined with sensations of touch. We draw the hand across a table; there is an arm sensibility, purely motor or energetic, which is distinct from every mode of passive sensation. There accompanies it, however, a series of tactile sensations, making a united experience, active and passive. If this conjunction150were to happen but once, nothing would be thought of it farther than as a mere experience of succession. Again, in another situation the sweep of the movement ends in a contact or sensation of touch, or begins in the loss of such a contact. So far, these are mere casual conjunctions, unions of moving energy and passive sensibility. But in the course of many trials, there arise uniform conjunctions of movement with passive sensibility: the same movement being associated with the same tactile series, or with the same beginning or ending of tactile sensation. Take the case of the movement of the hand over the surface of our own body. A certain definite start, and definite amount of exertion brings with it a uniform tactile sensation, as in drawing the hand over the face. This uniformity generates an expectation that the same sensation will follow on the same definite energy. Many such conjunctions are formed in this manner. There is an interesting variety of the experience of such concurrences; namely, when we reverse a movement, and find a series of sensations identified as the same in an inverted order. The hand passed along the side of a knife, experiences movement coupled with sensations, as often as the movement is made; the inverted movement inverts the sensations.

The supposition, hitherto, has been confined to Touch. When we take in sight, the scope for the operation is greatly enlarged. Almost all our movements are conjoined with optical changesâ€”sensations of colour and of visible form in a certain sequence. We speedily detect a number of uniform occurrences of movement and visible sensation. The same movement gives the same series of appearances at all times; and an inverted movement corresponds with an inverted order. Here too we attain to a number of uniformities of coincidence, with the expectation of future occurrence. A certain movement of the eyes is accompanied with an optical series, as scanning the starry heavens; as often as the movement is repeated from the same stand-point, the optical series is repeated; the inverted movement gives the inverted series. We151contract an expectation, that such a coincidence will occur in the future, and this expectation is our idea of the starry space.

Our idea of extended things is thus completed by sensation. It is a series of conjunctions, or associations, of movements and sensations, in a fixed order. We do not in our idea of space, command an entire view at one glance; the successive perception of points or limited portions is what we begin with, and is the character of the mindâ€™s working even after we are educated to the utmost. The co-existing in space, is the mindâ€™s potentiality of finding definite sensations by means of definite movements; and it seems impossible to assign any other meaning or import to the phenomena. The genesis of the idea of space determines our mode of settling the great question of the Perception of a material world.â€”B.

32It will be both useful and interesting to the inquiring reader, if I add to the analysis of these very complex ideas by the author of the present treatise, and to that by Mr. Bain, the analysis given of them by the other great living master of the Association psychology, Mr. Herbert Spencer. The following passages are from his â€œPrinciples of Psychology.â€ First, of Resistance:â€œOn raising the arm to a horizontal position and keeping it so, and still more on dealing similarly with the leg, a sensation is felt, which, tolerably strong as it is at the outset, presently becomes unbearable. If the limb be uncovered, and be not brought against anything, this sensation is associated with no other, either of touch or pressure.â€ This is the sensation of Muscular Tension.â€œAllied to the sensation accompanying tension of the muscles, is that accompanying the act of contracting themâ€”the sensation of muscular motion.â€¦ While, from the muscles of a limb at rest, no sensation rises; while, from the muscles of a limb in a state of continuous strain, there arises a continuous sensation which remains uniform for a considerable time; from the muscle of a limb in motion, there arises a sensation which is152ever undergoing increase or decrease, or change of composition.â€œWhen we express our immediate experiences of a body by saying that it ishard, what are the experiences implied? First, a sensation of pressure, of considerable intensity, is implied; and if, as in most cases, this sensation of pressure is given to a finger voluntarily thrust against the object, then there is simultaneously felt a correspondingly strong sensation of muscular tension. But this is not all: for feelings of pressure and muscular tension may be given by bodies which we call soft, provided the compressing finger follows the surface as fast as it gives way. In what then consists the difference between the perceptions? In this; that whereas when a soft body is pressed with increasing force, the synchronous sensations of increasing pressure and increasing muscular tension are accompanied by sensations of muscular movement; when a hard body is pressed with increasing force these sensations of increasing pressure and tension are not accompanied by sensations of muscular movement. Considered by itself, then, the perception of softness may be defined as the establishment in consciousness of a relation of simultaneity between three series of sensationsâ€”a series of increasing sensations of pressure; a series of increasing sensations of tension; and a series of sensations of motion. And the perception of hardness is the same, with omission of the last series.â€ (pp. 212, 218.)Of Extension; and first, of Form or Figure:â€œIt is an anciently established doctrine that Form or Figure, which we may call the most complex mode of extension, is resolvable into relative magnitude of parts. An equilateral triangle is one of which the three sides are alike in magnitude. An ellipse is a symmetrical closed curve, of which the transverse and conjugate diameters are one greater than the other. A cube is a solid, having all its surfaces of the same magnitude, and all its angles of the same magnitude. A cone is a solid, successive sections of which, made at right angles to the axis, are circles regularly decreasing in153magnitude as we progress from base to apex. Any object described as narrow is one whoso breadth is of small magnitude when compared with its length. A symmetrical figure is a figure in which the homologous parts on opposite sides are equal in magnitude. Figures which we class as similar to each other, are such that the relation of magnitude between any two parts of the one, is equal to the relation of magnitude between the corresponding parts of the other. Add to which, that an alteration in the form of anything, is an alteration in the comparative sizes of some of its partsâ€”a change in the relations of magnitude subsisting between them and the other parts, and that by continuously altering the relative magnitudes of its parts, any figure may be changed indefinitely. Hence, figure being wholly resolvable into relations of magnitude we may go on to analyze that out of which these relations are formedâ€”magnitude itself.â€ (pp. 224, 225.)Next therefore, of Magnitude:â€œWhat is a magnitude, considered analytically? The reply is, It consists of one or more relations of position. When we conceive anything as having a certain bulk, we conceive its opposite limiting surfaces as more or less removed from each other; that is, as related in position. When we imagine a line of definite length, we imagine its termini as occupying points in space having some positive distance from each other; that is, as related in position. As a solid is decomposable into planes; a plane into lines; lines into points; and as adjacent points can neither be known nor conceived as distinct from each other, except as occupying different places in spaceâ€”that is, as occupying not the same position, but relative positionsâ€”it follows that every cognition of magnitude, is a cognition of one or more relations of position, which are presented to consciousness as like or unlike one or more other relations of position.â€ (p. 226.)And finally, of Position:â€œThis analysis of itself brings us to the remaining space-attribute of bodyâ€”Position. Like magnitude, Position cannot be known absolutely; but can be known only relatively.154The notion of position is, in itself, the notion of relative position. The position of a thing is inconceivable, save by thinking of that thing as at some distance from one or more other things. The essential element of the idea will be best seen, on observing under what conditions only, it can come into existence. Imagine a solitary point A, in infinite space; and suppose it possible for that point to be known by a being having no locality, what now can be predicated respecting its place? Absolutely nothing. Imagine another point B to be added. What can now be predicated respecting the two? Still nothing. The points having no attributes save position, are not comparable in themselves; and nothing can be said of their relative position, from lack of anything with which to compare it. The distance between them may be either infinite or infinitesimal, according to the measure used; and as, by the hypothesis, there exists no measureâ€”as space contains nothing save these two points; the distance between them is unthinkable. But now imagine that a third point C is added. Immediately it becomes possible to frame a proposition respecting their positions. The two distances, A to B, and A to C, serve as measures to each other. The space between A and B may be compared with the space between A and C; and the relation of position in which A stands to B becomes thinkable, as like or unlike the relation in which A stands to C. Thus, then, it is manifest that position is not an attribute of body in itself, but only in its connection with the other contents of the universe.â€œIt remains to add, that relations of position are of two kinds: those which subsist between subject and object; and those which subsist between either different objects, or different parts of the same object. Of these the last are resolvable into the first. It needs but to remember, on the one hand, that in the dark a man can discover the relative positions of two objects only by touching first one and then the other, and so inferring their relative positions from his own position towards each; and on the other hand, that by vision no knowledge of their relative positions can be155reached save through a perception of the distance of each from the eye; to see that ultimately all relative positions may be decomposed into relative positions of subject and object.â€œThese conclusionsâ€”that Figure is resolvable into relative magnitudes; that magnitude is resolvable into relative positions; and that all relative positions may finally be reduced to positions of subject and objectâ€”will be fully confirmed on considering the process by which the space-attributes of body become known to a blind man. He puts out his hand and touching something, thereby becomes cognizant of its position with respect to himself. He puts out his other hand, and meeting no resistance above or on one side of the position already found, gains some negative knowledge of the thingâ€™s magnitudeâ€”a knowledge which three or four touches on different sides of it serve to render positive. And then, by continuing to move his hands over its surface, he acquires a notion of its figure. What, then, are the elements out of which, by synthesis, his perceptions of magnitude and figure are framed? He has received nothing but simultaneous and successive touches. Each touch established a relation of position between his centre of consciousness and the point touched. And all he can know respecting magnitude and figureâ€”that is, respecting the relative position of these points to each otherâ€”is necessarily known through the relative positions in which they severally stand to himself.â€œOur perceptions of all the space-attributes of body being thus decomposable into perceptions of position like that gained by a single act of touch; we have next to inquire what is contained in a perception of this kind. A little thought will make it clear that to perceive the position of anything touched, is really to perceive the position of that part of the body in which the sensation of touch is located. Whence it follows that our knowledge of the positions of objects, is built upon our knowledge of the positions of our members towards each otherâ€”knowledge both of their fixed relations, and of those temporary relations they are placed in by every change of muscular adjustment. That156this knowledge is gained by a mutual exploration of the partsâ€”by a bringing of each in contact with the othersâ€”by a moving over each other in all possible ways; and that the motions involved in these explorations, are known by their reactions upon consciousness; are propositions that scarcely need stating. But it is manifestly impossible to carry the analysis further without analysing our perception of motion. Relative position and motion are two ideas of the same experience. We can neither conceive motion without conceiving relative position, nor discover relative position without motion. In the present, therefore, we must be content with the conclusion that, whether visual or tactual, the perception of every statical attribute of body is resolvable into perceptions of relative position which are gained through motion.â€ (pp. 226â€”229.)In further prosecution of the analysis:â€œHow do we become cognizant of the relative positions of two points on the surface of the body? Such two points, considered as coexistent, involve the germinal idea of Space. Such two points disclosed to consciousness by two successive tactual sensations proceeding from them, involve the germinal idea of Time. And the series of muscular sensations by which, when self-produced, these two tactual sensations are separated, involve the germinal idea of Motion. The questions to be considered then areâ€”In what order do these germinal ideas arise? andâ€”How are they developed?â€œâ€¦ Taking for our subject a newly-born infant, let us call the two points on its body between which a relation is to be established, A and Z. Let us assume these points to be anywhere within reach of the handsâ€”say upon the cheek. By the hypothesis, nothing is at present known of these points; either as coexisting in Space, as giving successive sensations in Time, or as being brought into relation by Motion. If, now, the infant moves its arm in such a way as to touch nothing, there is a certain vague reaction upon its consciousnessâ€”a sensation of muscular tension. This157sensation has the peculiarity of being indefinite in all its commencement; indefinite in its termination; and indefinite in all its intermediate changes. Its strength is proportionate to the degree of muscular contraction. Whence it follows that as the limb starts from a state of rest, in which there is no contraction; and as it can reach a position requiring extreme contraction only by passing through positions requiring intermediate degrees of contraction; and as the degrees of contraction must therefore form a series ascending by infinitesimal increments from zero; the sensations of tension must also form such a series. And the like must be the case with all subsequent movements and their accompanying sensations; seeing that, be it at rest or in action, a muscle cannot pass from any one state to any other without going through all the intermediate states. Thus, then, the infant, on moving its arm backwards and forwards without touching anything, is brought to what we may distinguish as a nascent consciousnessâ€”a consciousness not definitely divisible into states; but a consciousness the variations of which pass insensibly into each other, like undulations of greater or less magnitude. And while the states of consciousness are thus incipientâ€”thus indistinctly separated, there can be no clear comparison of them; no thought, properly so called; and consequently no ideas of Motion, Time, or Space, as we understand them. Suppose, now, that the hand touches something. A sudden change in consciousness is producedâ€”a change that is incisive in its commencement, and, when the hand is removed, equally incisive in its termination. In the midst of the continuous feeling of muscular tension, vaguely rising and falling in intensity, there all at once occurs a distinct feeling of another kind. This feeling, beginning and ending abruptly, constitutes a definite state of consciousness; becomes, as it were, a mark in consciousness. By similar experiences other such marks are produced; and in proportion as they are multiplied, there arises a possibility of comparing them, both in respect to their degrees and their relative positions; while at the same158time, the feelings of muscular tension being, as it were, divided out into lengths by these superposed marks, become similarly comparable; and so there are acquired materials for a simple order of thought. Observe, also, that while these tactual sensations may, when several things are touched in succession, produce successive marks in consciousness, separated by intervening muscular sensations, they may also become continually coexistent with these muscular sensations; as when the finger is drawn along a surface. And observe further, that when the surface over which the finger is drawn is not a foreign body, but some part of the subjectâ€™s body, these muscular sensations, and the continuous tactual sensation joined with them, are accompanied by a series of tactual sensations proceeding from that part of the skin over which the finger is drawn. Thus, then, when the infant moves its finger along the surface of its body from A to Z, there are simultaneously impressed upon consciousness three sets of sensationsâ€”the varying series of sensations proceeding from the muscles in action; the series of tactual sensations proceeding from the points of the skin successively touched between A and Z; and the continuous sensation of touch from the finger-end.â€¦. As subsequent motions of the finger over the surface from A to Z always result in the like simultaneous sets of sensations, these, in course of time, become indissolubly associated. Though the series of tactual sensations, A to Z, being producible by a foreign body moving over the same surface, can be dissociated from the others; and though, if the cheek be withdrawn by a movement of the head, the same motion of the hand, with its accompanying muscular sensations, may occur without any sensation of touch; yet, when these two series are linked by the tactual sensation proceeding from the finger-end, they necessarily proceed together; and become inseparably connected in thought. Whence it obviously results that the series of tactual sensations A to Z, and the series of muscular sensations which invariably accompanies it when self-produced, serve as mutual equivalents; and being159two sides of the same experience, suggest each other in consciousness.â€œDue attention having been paid to this fact, let us go on to consider what must happen when something touches, at the same moment, the entire surface between A and Z. This surface is supplied by a series of independent nerve-fibres, each of which at its peripheral termination becomes fused into, or continuous with, the surrounding tissue; each of which is affected by impressions falling within a specific area of the skin; and each of which produces a separate state of consciousness. When the finger is drawn along this surface these nerve-fibres A, B, C, D â€¦ Z, are excited in succession; that isâ€”produce successive states of consciousness. And when something covers, at the same moment, the whole surface between A and Z, they are excited simultaneously; and produce what tends to become a single state of consciousness. Already I have endeavoured to shew in a parallel case, how, when impressions first known as having sequent positions in consciousness are afterwards simultaneously presented to consciousness, the sequent positions are transformed into coexistent positions, which, when consolidated by frequent presentations, are used in thought as equivalent to the sequent positions.fâ€¦ As the series of tactual160impressions A to Z, known as having sequent positions in consciousness, are, on the one hand, found to be equivalent to the accompanying series of muscular impressions; and on the other hand, to the simultaneous tactual impressions A to Z, which, as presented together, are necessarily presented in coexistent positions; it follows that these two last are found to be the equivalents of each other. A series of muscular sensations becomes known as equivalent to a series of coexistent positions; and being habitually joined with it, becomes at last unthinkable without it. Thus, the relation of coexistent positions between the points A and Z (and by implication all intermediate points) is necessarily disclosed by a comparison of experiences: the ideas of Space, Time, and Motion, are evolved together. When the successive states of consciousness A to Z, are thought of as having relative positions, the notion of Time becomes nascent. When these states of consciousness, instead of occurring serially, occur simultaneously, their relative positions, which were before sequent, necessarily become coexistent; and there arises a nascent consciousness of space. And when these two relations of coexistent and sequent positions are both presented to consciousness along with a series of sensations of muscular tension, a nascent idea of Motion results.fâ€œObjects laid upon the surface will come to be distinguished from each other by the relative lengths of the series they cover; or, when broad as well as long, by the groups of series which they cover.â€¦ By habit these simultaneous excitations, from being at first known indirectly by translation into the serial ones, will come to be known directly, and the serial ones will be forgotten: just as in childhood the words of a new language, at first understood by means of their equivalents in the mother tongue, are presently understood by themselves; and if used to the exclusion of the mother tongue, lead to the ultimate loss of it.â€ We see that â€œa set of [nervous] elements may be excited simultaneously as well as serially; that so, aquasisingle state of consciousness becomes the equivalent of a series of states; that a relation between what we call coexistent positions thus represents a relation of successive positions, and that this symbolic relation being far briefer, is habitually thought of in place of that it symbolizes; and that, by the continued use of such symbols, and the union of them with more complex ones, are generated our ideas of â€¦ extensionâ€”ideas which, like those of the algebraist working out an equation, are wholly unlike the ideas symbolized, and which yet, like his, occupy the mind to the entire exclusion of the ideas symbolized.â€â€”(pp. 222â€”224.)â€œThe development of these nascent ideas, arising as it does from a still further accumulation and comparison of experiences, will be readily understood. What has been above described as taking place with respect to one relation of coexistent positions upon the surface of the skinâ€”or rather, one161linear series of such coexisting positions, is, during the same period, taking place, with respect to endless other such linear series, in all directions over the body. The like equivalence between a series of coexistent impressions of touch, a series of successive impressions of touch, and series of successive muscular impressions, is being established between every pair of points that can readily be brought into relation by movement of the hands. Let us glance at the chief consequences that must ultimately arise from this organization of experiences.â€œNot only must there gradually be established a connection in thought between each particular muscular series, and the particular tactual series, both successive and simultaneous, with which it is associated; and not only must there, by implication, arise a knowledge of the special muscular adjustments required to touch each special part, but, by the same experiences, there must be established an indissoluble connection between muscular series in general and series of sequent and coexistent positions in general, seeing that this connection is repeated in every one of the particular experiences. And when we consider the infinite repetition of these experiences, we shall have no difficulty in understanding how their components become so consolidated, that even when the hand is moved through empty space, it is impossible to become conscious of the muscular sensations, without becoming conscious of the sequent and coexistent positionsâ€”the Time and Space, in which it has moved.â€œObserve again, that as, by this continuous exploration of the surface of the body, each point is put in relation not only with points in some directions around it, but with points in all directionsâ€”becomes, as it were, a centre from which radiate lines of points known first in their serial positions before consciousness, and afterwards in their coexistent positionsâ€”it follows, that when an object of some size, as the hand, is placed upon the skin, the impressions from all parts of the area covered being simultaneously presented to consciousness, are placed in coexistent positions before162consciousness: whence results an idea of the superficial extension of that part of the body. The idea of this extension is really nothing more than a simultaneous presentation of all the impressions proceeding from the various points it includes, which have previously had their several relative positions measured by means of the series of impressions separating them. Any one who hesitates respecting this conclusion, will, I think, adopt it, on critically considering the perception he has when placing his open hand against his cheekâ€”on observing that the perception is by no means single, but is made up of many elements which he cannot think of altogetherâ€”on observing that there is always one particular part of the whole surface touched, of which he is more distinctly conscious than of any otherâ€”and on observing that to become distinctly conscious of any other part, he has to traverse in thought the intervening parts; that is, he has to think of the relative positions of these parts by vaguely recalling the series of states of consciousness which a motion over the skin from one to the other would involve.â€ (pp. 257â€”263).These three different expositions of the origin of our ideas of Motion and Extension, by three eminent thinkers, agreeing in essentials, and differing chiefly in the comparative degrees of development which they give to different portions of the detail, will enable any competent reader of such a work as the present to fill up any gaps by his own thoughts. Many pages of additional commentary might easily be written; but they would not add any important thought to those of which the reader is now in possession; and belonging rather to the polemics of the subject than to its strictly scientific exposition, they would jar somewhat with the purely expository character of the present treatise.I will only further recommend to particular attention, the opinion of Mr. Spencer, also adopted by Mr. Bain, that our ascribing simultaneous existence to things which excite successive sensations, is greatly owing to our being able to vary or reverse the order of the succession. When we pass our hands163over an object, we can have the tactual and muscular sensations in many different orders, and after having them in one order, can have them in another exactly the reverse. They do not, therefore, become associated with each other in a fixed order of succession, but are called up in any order with such extreme rapidity, that the impression they leave is that of simultaneousness, and we therefore hold the parts of tangible objects to be simultaneous.â€”Ed.

â€œOn raising the arm to a horizontal position and keeping it so, and still more on dealing similarly with the leg, a sensation is felt, which, tolerably strong as it is at the outset, presently becomes unbearable. If the limb be uncovered, and be not brought against anything, this sensation is associated with no other, either of touch or pressure.â€ This is the sensation of Muscular Tension.

â€œAllied to the sensation accompanying tension of the muscles, is that accompanying the act of contracting themâ€”the sensation of muscular motion.â€¦ While, from the muscles of a limb at rest, no sensation rises; while, from the muscles of a limb in a state of continuous strain, there arises a continuous sensation which remains uniform for a considerable time; from the muscle of a limb in motion, there arises a sensation which is152ever undergoing increase or decrease, or change of composition.

â€œWhen we express our immediate experiences of a body by saying that it ishard, what are the experiences implied? First, a sensation of pressure, of considerable intensity, is implied; and if, as in most cases, this sensation of pressure is given to a finger voluntarily thrust against the object, then there is simultaneously felt a correspondingly strong sensation of muscular tension. But this is not all: for feelings of pressure and muscular tension may be given by bodies which we call soft, provided the compressing finger follows the surface as fast as it gives way. In what then consists the difference between the perceptions? In this; that whereas when a soft body is pressed with increasing force, the synchronous sensations of increasing pressure and increasing muscular tension are accompanied by sensations of muscular movement; when a hard body is pressed with increasing force these sensations of increasing pressure and tension are not accompanied by sensations of muscular movement. Considered by itself, then, the perception of softness may be defined as the establishment in consciousness of a relation of simultaneity between three series of sensationsâ€”a series of increasing sensations of pressure; a series of increasing sensations of tension; and a series of sensations of motion. And the perception of hardness is the same, with omission of the last series.â€ (pp. 212, 218.)

Of Extension; and first, of Form or Figure:

â€œIt is an anciently established doctrine that Form or Figure, which we may call the most complex mode of extension, is resolvable into relative magnitude of parts. An equilateral triangle is one of which the three sides are alike in magnitude. An ellipse is a symmetrical closed curve, of which the transverse and conjugate diameters are one greater than the other. A cube is a solid, having all its surfaces of the same magnitude, and all its angles of the same magnitude. A cone is a solid, successive sections of which, made at right angles to the axis, are circles regularly decreasing in153magnitude as we progress from base to apex. Any object described as narrow is one whoso breadth is of small magnitude when compared with its length. A symmetrical figure is a figure in which the homologous parts on opposite sides are equal in magnitude. Figures which we class as similar to each other, are such that the relation of magnitude between any two parts of the one, is equal to the relation of magnitude between the corresponding parts of the other. Add to which, that an alteration in the form of anything, is an alteration in the comparative sizes of some of its partsâ€”a change in the relations of magnitude subsisting between them and the other parts, and that by continuously altering the relative magnitudes of its parts, any figure may be changed indefinitely. Hence, figure being wholly resolvable into relations of magnitude we may go on to analyze that out of which these relations are formedâ€”magnitude itself.â€ (pp. 224, 225.)

Next therefore, of Magnitude:

â€œWhat is a magnitude, considered analytically? The reply is, It consists of one or more relations of position. When we conceive anything as having a certain bulk, we conceive its opposite limiting surfaces as more or less removed from each other; that is, as related in position. When we imagine a line of definite length, we imagine its termini as occupying points in space having some positive distance from each other; that is, as related in position. As a solid is decomposable into planes; a plane into lines; lines into points; and as adjacent points can neither be known nor conceived as distinct from each other, except as occupying different places in spaceâ€”that is, as occupying not the same position, but relative positionsâ€”it follows that every cognition of magnitude, is a cognition of one or more relations of position, which are presented to consciousness as like or unlike one or more other relations of position.â€ (p. 226.)

And finally, of Position:

â€œThis analysis of itself brings us to the remaining space-attribute of bodyâ€”Position. Like magnitude, Position cannot be known absolutely; but can be known only relatively.154The notion of position is, in itself, the notion of relative position. The position of a thing is inconceivable, save by thinking of that thing as at some distance from one or more other things. The essential element of the idea will be best seen, on observing under what conditions only, it can come into existence. Imagine a solitary point A, in infinite space; and suppose it possible for that point to be known by a being having no locality, what now can be predicated respecting its place? Absolutely nothing. Imagine another point B to be added. What can now be predicated respecting the two? Still nothing. The points having no attributes save position, are not comparable in themselves; and nothing can be said of their relative position, from lack of anything with which to compare it. The distance between them may be either infinite or infinitesimal, according to the measure used; and as, by the hypothesis, there exists no measureâ€”as space contains nothing save these two points; the distance between them is unthinkable. But now imagine that a third point C is added. Immediately it becomes possible to frame a proposition respecting their positions. The two distances, A to B, and A to C, serve as measures to each other. The space between A and B may be compared with the space between A and C; and the relation of position in which A stands to B becomes thinkable, as like or unlike the relation in which A stands to C. Thus, then, it is manifest that position is not an attribute of body in itself, but only in its connection with the other contents of the universe.

â€œIt remains to add, that relations of position are of two kinds: those which subsist between subject and object; and those which subsist between either different objects, or different parts of the same object. Of these the last are resolvable into the first. It needs but to remember, on the one hand, that in the dark a man can discover the relative positions of two objects only by touching first one and then the other, and so inferring their relative positions from his own position towards each; and on the other hand, that by vision no knowledge of their relative positions can be155reached save through a perception of the distance of each from the eye; to see that ultimately all relative positions may be decomposed into relative positions of subject and object.

â€œThese conclusionsâ€”that Figure is resolvable into relative magnitudes; that magnitude is resolvable into relative positions; and that all relative positions may finally be reduced to positions of subject and objectâ€”will be fully confirmed on considering the process by which the space-attributes of body become known to a blind man. He puts out his hand and touching something, thereby becomes cognizant of its position with respect to himself. He puts out his other hand, and meeting no resistance above or on one side of the position already found, gains some negative knowledge of the thingâ€™s magnitudeâ€”a knowledge which three or four touches on different sides of it serve to render positive. And then, by continuing to move his hands over its surface, he acquires a notion of its figure. What, then, are the elements out of which, by synthesis, his perceptions of magnitude and figure are framed? He has received nothing but simultaneous and successive touches. Each touch established a relation of position between his centre of consciousness and the point touched. And all he can know respecting magnitude and figureâ€”that is, respecting the relative position of these points to each otherâ€”is necessarily known through the relative positions in which they severally stand to himself.

â€œOur perceptions of all the space-attributes of body being thus decomposable into perceptions of position like that gained by a single act of touch; we have next to inquire what is contained in a perception of this kind. A little thought will make it clear that to perceive the position of anything touched, is really to perceive the position of that part of the body in which the sensation of touch is located. Whence it follows that our knowledge of the positions of objects, is built upon our knowledge of the positions of our members towards each otherâ€”knowledge both of their fixed relations, and of those temporary relations they are placed in by every change of muscular adjustment. That156this knowledge is gained by a mutual exploration of the partsâ€”by a bringing of each in contact with the othersâ€”by a moving over each other in all possible ways; and that the motions involved in these explorations, are known by their reactions upon consciousness; are propositions that scarcely need stating. But it is manifestly impossible to carry the analysis further without analysing our perception of motion. Relative position and motion are two ideas of the same experience. We can neither conceive motion without conceiving relative position, nor discover relative position without motion. In the present, therefore, we must be content with the conclusion that, whether visual or tactual, the perception of every statical attribute of body is resolvable into perceptions of relative position which are gained through motion.â€ (pp. 226â€”229.)

In further prosecution of the analysis:

â€œHow do we become cognizant of the relative positions of two points on the surface of the body? Such two points, considered as coexistent, involve the germinal idea of Space. Such two points disclosed to consciousness by two successive tactual sensations proceeding from them, involve the germinal idea of Time. And the series of muscular sensations by which, when self-produced, these two tactual sensations are separated, involve the germinal idea of Motion. The questions to be considered then areâ€”In what order do these germinal ideas arise? andâ€”How are they developed?

â€œâ€¦ Taking for our subject a newly-born infant, let us call the two points on its body between which a relation is to be established, A and Z. Let us assume these points to be anywhere within reach of the handsâ€”say upon the cheek. By the hypothesis, nothing is at present known of these points; either as coexisting in Space, as giving successive sensations in Time, or as being brought into relation by Motion. If, now, the infant moves its arm in such a way as to touch nothing, there is a certain vague reaction upon its consciousnessâ€”a sensation of muscular tension. This157sensation has the peculiarity of being indefinite in all its commencement; indefinite in its termination; and indefinite in all its intermediate changes. Its strength is proportionate to the degree of muscular contraction. Whence it follows that as the limb starts from a state of rest, in which there is no contraction; and as it can reach a position requiring extreme contraction only by passing through positions requiring intermediate degrees of contraction; and as the degrees of contraction must therefore form a series ascending by infinitesimal increments from zero; the sensations of tension must also form such a series. And the like must be the case with all subsequent movements and their accompanying sensations; seeing that, be it at rest or in action, a muscle cannot pass from any one state to any other without going through all the intermediate states. Thus, then, the infant, on moving its arm backwards and forwards without touching anything, is brought to what we may distinguish as a nascent consciousnessâ€”a consciousness not definitely divisible into states; but a consciousness the variations of which pass insensibly into each other, like undulations of greater or less magnitude. And while the states of consciousness are thus incipientâ€”thus indistinctly separated, there can be no clear comparison of them; no thought, properly so called; and consequently no ideas of Motion, Time, or Space, as we understand them. Suppose, now, that the hand touches something. A sudden change in consciousness is producedâ€”a change that is incisive in its commencement, and, when the hand is removed, equally incisive in its termination. In the midst of the continuous feeling of muscular tension, vaguely rising and falling in intensity, there all at once occurs a distinct feeling of another kind. This feeling, beginning and ending abruptly, constitutes a definite state of consciousness; becomes, as it were, a mark in consciousness. By similar experiences other such marks are produced; and in proportion as they are multiplied, there arises a possibility of comparing them, both in respect to their degrees and their relative positions; while at the same158time, the feelings of muscular tension being, as it were, divided out into lengths by these superposed marks, become similarly comparable; and so there are acquired materials for a simple order of thought. Observe, also, that while these tactual sensations may, when several things are touched in succession, produce successive marks in consciousness, separated by intervening muscular sensations, they may also become continually coexistent with these muscular sensations; as when the finger is drawn along a surface. And observe further, that when the surface over which the finger is drawn is not a foreign body, but some part of the subjectâ€™s body, these muscular sensations, and the continuous tactual sensation joined with them, are accompanied by a series of tactual sensations proceeding from that part of the skin over which the finger is drawn. Thus, then, when the infant moves its finger along the surface of its body from A to Z, there are simultaneously impressed upon consciousness three sets of sensationsâ€”the varying series of sensations proceeding from the muscles in action; the series of tactual sensations proceeding from the points of the skin successively touched between A and Z; and the continuous sensation of touch from the finger-end.â€¦. As subsequent motions of the finger over the surface from A to Z always result in the like simultaneous sets of sensations, these, in course of time, become indissolubly associated. Though the series of tactual sensations, A to Z, being producible by a foreign body moving over the same surface, can be dissociated from the others; and though, if the cheek be withdrawn by a movement of the head, the same motion of the hand, with its accompanying muscular sensations, may occur without any sensation of touch; yet, when these two series are linked by the tactual sensation proceeding from the finger-end, they necessarily proceed together; and become inseparably connected in thought. Whence it obviously results that the series of tactual sensations A to Z, and the series of muscular sensations which invariably accompanies it when self-produced, serve as mutual equivalents; and being159two sides of the same experience, suggest each other in consciousness.

â€œDue attention having been paid to this fact, let us go on to consider what must happen when something touches, at the same moment, the entire surface between A and Z. This surface is supplied by a series of independent nerve-fibres, each of which at its peripheral termination becomes fused into, or continuous with, the surrounding tissue; each of which is affected by impressions falling within a specific area of the skin; and each of which produces a separate state of consciousness. When the finger is drawn along this surface these nerve-fibres A, B, C, D â€¦ Z, are excited in succession; that isâ€”produce successive states of consciousness. And when something covers, at the same moment, the whole surface between A and Z, they are excited simultaneously; and produce what tends to become a single state of consciousness. Already I have endeavoured to shew in a parallel case, how, when impressions first known as having sequent positions in consciousness are afterwards simultaneously presented to consciousness, the sequent positions are transformed into coexistent positions, which, when consolidated by frequent presentations, are used in thought as equivalent to the sequent positions.fâ€¦ As the series of tactual160impressions A to Z, known as having sequent positions in consciousness, are, on the one hand, found to be equivalent to the accompanying series of muscular impressions; and on the other hand, to the simultaneous tactual impressions A to Z, which, as presented together, are necessarily presented in coexistent positions; it follows that these two last are found to be the equivalents of each other. A series of muscular sensations becomes known as equivalent to a series of coexistent positions; and being habitually joined with it, becomes at last unthinkable without it. Thus, the relation of coexistent positions between the points A and Z (and by implication all intermediate points) is necessarily disclosed by a comparison of experiences: the ideas of Space, Time, and Motion, are evolved together. When the successive states of consciousness A to Z, are thought of as having relative positions, the notion of Time becomes nascent. When these states of consciousness, instead of occurring serially, occur simultaneously, their relative positions, which were before sequent, necessarily become coexistent; and there arises a nascent consciousness of space. And when these two relations of coexistent and sequent positions are both presented to consciousness along with a series of sensations of muscular tension, a nascent idea of Motion results.

fâ€œObjects laid upon the surface will come to be distinguished from each other by the relative lengths of the series they cover; or, when broad as well as long, by the groups of series which they cover.â€¦ By habit these simultaneous excitations, from being at first known indirectly by translation into the serial ones, will come to be known directly, and the serial ones will be forgotten: just as in childhood the words of a new language, at first understood by means of their equivalents in the mother tongue, are presently understood by themselves; and if used to the exclusion of the mother tongue, lead to the ultimate loss of it.â€ We see that â€œa set of [nervous] elements may be excited simultaneously as well as serially; that so, aquasisingle state of consciousness becomes the equivalent of a series of states; that a relation between what we call coexistent positions thus represents a relation of successive positions, and that this symbolic relation being far briefer, is habitually thought of in place of that it symbolizes; and that, by the continued use of such symbols, and the union of them with more complex ones, are generated our ideas of â€¦ extensionâ€”ideas which, like those of the algebraist working out an equation, are wholly unlike the ideas symbolized, and which yet, like his, occupy the mind to the entire exclusion of the ideas symbolized.â€â€”(pp. 222â€”224.)

â€œThe development of these nascent ideas, arising as it does from a still further accumulation and comparison of experiences, will be readily understood. What has been above described as taking place with respect to one relation of coexistent positions upon the surface of the skinâ€”or rather, one161linear series of such coexisting positions, is, during the same period, taking place, with respect to endless other such linear series, in all directions over the body. The like equivalence between a series of coexistent impressions of touch, a series of successive impressions of touch, and series of successive muscular impressions, is being established between every pair of points that can readily be brought into relation by movement of the hands. Let us glance at the chief consequences that must ultimately arise from this organization of experiences.

â€œNot only must there gradually be established a connection in thought between each particular muscular series, and the particular tactual series, both successive and simultaneous, with which it is associated; and not only must there, by implication, arise a knowledge of the special muscular adjustments required to touch each special part, but, by the same experiences, there must be established an indissoluble connection between muscular series in general and series of sequent and coexistent positions in general, seeing that this connection is repeated in every one of the particular experiences. And when we consider the infinite repetition of these experiences, we shall have no difficulty in understanding how their components become so consolidated, that even when the hand is moved through empty space, it is impossible to become conscious of the muscular sensations, without becoming conscious of the sequent and coexistent positionsâ€”the Time and Space, in which it has moved.

â€œObserve again, that as, by this continuous exploration of the surface of the body, each point is put in relation not only with points in some directions around it, but with points in all directionsâ€”becomes, as it were, a centre from which radiate lines of points known first in their serial positions before consciousness, and afterwards in their coexistent positionsâ€”it follows, that when an object of some size, as the hand, is placed upon the skin, the impressions from all parts of the area covered being simultaneously presented to consciousness, are placed in coexistent positions before162consciousness: whence results an idea of the superficial extension of that part of the body. The idea of this extension is really nothing more than a simultaneous presentation of all the impressions proceeding from the various points it includes, which have previously had their several relative positions measured by means of the series of impressions separating them. Any one who hesitates respecting this conclusion, will, I think, adopt it, on critically considering the perception he has when placing his open hand against his cheekâ€”on observing that the perception is by no means single, but is made up of many elements which he cannot think of altogetherâ€”on observing that there is always one particular part of the whole surface touched, of which he is more distinctly conscious than of any otherâ€”and on observing that to become distinctly conscious of any other part, he has to traverse in thought the intervening parts; that is, he has to think of the relative positions of these parts by vaguely recalling the series of states of consciousness which a motion over the skin from one to the other would involve.â€ (pp. 257â€”263).

These three different expositions of the origin of our ideas of Motion and Extension, by three eminent thinkers, agreeing in essentials, and differing chiefly in the comparative degrees of development which they give to different portions of the detail, will enable any competent reader of such a work as the present to fill up any gaps by his own thoughts. Many pages of additional commentary might easily be written; but they would not add any important thought to those of which the reader is now in possession; and belonging rather to the polemics of the subject than to its strictly scientific exposition, they would jar somewhat with the purely expository character of the present treatise.

I will only further recommend to particular attention, the opinion of Mr. Spencer, also adopted by Mr. Bain, that our ascribing simultaneous existence to things which excite successive sensations, is greatly owing to our being able to vary or reverse the order of the succession. When we pass our hands163over an object, we can have the tactual and muscular sensations in many different orders, and after having them in one order, can have them in another exactly the reverse. They do not, therefore, become associated with each other in a fixed order of succession, but are called up in any order with such extreme rapidity, that the impression they leave is that of simultaneousness, and we therefore hold the parts of tangible objects to be simultaneous.â€”Ed.

164

There is one other term, which still requires explanation; and that is, IDENTITY, about which there would not have appeared any difficulty, had it not been for Personal Identity; which is, indeed, a complicated case, and, of course, involves the obscurity which great complexity implies.

We have already seen, on what account we use the marks, same, and different, when we apply them to two simple sensations, or when we apply them to two ideas, simple, or complex. In these cases, the terms are relative terms, and name the objects in pairs.

There is another case, that which now it is our business to explain, in which the name is not applied to two objects, but to the same object, at two different times. Thus it is, that I say, The bridge at Westminster, by which I crossed the Thames thirty years ago, is the same by which I crossed it yesterday. The crown which was placed on the head of George IV. at his coronation, is the same by which the kings of England have been crowned for many centuries. The words which we read in the Gospel of Matthew, are the same which were written by that evangelist. The words which we read in the poem called the Ã†neid are the same which were written by the poet Virgil. The church which is now at Loretto, is the same with that which belonged to the Virgin Mary at Nazareth, which in the month of May, in the year 1291, was165carried through the air by Angels, from Galilee to Tersato, in Dalmatia; and again on the 10th of December, 1294, about midnight, by what conveyance is not known, was set down in a wood in Italy, in the district of Ricanati, about a thousand paces from the sea.

It is evident, from the contemplation of these instances, which might be multiplied to any extent, that the wordSAME, in this mode of applying it, is merely the name of a certain case of Belief: a belief which, in some of the instances, is, memory; in some, is grounded upon testimony; in some, upon circumstantial evidence; and, in some, upon both testimony and circumstances. Thus, the case of belief respecting Westminster-bridge, which I mark by the word, same, is Memory. The cases of belief respecting the crown of England, respecting the words of the gospel, respecting the church of Loretto, marked respectively by the word same, are founded on testimony, joined with circumstances.

As we have already shewn wherein Belief, in all its cases, consists, we have implicitly afforded the exposition of Identity. From same, the concrete, comes, in the usual way, sameness, the abstract, dropping only the connotation of the concrete. And Identity and Sameness are equivalent terms.

From the importance, however, which has been attached to these words, it seems necessary to shew to the learner, somewhat more particularly, the mode of tracing the simple ideas composing the clusters which they are employed to mark.

The Lily, when it produces its brilliant flower in summer, I call the same, with the plant which began166to shew itself above the surface of the ground, in spring, from a bulb, which I had planted in a particular spot of my garden. I also called it the same, from one day to another, though changing every day in its size, and other appearances, from its germination to the present time. For what reason have I done so? On account of certain circumstances, which every body can enumerate; its rising from a certain root; the uninterrupted continuity, by means of the stalk, between the root and the other parts of the plant; its being always found in the same place, that is, in the same synchronous order with certain other things; its corresponding with other plants, the growth of which I have observed, and so on. If it had grown in a flower pot, and been transferred from one to another, the enumeration of the circumstances would have been different; the evidence of its having grown from the same root would have been drawn from other circumstances. When I say, then, that the Lily I see, with its flowers in July, is the same with the Lily just emerging from the ground in April, I only express my belief of its having sprung from a certain root, and of its having vegetated, in connexion with that root, in the way of the plants grouped in the class called Lily.

I have a male Calf, of singular beauty, produced from my cow. I observe him from day to day. From day to day I call him the Same; and I do so when he has grown a bull of the greatest size. When I do so, I merely express my belief in a certain train of antecedents and consequents, with which experience has rendered me familiar. There is a certain train of antecedents and consequents, known to me by167observation, which I call the birth, growth, maturity; and, in one word, the Life, of the animal. The birth, growth, and maturity of one animal, is one series of successions; the birth, growth, and maturity of another animal, is another series of successions. When I apply the name Same, then, to any animal, I merely express my belief, that my present sight of the animal is part of a particular series, of which that perception is the last link.

The case, it will not be doubted, is perfectly analogous, when I transfer the term from one of the lower animals to one of my fellow men. The birth, infancy, childhood, youth, manhood, of a human being, are names for different parts of a certain series of antecedents and consequents. This series is known to me by experience; that is, by sensation, by memory, and other cases of association. The life of one man is one series. The life of another man is another series. When I say, then, that a man is the same, I merely express my belief in one of those series; belief that the particular man, of the present instant, is the last link of such and such a chain, and not of any other.

It is, however, to be observed, that the chain, thus believed, and the evidence upon which it is believed, are different things; and that this evidence is different in different cases. In the case of a person whom I have lived with from his birth, and seen every day, the evidence, to a great degree, is sense and memory. Sometimes the sameness of an individual is proved in a court of justice, by evidence, such as is applicable to any other matters of fact; by written documents, marks on the body, articles of property found168with the child, and the testimony of those whose knowledge has been uninterrupted from one time to another.

It is not to be doubted, that when I transfer the word Same, from another man to myself, all that I do is to express my belief in one of those series; and the only difference in the case is, that it is a series of which I have evidence of a very particular kind, and of which many parts are known to me, which can be known to nobody else.

As far as memory reaches, the evidence, in regard to myself, is memory and sensation. In the case of Evidence by memory and sensation, we have observed a peculiarity, necessary to be remembered, that the Evidence, and the Belief, are not different things, but the same thing. The memory which I have of my own existence, that is, the memory of a certain train of antecedents and consequents, is the Belief of them; on account of which belief, I apply to myself the term same, in the same way as I apply it to any other of my fellow men.

But I apply the term same to myself beyond the point to which memory reaches; as far back, in short, as to other men. This is true: I believe, that a train of antecedents and consequents, corresponding to that which forms the existence of other men, has also formed my existence. Part of this train I believe, by consciousness, memory. Part, namely, that which precedes memory, I believe on other evidence. What that evidence is, it is not difficult to see. We have, in the first place, the evidence of testimony; namely, that of all the persons who knew us from our birth, to the time to which memory extends. We have next169the evidence of what happens in the existence of all other men; or that case of association which unites inseparably the idea of like antecedents with like consequents.

It may be said, however, that my belief in the Identity of other men, is a very different thing from belief in my own Identity; and that the foregoing exposition does not sufficiently account for the difference which every one remarks between them.

The foregoing exposition, when duly attended to, will be found to account completely for the difference. We have remarked, that the evidence which I have for a great part of the series, in the case of other men, and of myself, is remarkably different. In the case of other men, it consists of observation and memory; in the case of myself, it consists of consciousness and memory. In these several and respective circumstances, Observation, and Consciousness, the distinction wholly consists. The memory of a chain of facts observed, is the evidence in the one case. The memory of a chain of states of Consciousness, is the evidence in the other.

I doubt not that this, without further analysis, will be seen by many of my readers to be a complete solution of the question. It may, however, be still objected, that we resolve observation itself into states of consciousness; and, if so, that the memory of a chain of states of Consciousness, is the evidence in both cases.

This brings us to the very bottom of the matter. Every body recognises, at once, that the memory of a state of consciousness, and the memory of something170observed, are two distinct things; that the memory, for example, of one of my own sensations, and the memory of an outward fact, as of the death of my father, are specifically different: or, to take two cases still easier perhaps to distinguish; no one will say, that the memory of oneâ€™s own pain is any thing like the same state of consciousness with the memory of seeing another man in pain. In the one case, the state of consciousness remembered is the pain itself; in the other it is the sensations of sight or hearing, which indicated to me the pain of the other man, or called up the idea of his pain by association. In the one case, the memory is memory of my own sensations purely; in the other case, it is the memory of my sensations, as the evidence only of outward things.

Each of the terms, therefore, I, Thou, He, marks a particular chain of antecedents and consequents, terminating with the I, the Thou, the He, of the present moment. The I, the Thou, the He, of the present moment, is marked, by these terms,primarily; the preceding links are marked,secondarily, that is, connoted. When I say, â€œI, Thou, or He, did any thing,â€ it is the I, the Thou, the He, of the moment spoken of, that is specially noted. The rest of the chain is not particularly adverted to, except when there is particular occasion for it.

Since the I, the Thou, the He, stand for the names of three men, and equally denote the antecedents and consequents, forming what is familiarly called the thread of life, of each of those individuals; how does it happen, that the idea, which is called up by the term I, appears to be so different, from that which is171called up by the term Thou, or any term denoting the vital chain of any other man?

In what has been already stated, is found the answer. In that chain of antecedents and consequents which I mark by the term â€œsame man,â€ two species of things are included; 1. The antecedents and consequents which form the successive states of his body; 2. The successive states of his consciousness.

In knowing the antecedents and consequents, which form the successive states of my own body and of that of another man, the mode, though in some respects different, is, in so many respects, the same, that it does not here require explanation. But the mode of knowing the successive states of my own consciousness, and of those of other men, is totally different; and in this consists the peculiarity which appears to belong to the idea which I annex to the term I, or myself. The knowledge of my own states of consciousness is consciousness itself, for the present moment, and memory of that consciousness for all the past. Of the states of consciousness of other men, I have no direct knowledge. I draw my belief of them only from signs. These signs, too, are significant only by reference to my own states of consciousness. Certain things cognizable by my senses, are accompanied in myself by certain states of consciousness, single, or in trains. These objects of sense (sights, sounds, &c.) are closely associated with the ideas of those states of consciousness. When presented to me, therefore, as objects of sense to other men, they excite the ideas of those states of consciousness; and hence what I call my knowledge and belief of the mental trains of other men. It is not necessary to go further in the172analysis. It is very obvious, that two complex ideas must be different, which are formed in these different ways; nor is any thing more necessary to account for the difference between the idea annexed to the pronoun I, and that annexed to the pronoun Thou.33

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