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

by Thomas Brown

Footnotes

[74] Gray de Principiis Cogitandi, Lib. I. v. 130–134.

[75] Gray on the Pleasure arising from Vicissitude, Stanza I.—In v. i. the original has, instead of “in vain,” “now.”

[76] Reid's Inquiry into the Human Mind, c. iv. sect. 1.

[77] Pharsalia, lib. vii. v. 207—213.

[78] Darwin's Botanic Garden, Canto IV. v. 371—380.

[LECTURE XXI.]

ON HEARING—CONTINUED.

Gentlemen, after considering, in a former Lecture, some states of mind, which arise immediately from affections of our nerves, and which, therefore, I can see no reason for classing apart from our other sensations, I proceeded, in my last Lecture, to consider the feelings, which are more commonly termed sensations, beginning with the most simple of these, in the order of smell, taste, and hearing.

In the elucidation of these, my great object was to show, that there is nothing, in the mere states of mind, that constitutes the sensations of fragrance, sweetness, sound, which could have led us to ascribe them to corporeal objects as their causes,—more than in any of our internal joys or sorrows,—if we had had no other means of acquiring knowledge of those causes, than are afforded by the sensations themselves,—that, in short, we consider them as sensations, or external affections of the mind, because we have previously believed in an external world,—not that we believe in an external world, merely because we have had those particular sensations.

The various advantages, which these three senses afford, I endeavoured to point out to you; and, in particular occupied a great part of my Lecture, in illustrating the advantages for which we are indebted to our organ of hearing, as the medium of language, and by it, more or less directly, not of the high acquisitions of science and civilization only, but of the rudest forms of social communication, and almost of social existence.

After the remarks on this advantage received from language, which is unquestionably, and beyond all comparison, the most inestimable benefit which the sense of hearing affords,—it would be improper to omit wholly the mention of the pleasure, which we receive from it, as a source of musical delight,—of that expression of feeling, which itself, almost like verbal discourse, may be said to be a language, since it is the utterance of thought and emotion from heart to heart,—but which has a voice, as independent of the mere arbitrary forms of speech, as the tears of gratitude, or the smiles of love, that may indeed, give eloquence to words, but require no words to render them eloquent. Though, when very strictly considered, even the pure, and almost spiritual delight of music, may perhaps be counted only a pleasure of sense, it yet approaches, by so many striking analogies, to the nature of our intellectual enjoyments, that it may almost be said to belong to that class; and though,—relatively to minds that are capable of enjoyments more truly intellectual,—it is to be considered as a mere pastime or relaxation, it assumes a far higher character, in its relation to the general pleasures of common minds, and may be said, at least, to be the intellectual luxury of those, who are incapable of any other luxury, that deserves so honourable a name. And it is well, that there should be some intermediate pleasure of this sort, to withdraw for a while the dull and the sensual, from the grosser existence in which they may be sunk, and to give them some glimpses, at least, of a state of purer enjoyment, than that which is to be derived from the sordid gains, and sordid luxuries, of common life.

Of the influence,—whether salutary or injurious,—which music has upon the general character,—when cultivated, to great refinement, and so universally as almost to become a part of the habit of daily social life,—it is not, at present, the place to speak. But of its temporary influence, as a source of tranquillizing delight, there can be no doubt,—nor, perhaps too, of its occasional efficacy, in exciting emotions of a stronger kind, when peculiar circumstances may have predisposed to them in a very high degree. But there can be as little doubt, that by far the greater number of anecdotes of this kind, which have been handed down in ancient history, are as fabulous, as the existence of that god of music, to whose miraculous influence alone, they could, with any decent appearance of epic or dramatic truth, have been ascribed.

“Hear, how Timotheus' varied lays surprise,

And bid alternate passions fall and rise;

While at each change, the son of Lybian Jove

Now burns with glory, and then melts with love,—

Now his fierce eyes with sparkling fury glow,

Now, sighs steal out, and tears begin to flow;

Persians and Greeks like turns of nature found,

And the world's victor stood subdued—by sound!”[79]

On these lines, which allude to the celebrated ode of Dryden,—who adapted, with most happy application, to the burning of the Persian palace, an anecdote recorded of the power of Timotheus over the same great warrior, on another occasion,—I may remark, by the way, what influence the accidental composition of this ode has had, in giving almost a sort of dignity to the very madness of the act which it records. It is impossible for us,—even though we knew well how fictitious is the circumstance attached to it,—not to look upon the action, in a different light, from that in which we should have viewed it, if we had read only the historical account of it, as originating in a drunken debauch, at the instigation of a drunken prostitute.

Such is the influence of genius. Its power extends not over the present and the future merely, but, in some measure, also over the past, which might have seemed fixed forever. In spite of our conviction, we look upon an action of Alexander differently, because an individual existed, many centuries after him, and in a country which would then have been justly counted barbarous, by the very barbarians whom he overcame.

“Ebrio scorto de tanta re ferente sententiam, unus et alter, et ipsi mero onerati, assentiunt: Rex quoque fuit avidior quam patientior. ‘Quin igitur ulcisimur Græciam, et urbi faces subdimus?’ Omnes incaluerant mero; itaque surgunt temulenti ad incendendam urbem, cui armati, pepercerant.”[80]

Of the wonders, which were said, in ancient times, to have been performed, on the mind and body, by a judicious adaptation of musical sounds, to the nature of the particular case, intellectual, moral, or corporeal, I might read many histories to you, from the original authors, which would perhaps not be less truly ludicrous in the serious gravity of their narration, than in the affected solemnity of the fictitious personage whose speech I am about to quote. The experiment with which the quotation closes is, it must be allowed, a very powerful one, and certainly could not have been more successful, in the hands of Timotheus himself.

“The bare mention of music threw Cornelius into a passion. ‘How can you dignify,’ quoth he, ‘this modern fiddling with the name of music? Will any of your best hautboys encounter a wolf now-a-days with no other arms but their instruments, as did that ancient piper Pythocaris? Have ever wild boars, elephants, deer, dolphins, whales, or turbots, shewed the least emotion at the most elaborate strains of your modern scrapers, all which have been, as it were tamed and humanized by ancient musicians? Whence proceeds the degenerancy of our morals? Is it not from the loss of ancient music, by which (says Aristotle) they taught all the virtues? Else might we turn Newgate into a college of Dorian musicians, who should teach moral virtues to those people. Whence comes it that our present diseases are so stubborn? whence is it that I daily deplore my sciatical pains? Alas! because we have lost their true cure, by the melody of the pipe. All this was well known to the ancients, as Theophrastus assures us, (whence Cælius calls it loca dolentia decantare) only indeed some small remains of this skill are preserved in the cure of the Tarantula. Did not Pythagoras stop a company of drunken bullies from storming a civil house, by changing the strain of the pipe to the sober spondaeus? and yet your modern musicians want art to defend their windows from common nickers. It is well known that when the Lacedaemonian mob were up, they commonly sent for a Lesbian musician to appease them, and they immediately grew calm as soon as they heard Terpander sing: Yet I don't believe that the Pope's whole band of music, though the best of this age, could keep his holiness's image from being burnt on a fifth of November.’ ‘Nor would Terpander himself,’ replied Albertus, ‘at Billingsgate, nor Timotheus at Hockley in the Hole, have any manner of effect, nor both of them together bring Horneck to common civility.’ ‘That's a gross mistake,’ said Cornelius, very warmly, ‘and to prove it so, I have here a small lyra of my own, framed, strung, and tuned after the ancient manner. I can play some fragments of Lesbian tunes, and I wish I were to try them upon the most passionate creatures alive.’—‘You never had a better opportunity,’ says Albertus, ‘for yonder are two apple-women scolding, and just ready to uncoif one another.’ With that Cornelius, undressed as he was, jumps out into his balcony, his lyra in hand, in his slippers,—with a stocking upon his head, and waist-coat of murrey-coloured satin upon his body: He touched his lyra with a very unusual sort of an harpegiatura, nor were his hopes frustrated. The odd equipage, the uncouth instrument, the strangeness of the man and of the music, drew the ears and eyes of the whole mob that were got about the two female champions, and at last of the combatants themselves. They all approached the balcony, in as close attention as Orpheus's first audience of cattle, or that of an Italian opera, when some favourite air is just awakened. This sudden effect of his music encouraged him mightily, and it was observed he never touched his lyre in such a truly chromatic and enharmonic manner as upon that occasion. The mob laughed, sung, jumped, danced, and used many odd gestures, all which he judged to be caused by the various strains and modulations. ‘Mark,’ quoth he, ‘in this, the power of the Ionian, in that, you see the effect of the Æolian.’ But in a little time they began to grow riotous, and threw stones; Cornelius then withdrew. ‘Brother,’ said he, ‘do you observe I have mixed unawares too much of the Phrygian? I might change it to the Lydian, and soften their riotous tempers: But it is enough: learn from this sample to speak with veneration of ancient music. If this lyre in my unskilful hands can perform such wonders, what must it not have done in those of a Timotheus or a Terpander?’ Having said this he retired with the utmost exultation in himself, and contempt of his brother; and, it is said, behaved that night with such unusual haughtiness to his family, that they all had reason to wish for some ancient Tibicen to calm his temper.”[81]

That, in enlightened countries, so many wonders should have been related and credited,—if no phenomena that could justify them were truly observed,—may perhaps on first reflection, appear so unaccountable, as almost to induce belief of the wonders themselves, as less inexplicable than the very credit which was given to them. But it must be remembered, that, in all ages, and even in countries of philosophers, there is a very large fund of credulity in man,—which yields, very readily, to every thing that is not absolutely impossible, and which is even not very nice, in estimating what is impossible,—leaning always, whenever there is the slightest doubt on this point, with a very favourable inclination to the side of the possibility;—and, in the second place, that the phenomena of music are precisely of a kind, which gives this credulity the widest scope. They are pleasing in themselves, and of a kind therefore, on which it is gratifying to the imagination to dwell—their influence on the mind is felt in a very high and wonderful degree, even without any fabulous addition;—they are produced by instruments, which seem, in their sensible appearance, so little adequate to the production of them, that the result is almost like the effect of supernatural agency, to which we know not how to give any limits;—and, when a little mystery is once admitted, the imagination, which has fairly got over the difficulty of this first admission, is not very scrupulous afterwards as to degrees, but is sufficiently ready of itself to admit a great deal more, without pausing to consider its exact amount.

The phenomena of music, in addition to their general interest, are truly worthy, in another respect, of our astonishment, from that striking diversity of organic power in the perception of melody and still more of harmony which they exhibit in different individuals, in whom all other circumstances are apparently the same,—a diversity which has often attracted the attention of philosophers, and has led even those who have no great tendency to speculation of any kind, to wonder at least, which is the first step of all philosophizing. In the present instance, however, unfortunately, this first step is the only step which philosophers have been able to take. They have been obliged to desist, after all their efforts to proceed farther, and to submit to share, and even to acknowledge that they share, the ignorance of the vulgar. If, indeed, the want of musical ear had involved either a general defect of hearing, or a general slowness of discrimination in other cases of nice diversity, the wonder would not have been great. But those, who are without ear for music, perceive as readily as others, the faintest whisper;—they distinguish like them, the faintest shades of difference in the mere articulations of sound which constitute the varieties of language, nor the articulations only, but the differences also of the mere tones of affection or displeasure, grief or gaiety, which are so strikingly analogous to the varied expression of musical feeling;—and their power of discrimination in every other case, in which the judgment can be exercised, is not less perfect. Nay,—to increase still more the difficulty,—they are often as sensible, as others, of the beauty of series of tones of a different kind; and some of our best poets and declaimers,—who of course must have had a quick discernment of metrical rhythm, and of the melody of elocution,—have yet been incapable of distinguishing the musical relations of sounds, as reciprocally high or low,—the melody that results from them in certain successions, and the harmony or the discord of their union. That it depends, chiefly, or perhaps entirely, on the structure or state of the mere corporeal organ of hearing,—which is of a kind, it must be remembered, peculiarly complicated, and therefore susceptible of great original diversity in the parts, and relations of the parts that form it, is very probable; though the difference of the separate parts themselves, or of their relations to each other, may, to the mere eye, be so minute, as never to be discovered by dissection,—thus leaving, to every future race of inquirers, the same difficulty which has perplexed ourselves, and the same impossibility of overcoming it. In the sense of vision, I may remark, there is a species of defect, very analogous to the want of musical ear,—a defect, which consists in the difficulty, or rather the incapacity, of distinguishing some colours from each other—and colours which, to general observers, seem of a very opposite kind. As the want of musical ear implies no general defect of mere quickness of hearing, this visual defect, in like manner, is to be found in persons, who are yet capable of distinguishing, with perfect accuracy, the form, and the greater or less brilliancy of the coloured object;—and I may remark too, in confirmation of the opinion, that the want of musical ear depends on causes not mental but organic; that, in this analogous case, some attempts, not absolutely unsuccessful, have been made, to explain the apparent confusion of colours, by certain peculiarities of the external organ of sight. Though the one case, however, were to throw no light upon the other, it is still gratifying to philosophers, to have a case at all analogous, to which, when they are weary of considering what has baffled all their endeavours to explain it, they may have the comfort of turning away their attention, without the mortification of seeming absolutely to fly from the subject. Such is the strange constitution of our nature, that merely to have another difficulty presented to us, though it may yet be absolutely unsurmountable in itself,—if only it have some slight resemblance to a former difficulty,—seems to us almost as if we had succeeded in explaining the first;—and each difficulty, by a very convenient transposition, which our pride knows well how to make, supplies, according as we may have been considering the one rather than the other, the place of explanation to that which is afterwards to explain it, no less clearly, in its turn.

In considering sound relatively to its external cause, we give the name of vibration to the successive pulses, or alternate approaches and recessions of the particles of the elastic sounding body; and the word is a very convenient one for expressing this series. But still it may be necessary to warn you, that the word, though single, is not the less expressive of a plurality of states, which have no other unity, than as they are comprehended in this single word,—a word, like many other single words, by which we express the combination of various objects, or invented by us, merely to aid our weakness, that is incapable, without such helps, of conceiving or remembering even a small part of that wide series of physical changes, which we are able to discover in the universe, if each event of the series were to be distinguished by a peculiar name. This mere aid of our weakness, however, we are apt, by a very absurd, but a very general fallacy, to consider as something, much more dignified in its nature than a mere arbitrary verbal abbreviation,—as truly an explanation of the very phenomena, or series of phenomena, which it simply designates. You must not flatter yourselves, however, that you have advanced the slightest step, in explaining the connexion of sound with the pulses of air, when you have merely invented a brief term for those successive pulses, and ascribed the sound to vibration; you have, indeed, given a name to a series of corpuscular phenomena, but you have not discovered any thing additional to the phenomena themselves, which can be considered as explanatory to the changes produced.

What, then, is truly meant, when it is said, that, for producing the mental affection, which constitutes hearing, some previous vibration is necessary? It certainly cannot mean, as I have already remarked, that the vibration is any thing in itself different from the series of physical events which it expresses, however few or numerous these may be, since it is only the name which we give to them, when we consider them together; nor can it mean that the direct cause of the sensation is any thing different from the one organic state immediately preceding the sensation,—a state which may, indeed, have resulted from a long sequence of prior organic states, produced during the continued vibratory motion of the air, but which is itself, in its relation to the phenomenon which succeeds it,—that affection of the sentient mind which constitutes hearing,—to be considered independently of these prior states, that have no other relation to the mind, than as gradually inducing that ultimate organic state, which is the state that is followed by sensation. There is a part, less or greater, of the sensorial organ, which must be affected, in a certain manner, before the sensation of hearing can take place; and, in vibration, there is nothing but a repeated approach and secession of the vibrating particles. If vibration, then, or a series of pulses, be necessary, it is evident that a corresponding series of changes in the organ is necessary; that is to say, there is no one instant, at which the vibrating particles are in such a state relatively to the sensorial organ, that if no previous change had been excited in the organ itself, they could have produced in it immediately, the precise state, which is instantly followed by the mental affection of hearing. There must, therefore, be a series of changes, in the sensorial organ itself, the last of which only is followed by sensation. The particles of the air, or any other elastic medium, for example, must, in their first appulse, produce a certain state of the sensorial organ; in their second appulse, a different state, by acting on an organ, already affected in a certain manner; in their third appulse, a still different state; and thus successively, till, at last, they produce that particular definite state of the sensorial organ, in consequence of which, the mind becomes instantly sentient,—a state which could not have been produced by any single impulse of the particles on the unaffected organ, because then vibration, or a series of pulses, would not have been necessary.

To this successive modification of states of an organ, terminating in a particular result, different from each of the prior states, there are abundant analogies in the history of the mind, and many in the phenomena of sensation itself. One of the most remarkable of these is the production of the sensation of whiteness, by the rapid revolution of a cylinder, on which the separate prismatic colours, and the separate colours only, are painted, in certain proportions; each colour, in this case, acting on the organ already affected by a former colour, till a sensation altogether different from the result of each of them when separate, is their joint ultimate result, the sensation of whiteness, without any external object that is white.

In this way only, by a series of progressive organic affections, and not by any single affection, can the vibration of an elastic medium, as different from one simple unrepeated impulse, terminate in the production of sound. It is, in short, a name for this series of changes, and nothing more.

If, in a case so very obscure as that of musical ear, in which all that is truly evident, is, that in different individuals, there is a diversity of some kind or other—I could permit myself to indulge any conjecture with respect to this diversity,—I might perhaps, be inclined to look to the view now given of the real nature of vibration, and its progressive effects on the auditory part of our nervous system, as furnishing some slight ground, not, indeed, for any theory, which is far too presumptuous a word, but for the preference of one mere possibility, to other mere possibilities, which is all that can be hoped in any conjecture, on so very dim and impalpable a subject.

We have seen that the series of pulses of the vibrating air,—if vibration, or a series of pulses be necessary to sound,—must produce a series of changes in the sensorial organ, which produce no corresponding affection of the mind, till, at last, a state of the organ is produced, which is attended with sensation. This, and this only, can be meant, when we speak of vibration as the antecedent of sound,—a series of organic changes, and, after this series, an affection of the mind. In such circumstances, it is certainly more probable, that the organ thus affected with a series of progressive changes, does not pass instantly from the greatest change to the state in which it was originally, before the first pulse, but that it retains this state, for a time, however, short, or, at least, passes through some series of states, in its gradual return, so that, if a new vibration be excited by the pulse of any sounding body, before the organ of hearing have returned to its original state, the effect may be supposed to be different from that which it would have been, if the same vibration had been primarily communicated to the organ, in its state of rest, or in that state, which, from our want of a better word, may be termed its state of rest.

The phenomena most analogous to these vibratory affections of the ear, as depending on successive impulses, are unquestionably the phenomena of titillation, or rather, to express what is so familiar and simple, by a more homely and appropriate word, the phenomena of tickling. In this, the great circumstance distinguishing musical feeling, is to be found, that the feeling arises not from the separate impressions, but from their successions or co-existence. When the palm of the hand is gently tickled, as the finger passes rapidly and repeatedly over the palm, the parts first affected are again affected with various degrees of pressure, as the ear, in melody, is successively affected by repeated varieties of vibration; and various parts of the organ of touch exist, at the same moment, in various states, forming one joint result of sensation, as, in harmony, various vibrations of the organ of hearing co-exist, and blend together in one mingled delight. To produce tickling, a certain rapidity of succession is necessary; for, if the parts, first affected, have returned to their original state, before other parts begin to be affected, or themselves to be affected again, the slow motion, it is evident, may be continued, for any length of time, without any effect, different from that of simple pressure. The quicker, then, the return of the parts may be to their original state, the less will be the titillation; and, it is very probably, a difference in this quickness of return, which constitutes the difference of ticklishness, so remarkable in different individuals, who feel, equally, the light pressure of each separate touch. That there is a difference of ticklishness, in different persons, you all know; some being easily excited even to convulsive laughter, by slight motions, that scarcely produce any effect in others, beyond that of the simple primary sensation of touch. A person who is ticklish, and a person who is not ticklish, agree in receiving this first tactual sensation; but they differ afterwards, in this respect, that when the same slight impulse is rapidly repeated, on the same surface, it produces a livelier effect than before, in the one, but not in the other. The organ of the one who is not ticklish is in the same state, or nearly in the same state, when it receives the second, third, and fourth impression, as when it received the first, and no peculiar excitement, therefore, is produced. The organ of the other, more susceptible, or more tenacious of the affection produced, has not returned to its original state, when the rapid impression is repeated, and is, therefore, at every new impression, affected in a different manner.

Proceeding on the analogy of these phenomena,—of mere tickling, with which I may suppose you to be all acquainted,—an analogy which, striking as it is in many circumstances, I readily own, does not justify more than conjecture in the case to which I would apply it,—I conceive it to be, at least, not absolutely impossible, since a diversity of some kind, there must be, that in those who receive no pleasure from music, as in those who are not ticklish, there is a rapid return of the nervous organ, after each separate affection, to its original state; that each separate touch or pressure in the one case, and each separate tone in the other case, produces its particular effect,—that effect which it would have produced in all, if unaccompanied by any other tone in music, or slight pressure in tickling,—but that a succession of these produces no effect different from that which each would have produced singly. A certain interval is necessary for distinct hearing in every case; and, before this interval has passed, the auditory nerves, in this case, may be imagined to be again quiescent, or nearly quiescent.

I need not add, that, in an inquiry of this sort, all which is necessary, is to account for the mere original defect of pleasure; since, if the relations of notes, as reciprocally high or low, never gave any delight, the ear, having no object of interest in these successions, would soon habitually neglect them, and at length cease altogether to distinguish them, attending only to the verbal meaning of sounds, and not to their tone; in the same manner, as we pay little attention to another relative difference of voices as more or less loud, unless when the difference is very considerable, and not in those common differences of intensity which distinguish every voice in conversation from every other voice,—or as, after living long in a province, the dialect of which is distinguished by any accentual peculiarities, we at last become unconscious of these, and hear the words, as it were, stripped of their peculiarity of tone. In what is termed the cultivation of a musical ear, however, we have not an analogy merely, but a direct proof of this influence of habit. That the ear may be improved by cultivation, or, in other words, by nice attention to the differences of musical sound, every one knows; and if this attention can enable us, even in mature life, to distinguish sounds as different in themselves, which, but for the habitual attention, we should have regarded as the same, it may well be supposed, that continued inattention, from earliest infancy, may render us insensible of musical relations still more obvious and precise, than those which we have thus only learned to distinguish; or, which is the same thing, that continued attention from infancy to slight musical differences of sound,—an attention which may be regarded as the natural effect of pleasure received,—may render us capable of distinguishing tones as very dissimilar, the differences of which, however obvious at present, we should scarcely, but for such original attentive discrimination, have been able to detect. What, in comparison, the refined musical ear of a performer,—almost every hour, and every moment, of whose life has been spent amid sounds,

“Untwisting all the chains, that tie

The hidden soul of harmony,”—

is to a common musical ear, that common musical ear may be to those in whom this discriminating skill seems to be wholly or nearly defective. The refined musician,—who, but for the long practice of his art, would have shared that incapacity which now excites his wonder,—is astonished, that persons of common ear do not distinguish the nice differences which appear to him almost as remarkable as those differences which they are capable of perceiving; and the person of common musical ear only does the same thing, when he is astonished that the less refined differences, remarked by himself, are not obviously distinguishable by all mankind, or, at least, by all who have no deafness to incapacitate them from hearing the separate sounds. The discrimination in both has depended on previous attention, which has necessarily been greater in one case than in the other; and what attention can we suppose to have been originally given, if from the cause which I have ventured to state as a possible one in persons without musical ear, no pleasure had originally been felt by them in any sequence of notes as successive, and the whole value of sound been to them the meaning of which it was symbolically representative, which, accordingly, they have learned to discriminate in every case, as accurately as others.

I might follow out this speculation at much greater length; but I have already dwelt too long on what is at best a conjecture, and what, perhaps, even as a mere conjecture, is founded only on a slight analogy.

After the examination of the phenomena of Smell, Taste, and Hearing, which are peculiarly simple, I proceed to the consideration of Senses, which afford phenomena that are more complicated, or, at least, which seem more complicated, as considered in the mature state of the mind; when the sensations that arise from one set of organs, by frequent co-existence with sensations that arise from affections of other sets of organs, are, as it were, blended with them in one compound perception, and so permanently modified forever after, that it is difficult in all cases, and in many cases perhaps impossible, to form any accurate notion of the sensations as they existed in their original elementary state.

Since, of the two senses of Sight and Touch, that of Sight,—as far, at least, as we are able, by intellectual analysis at present to discover its original sensations,—is more simple, and more analogous to the senses before considered, I should be inclined, on these accounts, to proceed to the consideration of it, previously to any inquiry into the sense of Touch. But this order, though unquestionably the more regular, if we had to consider only the original sensations of each organ, would be attended with great inconvenience in considering their subsequent modified sensations; since those of Vision depend, in a very great degree, on the prior affections of Touch, with the nature of which, therefore, it is necessary for you to be acquainted in the first place. I am aware, indeed, that, in considering even Touch, I may sometimes find it necessary to refer, for illustration to the phenomena of Vision, though these have not been considered by us, and must, therefore, for the time, be taken upon trust. But when phenomena are at all complicated, such occasional anticipations are absolutely unavoidable. Sensation, indeed, says Aristotle, is a straight line, while intellect is a circle,— Αἴσθησις γραμμὴ, νοῦς κύκλος,—or to use the paraphrastic translation of Cudworth, in his treatise on Immutable Morality, “Sense is of that which is without. Sense wholly gazes and gads abroad; and, therefore, doth not know and comprehend its object, because it is different from it. Sense is a line, the mind is a circle. Sense is like a line, which is the flux of a point running out from itself; but intellect like a circle, that keeps within itself.”[82] That sense is not a circle is, indeed, true, since it terminates in a point; but far from being a straight line, it is one of the most perplexing of curves, and is crossed and cut by so many other curves,—into many of which it flows, and unites with them completely,—that when we arrive at the extremity of the line, it is almost impossible for us to determine with accuracy what curve it is, which, in the strange confusion of our diagram, we have been attempting to trace from its initial point.

I proceed, then, to the consideration of the phenomena of the sense of