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

If, indeed, it were in our power to be introduced to a society, like that of which Diderot speaks, in his Letter on the Deaf and Dumb, and to hold communication with them, all our doubts on this subject would be removed. “What a strange society,” says he, “would five persons make, each of them endowed with one only of our five different senses; and no two of the party with the same sense! There can be no doubt, that, differing, as they must differ, in all their views of nature, they would treat each other as madmen, and that each would look upon the others with all due contempt. It is, indeed, only an image of what is happening every moment in the world; we have but one sense, and we judge of every thing.”63– “There is, however,” he justly remarks, “one science, though but one science, in which the whole society of the different senses might agree, – the science which has relation to the properties of number. They might each arrive, by their separate abstractions, at the sublimest speculations of arithmetic and algebra; they might fathom the depths of analysis, and propose and resolve problems of the most complicated equations, as if they were all so many Diophantuses. It is perhaps,” he adds, “what the oyster is doing in its shell.”64

From such a society, – if, indeed, we could hold any communication with these profound algebraists, except in their common science of numbers, – we might undoubtedly learn, what are the direct immediate affections of mind, to which our senses individually give rise, and consequently, how much, while feeling has blended with feeling, they have reciprocally operated on each other. But, in our present circumstances, unaided by intercourse with such living abstractions, it is impossible for us to remove wholly this uncertainty, as to the kind and degree of influence, which experience may have had, in modifying our primary sensations. We may wish, indeed, to be able to distinguish our present feelings, from those which the same objects originally excited; but, since no memory can go back to the period, at which we did not perceive longitudinal distance, as it were, immediately by the eye, as little, we may suppose, can any memory go back to the period, when other sensations, less interesting than those of vision, were first excited. Could we trace the series of feelings, in a single mind, – as variously modified, in the progress from infancy to maturity, – we should know more of the intellectual and moral nature of man, than is probably ever to be revealed to his inquiry, – when in ages, as remote from that in which we live, and perhaps as much more enlightened, as our own age may be said to be in relation to the period of original darkness and barbarism, he is still to be searching into his own nature, with the same avidity as now, He must, indeed be a very dull observer, who has not felt, on looking at an infant, some desire to know the little processes of thought, that are going on in his curious and active mind; and who, on reflecting on the value, as an attainment in science, which the sagest philosopher would set on the consciousness of those acquisitions which infancy has already made, is not struck with that nearness, in which, in some points, extreme knowledge and extreme ignorance may almost be said to meet. What metaphysician is there, however subtile and profound in his analytical inquiries, and however successful in the analyses which he has made, who would not give all his past discovery, and all his hopes of future discovery, for the certainty of knowing with exactness what every infant feels? The full instruction, which such a view of our progressive feelings, from their very origin, in the first sensations of life, would afford, Nature, in her wisdom, however, has not communicated to us, – more than she has communicated to us the nature of that state of being, which awaits the soul after it has finished its career of mortality. Our existence seems, in our conception of it, never to have had a beginning. As far back as we can remember any event, there is always a period, that appears to us still farther back, the events of which we cannot distinguish; as, when we look toward the distant horizon, we see, less and less distinctly, in the long line which the sunshine of evening still illuminates, plains, and woods, and streams, and hills, more distant, half melting into air, beyond which our eye can find nothing, – though we are still certain, that other woods, and streams, and plains are there, and that it is only the imperfection of our sight, which seems to bound them as in another world. It is to man, when he thinks upon his own beginning, as if he felt himself in a world of enchantment, amid the shades and flowers of which he had been wandering, unconscious of the time at which he entered it, or of the objects that are awaiting him, when he shall have arrived at the close of that path, whose windings still lead him forward, – and knowing little more, than that he is himself happy, and that the unknown Being, who has raised this magnificent scene around him, must be the Friend of the mortal, whom he has deigned to admit into it.

“Well pleased he scansThe goodly prospect, – and, with inward smiles,Treads the gay verdure of the painted plain, —Beholds the azure canopy of heaven,And living lamps, that over-arch his head,With more than regal splendour, – bends his earTo the full choir of water, air, and earth;Nor heeds the pleasing error of his thought,Nor doubts the painted green or azure arch,Nor questions more the music's mingling sounds,Than space, or motion, or eternal time;So sweet he feels their influence to attractHis fixed soul, to brighten the dull gloomsOf care, and make the destined road of lifeDelightful to his feet. So, fables tell,The adventurous hero, bound on hard exploit,Beholds with glad surprise, by secret spellOf some kind sage, the patron of his toils,A visionary paradise disclosed,Amid the dubious wild; – With streams, and shades,And airy songs, the enchanted landscape smiles,Cheers his long labours, and renews his frame.”65

The philosophic use of the term sensation does not necessarily imply, what, in its popular use, is considered almost as involved in it; and perhaps, therefore, it may not be superfluous to warn you, that it is not confined to feelings, which are pleasurable or painful, but extends to every mental affection, that is the immediate consequence of impression on our organs of sense, – of which mental states or affections, many, and, as I am inclined to think, by far the greater number, are of a kind, that cannot be termed either agreeable or disagreeable. Of the objects of sight, for example, which are of such very frequent occurrence, how few are there, at which we look, either with pleasure or with pain, – if we except that indirect pleasure, which, in particular cases, they may afford, as communicating to us information, that is valuable in itself, or as gratifying even our idlest curiosity. To take one of the most striking cases of this sort, – though we may derive, from the perusal of a work that interests us, the purest delight, it is a delight, resulting only from the conceptions, which the author, in consequence of the happy contrivance of symbolic characters, has been able to transfuse, as it were, from his own mind into ours; but, during all the time of the perusal, sensations, almost innumerable, have been excited in us, by the separate characters, with which the pages are covered, that have never mingled even the faintest direct pleasure, with the general emotion, which they, and they alone, have indirectly produced.

“I apprehend,” says Dr Reid, “that, besides the sensations, that are either agreeable or disagreeable, there is still a greater number that are indifferent. To these we give so little attention, that they have no name, and are immediately forgot, as if they had never been; and it requires attention to the operations of our minds, to be convinced of their existence. For this end, we may observe, that, to a good ear, every human voice is distinguishable from all others. Some voices are pleasant, some disagreeable; but the far greater part can neither be said to be one or the other. The same thing may be said of other sounds, and no less of tastes, smells, and colours; and if we consider, that our senses are in continual exercise while we are awake, that some sensation attends every object they present to us, and that familiar objects seldom raise any emotion, pleasant or painful, – we shall see reason, besides the agreeable and disagreeable, to admit a third class of sensations, that may be called indifferent. The sensations that are indifferent, are far from being useless. They serve as signs, to distinguish things that differ; and the information we have concerning things external, comes by their means. Thus, if a man had no ear to receive pleasure from the harmony or melody of sounds, he would still find the sense of hearing of great utility; though sounds gave him neither pleasure nor pain, of themselves, they would give him much useful information; and the like may be said of the sensations we have by all the other senses.”66

It is as signs, indeed, far more than as mere pleasures in themselves, that our sensations are to us of such inestimable value. Even in the case to which I before alluded, of the symbolic or arbitrary characters of a language, when we consider all the important purposes to which these are subservient, as raising us originally from absolute barbarism, and saving us from relapsing into it, there might be an appearance of paradox, indeed, but there would be perfect truth in asserting, that the sensations which are themselves indifferent, are more precious, even in relation to happiness itself, than the sensations which are themselves accompanied with lively delight, or rather, of which it is the very essence to be delightful. Happiness, though necessarily involving present pleasure, is the direct or indirect, and often the very distant result of feelings of every kind, pleasurable, painful, and indifferent. It is like the beautiful profusion of flowers, which adorn our summer fields. In our admiration of the foliage, and the blossoms, and the pure airs and sunshine, in which they seem to live, we almost forget the darkness of the soil in which their roots are spread. Yet how much should we err, if we were to consider them as deriving their chief nutriment from the beams that shine around them, in the warmth and light of which we have wandered with joy. That delightful radiance alone would have been of little efficacy, without the showers, from which, in those very wanderings, we have often sought shelter at noon; or at least without the dews, which were unheeded by us, as they fell silently and almost insensibly on our evening walk.

With the common division of our sensations into five classes, – those of smell, taste, hearing, sight, touch, we have been familiar, almost from our childhood; and though the classification may be far from perfect, in reference to our sensations themselves, considered simply as affections of the mind, it is sufficiently accurate, in reference to the mere organs of sense; for, though our sensations of heat and cold, in one very important respect, which is afterwards to be considered by us, have much less resemblance to the other sensations which we acquire by our organs of touch, or at least to sensations, which we are generally supposed to derive from that organ, than to sensations, which we receive by the medium of other organs, our sensations of smell and sound for example – still, as they arise from an affection of the same organ, they may be more conveniently referred to the same, than to any other class; since, if we quit that obvious line of distinction, which the difference of organs affords, we shall not find it easy to define them by other lines as precise.

But whatever may be the arbitrary division or arrangement which we may form either of our sensations themselves, or of the organs that are previously affected, the susceptibility of the mind, by which it is capable of being affected by the changes of state in our mere bodily organs, must be regarded as, in every sense of the word, of primary value in our mental constitution. To the individual, indeed, it may be said to be in itself all the things which are around him, however near or afar; because it is truly that, by which alone all things near or afar become known to him. It constitutes by this mutual relation, which it establishes, a power of more than magic agency, before which the great gulf, that appeared to separate forever the worlds of matter and of spirit, disappears, – which thus links together substances, that seemed, in their nature, incapable of any common bond of union, – and which, bringing the whole infinity of things, within the sphere of our own mind, communicates to it some faint semblance of the omnipresence of its Author. “What is that organ,” – says an eloquent French writer, speaking of the eye, – “what is that astonishing organ, in which all objects acquire, by turns, a successive existence, – where the spaces, the figures, and the motions, that surround me, are as it were created, – where the stars, that exist at the distance of a hundred millions of leagues, become a part of myself, – and where in a single half inch of diameter, is contained the universe?” This power of external sense, which first awakes us into life, continues, ever after, to watch, as it were, round the life which it awoke, lavishing on us perpetual varieties of instruction and delight; and if, from the simple pleasures, and simple elementary knowledge which it immediately affords, we trace its influence, through all the successive feelings to which it indirectly gives rise, it may be said to exist, by a sort of intellectual and moral transmutation, in the most refined and etherial of all our thoughts and emotions. What Grey says of it, – in the commencement of his beautiful fragment De Principiis Cogitandi, addressed to his friend West, is not too high a panegyric, – that every thing delightful and amiable, friendship and fancy, and wisdom itself, have their primary source in it.

“Non illa leves primordia motusQuanquam parva, dabunt. Lætum vel amabile quicquidUsquam oritur, trahit hinc ortum; nec surgit ad auras,Quin ea conspirent simul, eventusque secundent.Hinc variæ vitai artes, ac mollior usus,Dulce et amicitiæ vinclum: Sapientia diaHinc roseum accendit lumen, vultuque sereno,Humanas aperit mentes, nova gaudia monstrans.Illa etiam, quæ te (mirum) noctesque diesqueAssidue fovit inspirans, linguamque sequentemTemperat in numeros, atque horas mulcet inertes,Aurea non alia si jactat origine Musa.”67

So much, indeed, of human knowledge, and of all that is valuable and delightful in human feeling, involves these elementary sensations, as it were in the very essence of the thoughts and feelings themselves, that one of the most acute of modern French metaphysicians, and, with scarcely an exception, all the philosophers of the French metaphysical school, who are his followers, have considered the whole variety of human consciousness, as mere sensation variously transformed; though, in stating the nature of this transformation, and the difference of the sensations as transformed from the primary forms of mere external feeling, they have not been so explicit, as the assertors of a system so paradoxical ought assuredly to have been. On the fallacies of this very prevalent theory of mind, however, which is afterwards to be examined by us fully, I need not at present make any remarks.

Though this excessive simplification of the phenomena of human thought and feeling is, however, far more than the phenomena truly allow, it is not the less certain, that all the varieties of our consciousness, though not mere transformations of external sense, are, when traced to their source, the results of sensation, in its various original forms. In inquiring into the phenomena of our senses, then, we begin our inquiry, where knowledge itself begins, and though the twilight, which hangs over this first opening of intellectual life, is perhaps only a presage, or a part of that obscurity which is to attend the whole track of human investigation, it still is twilight only, not absolute darkness. We can discover much, though we cannot discover all; and where absolute discovery is not allowed, there is still left to us a probability of conjecture, of which, in such limited circumstances, even philosophy may justly avail herself, without departing from her legitimate province.

LECTURE XIX

BRIEF NOTICE OF THE CORPOREAL PART OF THE PROCESS, IN SENSATION

The mental phenomena, of the class which is at present under our consideration, being those, which arise, in consequence of certain previous affections of our organs of sense, it is necessary, that we should take some notice of the corporeal part of the process; though it must always be remembered, that it is the last part of the process, the mental affection only, which truly belongs to our science, – and that, if this, in all its varieties, had been the result of any other species of affections of organs constituted in any other manner, – as long as there was the regular correspondence of certain mental affections with certain organic affections, – the philosophy of mind would have continued precisely the same as now. Our systems of anatomy, and of the physiology of our mere bodily frame, would indeed have been different, – but not that more intimate physiology, which relates to the functions of the animating spirit, whose presence is life, and without which our bodily frame, in all its beautiful adaptation of parts to parts, is a machine, as inert and powerless, as the separate atoms that compose it.

The great essential organ of all sensation is the brain, with its appendages, particularly the nerves that issue from it to certain organs, which are more strictly termed the organs of sense; as it is there the immediate objects, or external causes of sensation, the particles of light, for example, in vision, or of odour in smell, arrive, and come, as it were, into contact with the sensorial substance. Each organ, as you well know, has objects peculiar to itself, which it would be superfluous to enumerate; and since the blind are still sensible of sound, the deaf of colour, and both of smell, and taste, and touch, there must evidently be some difference, either in the sensorial substance itself which is diffused over the different organs, or in the mode of its diffusion and exposure in the different organs, from which this striking diversity of their relative sensibilities proceeds. The nervous matter however, considered separately from the coats in which it is enveloped, is of the same half-fibrous, but soft and pulpy texture, as the substance of the brain itself, and is in perfect continuity with that substance, forming, therefore, with it, what may be considered as one mass, as much as the whole brain itself may be considered as one mass; which has, indeed, for its chief seat the great cavity of the head; the

“Superas hominis sedes, arcemque cerebri;Namque illic posuit solium, et sua templa sacravit,Mens animi; – ”68

but which extends, by innumerable ramifications, over the whole surface, and through the internal parts of the body. The mind, in that central brain in which it is supposed to reside, communicating with all these extreme branches, has been compared, by a very obvious, but a very beautiful similitude, to the parent Ocean, receiving from innumerable distances the waters of its filial streams:

“Ac uti longinquis descendunt montibus amnes,Velivolus Tamisis, flaventisque Indus arenæ,Euphratesque, Tagusque, et opimo flumine Ganges,Undas quisque suas volvens, – cursuque sonoroIn mare prorumpunt; hos magno acclinis in antroExcipit Oceanus, natorumque ordine longoDona recognoscit venientum, ultroque serenatCoeruleam faciem, et diffuso marmore ridet.Haud aliter species properant se inferre novellæCertatim menti.”69

In the brain itself, the anatomist is able to shew us, with perfect clearness, many complicated parts, which we must believe to be adapted for answering particular purposes in the economy of life; but when we have gazed with admiration on all the wonders which his dissecting hand has revealed to us, and have listened to the names with which he most accurately distinguishes the little cavities or protuberances which his knife has thus laid open to our view, we are still as ignorant as before of the particular purposes to which such varieties of form are subservient; and our only consolation is, – for there is surely some comfort in being only as ignorant as the most learned, – that we know as much of the distinct uses of the parts as the anatomist himself, who exhibits them to us, and teaches us how to name them. A structure, in every respect different, though assuredly less fit than the present which has been chosen by infinite wisdom, might, as far as we know, have answered exactly the same end; which is as much as to say, that our ignorance on the subject is complete. The only physiological facts of importance, in reference to sensation, are, that if the nerves, which terminate in particular organs, be greatly diseased, the sensations which we ascribe to those particular organs cease; and cease, in like manner, if the continuity of the nerves be destroyed, by cutting them in any part of their course, or if, without loss of absolute continuity, their structure, in any part of their course be impaired by pressure, whether from tight ligatures drawn around them for the purpose of experiment, or from natural morbid causes. In short, if the brain and nerves be in a sound state, and certain substances be applied to certain parts of the nervous system, – as, for instance, sapid bodies to the extremities of the nerves of taste, or light to that expansion of the optic nerve, which forms what is termed the retina, – there is then instant sensation; and when the brain itself is not in a sound state to a certain extent, or when the nerve which is diffused on a particular organ is, either at this extremity of it, or in any part of its course, to a certain degree impaired, then there is no sensation, though the same external causes be applied. This very slight general knowledge of the circumstances in which sensation takes place, and of the circumstances in which it does NOT take place, is all the knowledge which physiology affords us of the corporeal part of the process; – and it is likely to continue so forever, – at least in all the more important respects of our ignorance, – since any changes which occur in the corpuscular motion, and consequent new arrangement of the particles of the substance of the brain and nerves, corresponding with the diversities of feeling during those particular states, – if such corpuscular motions or changes do really take place, – are probably far too minute to be observable by our organs; even though we could lay open all the internal parts of the brain to complete observation, without destroying, or at all affecting, the usual phenomena of life: —

In “following life through creatures we dissect,We loose it, in the moment we detect.”

Indeed, we are not able to do even so much as this; for life has already vanished, long before we have come upon the verge of its secret precincts. It is like a Magician, that operates at a distance on every side, but still keeps himself apart, within a narrow circle. If we remain without the circle, we may gaze with never-ceasing admiration, on the wonders that play in rapid succession before our eyes. But, if we rush within, to force an avowal, of the secret energy that produces them, the enchanter and the enchantments alike are fled.

The brain, then, and the various nerves of sense in continuity with it, may, when taken together, be considered as forming one great organ, which I would term briefly the sensorial organ, essential to life, and to the immediate production of those mental phenomena which constitute our sensations, and, perhaps, too, modifying in some measure, directly or indirectly, all the other phenomena of the mind.

“Dum mens alma caput cerebrique palatia celsaOccupat, et famulos sublimis dirigit artus,Et facili imperio nervorum flectit habenas,Illius ad nutum sensus extranea rerumExplorant signa, et studio exemplaria fidoAd dominam adducunt; vel qui statione locanturVicina, capitisque tuentur limina, ocelli,Naresque, auriculæque, et vis arguta palati;Vel qui per totam currit sparso agmine molemTactus, ad extremas speculator corporis aras.His sensim auxiliis instructa fidelibus, olimMens humilis nulloque jacens ingloria cultuCarceris in tenebris mox sese attolit in aurasDives opum variarum, et sidera scandit Olympi.”

Of the nature of the connexion of this great sensorial organ with the sentient mind, we never shall be able to understand more than is involved in the simple fact, that a certain affection of the nervous system precedes immediately a certain affection of the mind. But, though we are accustomed to regard this species of mutual succession of bodily and mental changes, as peculiarly inexplicable, from the very different nature of the substances which are reciprocally affected, it is truly not more so than any other case of succession of events, where the phenomena occur in substances that are not different in their properties, but analogous, or even absolutely similar; since, in no one instance of this kind, can we perceive more than the uniform order of the succession itself; and of changes, the successions of which are all absolutely inexplicable, or, in other words, absolutely simple, and unsusceptible, therefore, of further analysis, none can be justly said to be more or less so than another. That a peculiar state of the mere particles of the brain, should be followed by a change of state of the sentient mind, is truly wonderful; but if we consider it strictly, we shall find it to be by no means more wonderful, than that the arrival of the moon, at a certain point of the heavens, should render the state of a body on the surface of our earth, different from what it otherwise would naturally be or that the state of every particle of our globe, in its relative tendencies of gravitation, should be instantly changed, as it unquestionably would be, by the destruction of the most distant satellite of the most distant planet of our system, or probably too, by the destruction even of one of those remotest of stars, which are illuminating their own system of planets, so far in the depth of infinity, that their light, – to borrow a well-known illustration of sidereal distance, – may never yet have reached our earth, since the moment at which they darted forth their first beams, in the creation of the universe. We believe, indeed, with as much confidence, that one event will uniformly have for its consequent another event, which we have observed to follow it, as we believe the simple fact that it has preceded it, in the particular case observed. But the knowledge of the present sequence, as a mere fact, to be remembered, and the expectation of future similar sequences, as the result of an original law of our belief, are precisely of the same kind, whether the sequence of changes be in mind, or in matter singly, or reciprocally in both.