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

by Thomas Brown

Of pathless woods; or down the craggy steep

Hurl'd headlong, swam with pain the mantled pool;

Or scaled the cliff,—or danced on hollow winds,

With antic shapes, wild natives of the brain;”

it was still only the cliff, the wood, the pool, which we considered as external: the sorrow with which we mourned along our gloomy track, the pain with which we swam the turbid water, the horror which we felt at the antic shapes, with which we mingled in the ghostly dance, were felt to be wholly in ourselves, and constituted, while they lasted, the very feeling of our own existence.—The belief of an external world is, however, to come afterwards under our full examination:—It is sufficient, for the present, to know, that in the period after infancy, to which alone our memory extends, we are led, irresistibly, to believe in it; and that the belief of it, therefore, in whatever manner it may have originated in the imperfect perceptions of our infancy, is now, when those perceptions are mature, so completely beyond the power of argument to overcome, that it exists, as strongly, in those who reason against it, as in those who reason for it;—that the reference to a direct external cause, however, does not accompany every feeling of our mind, but is confined to a certain number of that long succession of feelings, which forms the varied consciousness of our life,—and that the feelings, with respect to which this reference is made, are the class of sensations, which, when combined with this reference, have commonly been distinguished by the name of perceptions. That we have no perfect evidence of the external existence thus ascribed by us,—independently of our own irresistible belief of it, may be allowed to the sceptic; and the reasoning of Doctor Reid on the subject, as far as he proceeds beyond the assertion of this irresistible belief, and attempts, what has been commonly regarded as a confutation of the scepticism on this point,—by representing it as proceeding on a mistake, with respect to the nature of our ideas,—is itself, as we shall afterwards find, nugatory and fallacious. But still, notwithstanding the errors of philosophers with respect to it, the belief itself is, in the circumstances in which we now exist, so truly a part of our constitution, that to contend against it in argument would be to admit its validity, since it would be to suppose the existence of some one whom we are fairly undertaking to instruct or to confute.

In what circumstance the intuitive belief,—if, as I have said, the belief be in any case intuitive,—arises; or rather, in how large a proportion of cases, in which the reference seems primary and immediate, it is, more probably, the effect of secondary associations transferred from sense to sense, will appear better after the minute analysis on which we are to enter, of the different tribes of our sensations.

In referring to the particular class of sensations, and consequently to an external cause, a certain number only of the affections of our mind, there can be no doubt, that we proceed now, in the mature state of our knowledge, with more accuracy, than we could have attained, in that early period of life, when our original feelings were more recent. We have now a clearer and more definite belief of an external world, and of objects of sensations separate from our sensations themselves; without which general belief, previously obtained, we should as little have ascribed to an external organic cause many of our feelings, which we now ascribe to one—our sensations of sound and fragrance, for example,—as we now ascribe to such an immediate external cause, our emotions of joy or sorrow. A still more important acquisition, is our knowledge of our own organic frame, by which we are enabled, in a great measure, to verify our sensations,—to produce them, as it were at pleasure, when their external objects are before us, and in this way to correct the feelings, which have risen spontaneously, by those, which we ourselves produce. Thus, when, in reverie, our conceptions become peculiarly vivid, and the objects of our thought seem almost to exist in our presence; if only we stretch out our hand, or fix our eyes on the forms that are permanently before us, the illusion vanishes. Our organ of touch or of sight, is not affected in the same manner, as if the object that charms us in our musing dream, were really present; and we class the feeling, therefore, as a conception,—not as a sensation,—which, but for the opportunity of this correction, we should unquestionably, in many instances, have done.

But though, in forming the class of our sensations, we derive many advantages from that full knowledge which the experience of many years has given, we purchase these by disadvantages which are perhaps as great, and which are greater, from the very circumstance, that it is absolutely out of our power to estimate their amount. What we consider as the immediate sensation, is not the simple mental state, as it originally followed that corporeal change, which now precedes it; but, at least in the most striking of all the tribes of our sensations, is a very different one. We have the authority of reason, a priori, as shewing no peculiar connexion of the points of the retina with one place of bodies more than with another; and we have the authority also of observation, in the celebrated case of the young man who was couched by Cheselden, and in other cases of the same peculiar species of blindness, in which the eyes, by a surgical operation, have been rendered for the first time capable of distinct vision, that if we had had no organ of sense but that of sight, and no instinctive judgment had been superadded to mere vision, we should not have had the power of distinguishing the magnitude and distant place of objects;—a mere expanse of colour being all which we should have perceived, if even colour itself could in these circumstances, have been perceived by us as expanded. Yet it is sufficient now, that rays of light, precisely the same in number, and in precisely the same direction, as those which at one period of our life, exhibited to us colour, and colour alone, should fall once more on the same small expanse of nerve, to give us instantly that boundlessness of vision, which, almost as if the fetters of our mortal frame were shaken off, lifts us from our dungeon, and makes us truly citizens, not of the earth only, but of the universe. Simple as the principle may now seem, which distinguishes our secondary or acquired perceptions of vision from those which were primary and immediate, it was long before the distinction was made; and till a period which—if we consider it in relation to those long ages of philosophic inquiry, or, rather, most unphilosophic argumentation, which had gone before—may be considered almost as in our own time, longitudinal distance was conceived to be as completely an original object of sight as the varieties of mere colour and brilliancy. There may, therefore—though we have not yet been able, and may never be able, to discover it,—be a corresponding difference in our other sensations, which now seem to us simple and immediate. In the case of sound, indeed, there is a very evident analogy to these visual acquired perceptions; since a constant reference to place mingles with our sensations of this class, in the same manner, though not so distinctly, as in our perceptions of sight. We perceive the sound, as it were near or at a distance, in one direction rather than in another; as, in the case of longitudinal distance in vision, we perceive colour at one distance rather than at another. Yet there is as little reason, from the nature of the organic changes themselves, to suppose, that different affections of our auditory nerves should originally give us different notions of distance, as that such notions should originally be produced by different affections of the retina: and, as in sight and hearing, so it is far from improbable, that, in all our senses, there may, by the reciprocal influence of these upon each other, or by the repeated lessons of individual experience in each, be a similar modification of the original simple feelings, which, in that first stage of existence that opened to us the world and its phenomena, each individual organ separately afforded. Our reasoning with respect to them, therefore, as original organs of sense, may, perhaps, be as false, as our chemical reasoning would be, were we to attempt to infer the properties of an uncombined acid, or alkali, from our observation of the very different properties of a neutral salt, into the composition of which we know that the acid or the alkali has entered.

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.