In addition to this direct vivifying influence of the desire itself, some part,—and, perhaps a very considerable part—of the brightening of the object, during attention, may arise indirectly from the mere muscular adaptation of the organ. I do not speak merely of that internal adaptation, whatever it may be, which accommodates the organ to the object, and, therefore, varies with the distance of the object, but of that simpler contraction, which keeps the organ, as a whole, steadily fixed. It is proved by many facts, that a certain time is necessary, for vision, and, probably, in like manner, for all our perceptions. A cannon ball, for example, though it must have reflected light to us, during its passage, may yet pass before our eyes, so rapidly, as not to be perceived; and, if a part of the eye be affected, in a certain manner, by one colour, and a different colour fall upon it so rapidly after the first, that the former affection has not previously ceased, the result is not the visual affection, which the second colour alone would have produced, but that which would have arisen at once from a mixture of the two colours. In this way, in an experiment which has been often performed, for the demonstration of this simple and beautiful fact; if a cylinder be painted in longitudinal bars, with the prismatic colours, in certain proportions, and be revolved rapidly on its axis, its surface to the eye will not seem to present any one of the colours, which are really painted on it, but an uniform whiteness, which it has not, on a single point of its whole surface.
If rays of different colours, falling in rapid succession, on the same points of the retina, thus seem to mingle with each other, and produce one confused effect, it must evidently be of great importance, for distinct vision, that the eyes should be so fixed, that the rays from the objects which we wish to observe, may not fall, on some parts of the retina, previously affected by the light of other objects, but, as much as possible, on the same parts, during the whole time of our observation. This can be done, as I have said, only by the continued agency of certain muscles; and hence arises that feeling of muscular effort, of which we are conscious in the process. How difficult is it for us, to keep a muscle, for any length of time, in the same exact point of contraction, without the slightest deviation from this point, is well known to physiologists; and, it is not wonderful, therefore, that in attention, we should be conscious of a considerable effort, in endeavouring to fix steadily any of our organs. The power of thus fixing our muscles, is a power which improves by habitual exercise; and it is probably very much in this way, that the practised eye is able so rapidly to distinguish the minute parts of objects, which require from others a much longer effort of attention.
But, whatever the effect of the muscular adaptation may be, it is not the less certain, if we reflect on our feelings, that the mental part of the process of attention involves nothing more, in addition to the primary perception, which is its object, than desire with expectation. This is all of which we are truly conscious, previously to the brightening of the perception itself, to which we are said to attend;—a brightening, which, from the general laws of emotion, might very naturally be expected as the result of the union of desire, with any of our sensations. In such circumstances, then, it is not wonderful, that we should remember best the objects to which we pay most attention, since this is only to say, that we remember best the objects on which we have dwelt longest, and with greatest interest, and which we have, therefore, known most accurately.
Such are our sensations or perceptions, when united with desire, exhibiting appearances, which seem, at first, to indicate, though they do not truly indicate, a peculiar power or susceptibility of the mind. We shall find, in considering our intellectual states of mind, the order of mental phenomena, to which we next proceed, that the union of desire with these, has led, in like manner, to the belief of many distinct intellectual powers, which yet, like attention, admit of being analyzed into simpler elements. These intellectual phenomena themselves, in their simple state, must, however, be first examined by us.
Having now, then, offered all the observations for which our limited course allows me room, on the very important primary class of external affections of the mind, I proceed according to our general division, to consider the secondary class of its internal affections; those states of it, which are not the result of causes foreign to the mind itself, but immediate consequents of its own preceding feelings.
The Divine Contriver of our mental frame, who formed the soul to exist in certain states, on the presence of external things, formed it also to exist, in certain successive states, without the presence or direct influence of any thing external; the one state of the mind, being, as immediately the cause of the state of mind which follows it, as, in our external feelings, the change produced, in our corporeal organ of sense, is the cause of any one of the particular affections of that class. In the one class, that of our internal affections, the phenomena depend on the laws which regulate the successive changes of state of the mind itself. In the other class, that of our external affections, they depend on the laws of the mind, indeed, which is susceptible of these peculiar changes of state; but they depend, in an equal degree, on the laws which give to matter its peculiar qualities, and, consequently, its peculiar influence on this mental susceptibility. If light were to be annihilated, it is very evident, that, though our mind itself were to continue endowed with all its present susceptibilities, it never again could behold the sun, around whose cold and gloomy mass our earth might still revolve as now; nor, in such circumstances, is there any reason to suppose that it would exist in any one of those various states, which constitute the delightful sensations of vision. These sensations, then, depend on external things, as much as on the mind itself. But, though after we have once been enriched with the splendid acquisitions, which our perceptive organs afford us, every thing external were to vanish, not from our sight merely, but from all our senses, and our mind alone were to exist in the infinity of space, together with that Eternal Majesty which formed it,—still thought after thought, and feeling after feeling, would arise, as it were, spontaneously, in the disembodied spirit,—if no change in its nature were to take place; and the whole world of light, and fragrance, and harmony, would, in its remembrance, almost rise again, as if outliving annihilation itself. It is by this capacity of internal change of state, indeed, that the soul is truly immortal, which, if it were capable of no affections, but those which I have termed external, would itself be virtually as mortal as all the mortal things that are around it; since, but for them, as causes of its feelings, it could not, in these circumstances, of complete dependence, have any feelings whatever, and could, therefore, exist only in that state of original insensibility, which preceded the first sensation that gave it consciousness of existence. It is, in the true sense of immortality of life, immortal, only because it depends for its feelings, as well as for its mere existence, not on the state of perishable things, which are but the atmosphere that floats around it, but on its own independent laws; or, at least,—for the laws of mind, as well as the laws of matter, can mean nothing more,—depends, for the successions of its feelings, only on the provident arrangements, of that All-foreseeing Power whose will, as it existed at the very moment at which it called every thing from nothing, and gave to mind and matter their powers and susceptibilities, is thus, consequently, in the whole series of effects, from age to age, the eternal legislation of the universe.
Even while our soul is united to this bodily frame, and continually capable of being affected by the objects that are continually present with it, by far the greater number of our feelings are those which arise from our internal successions of thought. Innumerable as our perceptions are, they are but a small part of the varied consciousness of a day. We do not see, or feel, objects merely, for this alone would be of little value,—but we compare them with each other,—we form plans of action, and prosecute them with assiduous attention,—or we meditate on the means by which they may most effectually be prosecuted; and with all our perceptions of external things, and plans of serious thought, a continued fairy work of involuntary fancy, is incessantly mingling, in consequence of the laws of suggestion in the mind itself, like the transient shadows, on a stream, of the clouds that fled over it, which picture on it their momentary forms, as they pass in rapid variety, without affecting the course of the busy current, which glides along in its majestic track, as if they had never been. If we had the power of external sense only, life would be as passive as the most unconnected dream, or rather far more passive and irregular than the wildest of our dreams. Our remembrances, comparisons, our hopes, our fears, and all the variety of our thoughts and emotions, give a harmony and unity to our general consciousness, which make the consciousness of each day a little drama, or a connected part of that still greater drama, which is to end only with the death of its hero, or rather with the commencement of his glorious apotheosis.
How wide a field the internal affections of the mind present, without dependence on the system of material things,—with which we are connected, indeed, by many delightful ties, but by ties that have relation only to this mortal scene,—is proved in a very striking manner, by the increased energy of thought which we often seem to acquire in those hours of the quiet of the night, when every external influence is nearly excluded,—the hours of inward meditation, in which the mind has been poetically said, to retire into the sanctuary of its own immense abode, and to feel there and enjoy its spiritual infinity, as if admitted to the etherial dwellings and the feasts of the Gods.
“Nonne vides, quoties nox circumfunditur atra
Immensi terga Oceani terramque polumque,