By the aid of the touch, then, we have associated the visual phenomena with thing which are not the organ of vision; and well it is for us that we have done so betimes, and before we were aware of the eye's existence. Had the eye been indicated to us in the mere act of seeing; had we become apprised of its existence before we had associated our visual sensations with the tangible objects constituting the material universe, the probability, nay the certainty, is that we would have associated them with this eye, and that then it would have been as impossible for us to break up the association between colours and the organ, as it now is for us to dissolve the union between colours and material things. In which case we should have remained blind, or as bad as blind; brightness would have been in the eye when it ought to have been in the sun; greenness would have been in the retina when it ought to have been in the grass. A most wise provision of nature it certainly is, by which our visual sensations are disposed of in the right way before we obtain any knowledge of the eye. And most wisely has nature seconded her own scheme by obscuring all the sources from which that knowledge might be derived. The light eyelids—the effortless muscular apparatus performing its ministrations so gently as to be almost unfelt—the tactual sensations so imperceptible when the eye is left to its own motions, so keen when it is invaded by an exploring finger, and so anxious to avoid all contact by which the existence of the organ might be betrayed. All these are so many means adopted by nature to keep back from the infant seer all knowledge of his own eye—a knowledge which, if developed prematurely, would have perverted the functions, if not rendered nugatory the very existence of the organ.
But, secondly, we have to consider the stage of the process in which vision is in some way associated with an object which is not any of the things with which the visual sensations are connected. It is clear that the process is not completed—that our task, which is to dissolve the primary synthesis of vision and its phenomena, is but half executed, unless such an object be found. For though we have associated the visual sensations (colours) with something different from themselves, still vision clings to them without a hair's-breadth of interval and pursues them whithersoever they go. As far, then, as we have yet gone, it cannot be said that our vision is felt or known to be distanced from the fixed stars even by the diameter of a grain of sand. The synthesis of sight and colour is not yet discriminated. How, then, is the interval interposed? We answer, by the discovery of a tangible object in a different place from any of the tangible objects associated with colour; and then by associating, in some way or other, the operations of vision with this object. Such an object is discovered in the eye. Now, as has frequently been said, we cannot associate colours or the visual sensations with this eye; for these have been already disposed of otherwise. What, then, do we associate with it—and how? We find, upon experiment, that our apprehension of the various visual sensations depends on the presence and particular location of this small tangible body. We find that the whole array of visual phenomena disappear when it is tactually covered, that they reappear when it is reopened, and so forth. Thus we come in some way to associate vision with it—not as colour, however, not as visual sensation. We regard the organ and its dispositions merely as a general condition regulating the apprehension of the visual sensations, and no more.
Thus, by attending to the two associations that occur,—the association (in place) of visual sensations with tangible bodies that are not the eye; and the association (in place) of vision with a small tangible body that is the eye—the eye regarded as the condition on which the apprehension of these sensations depends; by attending to these, we can understand how a protensive interval comes to be recognised between the organ and its objects. By means of the touch, we have associated the sensations of vision with tangible bodies in one place, and the apprehension of these sensations with a tangible body in another place. It is, therefore, impossible for the sight to dissolve these associations, and bring the sensations out of the one place where they are felt, into the other place where the condition of their apprehension resides. The sight is, therefore, compelled to leave the sensations where they are, and the apprehension of them where it is; and to recognize the two as sundered from each other—the sensations as separated from the organ, which they truly are. Thus it is that we would explain the origin of the perception of distance by the eye; believing firmly that the sight would never have discerned this distance without the mediation of the touch.
Rightly to understand the foregoing reasoning—indeed to advance a single step in the true philosophy of sensation—we much divest ourselves of the prejudice instilled into us by a false physiology, that what we call our organism, or, in plain words, our body, is necessarily the seat of our sensations. That all our sensations come to be associated in some way with this body, and that some of them even come to be associated with it in place, is undeniable; but so far is it from being true, that they are all essentially implicated or incorporated with it, and cannot exist at a distance from it, that we have a direct proof to the contrary in our sensations of vision; and until the physiologist can prove (what has never yet been proven) an à priori necessity that our sensations must be where our bodies are, and an à priori absurdity in the contrary supposition, he must excuse us for resolutely standing by the fact as we find it.
This is a view which admits of much discussion, and we would gladly expatiate upon the subject, did time and space permit; but we must content ourselves with winding up the present observations with the accompanying diagram, which we think explains our view beyond the possibility of a mistake.
| A | ||
| Ba | áC |
Let A be the original synthesis, or indiscrimination of vision and its sensations—of light and colours. Let á be the visual sensations locally associated by means of the touch with the tangible bodies C before vision is in any way associated with B—before, indeed, we have any knowledge of the existence of B. Then let a, the general condition on which the sensations, after a time, are found to depend, and in virtue of which they are apprehended, be locally associated with B—the eye discovered by means of the touch—and we have before us what we cannot help regarding as a complete rationale of the whole phenomena and mysteries of vision. Now, the great difference between this view of the subject and the views of it that have been taken by every other philosopher, consists in this, that whereas their explanations invariably implicated the visual sensations á with B from the very first, thereby rendering it either impossible for them to be afterwards associated with C, or possible only in virtue of some very extravagant hypothesis—our explanation, on the contrary, proceeding on a simple observation of the facts, and never implicating the sensations á with B at all, but associating them with C à primordiis, merely leaving to be associated with B, a, a certain general condition that must be complied with, in order that the sensations á may be apprehended,—in this way, we say, our explanation contrives to steer clear both of the impossibility and the hypothesis.
We would just add by way of postscript to this article—which, perhaps, ought itself to have been only a postscript—that with regard to Mr Bailey's allegation of our having plagiarised one of his arguments, merely turning the coat of it outside in, we can assure him that he is labouring under a mistake. In our former paper, we remarked that we could not see things to be out of the sight, because we could not see the sight itself. Mr Bailey alleges, that this argument is borrowed from him, being a mere reversal of his reasoning, that we cannot see things to be in the sight, because we cannot see both the sight and the things. That our argument might very naturally have been suggested by his, we admit. But it was not so. We had either overlooked the passage in his book, or it was clean out of our mind when we were pondering our own speculations. It did not suggest our argument, either nearly or remotely. Had it done so, we should certainly have noticed it, and should probably have handled both Mr Bailey's reasoning and our own to better purpose, in consequence. If, notwithstanding this disclaimer, he still thinks that appearances are against us, we cannot mend his faith, but can merely repeat, that the fact is as we have stated it.