ively, or intuitively, from the mere act of seeing, that the eye is the organ of vision, that it forms a part of the body we behold, and is located in the head, it requires no conjurer to prove that we must have an instinctive, or intuitive, knowledge of visible things as larger than that organ, and, consequently, as external to it. In this case, no process of association is necessary to account for our knowledge of the distance of objects. That knowledge must be directly given in the very function and exercise of vision, as every one will admit, without going to the expense of an octavo volume to have it proved.
But we hold that no truth in mental philosophy is more incontestable than this, that the sight originally, and of itself, furnishes us with no knowledge of the eye, as we now know that organ to exist. It does not inform us that we have an eye at all. And here we may hazard an observation, which, simple as it is, appears to us to be new, and not unimportant in aiding us to unravel the mysteries of sensation; which observation is, that, in no case whatever, does any sense inform us of the existence of its appropriate organ, or of the relation which subsists between that organ and its objects, but that the interposition of some other sense[1] is invariably required to give us this information. This truth, which we believe holds good with regard to all the senses, is most strikingly exemplified in the case of vision, as we shall now endeavour to illustrate.
Let us begin by supposing that man is a mere "power of seeing." Under this supposition, we must hold that the periphery of vision is one and the same with the periphery of visible space; and the two peripheries being identical, of course whatever objects lie within the sphere of the one must lie within the sphere of the other also. Perhaps, strictly speaking, it is wrong to say that these objects are apprehended as internal to the sight; for the conception of internality implies the conception of externality, and neither of these conceptions can, as yet. be realized. But it is obvious what he expression internal means; and it is unobjectionable, when understood to signify that the Seeing Power, the Seeing Act, and the Seen Things, co-exist in a synthesis in which there is no interval or discrimination. For, suppose that we know instinctively that the seen things occupy a locality separate from the sight. But that implies that we instinctively know that the sight occupies a locality separate from them. But such a supposition is a falling back upon the notion just reprobated, that the mere act of seeing can indicate its own organ, or can localise the visual phenomena in the eye—a position which, we presume, no philosopher will be hardy enough to maintain, when called upon to do so, broadly and unequivocally. The conclusion, therefore, is irresistible, that, in mere vision, the sight and its objects cling together in a union or synthesis, which no function of that sense, and no knowledge imparted to us by it, (and, according to the supposition, we have, as yet, no other knowledge,) can enable us to discriminate or dissolve. Where the seeing is, there is the thing seen, and where the thing seen is, there is the seeing of it.
But man is not a mere seeing animal. He has other senses besides: He has, for example, the sense of touch, and one of the most important offices which this sense performs, is to break up the identity or cohesion which subsists between sight and its objects. And how? We answer, by teaching us to associate vision in general, or the abstract condition regulating our visual impressions, with the presence of the small tangible body we call the eye, and vision in particular, or the individual sensations of vision, (i.e. colours,) with the presence of immeasurably larger bodies revealed to us by touch, and tangibly external to the tangible eye. Sight, as we have said, does not inform us that its sensations are situated in the
- ↑ It would not be difficult to show., that as, on the one hand, distance is not involved in the original intuitions of sight, so, on the other hand, proximity is not involved in the original intuitions of touch; but that, while it is the touch which establishes an interval between the organ and the objects of sight, it is the sight which establishes no interval between the organ and the objects of touch. Sight thus pays back every fraction of the debt it has incurred to its brother sense. This is an interesting subject, but we can only glance at it here.
