quality of the sensations of taste and smell. The pleasure and pain also which is involved in the systemic sensations and in odours and tastes is pleasure and pain of the same mode; for it will be seen shortly that a distinction in the mode of pleasure and pain must be drawn, when we come to speak of sensations where the formal element is involved in greater complexity. By anticipation then it may be said, that the pleasure and pain of all the foregoing sensations may be called pleasure and pain of enjoyment, as distinguished from pleasure and pain of admiration; a distinction drawn by Kant, in the Kritik der Urtheilskraft, 13, 14. The two lowest of the special senses, smell and taste, may accordingly be classed apart, making a transition or intermediate group between the systemic sensations and the remaining three special senses. And the same remarks will apply to them as to the systemic sensations, with reference to their combination with emotions, namely, that it is by their being represented with their pleasure and pain, so as to form the framework of an emotion. 3. The lowest of the three remaining special senses is touch. In it a new formal element is con tained, the superficial extension of space; the matter of touch is always the same, the feeling of hardness, resistance, or contact, which cannot be described but must be felt, and has no single name but that of the sense itself- touch. The object of touch consists of these two elements, this sensation and superficial extension; these two elements are however variously combined, and their various combinations are the different specific qualities which we apprehend by touch, and which stand to it in the same relation as Book I. $ 10. The special senses. Touch. BOOK I. PART I. § 10. The special senses. These per odours to smell and sapours to taste. 4. As to the inseparability of the form of superficial extension from touch, as an element of its perceptions, it may be remarked that even what we popularly call a point, as the point of a needle, has superficial extension; nor is this only a property given to touch by a supervening reflection, for it can never be taken from it in thought; and if a mathematical point be thought of, this is no tangible thing but a logical abstraction. The least tangible object, then, has superficial extension, and it is no valid objection to urge that we are unable by touch alone to distinguish whether a point or a surface of the skin is touched, or how large a surface, or in what position or direction it is touched; for this only affects the interpretative or discriminative acuteness of the sense of touch, a point touched and a surface touched differing from each other in degree only, and a point being nothing but an extremely small surface. 5. The sense of touch adds nothing to the differences of mode already remarked in the material element of perception; it has quality, intensity, pleasure and pain; but the qualities, roughness, smoothness &c. are such as to be distinguished from each other, not by a difference of quality in their material element, as in all the foregoing senses, but by a difference in the relation of their formal to their material element, and to the different degrees of intensity in the latter. Space comes forward first in touch, and then only in two of its dimensions, length and breadth, or superficial extension. This however causes or enables touch to combine with another sense, sight, which is always in the same way bound up with the same two dimensions of space. of the matter of these two senses and the community of their form, space, are what enables them to combine into a single perception or a single object. This object, namely, superficial extension with two kinds. The difference BOOK I. § 10. The special senses. BOOK I. § 10. The special senses. of qualities, tangible and visible, then by a further process, a process of representation and reasoning, completes itself as a solid, or developes out of itself the third dimension of space. For superficial extension is at first incomplete, that is, it is not originally perceived as distinct from and opposed to depth, which is the way in which we now think of it, after that the perception of depth has arisen to contrast it with; but it must be conceived, at this first stage, as indifferent to whether depth will be added to it or not; a conception which we may perhaps realise by such an image as that of the flat surface of a great water-lily leaf, the Victoria Regia for instance, which from above appears flat, but, when the edge is lifted up, and the under surface seen, exhibits a deep furry network of ribs by which it supports itself and penetrates and grasps the underlying surface of the water. An attempt has been made in "Time and Space" § 13 to exhibit the mode in which this completion of space in three dimensions takes place. The criterion of completion is not the notion of space in three dimensions itself, applied by us to the phenomena out of our present after-developed knowledge; but the criterion consists solely in the fact that the third dimension of space harmonises completely with what was expectant, as it were, in the superficial extension, while it requires no further completion itself, expects nothing further, but looks back, as it were, to what has gone before, contains an answer but no further question. 6. The sensations of temperature, heat and cold, when external to the body, must be considered as a special kind of sense, akin to touch in having as its organ the nerves distributed to the surface of the skin, and in being produced only by stimuli applied to that surface, so that superficial extension is perceived in all sensations of heat and cold just as it is in touch, but having a material element very dif ferent from the sensations of touch and closely allied to sensations of the sensus communis, such as lesion, cutting, aching, pricking, and to those sensations of taste which are from this circumstance called hot tastes, as of pepper and ginger. It is probable that the stimuli producing the sensations of heat and cold. must produce some molecular change in the skin surrounding the nerve extremities which they affect, in a way similar to the stimuli of taste and smell; so that the sensations of heat and cold might not unaptly be called the chemical mode of touch. Although in this respect their place in the scala sensuum would be between the senses of taste and touch, and they might be considered as a sixth special sense, yet this rank must be denied them if we consider their poverty in sensational qualities, and consequent defect of educability. For which reason I continue to class them among systemic sensations. § 11. 1. In the remaining two senses, hearing and sight, a much higher and more complex field of sensation is entered; in both of these an entirely new mode of sensation is added to those already remarked, for not only are they special senses, and not only are their opposite qualities more distinctly opposed to each other than was the case in touch, but they both contain, besides the modes of quality, intensity, pleasure and pain, a new mode, which in hearing is the mode of pitch. In all sound, which is the matter of hearing, three things are to be distinguished, for which see the valuable work of Prof. Helmholtz, Die BOOK I. § 10. The special senses. $ 11. Hearing. |