The World as Will and Representation, Volume II), says that the outer sense, or the receptivity for external impressions as pure data for the understanding, is divided into five senses, which conform to the four elements, or to the four conditions or states of aggregation, together with that of imponderability.
Thus the sense for the firm (earth) is touch, for the fluid (water) is taste, for the vaporous, i.e., the volatile (vapour, exhalation) is smell, for the permanently elastic (air) is hearing, for the imponderable (fire, light) is sight. The second imponderable, namely heat, is really an object not of the senses, but of general feeling; hence it always affects the will directly as pleasant or unpleasant.He goes on to define the dignity of the senses, arguing that sight is the most refined sense, followed by hearing:
Sight has the highest rank, inasmuch as its sphere is the most far-reaching, and its receptivity and susceptibility the keenest. This is due to the fact that what stimulates it is an imponderable, in other words, something hardly corporeal, something quasi-spiritual. Hearing has the second place, corresponding to air. Touch, however, is a thorough, versatile, and well-informed sense. For whereas each of the other senses gives us only an entirely one-sided account of the object, such as its sound or its relation to light, touch, which is closely bound up with general feeling and muscular power, supplies the understanding with data regarding simultaneously the form, size, hardness, smoothness, texture, firmness, temperature, and weight of bodies; and it does all this with the least possibility of illusion and deception, to which all the other senses are far more liable. The two lowest senses, smell and taste, are not free from a direct stimulation of the will; thus they are always agreeably or disagreeably affected, and so are more subjective than objective.He suggests that there exists some kind of an antagonism between sound and sight. Here’s how he compares the two senses:
Perceptions through hearing are exclusively in time; hence the whole nature of music consists in the measure of time, and on this depends not only the quality or pitch of tones by means of vibrations, but also their quantity or duration by means of the beat or time. The perceptions of sight, on the other hand, are primarily and predominantly in space; but secondarily, through their duration, they are in time also.
Sight is the sense of the understanding that perceives; hearing is the sense of the faculty of reason that thinks and comprehends. Visible signs only imperfectly take the place of words; therefore I doubt whether a deaf and dumb person, able to read but with no conception of the sound of the words, operates as readily in his thinking with the merely visible concept-signs as we do with the actual, i.e., audible words. If he cannot read, he is, as is well known, almost like an irrational animal; whereas the man born blind is from the beginning an entirely rational being.He speculates that sound can be disturbing for the mind, whereas sight isn’t:
Sight is an active, hearing a passive sense. Therefore, sounds affect our mind in a disturbing and hostile manner, the more so indeed, the more active and developed the mind They can destroy all ideas, and instantly shatter the power of thought. On the other hand there is no analogous disturbance through the eye, no immediate effect of what is seen as such on the activity of thinking (for naturally it is not a question here of the influence of the perceived objects on the will), but the most varied multiplicity of things before our eyes admits of entirely unhindered and undisturbed thinking Accordingly, the thinking mind lives in eternal peace with the eye, and at eternal war with the ear.