Whether one element is dominant in any given sense organ.
Next, one inquires whether one element is dominant in any given sense organ.
1. It seems not. For that which consists in a mean proportion of certain other things, possesses none of them predominantly. But a mean proportion of tangibles is present in touch. Therefore, in touch there is no element that dominates.
2. In addition, if one element is dominant in some sense organ, earth and water will be dominant in any sense organ, because these prevail in all mixed bodies, according to the Philosopher in the second book of On the Soul and in On Sense and the Sensed. But the one in which water is dominant is sight. Therefore, there are not several senses.
The Philosopher says the opposite in the text.
One must reply that, according to the Philosopher in the second book of On the Soul, the nature of the organ and of the medium and of the object are one and the same. But they are the same in diverse ways, because the nature of the organ and of the medium is the same as if of two things receptive of the same thing, but the nature of the medium and of the object is the same just as the nature of act and potency, because the object assumes the role of the agent, and the organ and the medium the role of the one undergoing change. This is why the nature is said to be the same, because it is analogous, since that which is the organ and medium in potency, is the object in act. But in every object some one element is dominant, so that in smell the hot and the dry dominate, and this is the same nature as fire. And the clear and the bright is in color, and this belongs to the nature of air, and so too for the others.
And this is also apparent with regard to the medium, because whatever things perceive the same thing received that thing through some common nature. But the organ and the medium receive the sensible; therefore, they do so through some common nature. But the medium receives only through something that is found in the element; therefore, the organ does not. This is because taste and touch are changed in a material waytouch by being warmed, and taste by becoming moistenedand therefore in their organs something earthy is especially dominant, for example, earth. But sound changes with local motion mediating the change, and this is why a light element predominates in the organ perceptive of it, and air is of this sort. And likewise for sight. And in smell the hot and the dry dominate, because it is changed by altering, since it is not changed by warming.
One must understand, nevertheless, that this dominance can be understood in two ways: materially and formally. If materially, then the various elements are not dominant in the diverse organs, since earth and water dominate in every organ. If formally, then the proposition is true because for an element to dominate in some organ means nothing else than that the organ has a certain disposition toward an element that is especially analogous to the object. Through this disposition the organ is receptive of the object, just as on account of clearness and brightness the eye is receptive of something visible.
1. To the first argument one must respond that, formally speaking, touch consists in a mean proportion of the elements, for otherwise it would not perceive the extremes. With respect to their material, however, earth and water dominate, just as in every mixed body.
2. In the same way the response to the second argument is clear. For this reason, etc.
Whether the organ of touch and taste is in the heart and whether the organs of the other senses are in the head.
One inquires further whether the organ of touch and taste is in the heart and whether the organs of the other senses are in the head.
1. It seems not. What is common to all is proper to none. But the heart is common to all the senses; therefore, it will not be specific to any one of them.
2. In addition, if the organ of taste were in the heart, since the heart infuses its power into all parts, then it would not perceive a taste more through one part than through another but rather would perceive a taste through every part, just like touch. But this is not true, because taste thrives in the tongue and not in the other parts, and thus, etc.
3. In addition, a more noble location is due to a more noble power. But sight is a more spiritual sense. Therefore, it demands a more noble location, and this is the heart. Therefore, it has to be situated in the heart, more than does the organ of taste and touch.
The Philosopher says the opposite.
One must respond that principally and naturally taste and touch must be next to the heart, but the other senses must be in the head. And the reason for this is that nothing is sensed without heat. But earth is especially dominant in the organ of touch and taste, and as a result that organ, left to itself, is cold and is incapable of sensation, and this is why nature, wise in its wisdom (which, according to Galen in On Critical Days [De criticis diebus], is boundless), ordained that the organ of touch and taste be next to the heart. This is so that they may receive heat, which they do not have by virtue of their complexion, from the heart, which is the source of heat, taking it by participation in and by the influence of the heart. And an indication of this is that when any part of the body is injured by something tangible, the pain passes immediately to the heart. The other senses, however, are more spiritual. Thus, they would be impaired more by the excess heat of the heart if they were situated there. So if the organ of sight were next to the heart, the glacial humor, in which sight thrives, would be easily dissolved, and the organ of smell would be burned by too much heat. And likewise the air, connatural to hearing, would be overly moved by the excessive heat of the heart. This is why these three senses are situated in the head. For nature is provident and on its own would never provide defective coverings for these parts, like the eyelids for the eye, and for smell the protective covering within the nostrils, and for hearing the [outer] ears as well as the twists and turns within the ears. Nevertheless, these exist in diverse ways among animals, because some animals have a refined sense of smell and have a covering over it, and these do not smell unless the covering is lifted up, and they smell only while breathing. Others have a stronger olfactory organ that is not easily damaged, and ones like this do not have a covering nor do they smell [only] while breathing. It is the same for the eyes. Those having tough eyes, like fish, do not have eyelids but those that have sharp eyes do have eyelids. And if the eyelids are made of a soft, light flesh, then the animal closes its eye with the upper eyelid. If, however, the eyelid is tough, then it closes its eye with the lower eyelid, like the hen or birds, or with a membrane stretched out from the corner of the eyelids, like birds of prey, like the sparrow hawk [nisus] and others like it, because animals such as these cannot move the upper eyelid without straining their eyes. And such are the animals that have a rough flesh or a rough and spiny hide owing to the insertion of feathers, and the serpents, which have a rough and scaly hide.
1. On to the arguments. To the first argument one must reply that although the heart is a member common to each sense, nevertheless one sense may require the heart's influence in a more immediate way than another sense, such as those that exist for the sake of life's soundness. Those, however, which are for cognition do not require as much.
2. To the second argument one must respond that touch perceives tangible qualities and is the guardian of the entire body, and this is why tangible qualities are perceived in every part of the body, through the power of touch. But taste perceives only the nutriment, which is taken in from outside, and because the entrance of the nutriment from outside is not apparent in every part of the body, the power of taste does not flourish in every part of the body, but only in the mouth and on the tongue. Thus the tongue receives the species of flavor and entrusts it to the heart through the nerves.
3. To the third argument one must respond that something which is nobler in itself nevertheless is not nobler in comparison to something else. The eye is one of the most noble parts of the body. Nevertheless, it would not be fitting for the entire body to be just like the eye, because then it would be liable to injury. Thus, although a middle position is the most noble, nevertheless it would not be the most suitable for the eye, because vision is especially spiritual, and material, active qualities especially flourish in a middle position, and extremes of heat would impair the spiritual nature of vision. An indication of this is that sight enjoys a tempered cold more than heat, since the eye is injured more by fire and by looking at it than by water, because fire dissolves the tender substance of the eye, whereas cold water congeals the visual spirits and strengthens them, according to Avicenna. And this is why, etc.
-  This seemingly senseless statement may refer to a situation that exists in certain animals who submerge beneath water. Hippopotamuses, seals, walruses, and amphibians have just such a mechanism in their nostrils.
-  The membrane is the nictitating membrane. On the nisus, see DA 23.24.129(83) (SZ 2: 1639).