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and body are concerned, and it is therefore necessary to discuss the physical machinery by which perception is effected. The first—the object of sensation-calls for more remark. Aristotle it should be noted distinguishes between three kinds of objects of sense—a special, a common, and an incidental object'. It is the first of these three objects of sensation with which we have meanwhile to do. Each single sense, Aristotle holds, has a special quality assigned to it: and the sense as such never goes beyond this quality? Thus the object of sight, we shall find, is colour, the object of hearing sound : and thus sight never gets beyond perceiving colours, hearing beyond perceiving sounds : if we do go beyond it and refer our sensation to a thing or person, we have passed beyond the special sensible, and, interpreting our sensation, have reached what Aristotle calls the incidental object of sensation'. It is then only this special sensible—this idcov aio Ontóv—with which we are meanwhile concerned, and with regard to each special sense our first inquiry (first, because, as we have seen, the object is prior to the faculty) must be—what is the object with which it is concerned. But not only have we to discuss the object and the organ: the perceptive act also involves a medium. The impression which effects perception is no actual contact between the object and the organ: in fact, if the object be placed directly on the organ (e.g. the eye) no perceptive act whatever will result.. Rather, perception is the result of a movement which is communicated by the object to some intervening substance, and is thence transmitted to the organ of perception. And thus it becomes an essential part of an analysis into the separate senses to inquire what is the nature of the media by which the sensible quality, which is the real object of sensation, is transmitted to the organ of perception.
ΙΙ. 6, 4184ΙΙ: λέγω δ' ίδιον μεν και μη ενδέχεται έτέρα αισθήσει αισθάνεσθαι, οίον όψις χρώματος. Cp. Plato, Theaetetus 184 Ε: ή και εθελήσεις ομολογείν α δι' ετέρας δυνάμεις αισθάνει, αδύνατον είναι δι' άλλης ταύτ' αισθέσθαι, οίον α δι' ακοής, δι' όψεως, ή α δι' όψεως, δι' ακούς; 3 De An. II. 6, 418*20.
II. 7, 419925—30. III. 13, 435*15.
VIII. THE SPECIAL SENSES.
To Aristotle, as to the ordinary understanding, there are five distinct senses which require to be considered by the psychologist'. The first chapter of the third book of the Psychology even tries to make it appear that we do not possess more: but the reasoning, however we may try to connect it, is distinctly inconclusive. These senses stand to one another in a relation not unlike that in which the different forms or faculties of soul are connected. Just as the vegetative capacities are regarded as the basis on which all the other faculties repose, so in like manner touch is the sense which all the other senses presuppose. Touch is, in fact, the most common of all the perceptive faculties: it is that which all animals necessarily possess : and its final cause is of a humbler nature than that of the other senses. Sight and hearing are directed to our moral advancement, our intellectual development-they are Toù eŮ sav éveka: whereas touch and taste are intended for our bare subsistence, contribute to nothing but our animal existence, are in short simply toû Sîv vexa. And hence presumably it is that Aristotle begins his analysis of the different senses with sight, and ends with touch, treating, that is, the senses not in the order of history but in that of nature. But it seems here more in accordance with the course we have previously followed to proceed from the lower to the higher, and thus begin with touch and gradually end with hearing and sight.
Touch is a sense of which Aristotle finds the analysis peculiarly perplexing. Each of the three points, which we noticed (p. Ixii.) as requiring to be studied, presents some difficulty. As to its object—how comes it that the sense perceives qualities so opposite as hot and cold, dry and moist, hard and soft? Qualities so different as these cannot be brought under any one common category; and yet none the less, each sense, it is to be presumed, perceives one class of objects. The difficulty here stated Aristotle can hardly be said to solve. He reminds us that the other senses have also sometimes a variety of opposites between which they have to judge: and he finally determines the object of the sense of touch as the distinctive qualities of body as body', these qualities being further explained as those which characterize the different elements, viz. hot and cold, dry and moist. Yet these qualities, Aristotle elsewhere tells us, cannot be reduced to fewer?: and thus his answer really leaves the matter where it was. On the difficulties connected with the organ and the medium Aristotle is more satisfactory. Immediately, of course, the flesh might be supposed to be the organ of sense-perception. But this result is scarcely in accordance with what happens in the other senses. There, when the object is placed directly on the organ of sense, no perception whatever is possible: and it might be expected that were flesh the organ of touch it would be equally unable to perceive through immediate contact. The fact in short would seem to be that the real organ of touch is something inward”, and that the flesh is simply the medium by which the tangible qualities of body are transmitted. Nor does the fact that we appear to perceive these qualities by immediate contact invalidate such a conclusion. Were a membrane spread over the flesh, we should equally appear to perceive through contact on the part of the object with this membrane, while at the same time no one would maintain this membrane to be the organ of perception. Flesh then is simply the medium of touch": although it must be added that the medium here does not play the same part as it does in some among the other senses. It is, that is to say, not so much the vehicle as the concomi
1 Hist. An. iv. 8, 532629. ? III. 13, 43562. 3 De Sensu, 1, 437o4. De An. III. 3, 4299 3. - De An. II. II, 422b-424*.
1423b27, άπται μεν ούν εισίναι διαφοραι του σώματος ή σώμα.
2 De Generatione, ΙΙ. 2, 33024, δήλον τοίνυν ότι πάσαι αι άλλαι διαφοραι ανάγονται εις τας πρώτας τέτταρας: αύται δ' ουκέτι εις ελάττους: ούτε γάρ το θερμόν όπερ υγρών ή όπερ ξηρόν.
3 Part. Αn. 11. το, 656535, ουκ έστι το πρώτον αισθητήριον ή σαρξ αλλ' εντός. • Do Αn. 11. Π, 423526, ώστε το μεταξύ του άπτικού ή σάρξ.
tant of sensation—the mode in which our sensations of touch are gained may be compared with the manner in which a man may be wounded through his shield'.
Taste is viewed by Aristotle as a species of touch, differing only in that, while touch is disseminated over the whole body, taste is restricted to a single part of it—the tongue. Its object is flavour (xuuós): and this is undoubtedly some modification of the moist or watery. But how it is that flavours originate from water is a question on which Aristotle finds divergent views are entertained. It cannot be, as Empedocles maintained, that water contains implicitly the various flavours in it; nor can it be, as Democritus perhaps held, that water is an atomic compound which contains the germs of all flavours, so that some may originate from one part, others from another part: rather it must be some affection of the water at the hands of some productive agent which produces flavour Flavour is accordingly defined by Aristotle as such a kind of affection produced in what is moist by what is dry as transforms the mere potential capacity of taste into actual exercise*. Of flavour various kinds are enumerated and compared with the different kinds of colour. The simple flavours are, like the simple colours, two in number-sweet and bitter—while the others may be regarded as modifications of these two primary kinds. The organ of taste can be as little localized as can that of touch. Popularly, of course, the tongue is regarded as the part concerned with the perception of flavours : and Aristotle often speaks as if he held himself the tongue to be the instrument of taste. But this of course is only a concession to the customary language
1423b14, των απτών ουχ υπό του μεταξύ άλλ' άμα τω μεταξύ αισθανόμεθα ώσπερ ο δι' ασπίδος πληγείς. 2 De An. II, 10.
De Sensu, C. 4. 3 De Sensu, 4, 441820, λείπεται δη τω πάσχειν τι το ύδωρ μεταβάλλειν.
4 44119, και έστι τούτο χυμός το γιγνόμενον υπό του ειρημένου ξηρού πάθος εν τω υγρώ της γεύσεως της κατά δύναμιν άλλοιωτικόν εις ενέργειαν. .
5 422θΙο; 442812, ώσπερ δε τα χρώματα εκ λευκού και μέλανος μίξεώς έστιν, ούτως οι χυμοί εκ γλυκέος και πικρού. .
6 Hist. An. IV. 8, 53.3*26.
of mankind : in reality, Aristotle views the tongue as little more than medium in the transmission of the flavour of external objects. Neither however in taste nor touch is the medium some external body as it is in the case of sight or hearing: rather, whereas sight, smell and hearing act at a distance from their object, touch and taste operate in close proximity by means of almost actual contact'. At first sight, water might be thought to be the medium in the case of taste: but still, though “if we were in the water we should perceive anything sweet cast into it, our perception would be the result, not of the intervening medium, but simply of the mingling of the sweet thing with the water?." Still it is at least evident that the tongue must be potentially moist in order to perceive the different flavours. At the same time it must preserve that condition of indifference and equidistance from the two extremes of moist and dry without which no perceptive faculty is capable of action'. And thus the sick, Aristotle adds by way of explanation, have but an imperfect sense of flavours because their tongue is imbued with such an amount of moisture as makes it impossible for them to acquire the taste of other flavours.
Smello Aristotle finds a sense which is somewhat difficult to analyse: just as up to the present day it has been treated with much less success than any of the other senses. The reason for this backward condition of psychology in regard to odours is, Aristotle thinks, due to its defective development in man. While man possesses a much finer sense of touch than any other animal, “ we do not,” he adds, “possess the sense of smell in anything like the same degree of delicacy as that in which it is possessed by other animals.” In the case of man, scent would seem to be merely a sort of concomitant upon feelings of pain and pleasure and to be perceived only indirectly, | 11. 11, 42366. 422811, ουκ ήν δ' αν η αίσθησις ημίν δια του μεταξύ αλλά το μιχθήναι το υγρώ.
• De An. II. 9. De Sens. c. 5.