Lecture 19 — The object of smell

It is not so easy to come to conclusions about odor and the odorous as about the sense-objects already discussed. What odor is, is less obvious than what sound is, or the visible or light, the reason being that our sense of smell lacks precision; it is inferior to that of many animals. For man smells but feebly, discerning nothing odorous save with some special pleasure or pain, as though our organ for the perception of smells were indeterminate. It is arguable indeed that, as hard-eyed animals sense colors, yet such that delicate differences are not sharply defined to them, except as these cause fear or not, so are smells to the human race.

For it seems that, while smell has an analogy with taste, and the species of flavors with things that belong to odors, yet we have a sharper perception of taste, because this is a sort of touch—the sense which man possesses to the highest degree of precision. Whereas in the other senses he is inferior to many animals, by touch he can discriminate with exactness far beyond the rest of the animal world. Hence man is the most prudent of the animals. A sign of this is that within the human race, men are naturally clever or not in accordance with this sense, and in accordance with no other. For coarse-fleshed people are mentally inert, while the tender-fleshed are well suited.

As some flavors are sweet and some bitter, so with odors. But some things are analogously endowed with flavor and odor, I mean, have a sweet taste and sweet smell. In others, however, these qualities are contrary. Likewise, odors are pungent, harsh, sharp or oily: but since, as we have said, odors are not very distinct, whereas flavors are, they take their names from the latter, according to resemblance. For the sweet comes from saffron and honey: the pungent from thyme; and so in other cases.

Furthermore, as hearing (and the same obtains in each of the senses) bears on the audible and the inaudible (and sight on the visible and the invisible), so smell is of the odorous and the odorless. The odorless is either that which simply cannot have a smell at all or that which has smell but a small and feeble one. The same can be said of the tasteless.

479. It is not so easy to come to conclusions (421a7). Having dealt with the visible and the audible, the Philosopher now considers smell and its object. His treatment has two parts.

In the first, he examines this object as such;

in the second, at smelling also (421b8; [491]), the manner in which it affects the sense.

About the first, he does two things:

first, he determines the object as it is in itself;

second, he turns, at furthermore, as hearing (421b3; [490]), to consider a certain odorless object which falls within the range of smell.

The former consideration again subdivides:

first, he shows the difficulty of reaching determinate conclusions about smell;

second, he explains how we can come to know about the odorous, at for it seems that smell has an analogy (421a16; [481]).

First, then, he observes that it is not so easy to reach conclusions about smell and its object as it was about the sense-objects discussed hitherto, the audible and the visible. For what odor is, is less obvious to us than what sound is, or the visible, or light, or other things of that sort.

480. The reason, he says, is that our sense of smell is not so strong that we can distinctly and unerringly discern its object, for this sense is inferior in us than in many other animals.

The reason is that, as the sense organ ought to be proportioned to its sense-object, and as smell is caused by the warm and dry, therefore a good organ of smell will be predominantly a warm, dry organ. Now, the brain of man, close to which lies the organ of smell, is, as the Philosopher says in Parts of Animals, larger in proportion to his body than that of any other animal; (Aristotle, Parts of Animals 2.7, 653a27–28.) and since the brain itself is cold and moist, the human sense of smell is proportionately impeded by it.

Man smells but feebly—discerning nothing unless it is strongly odorous and causes pleasure or its contrary; and this is because his sense of smell is lacking in a keen and exact discernment of its object. Hence, one may reasonably opine that the human race stands with respect to perceiving odors in the same way as hard-eyed animals, such as locusts and certain types of fish, stand with respect to perceiving colors; for these animals, on account of their weak vision and ill-suited organs, see only what is very obviously visible and as such is apt to frighten them or the contrary.

481. Then, at for it seems that (421a16), he shows how differences of odor are made known to us. And about this, he does two things.

First, he shows how differences of odor are brought home to us by comparison with differences of taste.

Second, he shows how differences of odor correspond to differences of taste, at as some flavors (421a26; [487]).

First, then, he remarks that the sense of smell in man seems to have some relation and proportion to taste; and the species of flavor (that is, savor) to those of odor. Now, things unknown become known through what is more evident. Since, then, the varieties of flavor are clearly evident to us, those of smell, which are not so, but which have a certain affinity to those of flavor, are made known to us through their likeness to them.

482. Now, the varieties of flavor are evident to us because man has a sharper sense of taste than other animals, taste being a sort of touch, which man possesses to the highest degree of precision, compared to the other animals; whereas in the other senses, man falls short of some animals. For certain animals see and hear and smell better than man, but the touch of man is very different in the precision of its knowledge from that of other animals.

483. Hence this pre-eminence of touch in man is the reason why man is the most prudent of the animals; moreover, within the human race it is due to their sense of touch that we take it that some are naturally clever and some not, and not due to any other sense. For those whose flesh is tough and consequently whose sense of touch is poor are inert in their mind, while those who are tender-fleshed and, in consequence, with a fine sense of touch, are mentally well suited. This too is why the other animals have flesh of a coarser texture than man.

484. Yet it might seem that aptitude of the mind corresponds to excellence of sight more than that of touch, for sight is the more spiritual sense and reveals better the differences between things. Still, there are two reasons for maintaining that excellence of mind is proportionate to fineness of touch.

In the first place, touch is the foundation of all the other senses; for obviously the organ of touch pervades the whole body, so that the organ of each of the other senses is also an organ of touch, and the sense of touch by itself constitutes a being as sensitive. Therefore, the finer one’s sense of touch, the better, simply speaking, is one’s sensitive nature as a whole, and consequently the better one’s intellectual capacity. For a fine sensitivity is a disposition to a fine intellect. But an exceptionally good hearing or sight does not imply that the sensitivity as a whole is finer, but only that it is so in one respect.

485. The other reason is that a fine touch is an effect of a good bodily constitution or temperament. For as the organ of touch is itself necessarily endowed with tangible qualities (being composed of the elements), it needs to be in a condition of potency to extremes of the tangible, at least by itself constituting a mean between them. Now, nobility of soul follows upon a good bodily constitution, because forms are proportionate to their matter. It follows that those whose touch is good are so much the nobler in nature and have a more penetrating mind.

486. Another question that arises is why the species of odor are named from the species of taste more than from the tactile qualities, if touch is the most exact of the senses.

I answer that both odor and flavor are caused by a determinate combination of elemental qualities; consequently, the species of odor corresponds to the species of flavor more than to the simple tangible qualities.

487. Next, when he says, as some flavors are sweet (421a26), he explains how the kinds of odor correspond to flavors or taste, observing that as we distinguish these as sweet and bitter, so do we also with odors. But it must be known that some things are analogously endowed with flavor and odor, that is to say, a sweet taste and a sweet smell, others, on the contrary, have an agreeable flavor but a disagreeable smell, or the converse.

488. The reason for this is that flavor consists in an aqueous liquid that is somewhat digested, and odor consists in dry air that is modified in some way. Now, it sometimes happens that both substances, a fine air and a heavier liquid, are each combined in an appropriate proportion; and then both odor and flavor are pleasing. But if this appropriate proportion is found in one and not in the other, then the one will be pleasing but the other not so. And what has been said of sweet and bitter, the extremities in flavor that are transferred to odors, can be applied also to the sour and the pungent, that is, astringent or harsh, and the acidic and the oily: these flavor-qualities can be attributed to the odorous.

489. But although odors and flavors do not always and in all respects correspond, nevertheless since, as we have said, odors are not very distinct and evident, whereas flavors are, odors take their names from their resemblance to flavors; for on the whole, odors correspond to flavors. For a sweet smell and taste come from saffron and honey, a pungent smell and taste come from thyme; and so with other flavors and odors.

490. Then, at furthermore, as hearing (421b3), he shows how odorless things are perceptible to smell. As hearing, he says, is of the audible and inaudible, and sight of the visible and invisible (because opposites are known by one and the same power, and a lack is known only by means of what is lacking), so smell is of the odorous and the odorless.

But there are two senses of the term odorless: it can mean that which simply cannot have a smell at all, such as all simple bodies, or what has a little or a faint smell. And the same is true of the tasteable and the tasteless.