SMELL. ITS OBJECT
IT is not so easy to come to conclusions about odour and the odorous as about the sense-objects already discussed. What odour 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 disgust, as though our organ for the perception of smells were defective. It is arguable indeed that, as hard-eyed animals see colour, yet so that delicate differences are not sharply defined to them, except as these cause fear or not, so are smells to the human species.§§ 479-80
For it seems that while smell has an analogy with taste, and the species of savour with odours, 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 sagacious of animals. A sign of this is that within the human race, men are gifted or not intellectually in virtue of this sense, and of no other. For coarse-bodied people are mentally inert, whilst the tenderly-fleshed are quick of understanding.§§ 481-6
As some flavours are sweet, some bitter, so with odours. But some things are analogously endowed with savour and odour: I mean, have a pleasant taste and pleasant smell. In others, however, these qualities are contrary. Likewise odours are pungent, harsh, sharp or oily: but since, as we have said, odours are not very distinct, whereas flavours are, they take their names from the latter, according to resemblance. For a sweet smell comes from saffron and honey: a pungent smell from thyme; and so in other cases.§§ 487-9
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 odourless. The odourless is either that which simply cannot have a smell at all, or that which has smell but a poor one and feeble in quality. The same can be said of the tasteless.§ 490