De Anima

The object of taste is a species of tangible. And this is the reason why it is not perceived through a foreign body as medium: for touch employs no such medium either. The body, too, in which the flavour resides, the proper object of taste, has the moist, which is something tangible, for its external matter or vehicle. Hence, even if we lived in water, we should still perceive anything sweet thrown into the water, but our perception would not have come through the medium, but by the admixture of sweetness with the fluid, as is the case with what we drink. But it is not in this way, namely, by admixture, that colour is perceived, nor yet by emanations. Nothing, then, corresponds to the medium; but to colour, which is the object of sight, corresponds the flavour, which is the object of taste. But nothing produces perception of flavour in the absence of moisture, but either actually or potentially the producing cause must have liquid in it: salt, for instance, for that is easily dissolved and acts as a dissolvent upon the tongue.

Again, sight is of the invisible as well as the visible (for darkness is invisible and this, too, sight discerns as well as light) and, further, of that which is exceedingly bright, which is likewise invisible, though in a different way from darkness. Similarly hearing has to do with noise and silence, the former being audible, the latter inaudible, and, further, with loud noise, to which it is related as vision is to brightness, a loud and a violent sound being in a manner just as inaudible as a faint sound. The term invisible, be it noted, is applied not only to that which it is wholly impossible to see, which corresponds to other cases of the impossible, but also when a thing has imperfectly or not at all its natural properties, answering to the footless and the kernel-less. So, too, taste has for object The object mot only that which can be tasted, but also the tasteless, of taste. = by which we mean that which has little flavour or hardly any at all, or a flavour destructive of the taste. Now in flavour this distinction is supposed to start with the drinkable and the

undrinkable. Both are tastes of a sort, but the latter is poor or destructive of the faculty of taste, while the former is naturally adapted to it. The drinkable is the common object of touch and of taste. But, since the object of taste is moist, the sense-organ which perceives it must be neither actually moist nor yet incapable of becoming moist. For taste is acted upon by the object of taste as such. The organ of taste, then, which needs to be moistened, must have the capacity of absorbing moisture without being dissolved, while at the same time it must not be actually moist. A proof of this is the fact that the tongue has no perception either when very dry or very moist. In the latter case the contact is with the moisture originally in the tongue, just as when a man first makes trial of a strong flavour and then tastes some other flavour; or as with the sick, to whom all things appear bitter because they perceive them with their tongue full of bitter moisture.

As with the colours, so with the species of flavour, there are, Species of firstly, simple flavours, which are opposites, the sweet and the bitter; next to these on one side the succulent, on the other the salt; and, thirdly, intermediate between these, the pungent, the rough, the astringent and the acid.'These seem to be practically all the varieties of flavour. Consequently, while the faculty of taste has potentially the qualities just described, the object of taste converts the potentiality into actuality.