On Sense And The Sensible   

states of sensation, others, means of defending and safe-guarding

it, while others, again, involve its destruction or negation. Now it

is clear, alike by reasoning and observation, that sensation is

generated in the soul through the medium of the body.

We have already, in our treatise On the Soul, explained the nature

of sensation and the act of perceiving by sense, and the reason why

this affection belongs to animals. Sensation must, indeed, be

attributed to all animals as such, for by its presence or absence we

distinguish essentially between what is and what is not an animal.

But coming now to the special senses severally, we may say that

touch and taste necessarily appertain to all animals, touch, for the

reason given in On the Soul, and taste, because of nutrition. It is by

taste that one distinguishes in food the pleasant from the unpleasant,

so as to flee from the latter and pursue the former: and savour in

general is an affection of nutrient matter.

The senses which operate through external media, viz. smelling,

hearing, seeing, are found in all animals which possess the faculty of

locomotion. To all that possess them they are a means of preservation;

their final cause being that such creatures may, guided by

antecedent perception, both pursue their food, and shun things that

are bad or destructive. But in animals which have also intelligence

they serve for the attainment of a higher perfection. They bring in

tidings of many distinctive qualities of things, from which the

knowledge of truth, speculative and practical, is generated in the

soul.

Of the two last mentioned, seeing, regarded as a supply for the

primary wants of life, and in its direct effects, is the superior

sense; but for developing intelligence, and in its indirect

consequences, hearing takes the precedence. The faculty of seeing,

thanks to the fact that all bodies are coloured, brings tidings of

multitudes of distinctive qualities of all sorts; whence it is through

this sense especially that we perceive the common sensibles, viz.