On The Soul   

only. Those we have mentioned are the nutritive, the appetitive, the

sensory, the locomotive, and the power of thinking. Plants have none

but the first, the nutritive, while another order of living things has

this plus the sensory. If any order of living things has the

sensory, it must also have the appetitive; for appetite is the genus

of which desire, passion, and wish are the species; now all animals

have one sense at least, viz. touch, and whatever has a sense has

the capacity for pleasure and pain and therefore has pleasant and

painful objects present to it, and wherever these are present, there

is desire, for desire is just appetition of what is pleasant. Further,

all animals have the sense for food (for touch is the sense for food);

the food of all living things consists of what is dry, moist, hot,

cold, and these are the qualities apprehended by touch; all other

sensible qualities are apprehended by touch only indirectly. Sounds,

colours, and odours contribute nothing to nutriment; flavours fall

within the field of tangible qualities. Hunger and thirst are forms of

desire, hunger a desire for what is dry and hot, thirst a desire for

what is cold and moist; flavour is a sort of seasoning added to

both. We must later clear up these points, but at present it may be

enough to say that all animals that possess the sense of touch have

also appetition. The case of imagination is obscure; we must examine

it later. Certain kinds of animals possess in addition the power of

locomotion, and still another order of animate beings, i.e. man and

possibly another order like man or superior to him, the power of

thinking, i.e. mind. It is now evident that a single definition can be

given of soul only in the same sense as one can be given of figure.

For, as in that case there is no figure distinguishable and apart from

triangle, &c., so here there is no soul apart from the forms of soul

just enumerated. It is true that a highly general definition can be

given for figure which will fit all figures without expressing the

peculiar nature of any figure. So here in the case of soul and its

specific forms. Hence it is absurd in this and similar cases to demand