CHAPTER III

THE SOUL'S POWERS IN GENERAL

             OF the soul's powers already spoken of all are present in some, certain only are present in others, and one only in yet others. By the powers of the soul we mean the vegetative, the sensitive, the appetitive, the locomotive and the intellectual.§§ 279-87

             In plants there is only the vegetative; in other living things, this and the sensitive; but if the sensitive is present, so must the appetitive be. For appetition means desire, and anger and will. Now all animals have the sense of touch; and where sensation is found there is pleasure and pain, the pleasant and the repugnant. What has these has appetite, this being desire for a pleasurable object.§§ 288-9

             Further; all have a sense of nutriment, inasmuch as touch is this sense. For all living beings are nourished by things dry and wet or hot and cold; and the sense of touch is of these. But they are nourished by the other sense-objects only indirectly. Sound, colour and smell contribute nothing to nutrition; and as for savour, it is found in objects of touch. Hunger and thirst being appetites, hunger for the hot and dry and thirst for the cold and liquid, savour is as it were the delectable in these. We must settle these questions later; for the present let us only say that animals endowed with touch have appetition also. The case of imagination is not clear and must be examined later. Some animals, again, have local motion; some intellect and mind--such as men and whatever other beings there are of a like nature, or of one even more excellent.§§ 290-4

             It is therefore clear that the idea of soul must be one in the same way as that of figure: for as there is no figure other than the triangle and those that derive from it, so there is no soul apart from the aforesaid. There will be, however, in the case of figures a general idea applicable to all figures, yet proper to none. Likewise with these souls just mentioned. Hence it is absurd to seek a common definition in this matter (or in any other) which will be that of no existing thing, and on the other hand, to seek to define in terms of the individual species without taking into account such a common definition. There is indeed an analogy between what holds of figures and what holds of the soul. For in that which is consequent there is always potential that which is primary, both in figures and in animate beings. As the triangle is contained in the square, so is the vegetative in the sensitive.§§ 295-8