[There are] three vegetative faculties of the soul: the faculty of nourishing, of growth, and of begetting. And they are called "vegetative" because they are the only ones that can be seen in the plants. Now we are not only human beings and animals but also ensouled beings. And insofar as we are human beings we have rational faculties, but insofar as we are animals we have irrational faculties, and insofar as we are ensouled beings we have vegetative faculties. For we call the plants ensouled beings as well. Indeed, it is characteristic of ensouled beings to take nourishment, to grow, and to beget things similar to themselves. And these same things are said both to live and to die, and life and death occur because of the presence and the absence of the soul [respectively]. Now those living things that have superior faculties of life also have inferior faculties by necessity; but the reverse is not the case. For it is not possible to have rational faculties if one has not previously had inferior faculties. Indeed, among the senses, it is not possible that the one who does not participate in the lower one participates in the higher one. Certainly those living things that take part in the sense of sight also take part in the sense of hearing and in the rest of senses, and those living things that participate in the sense of hearing also take part in the sense of smell, taste, and touch. Nevertheless, not all those living things that participate in the sense of smell, taste, and touch participate in all ways in the sense of sight (for example, that is the case of the blind-rat)[1]. And not all those living things that participate in the sense of touch participate in the other senses, either: for instance, the sponges participate in touch but they do not take part in any other senses. Therefore, the one who does not participate in an inferior faculty cannot take part in a superior faculty. And this does not happen because the superior faculties need the inferior ones in order to exist; on the contrary, the body is not able to participate in the superior faculties if it does not previously partake of the inferior ones.