On the Soul (De Anima) with Simplicius Commentary

The vine comes from a vine, and the olive from an olive. In short, we are men, animals, and animated natures. As men, we have the rational powers already enumerated; as animals, we have the irrational powers; and as animated beings, we have the vegetative powers. We say that plants are also animated, since to be nourished, to be increased, and to generate similar beings pertains to animated natures. Plants are therefore said to live and die, for life and death are produced by the presence or absence of the soul.

Such beings as have the more excellent lives also possess, by necessity, those that are subordinate; but the converse is not true. It is not possible for the rational powers to be possessed without the prior possession of the subordinate ones. In the senses, also, it is not possible for an animal to participate in a more excellent sense without participating in a subordinate one. Animals that participate in sight also participate in hearing and the other senses; those that participate in hearing also have smell, taste, and touch. But they do not all participate in sight, as is evident in the mole. Indeed, some animals only participate in touch, such as the sponge.

It is not that the superior powers require the inferior for their own subsistence; rather, the body cannot participate in the more excellent unless it previously participates in the subordinate powers. Thus, the body cannot participate in the irrational without a previous participation in the vegetative power, nor in the rational without participation in both.