It is true that our rational soul depends indirectly on the organism inasmuch as the soul draws from the sense perceptions material for abstract knowledge, and therefore the human soul naturally tends to be united to a body. But such a dependence does not affect the very essence or nature of the soul which is of a superior kind. Being spiritual, the soul has no quantitative or material parts in it. If one folds a corporeal thing, for example a sheet of paper, only a part covers another part, but the whole sheet cannot be completely folded upon itself. Thus, if the soul were composed of quantitative parts consciousness would be partially but not totally imposed upon itself.
Simplicity means absence of composition.
Only God could annihilate it. As the soul is naturally capable of surviving death, and as on the other hand it is naturally destined to inform or determine a body and to find in the senses the channels of its knowledge, a new union after death, with a body which will thereby become its own, does not involve any contradiction. Moreover, the intermediate state of the disembodied soul was regarded as provisional and incomplete. The arguments of Plato's Phaedon are completed by the reasoning of the De Anima of Aristotle, and the De immortalitate of Augustine. The Schoolmen without exception continue the line of Spiritualist philosophers.