.life is synonymous with activity. It is easier to understand how inanimate objects are moved by something already in motion than to understand how animate entities are moved. Animate entities have a source of immanent activity ( coming from within).called soul. In vegetative and animal life the “soul” is composed of matter and can communicate this life to entities that are similar. In humans there is an activity that transcends physical sensation even though in this life, its present mode of existence it is “extrinsically” dependent on matter (meaning matter is not necessary for its activity in itself, or its nature, but it is united to the physical and limited by the physical-union of body and soul) This activity is called “cognition”, the activity of the intellect in union with the brain which collects sense impression from the physical world. Also there is the activity of the will, called volition, the power of choice. These faculties belong to the rational soul of man. Metaphysicians reached the conclusion that the human soul is spiritual because the nature of this activity called cognition, abstraction, self-consciousness, reflection. Matter is incapable of self-consciousness, autonomic activity as shown in humans. Nor can matter organize itself, it needs an organizer. The soul is call an intellective agent that keeps the body organized. When the body can no longer support the activity of the soul (the principal of animate activity in humans,) it changes it mode of existence to that of its own nature, no longer united to matter, but pure spirit. This means the intellect is no longer restricited in the activity of knowing, it now is infused with knowledge directly from God who is Truth. Also the will is united to the Truth that the intellect perceives, this is call “The Beatific Vision” or union with God.

p.s. The soul is not matter so it is not effected… by material corruption.