It follows an argument, from which it is proved that the soul never dies and that it is immaterial.
Life is or it is not self-movement.
If it is self-movement, it concentrates itself in a single unextended point that moves the whole body.
If it is not self-movement, it is scattered in an infinity of particles, whose movement produces the whole body's movement.
In the first case life would be something qualitative. In the second one, it would represent only one degree of quantity.
If life is quantity, it can only be an amount of extended matter. And, given that there is matter everywhere, life in it would not be able to disappear suddenly (unless life was only a certain kind of matter, which remains to be proved). For the same reason, it doesn't have any beginning.
Therefore, accepting the former premise, every life is eternal or, at least, it is attached simultaneously with matter's existence.
Abiogenesis would be, then, nonsense: it is not that life arises from dead stuff, but that dead stuff is another form of life.
That is to say, death is nothing but life's metamorphosis.
However, if life is not a quantity of matter but a quality of it, it cannot be increased or diminished in degree. It can only be gained or lost in an absolute sense.
If it is absolutely gained, it doesn't depend on composition processes like the ones given in matter.
If it doesn't depend on them, it is immaterial. And if it depends on them, it is immortal, as far as it cannot be destroyed.
But, if it is immaterial, it is immortal too.
And if it is material and immortal, being matter perishable, there is something in it which is not matter.
Thus, life, whose formal reason is the soul or self-movement, is immortal and immaterial, which was to be demonstrated.
Theological Miscellany:
http://www.miscelaneateologica.tk
