Soul is the ultimate vital principle, at least radically, of vital operations. The soul is the substantial form of a living body, which is composed of matter and form.¹⁸ The substantial form of an organism, or living body, can be a material substantial form if it is intrinsically dependent on material in its essence and operations, or it can be spiritual substantial form if it is only extrinsically dependent on the material subject in its essence and in its operations.¹⁹

The human soul is the substantial principle active and receptive of all the rational operations of man.²⁰ Since there is just one ultimate vital principle in man, and although the soul is entitatively spiritual, it is also the radical principle of vegetative and sensitive life in man. The soul is really distinct from the body.²¹ Soul and body of man exist in substantial unity, that is, a condition of being that is undivided precisely as being, and so which has one act of being.²² The soul of man is subsistent form by nature not time, first it is created and then united with material.²³

The vital principle (soul) of plants and animals arises only through eduction from the material which they inform, and not creation.²⁴ Proof: Whatever is finite and contingent does not have being from itself, but takes being from another, which makes it. But, whatever is made, either is made independent of its previously made subject (which is the definition of creation, which produces from nothing of self or subject), or is made dependent on its previously made subject (which is production from nothing of self but something of the subject, which is the definition of eduction). Therefore, the soul of plants and animals originate by eduction from the material.²⁵ Second Proof: The material nature of the soul of plants and animals can be deduced from its operations, which are intrinsically dependent on material (Confer: Aquinas Summa Contra Gentiles 2. 86).²⁶

Creation is the production of a thing from nothing of one’s self, and from nothing from the subject.²⁷ Creation is opposed to eduction, which is production of a thing from nothing of one’s self but not production of a thing from nothing of the subject.

Generation of a living individual is its production or constitution from the previously constituted subject.²⁸ Generation is properly predicated of beings composed of matter and form. The same is predicated of education, with respect to the form of the composit which is produced in generation from the material already constituted by another act.

Parents are two living individuals of the human species, of distinct sex, from whom a new living human individual arises, who is called their child.²⁹

Spirituality is a condition of being and operating independent of matter.³⁰ Intrinsic independence indicates not caused by another. Extrinsic independence means not conditioned or limited by another.