What answer can be made by those declaring soul to be corporeal? Is every part of the soul, in any one body, soul entire, soul perfectly true to its essential being? and may the same be said of every part of the part? If so, the magnitude makes no contribution to the soul’s essential nature, as it must if soul [as corporeal] were a definite magnitude: it is, as body cannot be, an “all-everywhere,” a complete identity present at each and every point, the part all that the whole is. Enneads: IV VII. 5
It is easy to show that if the Soul were a corporeal entity, there could be no sense-perception, no mental act, no knowledge, no moral excellence, nothing of all that is noble. Enneads: IV VII. 6
That this opinion is untenable has already been shown at length. The soul is a prior [to body], the accord is a secondary to the lyre. Soul rules, guides and often combats the body; as an accord of body it could not do these things. Soul is a real being, accord is not. That due blending [or accord] of the corporeal materials which constitute our frame would be simply health. Each separate part of the body, entering as a distinct entity into the total, would require a distinct soul [its own accord or note], so that there would be many souls to each person. Weightiest of all; before this soul there would have to be another soul to bring about the accord as, in the case of the musical instrument, there is the musician who produces the accord upon the strings by his own possession of the principle on which he tunes them: neither musical strings nor human bodies could put themselves in tune. Enneads: IV VII. 8
What, then, is the soul’s Being? If it is neither body nor a state or experience of body, but is act and creation: if it holds much and gives much, and is an existence outside of body; of what order and character must it be? Clearly it is what we describe as Veritable Essence. The other order, the entire corporeal Kind, is process; it appears and it perishes; in reality it never possesses Being, but is merely protected, in so far as it has the capacity, by participating in what authentically is. Enneads: IV VII. 8