19. Are we to think of the indivisible phase of the soul and the divided as making one thing in a coalescence; or is the indivisible in a place of its own and under conditions of its own, the divisible being a sequent upon it, a separate part of it, as distinct as the reasoning phase is from the unreasoning?
The answer to this question will emerge when we make plain the nature and function to be attributed to each.
The indivisible phase is mentioned [in the passage of Plato] without further qualification; but not so the divisible; "that soul" we read "which becomes divisible in bodies"- and even this last is presented as becoming partible, not as being so once for all.
"In bodies": we must then, satisfy ourselves as to what form of soul is required to produce life in the corporeal, and what there must be of soul present throughout such a body, such a completed organism.
Now, every sensitive power- by the fact of being sensitive throughout- tends to become a thing of parts: present at every distinct point of sensitiveness, it may be thought of as divided. In the sense, however, that it is present as a whole at every such point, it cannot be said to be wholly divided; it "becomes divisible in body." We may be told that no such partition is implied in any sensations but those of touch; but this is not so; where the participant is body [of itself insensitive and non-transmitting] that divisibility in the sensitive agent will be a condition of all other sensations, though in less degree than in the case of touch. Similarly the vegetative function in the soul, with that of growth, indicates divisibility; and, admitting such locations as that of desire at the liver and emotional activity at the heart, we have the same result. It is to be noted, however, as regards these [the less corporeal] sensations, that the body may possibly not experience them as a fact of the conjoint thing but in another mode, as rising within some one of the elements of which it has been participant [as inherent, purely, in some phase of the associated soul]: reasoning and the act of the intellect, for instance, are not vested in the body; their task is not accomplished by means of the body which in fact is detrimental to any thinking on which it is allowed to intrude.
Thus the indivisible phase of the soul stands distinct from the divisible; they do not form a unity, but, on the contrary, a whole consisting of parts, each part a self-standing thing having its own peculiar virtue. None the less, if that phase which becomes divisible in body holds indivisibility by communication from the superior power, then this one same thing [the soul in body] may be at once indivisible and divisible; it will be, as it were, a blend, a thing made up of its own divisible self with, in addition, the quality that it derives from above itself.