Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Manichæan Controversy.: Chapter 16

Chapter 16.—The Soul, Though Mutable, Has No Material Form.  It is All Present in Every Part of the Body.

But why speak of truth and wisdom which p. 137 surpass all the powers of the soul, when the nature of the soul itself, which is known to be mutable, still has no kind of material extension in space?  For whatever consists of any kind of gross matter must necessarily be divisible into parts, having one in one place, and another in another.  Thus, the finger is less than the whole hand, and one finger is less than two; and there is one place for this finger, and another for that, and another for the rest of the hand.  And this applies not to organized bodies only, but also to the earth, each part of which has its own place, so that one cannot be where the other is.  So in moisture, the smaller quantity occupies a smaller space, and the larger quantity a larger space; and one part is at the bottom of the cup, and another part near the mouth.  So in air, each part has its own place; and it is impossible for the air in this house to have along with itself, in the same house at the same moment, the air that the neighbors have.  And even as regards light itself, one part pours through one window, and another through another; and a greater through the larger, and a smaller through the smaller.  Nor, in fact, can there be any bodily substance, whether celestial or terrestrial, whether aerial or moist, which is not less in part than in whole, or which can possibly have one part in the place of another at the same time; but, having one thing in one place and another in another, its extension in space is a substance which has distinct limits and parts, or, so to speak, sections.  The nature of the soul, on the other hand, though we leave out of account its power of perceiving truth, and consider only its inferior power of giving unity to the body, and of sensation in the body, does not appear to have any material extension in space.  For it is all present in each separate part of its body when it is all present in any sensation.  There is not a smaller part in the finger, and a larger in the arm, as the bulk of the finger is less than that of the arm; but the quantity everywhere is the same, for the whole is present everywhere.  For when the finger is touched, the whole mind feels, though the sensation is not through the whole body.  No part of the mind is unconscious of the touch, which proves the presence of the whole.  And yet it is not so present in the finger or in the sensation as to abandon the rest of the body, or to gather itself up into the one place where the sensation occurs.  For when it is all present in the sensation in a finger, if another part, say the foot, be touched, it does not fail to be all present in this sensation too:  so that at the same moment it is all present in different places, without leaving one in order to be in the other, and without having one part in one, and another in the other; but by this power showing itself to be all present at the same moment in separate places.  Since it is all present in the sensations of these places, it proves that it is not bound by the conditions of space. 281

Footnotes

[Modern mental physiologists differ among themselves as regards the presence of the mind throughout the entire nervous system; some maintaining the view here presented, and others making the brain to be the seat of sensation, and the nerves telegraphic lines, so to speak, for the communication of impressions from the various parts of the body to the brain.  Compare Carpenter:  Mental Physiology, and Calderwood:  Mind and Brain.—A.H.N.]