[25] Let us see in what way that which occupies the fourth place in ourselves too is of such a nature as to be eminently and peculiarly incomprehensible. The factors in us of highest significance are four, body, sense-perception, speech, mind. Three of these are not obscure in all their aspects, but contain in themselves some indications by which they can be understood.
[26] What do I mean? We know that the body is threefold in dimensions and sixfold in movements, having three dimensions, length, depth, breadth, and twice as many, namely six, movements, upward, downward, to the right, to the left, forward, backward. Nor are we ignorant that it is a vessel for the soul, and we are perfectly aware that it comes to maturity, wears out, grows old, dies, is dissolved.
[27] With respect to sense-perception, also, we are not wholly dim-sighted, and blind, but we are able to say that it is divided into five parts, and that each part has its special organs fashioned by Nature, eyes for seeing, ears for hearing, nostrils for smelling, and for the others the organs in which they find their fit place, and that they are understanding’s messengers, bringing to it reports of colours, forms, sounds, distinct scents and savours, in a word, of material substances and their qualities, and that they are bodyguards of the soul, making known all that they have seen or heard. And should any hurtful thing approach from without, they are aware of it beforehand, and on their guard against it, lest it should stealthily make its way in and cause incurable damage to their mistress.
[28] Sound, too, does not entirely elude our discernment. We know that one sound is shrill, another deep, one tuneful and melodious, another discordant and most unmusical, and again, one louder and another softer. They differ also in countless other respects, in genera, tone colours, intervals, conjunct or disjunct systems, and harmonies of the fourth, the fifth, the octave.
[29] In articulate sound, moreover, an advantage possessed by man alone of all living creatures, there are particulars of which we are aware; as, for example, that it is sent up from the understanding, that it is in the mouth that it acquires articulation, that it is the beat or stroke of the tongue that imparts articulation and speech to the tension of the voice, but does not produce simply just an idle sound and unshapen noise, since it holds to the suggesting mind the office of its herald and interpreter.