Tertullian — A Treatise on the Soul 6

These conclusions the Platonists disturb more by subtlety than by truth . Every body, they say, has necessarily either an animate nature or an inanimate one. If it has the inanimate nature, it receives motion externally to itself; if the animate one, internally. Now the soul receives motion neither externally nor internally: not externally, since it has not the inanimate nature; nor internally, because it is itself rather the giver of motion to the body. It evidently, then, is not a bodily substance, inasmuch as it receives motion neither way, according to the nature and law of corporeal substances. Now, what first surprises us here, is the unsuitableness of a definition which appeals to objects which have no affinity with the soul .

For it is impossible for the soul to be called either an animate body or an inanimate one, inasmuch as it is the soul itself which makes the body either animate, if it be present to it, or else inanimate, if it be absent from it. That, therefore, which produces a result, cannot itself be the result, so as to be entitled to the designation of an animate thing or an inanimate one. The soul is so called in respect of its own substance. If, then, that which is the soul admits not of being called an animate body or an inanimate one, how can it challenge comparison with the nature and law of animate and inanimate bodies?

Furthermore, since it is characteristic of a body to be moved externally by something else, and as we have already shown that the soul receives motion from some other thing when it is swayed (from the outside, of course, by something else) by prophetic influence or by madness , therefore I must be right in regarding that as bodily substance which, according to the examples we have quoted, is moved by some other object from without. Now, if to receive motion from some other thing is characteristic of a body, how much more is it so to impart motion to something else! But the soul moves the body, all whose efforts are apparent externally, and from without.

It is the soul which gives motion to the feet for walking, and to the hands for touching, and to the eyes for sight, and to the tongue for speech — a sort of internal image which moves and animates the surface. Whence could accrue such power to the soul , if it were incorporeal? How could an unsubstantial thing propel solid objects? But in what way do the senses in man seem to be divisible into the corporeal and the intellectual classes? They tell us that the qualities of things corporeal, such as earth and fire, are indicated by the bodily senses — of touch and sight; while (the qualities) of incorporeal things — for instance, benevolence and malignity — are discovered by the intellectual faculties.