On the Soul, to Tatian

Opening address and plan of the treatise§1

Gregory opens the work by addressing Tatian, explaining why he agreed to write on the soul without scriptural testimonies and outlining the order of inquiry he will follow.

How the soul can be known: by what it does§2

Gregory sets out how the soul can be known: things of sense are known by the senses, but things of the understanding are known from what they do, so the soul is known from its effects.

2All things are either known by the senses or grasped by the understanding. Of these, the things that fall under the senses are shown well enough by the senses themselves, for as soon as a sense is brought to bear on a thing, it presents to us the image and form of the object before it. But things grasped by the understanding are perceived not from themselves but from their actions and effects. Since the soul, then, cannot be known from itself, it may rightly be known from its effects.

That the soul exists: it moves the body and gives it life§3

The body moves neither from outside, like lifeless things, nor by its own nature, like fire, since it stops moving at death; so it is moved by the soul, which gives it life.

3When our body moves, it is moved either from outside or from within. That it is not moved from outside is clear from this: it is moved neither by pushing nor by pulling, as inanimate things are. And though it is moved from within, it is still not moved by nature, as fire is. For fire never stops moving as long as it exists, but the body, once it has died, ceases to move, even though it is still a body. If, then, it is moved neither from outside, like inanimate things, nor by nature, like fire, it is plain that it is moved by the soul, which also supplies it with life. So if it is established that the soul gives our body its life, then the soul is also known from its effects.

That the soul is a substance§4

The soul fits the definition of substance, since it stays one and the same while receiving opposite qualities such as justice and injustice; and what gives life to the body, itself a substance, must also be a substance.

4Further, that the soul is a substance is shown as follows. First, because the definition of substance rightly fits it as well. That definition runs like this: a substance is that which, while remaining one and the same in number, receives contraries in turn. That the soul, without departing from its own nature, receives contraries in turn is plain to everyone, I think. For justice and injustice, courage and cowardice, temperance and intemperance are seen in it by turns, and these are contraries. Since it is the property of substance to receive contraries in turn, and this same property belongs to the soul, the soul will therefore be a substance.

Moreover, since the body is a substance, the soul too must be a substance. For it cannot be that what receives life is a substance, while what gives life is not a substance, unless perhaps someone is so mad as to claim that what is not is the cause of what is; or again, to hold that a thing whose very being so depends on another that it cannot exist without it is the cause of the very thing on which it depends.

That the soul is not a body§5

Five arguments show that the soul is not a body: how it is present in the body, how it moves, how it is nourished, the dilemma of whether it is animate, and its lack of color, size and shape.

5We have shown above that the soul is in our body; we must now learn how it is in the body. For if it lies against the body as one stone lies against another, it follows that the soul is a body, and that not the whole body is animate, since the soul clings only to some part of it. But if it is mixed and blended with the body, it will have fallen from what properly makes it a soul; it will consist of many parts and will not be simple. For what has many parts can be divided and dissolved; what can be divided is composite; and what is composite can be divided in three ways. Again, a body joined to a body increases its bulk; but the soul, being in the body, does not make it swell, but rather makes it alive. The soul, therefore, is not a body but incorporeal.

Besides this, if the soul were a body, it would be moved either from outside or from within. But it is not moved from outside, for it is moved neither by pushing nor by pulling, as inanimate things are. Nor is it moved from within, as animate things are, for it is absurd to speak of a soul of the soul. The soul, then, is not a body; it is therefore incorporeal.

Again, if the soul is a body, it also has qualities that the senses perceive, and it is nourished. But it is not nourished. But if it is nourished, it is not nourished in a bodily way, as a body is, but in an incorporeal way, for it is nourished by reason and by the word. It does not, then, have qualities the senses can perceive. For justice is not seen with the eyes, nor courage, nor anything else of that kind, and these are the qualities of the soul. The soul, therefore, is not a body; it is incorporeal.

Further, since every bodily substance is divided into animate and inanimate, let those who claim that the soul is a body tell us whether they want it called animate or inanimate.

Finally, if every body has color, quantity and shape, and nothing of the kind is seen in the soul, then the soul is not a body.

That the soul is simple§6

The arguments that show the soul is not a body also show that it is simple, since it has no parts and cannot be divided.

6The same arguments, then, that show the soul to be without body also show, above all, that it is simple. For if it is not a body, and every body is composite, and what is composite consists of parts, then the soul will not consist of many parts either. And since it is incorporeal, it will be simple, because it is not composite and cannot be cut into parts.

That the soul is immortal§7

Three arguments show that the soul is immortal: what is simple cannot be dissolved, what moves itself never stops moving, and the soul's own evils do not take away its life.

7It seems to me to follow that what is simple is also immortal. Listen to how this is so. Nothing that exists destroys itself; otherwise it would not have existed even in the beginning. Things that are destroyed are destroyed by contraries. For everything that is destroyed is dissolved; what is dissolved is composite; what is composite has many parts; what consists of parts consists, of course, of parts that differ; and what differs is not the same. Since, then, the soul is simple and does not consist of many parts, because it is neither composite nor able to be dissolved, it follows that it is indestructible and immortal.

Moreover, whatever is set in motion by another's movement, and has its power of living not from itself but from what moves it, lasts as long as it is kept in being by that power working within it; when that power ceases, the thing it was moving must also cease. So, since the soul is moved by itself, it never ceases to be. For these things follow one from another in this way: what is moved by itself is always moved; what is always moved never fails; what never fails has no end; what has no end is not destroyed; what is not destroyed is immortal. If, then, the soul is moved by itself, as was shown above, it will be, by the force of the reasoning just set out, indestructible and immortal.

Again, whatever is not destroyed by its own evil cannot be destroyed. Evil is contrary to good, and so it has the power to destroy it. For the evil of the body is nothing other than suffering, disease and death, just as, on the other side, its excellence is beauty, life, health and a sound constitution. If, then, the soul is not destroyed by its own evil, and the evil of the soul is fear, intemperance, envy and the like, none of which takes from it the power of living and moving, then the soul is immortal.

That the soul is rational§8

Three arguments close the treatise by showing that the soul shares in reason: it discovered the useful arts, the senses alone cannot judge things truly, and the soul plans within itself before it acts.

8Further, that our soul shares in reason can be shown by many arguments. First, from the fact that the soul itself discovered the arts that are useful to our life. For no one would say that they were found at random or by some chance, since no one could show that they are idle or useless to life. If, then, the arts contribute to the benefit of life; and useful things are also praiseworthy; and praiseworthy things are gained by reason; and the arts themselves are discoveries of the soul: then our soul shares in reason.

Next, it is also shown that our soul is endowed with reason from the fact that our senses are not sufficient for grasping things. For we cannot come to know things by the mere application of the senses. And that we do not wish to stop at the senses is plain at once from this: unless reason helps them, the senses cannot tell apart and distinguish things that are equal in shape and alike in color but different in nature. Since, then, the senses without reason bring false images and forms of things before us, we must consider whether things can truly be grasped or not. If they can be grasped, we have another power besides the senses, and a higher one, by which we may come to know them. But if they are not grasped, we shall not be able to reach even those things that are seen otherwise than they are. That things are perceived by us is clear, if from nothing else, from the fact that we put them fittingly to our uses and turn them again into whatever we wish. So if we have shown that things can be grasped, and this cannot be done by the senses without reason, since they set false notions before us, then it will surely be the mind that distinguishes and judges all things by reason and knows things as they truly are. And the mind is the part of the soul adorned and enlightened with reason. The soul, therefore, shares in reason.

Finally, it is shown from the fact that we do nothing that we have not first sketched out and defined for ourselves; and this is nothing other than the dignity of the soul. For knowledge of things does not come to it from outside; rather, it adorns things, as it were, with its own designs and conceptions, and so it first paints and sketches a thing within itself, so that it may afterward bring it out into the open. The dignity of the soul, moreover, is nothing other than doing all things by reason, and by this it also differs from the senses. It has now been shown, therefore, that the soul is endowed with reason.