The Divine Institutes

It remains to speak of the soul, although its system and nature cannot be perceived. Nor, therefore, do we fail to understand that the soul is immortal, since whatever is vigorous and is in motion by itself at all times, and cannot be seen or touched, must he eternal. But what the soul is, is not yet agreed upon by philosophers, and perhaps will never be agreed upon. For some have said that it is blood, others that it is fire, others wind, from which it has received its name of anima, or animus, because in Greek the wind is called anemos and yet none of these appears to have spoken anything. For if the soul appears to be extinguished when the blood is poured forth through a wound, or is exhausted by the heat of fevers, it does not therefore follow that the system of the soul is to be placed in the material of the blood; as though a question should arise as to the nature of the light which we make use of, and the answer should be given that it is oil, for when that is consumed the light is extinguished: since they are plainly different, but the one is the nourishment of the other. Therefore the soul appears to be like light, since it is not itself blood, but is nourished by the moisture of the blood, as light is by oil.

But they who have supposed it to be fire made use of this argument, that when the soul is present the body is warm, but on its departure the body grows cold. But fire is both without perception and is seen, and burns when touched. But the soul is both endowed with perception and cannot be seen, and does not burn. From which it is evident that the soul is something like God. But they who suppose that it is wind are deceived by this, because we appear to live by drawing breath from the air. Varro gives this definition: “The soul is air conceived in the mouth, warmed in the lungs, heated in the heart, diffused into the body.” These things are most plainly false. For I say that the nature of things of this kind is not so obscure, that we do not even understand what cannot be true. If any one should say to me that the heaven is of brass, or crystal, or, as Empedocles says, that it is frozen air, must I at once assent because I do not know of what material the heaven is? For as I know not this, I know that. Therefore the soul is not air conceived in the mouth, because the soul is produced much before air can be conceived in the mouth. For it is not introduced into the body after birth, as it appears to some philosophers, but immediately after conception, when the divine necessity has formed the offspring in the womb; for it so lives within the bowels of its mother, that it is increased in growth, and delights to bound with repeated beatings. In short, there must be a miscarriage if the living young within shall die. The other parts of the definition have reference to this, that during those nine months in which we were in the womb we appear to have been dead. None, therefore, of these three opinions is true. We cannot, however, say that they who held these sentiments were false to such an extent that they said nothing at all; for we live at once by the blood, and heat, and breath. But since the soul exists in the body by the union of all these, they did not express what it was in its own proper sense; for as it cannot be seen, so it cannot be expressed.