BODY AND SOUL

The question of body and soul has been called by a German philosopher the Weltknoten, which means the “knot of the world.” This is supposed to express the fact that as one’s philosophy of body and soul changes, so does one’s entire Weltanschauung, or worldview. The peculiar position that man occupies between heaven and earth is at issue in the question of how body and soul come together in him.

Christian writers often say that they want to avoid any and every dualism of body and soul in their philosophy of human nature. They are right to say this, for reasons that we will give below; but at the same time it must also be said that Christians recognize, if not a dualism, then at least a duality of body and soul. This duality can already be gathered from the Genesis account of the creation of man, from which we see that man is composed of something taken from the earth and something sprung directly from God.

The Immateriality of the Soul • The early Greek philosophers were unable to conceive of nonmaterial being; even in speaking of the soul they employed material and physical categories. Plato (427-347 B.C.) worked a revolution in human thought by conceiving for the first time of immaterial being and by arguing for the first time for the immateriality of the soul. One of his main arguments, which continues to be used to this day, runs as follows.
The human intellect is capable of understanding eternal being in the form of the timelessly valid essences of things. This means that the human intellect is capable of understanding immaterial being. For since material being is signed by corruptibility and change, and is thus subject to time, eternal being can only be immaterial. But if the intellect knows immaterial being, and is in fact never so much itself as when it knows it, then the intellect must itself be immaterial: Being so deeply akin to that which is eternal and immaterial, and resonating so profoundly with it, the intellectual part of the soul must itself be immaterial.

Aristotle (384-322 B.C.) developed a variant of this argument by showing that the object of intellectual knowledge is something general or universal (e.g., what we understand is not in the first place this or that man, but rather man as such, or man in principle). Now, the universal is immaterial, matter always existing only as a concrete this or that. But man could not know the immaterial universal if his knowing were itself altogether material, for how should a concrete bodily organ be receptive to that which is universal and thus nonbodily? It follows that his knowing involves a nonbodily or immaterial principle.

St. Augustine developed an original argument that enables us almost to touch and feel the immateriality of our soul (On the Trinity, Bk. X). Each person, he said, experiences himself within himself in a most intimate way; each knows within himself that he suffers and loves and understands; each knows these things by living them, by having them as his own experiences. Now, if a person were in this innermost center of himself something bodily, then he would have to experience with just this unique intimacy and inwardness that bodily thing that he was. But no one ever finds any bodily organ (like the brain) in his innermost self-presence. Whenever one thinks about a bodily organ, trying to identify one’s very self with it, one can only think about it at a distance from oneself and over against oneself; try as one will, one cannot experience it within oneself. It follows that each person is something nonbodily in his innermost self.

Some will find the argument simpler still if we just point out that the inner world that each knows in himself does not take up any space. For example, the anguish that I suffer within myself does not take up any space; it does not stand in any spatial relation to other things happening in my inner life, such as my reflecting on the meaning of the suffering. Since matter, whatever else it is and does, always takes up space, the human person must have something in himself that, as it takes up no space, has no matter to it.

Notice that these last two arguments show the immateriality not just of acts of rational understanding but of all acts and experiences of persons.
Substantial Difference Between Body and Soul • But there is a famous retort to all such arguments from the side of the materialists. They say that what we call an immaterial soul is really only a kind of quality or property of the brain or of the body as a whole. Just as the beauty of a painting is not a physical something in the sense in which the colors of the painting are physical, and yet the beauty is nothing but a quality of the physical painting, so with the immaterial soul: Though immaterial, it inheres as a kind of property in the material body. If this materialistic response is correct, then we have not gone beyond a fundamentally materialistic view of the soul.

Already some ancient Greek philosophers took this refined materialist position – and already Plato and Aristotle refuted it decisively. The main Platonic argument is based on our freedom in governing our bodies. We have it in ourselves to resist the promptings of the body; for the sake of some good that we have understood, we can act in our body in such a way as to govern the body and not be governed by it. But how, Plato asks, can a dependent quality act on its own initiative against that on which it depends? Could the beauty of the painting act back on the picture so as to change the colors or to delete something in the picture? Just as beauty is too passive in relation to the elements of the painting to take any such initiative, so the soul would be too passive to take any such initiative if it were nothing but a quality of the body. But since the soul can and often does take this initiative toward the body, it is essentially more in its immateriality than just the immaterial property of the body.

But what is this “more”? Most of the great Christian philosophers have explained it in terms of the substantiality of the soul. For Aristotle, a substance is a being that exists on its own and in itself and not merely as a part or an attribute of another being. Thus any human being is a substantial being, since it is not a part or an attribute of any other being. But we have also to say that the human soul alone is substantial being. The immaterial soul is not a mere part or an attribute of the body or of the body-soul composite; it has just that being of its own that we call its substantiality. St. Thomas Aquinas thinks that this being-of-its-own is expressed in the fact that the soul is capable of certain activities, such as rational understanding or free choosing, which belong not to the body-soul composite but to the soul alone.

With such arguments we establish the immaterial substantiality of the human soul. This implies that there is a substantial difference between body and soul in man. On this basis, one can proceed to argue for the immortality of the soul, that is, for its capacity to survive the death of the body. For clearly, if the refined materialistic view of the soul were true, there could be no immortality. On the same basis, one can also argue for the impossibility of the soul being generated by the parents in the same way in which the body is generated; an immaterial substantial soul can only be directly created by God, as the Church also teaches.

Unity of Body and Soul • It may seem that we have gone so far in asserting the difference between body and soul as to portray each human being as composed of two substances or two beings, and that we can no longer make sense of the idea that each is in fact one being. It may seem so, but it is not really so. We can in fact now proceed to affirm that the soul is the form of the body, and to do so not in spite of all that has been said but rather on the very basis of it.

This idea of the soul as form, which derives from Aristotle, has been taken by the Church into her own doctrine (Ecumenical Council of Vienne [1312], constitution Fidei Catholicae). To call the soul the form of the body is of course not to say that it is merely the external shape of the body, nor is it to say that it is the internal structure of the body. It is rather to say that the soul, out of the abundance of its own nonbodily life of understanding and willing and loving, “in-forms” the body, making it to be a living body, and not only a living body but a bodily expression of the soul’s own more-than-bodily life. It is not enough to say that the soul acts on the body and governs it and that the body acts on the soul; such interaction between body and soul, though of course it exists, falls short of the intimate union of the two expressed by saying that the soul makes the body live and even incorporates the body into its own higher spiritual life, raising it far above the merely physical. The soul does not just use the body, though it does that too, but it also dwells in the body, is present in it, indeed exists as embodied.

Philosophers have tried to put the idea that the soul is the form of the body together with the other idea – apparently opposed to the first – that the soul has its own substantiality. They have argued that the strength and independence of being implied in substantiality is the very source of the soul’s power to inform; but that which it informs is taken into itself in such a way that what results is one composite body-soul being. Insofar as the soul has its own substantiality, it might say of the body, “I have a body”; but insofar as it informs the body, incarnating itself in the body, it might say of it, “I am my body.” St. Thomas puts the two ideas together in a single phrase when he calls the soul the substantial form of the body.

Christian philosophers, and they almost alone among philosophers, have gone one step further and argued that the soul is incomplete apart from its bodied state. Inspired by their faith in the creation and redemption of matter and of bodies, they have said that, while the human soul can, and in fact for a time does, exist as disembodied, in this state it suffers an unnatural mode of existence, and can be fully itself only as embodied. This leads to the result that the soul, for all its substantiality, is called by these philosophers an incomplete substance or an imperfect substance, the really complete substance being not the soul alone but the body-soul composite.

True and False Dualism • For those affirming that the soul is the form of the body there are various unacceptable versions of body-soul dualism. If, for instance, one says that the body is only an encumbrance for the soul, or if one even goes so far as to say that the soul would be pure and happy but for the body, then one has fallen into an erroneous dualism. Or if one says that the soul only uses the body as an instrument or uses the body as raw material, then one would have a dualism different indeed but no less erroneous. On the other hand, there is a duality of body and soul that we must affirm. To affirm the substantial difference of body and soul need have nothing to do with these dualistic excesses; far from interfering with the truth about the soul as form of the body, this affirmation underlies it.

The proper understanding of the unity of body and soul in man is all-important for maintaining Catholic sexual moral teaching. As John Paul II shows in his encyclical The Splendor of Truth, Veritatis Splendor, 48-49, dissent in contemporary moral theology comes in good measure from certain dualisms of body and soul that imply an excessively spiritualistic image of man.
In conclusion, let us guard not only against a false dualism but also against a certain rationalism. Much as philosophy can understand about body and soul in man, there always remains something impenetrable and mysterious for us about how exactly man exists between heaven and earth as an embodied spirit – about how exactly that which takes up no space can inform so intimately that which is spread out in space. According to St. Augustine, “the way in which spirits are united with bodies is altogether marvelous and cannot be understood by man – yet this [unity of body and soul] is man himself.”

See: Human Person; Immortality; Sexuality, Human; Theology of the Body.

Suggested Readings: CCC 362-368. Council of Vienne, Fidei Catholicae, Denzinger-Schönmetzer, 902. Vatican Council II, Pastoral Constitution on the Church in the Modern World, Gaudium et Spes, 14. Plato, Phaedo. St. Augustine, On the Trinity, X. St. Thomas Aquinas, Summa Theologiae, I, qq. 75-76.

John F. Crosby




Russell Shaw. Our Sunday Visitor's Encyclopedia of Catholic Doctrine. Copyright © 1997, Our Sunday Visitor.

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Last Updated: Sunday, April 01, 2001 03:24:19 PM