Mind and Body, Medieval and Modern: Augustine and Thomas Aquinas Versus Descartes

by David McGraw

Part I

In order to examine rightly whether materialism is true of the human person, one must first understand what is at stake and what alternatives there may be. In this age of Western philosophical history, that point entails that one must begin by resolving some of the errors and confusions derived from Rene Descartes. Like his predecessors, Descartes said materialism is not true of the human person, but what he meant be this denial turns out to be seriously different from what they meant.
Descartes thought of himself as a "second Augustine." In fact, the comparison of Descartes with Augustine shows rather clearly where they differ and where Descartes went wrong.
Saint Augustine exalted number as the principle of material things. Indeed, in one way, Augustine would almost be willing to agree to the thesis that material objects have only mathematical attributes, but not in the way Descartes imagined. The exact difference between them on this point is the heart of the dispute.
Augustine accepted and used Aristotle's analysis of material objects when it served his purposes, but his basic framework was Platonic or Neoplatonic. This comes out clearly in his analysis of how matter is informed. Divine wisdom is the principle of cosmic order. A dead body partakes of Divine wisdom only in the least and lowest measure. Because of this, the dead body has only number but not life or reason. In this way, and in this way only, Augustine would almost agree that material things have only mathematical attributes. Bodies have nothing more than number, measure, and weight only as being comparatively weak and shadowy on this basis.
Again, God creates matter and so must in some way contain material attributes within Himself. But He contains these attributes only by comprehending them within His knowledge and power, not by exemplifying or displaying them within His own nature. Mathematical attributes are not aspects of the Divine nature, and they are not a spillover or overfolw from the Divine nature, for there is no spillover or overflow. There is creation. God makes there be things that are not Himself and that receive from Him.
Augustine proclaimed all this, and Descartes would say he affirmed it. But Descartes did not follow out the consequence. A rational creature is superior to a dead body because God gives more to the one that to the other, and the same God is giving in both cases, although in different measures. Thus, when a created spirit does not have various mathematical attributes, this is not because it lacks something that matter has. It is rather that a created spirirt is so richly powerful by nature as to transcend the whole order of material being, including the attributes proper to material things.
The same God gives existence and attributes to both soul and body. This point is critically important. Augustine considered that matter sits at the bottom of the hierarchy of the universe. But Descartes was really denying that there is any hierarchy of the universe. Matter has the mathematical attributes, but the soul does not. Thus, they belong to different orders of being. Plato and Augustine might have to argue about whether matter is too weak and shadowy to contain or support mental life. But for Descartes, such life is simply irrelevant to matter. Mental life belongs to the soul instead of the body because the soul is the right kind of thing, and the body is the wrong kind of thing, to have these functions. So, if matter may be said to be weak, this is not because it is lacking compared to the soul. It is only because matter does not share in any law or structure that makes the connection of soul and body possible. Descartes strips down matter, but chiefly because he strips down the whole universe by denying such laws and structures.
Along this line, Descartes did not really share Augustine's strict opposition to materialism, although he would say he did. Descartes agreed with Augustine that God is totally immaterial and incorporeal. However, the concept of being purely spiritual did not mean to Descartes what it meant to his predecessors. His concept was negative in the wrong way.
The old positive concept is of levels of power and perfection that cannot be captured within matter. A pure spirit is unextended, but not because it lacks anything. Rather, it is not limited by space. Thus, God "virtually" contains attributes that He does not display. Somewhat analogously, the human soul comprehends but does not exemplify extension. More properly, the soul exemplifies extension by developing and maintaining the body, but not within itself. Descartes may have thought in these terms about God, but he did not think this way about the soul. But Augustine thought this way about both God and the soul.
On this basis, it is almost as if Descartes did not really think materialism is false of the human person after all. The reason is that the soul cannot rightly be said to be superior to the body, since the inner functioning of the soul belongs to a different order of being from the life of the body. It is almost as if the soul exercises mental life instead of developing and maintaining the body. On the other side, Augustine was very clear that the soul to which mental life belongs is the same soul that animates the body.
Yet Augustine agreed with Descartes that the human soul is numerically separate from the body and all its parts. Once again, however, the soul is separate from the body as superior to the body. It is not as though body and soul were beings of different orders that had to be magically joined at the pineal gland.
Then again, perhaps the challenge is to know what may be involved in transcending the whole order of material being in this way. In fact, Augustine himself found this hard to understand. His breakthrough came when he read the books of the "Platonists." Now, Plato was concerned with the fact of reasoning, and there is an obvious way in which reasoning involves going beyond material limitations. Given this, one can then think of things with this capability as belonging to some superior order of being (which is what Plato did in contemplating the soul).
In what way does reasoning go beyond material limitations? One who reasons is concerned with abstract principles that apply generally. (For instance, a veterinarian may think abstractly about dogs in general.) These principles apply fully and undividedly to each of a multitude of things. (The whole of what the veterinarian knows about dogs applies in its totality to each of Fido, and Rover, and Spot, and so on.) On the other side, the concrete example is just that, an example of the principles it embodies. (The veterinarian is aware of the particular dog Sparky as a given instance of what he knows.) Again, one who reasons can cut across time and space to contemplate the events and situations of remote ages and remote regions. (An astronomer does this in thinking about galaxies long ago and far away.) Indeed, reasoning involves latching onto principles that stand fast forever, beyond time and change. (Mathematics is an obvious illustration of this.) Through reasoning, one can go beyond the limits even of actual reality to be concerned with hypothetical cases. (A scientist can think about would result if such and such were to happen.) On all these points, one who reasons reaches beyond the limitations of the material.
What must be noted here is that, in view of all these considerations, knowledge based on reasoning is also superior to knowledge based on observing through the senses. Unhappily, Descartes lumped together intellectual functioning and sensory experience as mental, in contradistinction to the material. In doing this, he ended up downgrading the traditional division between sense and intellect. This error was cirtical. For sensory experience does not have these benefits, and so it stands with the material, across the great divide from intellectual functioning. Therefore, one who stands within the tradition derived from Descartes may well find the idea of spirit as superior to matter hard to understand, for he has lost sight of the principal manifestation of this superiority in ordinary human experience.
With all these considerations in view, one may go back and examine whether materialism is true of the human person. Perhaps the first thing to note is that the modern version of the problem about mind and body is not the version that was important in earlier centuries. A philosopher concerned with the modern problem will answer crude versions of materialism by saying these theories cannot account for the mental life of a dog or a cat, let alone that of a man or a woman. This answer, however, is clearly not relevant to the problem as Plato understood it. Plato argued that the soul is not merely a function or combination of bodily processes, for it can exercise effective control over animal appetites. This reply belongs to a different world from that of the modern version.
In earlier centuries, it was considered that the material world is reasonably rich, as opposed to being stripped down in the manner of Descartes. The question was whether, given this, the human subject must then include some level or layer above the material. Plato said yes, as did Aristotle, Augustine, and Thomas Aquinas. They said this because they believed (1) the distinctive functions of intellect and will reach above the material and (2) these functions cannot really be constructed from lower level processes.Whether all this is correct or not, these thimkers at least asked the right questions more than those who follow Descartes.