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Christianity and Aristotelian Metaphysics

In a recent discussion with Suzanne McCarthy, my views were compared to Aristotle's, and I pointed out that I am really more of a Platonist and am often irritated at the continuing dominance of basically Aristotelian metaphysical ideas in Christian philosophy. In this post I will discuss the nature of these Aristotelian metaphysical claims, the manner in which they have been incorporated into Christian thought, and my reasons for objecting to said incorporation.

Before I start, I should note that I am not an expert on Aristotle, so I will be examining only basic points of Aristotelian metaphysics, and relying on interpretations that I take to be fairly uncontroversial. Of course, since I am not an expert, I could also be wrong in taking my interpretations to be uncontroversial. This is a blog discussion, not a research paper.

Aristotle is a "common sense" philosopher. In stark contrast to Plato, his teacher, he is eager to embrace the basic assumptions of his culture, and even searches for truth in facts about the Greek language. (See especially the Categories.) He is responsible for the "subject/predicate" distinction in grammar (that is, the so-called "Aristotelian predicate" which consists of the part of the sentence which is not the subject, as opposed to the "Fregean predicate," which is a somewhat different concept), and he saw this as a window to the way the world works. He claimed that the world consisted of "substances" (the things that can be subjects of sentences) and that these substances have properties. The properties are the things that might be predicated of the substance. That is, in sentences like "I am a philosophy student," we state that some substance ("I") has a particular property (belongs to the class of substances which are philosophy students). Some properties are essential - that is, if they changed the substance would lose its identity and become a different substance. Others are accidental - that is, the substance retains its identity if they change over time. If I was a philosophy student essentially then when I graduated I would become a different person. Since this is not the case, it is safe to say that I am a philosophy student only accidentally. (Although I can assure you that I became a philosophy student quite intentionally and with much effort! "Accidentally" in this context merely means non-essentially.) These essences, that is, collections of properties which define what it is to be something, are logical entities which are instantiated by certain individuals (but, again in contrast to Plato, Aristotle holds that the actual individuals are the "real" things, not the essences).

According to Aristotle, substances have a two-fold nature: they are "form" and "matter." Aristotelian theories that posit this two-fold nature are called hylomorphic theories. Matter, on this view, is the basic "stuff" of the world. "Form" is what gives it its identity as a unique entity. This exists in a sort of hierarchy. For instance, my form is my soul, and my matter is my body. The form of my body is its "vegatative soul," which is the organizing principle that takes care of blood flow, growth, digestion, etc. (but not motion - there is an "animal soul" in between the vegetative and rational souls). The matter of my body is the organs of which is made. Each organ, in turn, has form and matter, and so on.

The school of Medieval Christian philosophers known as the Scholastics were Aristotelians. During this time, Aristotelian metaphysics became a part of Catholic orthodoxy. In fact, this started very early.

The earliest example of which I am aware is the Chalcedonian Declaration of 451 AD. The Greek text of the Creed is available, with some glossary and commentary here, and there is an English translation in the Wikipedia article. This creed contains many technical terms of Aristotelian metaphysics, and by their use becomes dependent on this type of metaphysical theory. For instance, the Creed affirms that Christ is "co-essential [Gr. homoiousion] with the Father according to divinity." The claim is that Christ, considered in terms of his divinity, has the same Aristotelian essence as the Father (more on this later). Next, it claims that he is "co-essential with us according to humanity." Christ, then, instantiates two disparate Aristotelian essences: the essence of divinity and the essence of humanity. This means that he has all the properties one must have to be divine, and also all the properties one must have to be human. Note, however, that I have just stated this in non-Aristotelian language, so thus far we are merely using the apparatus of Aristotelian metaphysics, but have not made ourselves dependent on it.

Later the Creed affirms that Christ exists as two natures (phuseis) united in one person (prosopon) and one substance (hupostasis). In Aristotle, a phusis is "nature as an originating power" (LSJ, s.v. 4.1). prosopon meaning person is a later usage and is not found in Aristotle. (The word literally means "face" and in Aristotle's time the widespread figurative use was for "appearance," but by the time of the New Testament and all the more so in the later time of the Chalcedonian Creed, the word had come to mean "person.") Aristotelian hupostasis is the ontologically fundamental substance, the really real thing. I think a contrast between prosopon and hupostasis is probably intended here, meaning that Christ, despite having two essences and two natures (the latter can, I suppose, be interpreted as saying merely that Christ has both a divine origin as the only begotten of the Father existing from eternity, and a human origin as a man born from the womb of a human woman at a specific moment in history), is united both as to his outward manifestation and as to his fundamental nature.

Still, one need not affirm all of Aristotelian metaphysics to accept the Council of Chalcedon. One need only accept some metaphysical theory on which all of the concepts just mentioned (ousia, phusis, prosopon, and hupostasis) have meaning. This can probably be done, with a bit of finagling, on any theory that accepts the substance/property model of the world, which is so deeply ingrained in most (all?) human languages that it is nearly impossible to think or act without implicitly assuming it, so this is a fairly minimal requirement.

Later on, the Scholastics made good use of Aristotelian language in examining theological questions. For instance, they stated that God's essence includes existence, and so God is identical with his essence, whereas we are merely instantiations of our essence (or essences - there is and always has been some dispute between Aristotelians as to whether there is a single essence of humanity, or a unique essence of every human being or both).

However, the Scholastics and other Medieval theologians and Church leaders also constructed doctrines that depended far more heavily on actually believing the substance of Aristotle's metaphysics than does the Chalcedonian Creed. The most egregious example is the Roman Catholic doctrine of transubstantiation. In the Canons and Decrees of the Council of Trent Session 13, Canon 2, a strict definition of orthodoxy is given stating,

If any one saith, that, in the sacred and holy sacrament of the Eucharist, the substance of the bread and wine remains conjointly with the body and blood of our Lord Jesus Christ, and denieth that wonderful and singular conversion of the whole substance of the bread into the Body, and of the whole substance of the wine into the Blood-the species Only of the bread and wine remaining-which conversion indeed the Catholic Church most aptly calls Transubstantiation; let him be anathema.

I was unable to find the Latin text of this online (and my Latin is really bad anyway), but the standard explanation of transubstatiation (see, e.g., Wikipedia) seems to be that "substance" here is the Aristotelian hupostasis previously discussed, and the "species" of the bread and wine which remains is the collection of properties associated with the bread and wine, so that the bread and wine takes on the real substance of the body and blood of Christ, displacing the substance of bread and wine entirely. The substances of the body and blood of Christ are apparently able to take on the form of bread and wine without losing their essences. This requires a host (no pun intended) of metaphysical assumptions. For instance, there must be fundamental "substances" of the body and blood of Christ which do not have any observable essential properties. (What are their non-observable essential properties? If they don't have any, in what does their essence consist?) Furthermore, we must believe that it is possible for one substance to transmute into another, which seems to require that there be some kind of basic matter which is independent of the substances, as there might be on a hylomorphic view. This metaphysical picture is getting to be detailed and complicated, and this is only the beginning. Anyone who does not hold such a metaphysical view is implicitly also declared anathema by the Council.

This is my primary objection to the importation of Aristotelian metaphysics to Christian doctrine: a complicated and detailed metaphysical system which is in no way essential to the Christian revelation becomes part of a test of orthodoxy. However, my difficulty accepting it goes further.

Today, Christian philosophers continue to be predominantly Aristotelian. I haven't made an exhaustive statistical survey to show this or anything, so it may be merely that the Christian philosophy I have read is not a representative sample, but I don't think so. For instance, a look at part one of Richard Swinburne's The Christian God shows that Swinburne, one of the dominant figures of Christian philosophy today, retains many metaphysical assumptions from Aristotle. In that book, he does not even discuss any of the objections to them. Furthermore, looking over a few issues of the journal Faith and Philosophy, which is published by the Society of Christian Philosophers, will show that Medieval Aristotelians, especially Thomas Aquinas, receive far more attention than the early moderns, although the latter group was composed almost entirely of Christians.

This is deeply troubling to me for a number of reasons. The first is that it is extremely problematic to allow views to appear to be essential to Christianity when they are not. For instance, think of the number of people who have been turned off to Christianity because they think it means supporting all of the policies of the Republican party, when this in fact has nothing to do with the basic message of faith. This is especially important in light of the fact that modern science requires the rejection of many points of Aristotelianism which to the modern thinker can make a system that requires one to accept any part of Aristotelian metaphysics suspect. But Christianity is not such a system. The second critical point is that I believe these Aristotelian views to be just plain wrong (the reasons why are a topic for another post).

I can only speculate as to the reasons for the continuing prevalence of these views. One speculation I might make is that the Catholic and Episcopal churches are more encouraging of philosophical pursuits than most other churches, and so Christian philosophy tends to have a Catholic/Episcopal bias. (I have reason to suspect that there might be a Calvinist bias in academic theology for similar reasons.) Whatever the case, I believe it is extremely important for Christians to critically examine these assumptions and engage with the world of secular metaphysics, as Peter van Inwagen has so admirably done. While Aristotle's influence persists, serious Aristotelianism seems to be rare in secular metaphysics (again, I haven't done an exhaustive survey, I'm just drawing on what I've read), so the assumptions made by Christian metaphysicians, or the things they are unwilling to challenge, may be hindering them from having effective dialog with the rest of the world of philosophy.

Posted by Kenny at January 7, 2006 3:48 PM