Today, I had a brief discussion with someone who had questions about the distinction between Anhypostasis, Enhypostasis, and how the terms function in Christology. I thought it would be beneficial to write up a brief post explaining this, so here we go.
This post requires a bit of basic terminology. So these are really rough definitions of the key terms.
Ousia – A nature. The metaphysical substance which underlies the existence of a given kind of thing.
Hypostasis – A concrete, discernible, and distinct instance of a given ousia/physis.
Now, a full explanation of the history of these terms and their development throughout the 4th and 5th centuries is beyond the scope of this post. Michael Horton’s chapter in either Pilgrim Theology or the Christian Faith has an excellent overview if you want more details.
Now, in the 5th century, the debate which had centered on the reality of Christ as being truly divine as well as truly human shifted to try to parse out exactly HOW Christ was truly divine as well as truly human. Because of this debate, terminology had to be fleshed out. It was not enough to say that Christ was a hypostasis that was both an instance of the divine ousia as well as an instance of an human ousia. Left unqualified this results in either Eutychianism (that Christ is a divine person who absorbs human nature) or Nestorianism (that Christ is actually two hypostases).
Primarily articulated by Cyril of Alexandria, a distinction between an anhypostatic ousia, an enhypostatic ousia, and a hypostatic ousia began to take shape.
Hypostatic – An ousia that exists as or in a hypostasis (there is a world of difference between “as” and “in” regarding this discussion, but again… this is a blog post, not a dissertation). Most ousiai are hypostatic in that in general each hypostasis is of one and only one ousia.
Anhypostatic – An ousia that exists simpliciter, apart from existence as or in a hypostasis. It is important to note here that this is an entirely theoretical ousia that does not exist.
Enhypostatic – An ousia that exists attached to an already existing hypostasis.
These may seem like arcane terms, but in reality they are quite simple. An example will probably help.
I am a hypostasis of a human ousia. This means that the human ousia that is me is concrete, discrete, and distinct from other ousia.
The Father, Son (prior to the incarnation), and the Spirit are each hypostases of the divine ousia. Since they share a single ousia, they are concrete, discrete, and distinct in that each are distinct hypostases of that divine nature.
In the above examples, my human ousia is hypostatic because it is a distinct instance of a human ousia. the divine ousia is hypostatic (tri-hypostatic actually… but again… not a dissertation) in that there are three distinct instances of the single divine ousia.
That brings us to the quandary of Christ and his two natures. It is uncontroversial, and rather straight forward, that the divine ousia was always eternally hypostatic in the person of God the Son. However, where it becomes complicated is when the human ousia was assumed by the divine hypostasis, God the Son.
If this ousia was hypostatic in the traditional sense, then it was a hypostasis. Thus, the term enhypostatic began to be used to describe the way that this second ousia existed. It existed not as its own hypostasis, but as an attached ousia to the divine hypostasis. Thus, Christ possesses two ousiai. The first is the divine ousia which is and always has been hypostatic. The second is a human ousia which came into existence as an attached enhypostatic ousia. This is why theologians say that Christ is not a human person (which is a synonym for hypostasis) but that he is a divine person with a human nature. Another way to say this is that Christ’s human nature is not personal in and of itself, but is personalized by becoming part of the divine Logos (who is a personal).
To see a couple of examples of why this is important, lets see how these terms might be used to describe various Christological errors.
Adoptionism – Christ is a hypostatic human ousia, which is made divine by means of the addition of an enhypostatic divine ousia
Arianism – Christ is a hypostatic non-divine ousia
Originism – Christ is an eternally hypostatic human ousia which was once unified with an eternally hypostatic divine ousia, who willingly separated from this eternally hypostatic divine ousia in order to show other eternally hypostatic human ousiai how to return to the eternally hypostatic divine ousia
Apollinarianism – Christ is a partial hypostatic human ousia which is completed by the indwelling of the hypostatic divine ousia
Eutychianism – Christ is a hypostatic divine ousia which is made human by the absorption of a semi-enhypostatic human ousia (the nature is absorbed, but none of the attributes of that nature are communicated to the hypostasis)
Nestorianism – Christ is a loose fusion of both a hypostatic divine ousia, and a hypostatic human ousia
Orthodoxy – Christ is an eternally hypostatic divine ousia to which a created enhypostatic human ousia was added