Program / Course 9: Christology and Pneumatology / Lesson 3.3
What you will learn
- Define nature, person and hypostasis as these words are used in Christology.
- Explain the phrase hypostatic union in plain language.
- Explain why the church says the Son took a human nature and not a human person.
- Evaluate the common analogies for the union and say where each fails.
The big idea
Hypostatic union is the name for what Chalcedon confesses: the divine and human natures of Christ are united in one hypostasis, one individual subject, the eternal Son. A nature is what something is. A person, or hypostasis, is who someone is. The Son was already who he was. In the incarnation he took on a human nature as his own, so that the one who is born, hungry and crucified is the same one who is God. Every picture offered for this union breaks down at some point, and the church treats it as a mystery to be guarded, not solved.
Key terms
- Hypostasis
- A Greek word for an individual, concrete existing subject. In Trinitarian theology it names each of the three persons. In Christology it names the one subject who is both God and man.
- Hypostatic union
- The union of divine and human natures in the one hypostasis of the Son. The phrase became standard after Chalcedon.
- Nature
- What a being is: the set of qualities that make it the kind of thing it is. Human nature includes body, mind and will. Divine nature includes being uncreated and unchanging.
- Person
- In this context, an individual subject who has a nature, acts and can be addressed as I. A classic ancient definition describes a person as an individual substance of a rational nature.
- Anhypostasia and enhypostasia
- Terms from later Greek theology. Roughly: Christ’s human nature has no independent personal existence apart from the Son (anhypostasia), and it has its personal existence in the Son (enhypostasia). Their exact meaning and history are debated.
- Assumption
- The word used for the Son taking on human nature. The Son assumed human nature, in the sense of taking it to himself.
- Perichoresis
- A Greek word for mutual indwelling, used for the Trinitarian persons and, by John of Damascus, for the interpenetration of Christ’s two natures.
Background
Chalcedon said that the two natures come together in one person and one hypostasis. This lesson tries to explain what those words mean, using the later tradition that grew from the Definition. It is the most technical lesson of the course, and a patient reader will notice that each term has been used with care so as to exclude a specific error.
The phrase hypostatic union does not appear in the Definition itself. It gained currency in later writers. It is a convenient name, and all Chalcedonian traditions use it in some form, but its explanation has been developed in different ways in the East and West.
Step-by-step explanation
Step 1: Nature and person
Ordinary speech blurs two questions: what are you, and who are you? The first is about nature, the second about the individual. All human beings share one human nature, yet each is a different person. In the Trinity, the three persons share one divine nature. The words were fixed for the Trinity by the Cappadocian Fathers: one ousia or being, three hypostases or persons.
Christology applies the same distinction in the opposite direction. In the Trinity, one nature and three persons. In Christ, two natures and one person. The person is the Son, the second person of the Trinity. The natures are divine, which he has from eternity, and human, which he took in time.
Step 2: What the Son took
The tradition says that the Son took a complete human nature: a body, a rational soul, a mind and a will. It does not say he took a human person alongside himself, as though there were a man named Jesus whom God joined to himself. That was the picture critics feared in Nestorius. Rather, the human nature has its existence in the Son, who is its subject.
This is the sense of the terms enhypostasia and anhypostasia as used by many later theologians. The human nature of Christ is not impersonal or incomplete. It is fully human, but the one who lives it is the Son. Some theologians have objected that this leaves Christ without a human center of consciousness, and others reply that this misunderstands the term person.
Step 3: How the union is described
The union is real, not just a matter of agreement or presence. Cyril insisted that the Word made flesh his own. It is without confusion: the divine does not become human or the reverse. It is without division: what happens to the humanity happens to the Son. It is also without change in the Son: he does not stop being God by becoming man, but takes on what he was not.
John of Damascus, in the eighth century, described the natures as penetrating each other, with the divine nature permeating the human and not the reverse. He used the picture of iron heated in a fire: the iron remains iron and the fire remains fire, yet the iron burns. This image was used by earlier writers, too.
Step 4: Pictures and their limits
Writers have used several analogies. Body and soul form one human being, though in Christ the natures are far more unlike. The sun and its light suggest a shared source, but they cannot represent two natures in one subject. Fire in iron shows interpenetration, but fire and iron are both created things. Each picture shows one aspect and fails at another.
A good habit is to use an analogy only to rule out one error. Body and soul show that one person can have two kinds of life. They do not show that God can unite to humanity. The tradition itself warns that the union is unlike anything else, since it joins the creator and a creature.
Step 5: Objections and replies
A common philosophical objection is that being divine and being human involve contradictory properties: unlimited and limited, unchanging and growing. How can one subject have both? The traditional reply is that the properties belong to different natures, and the one subject has them in different respects. Critics say this does not remove the difficulty, and some modern philosophers have proposed alternatives.
Another objection, from some Protestant, Orthodox and Catholic writers, concerns the human will and mind. If Christ’s human nature has no human person, is it a full human life? The tradition replies that a human will and mind are properties of nature, and that he truly has them, which the Third Council of Constantinople later confirmed. The debate continues, and the Definition leaves room for several accounts.
- In ordinary speech, when are nature and person confused?
- Why is the Trinity described as one nature in three persons and Christ as two natures in one person?
- What difficulty arises if the Son took a human person?
- What does the iron and fire image help to show, and what does it hide?
- How would you state the objection from contradictory properties in your own words?
- Why might a tradition insist that the union is a mystery?
Examples
Who is hungry?
The Gospels say Jesus was hungry in the wilderness. On the traditional account, the one who is hungry is the Son, but hunger belongs to his human nature. Divine nature does not hunger. The sentence is true of the person, by way of the human nature. This pattern recurs in the next module.
Iron and fire
John of Damascus used the heated iron to say that the humanity is not replaced but filled with divine power. Others have noted that fire and iron are each created things with physical limits, so the picture cannot show the creator joined to a creature.
A constructed puzzle
A student asks: when Jesus slept, who was running the universe? The traditional answer is that the Son, as divine, was never absent from his work, while as man he slept. Each half of the answer belongs to a different nature. Many students find this the point where the doctrine begins to make sense, and others find it where it breaks. (A constructed question.)
Different perspectives
Catholic
Catholic theology, especially in the line of Thomas Aquinas, explains the union as a union in the person of the Word and not in the natures, and says the human nature subsists in the Word. The Catechism states that the Son assumed a human nature while remaining a single divine person.
Orthodox
Orthodox theologians follow the Fathers, especially Cyril, Maximus and John of Damascus, and treat the union as a mystery known by faith and by participation in worship. They often stress that the human nature is deified by its union with the Word.
Protestant
Reformed theology teaches the union in the person while insisting that the natures remain distinct. Lutheran theology stresses a very close sharing of properties between the natures. These emphases lead to different views of the Lord’s Supper, discussed in the next module.
Modern philosophical theology
Some contemporary Christian philosophers defend the classical view, while others propose models in which the Son has a human mind with divine access or in which divine and human minds are layered. Others argue that the classical view cannot be made consistent. These are active debates among believers and non-believers.
Why it matters
The hypostatic union is the technical center of Christology. Its logic shows up later in the discussion of suffering, knowledge and worship. Even readers who find it hard can see that it is built to protect two claims: that God is truly present in Jesus and that Jesus is truly one of us.
Common misunderstandings
Misunderstanding: Hypostatic union means God and a man were stuck together.
Correction: That is the view the church called Nestorian. The tradition says there is one subject, the Son, who has taken human nature to himself. The union is in the person, not a joining of two persons.
Misunderstanding: If Christ had no human person, he was not fully human.
Correction: The tradition holds that he has all that belongs to human nature: body, soul, mind and will. Whether that is enough for full humanity is debated, but the claim is not that anything is missing from his nature.
Misunderstanding: There is an agreed analogy that explains the union.
Correction: No analogy is agreed. Writers use several and warn that all fail. Treat each as a tool, not an explanation.
Knowledge check
What is the difference between a nature and a person in Christology?
A nature is what something is, such as human or divine. A person or hypostasis is who someone is, an individual subject. In the Trinity there is one nature and three persons. In Christ there are two natures and one person, the eternal Son, who has both natures.
Why does the tradition say the Son took a human nature and not a human person?
If the Son had joined himself to a human person, there would be two subjects, which is the picture of two sons that Cyril opposed in Nestorius. So the tradition says the human nature has its existence in the Son, who is its subject. The human nature is complete, but the one who lives it is the Son.
What does the image of heated iron show, and what does it fail to show?
It shows that two things can be united without one being replaced, since the iron stays iron and burns with fire. It fails because both are created, and the union of the creator with a creature is unlike any other union. Writers use it to exclude confusion, not to explain.
Name one objection to the hypostatic union and one reply.
One objection is that divine and human properties contradict, since God is unlimited and a man is limited. The traditional reply is that the properties belong to different natures and so are true of the one person in different respects. Critics say this only restates the problem. Others propose alternative models.
Think it through
- Which analogy for the union do you find most helpful, and why?
- How much of this doctrine do you think must be understood to be believed?
- What would be lost if the Son had joined himself to a human person?
- How does this lesson change your understanding of the creeds’ use of the word person?
Independent assignment
An explanation for a friend
In your own notebook, write 500 to 700 words. Explain the hypostatic union to a friend who knows nothing of the doctrine. Use the terms nature and person, one analogy and its limits, and one objection with a reply. Then add a short paragraph on which part you found hardest to explain and why. Do not send this to anyone.
Further study
- John of Damascus, An Exposition of the Orthodox Faith Read the book on the incarnation, including the image of the iron and fire.
- Thomas Aquinas, Summa Theologiae Read selectively in the third part on the union of the incarnate Word.
- Catholic Church, Catechism of the Catholic Church Read the paragraphs on the two natures and one person.
- Alister E. McGrath, Christian Theology: An Introduction Read selectively on the person of Christ.
- John 1:14 The Word became flesh.
- Colossians 2:9 In him dwells the fullness of deity bodily.
- Philippians 2:7 He took the form of a servant.