My research topic is early Christian theology. In particular, I specialize in classic Christology. Christology is the field of theology which explores who Jesus Christ is. According to the teaching of Christianity, the Logos (Son) of God took on humanity in the incarnation and was born in this world as Jesus Christ. Therefore, Jesus is fully God and fully Man. As the incarnate Logos of God, he experienced human suffering and death on the cross. After three days, he was raised from the dead.

Through his death on the cross, human sins are forgiven. In his resurrection, he revealed eternal life to us and assured us of salvation. Because of being both God and Man, Jesus saved human beings by his death and resurrection.

The divinity and the humanity in Jesus—one nature or two natures

Classic Christology was established in the fifth century. However theological disagreements in the understanding of Christology split the Church into the Catholic Church, the Eastern Orthodox Church, and the Oriental Orthodox Churches.

In particular, disagreement over the nature of Jesus Christ caused a division in the Church. The Catholic Church and the Eastern Orthodox Church hold that Jesus has two natures (a divine nature and a human nature) which are united in one single person. This is the Christological doctrine which was defined in the Council of Chalcedon in 451.

By way of contrast, there are also people who assert that Jesus has only one nature. They also recognize that Jesus is both God and Man, but they hold that Jesus has one nature because the divinity and the humanity are tightly united in the one nature of the incarnate Logos of God.

They rejected the decision of the Council of Chalcedon and established the Oriental Orthodox Churches. Even today, the pro-Chalcedonian churches and the anti-Chalcedonian churches continue to discuss whether Jesus has two natures or one nature.

Doctrinal discussions in the Church are deeply connected to the life of modern people

Some people may think that a discussion about the nature of Jesus is futile. However, the issue of the nature of Jesus is deeply connected to the essence of human salvation in Christianity—how did God save humankind in Jesus Christ? This is why theologians cannot make any concessions in regard to this issue.

In the 20th century, an ecumenical movement started and developed dialogue among the churches. This movement explores commonalities in doctrinal discussions between the churches at a deep level while respecting the tradition of the doctrines of each church.

All churches have the common understanding that Jesus Christ is both God and Man, even though they hold that Jesus has one nature or two natures. Therefore, the Christological difference of one nature and two natures is a difference in how to express Jesus, who is fully God and fully Man. The first step is to find common points between the two sides. The second step is to realize the differences of expression in the doctrine of each church. Thus, there is a great meaning in researching doctrines for ecumenical dialogue.

In Eastern Europe and the Middle East, religion is an important part of the social structure. The thoughts of the churches are deeply connected to local communities. When the churches dialogue with one another and reconstruct their relationships, the people also can start dialoguing and understanding one another in their local communities.

The book I recommend

Loyola no Sei Igunachio Jijoden”(Autobiography of Saint Ignatius of Loyola)
by Saint Ignatius of Loyola, Japanese translation by Antonio Evangelista, edited by Sung-il Lee, Don Bosco sha

I read this book when I was a student. I was impressed by the conversion of Ignatius. He experienced conversion and came to follow Jesus. Eventually, he founded the Society of Jesus with his companions.  The life of Ignatius inspired me to follow Jesus.

Interviewed: May 2024