This interview is excerpted from Commonweal.

Robert E. Kennedy, S.J., is an American Catholic priest and a Zen master. Ordained a priest in Japan in 1965, he was installed as a Zen teacher in 1991 and was given the title Roshi or master in 1997. Kennedy teaches theology and Japanese at St. Peter's College in New Jersey and is a practicing psychotherapist in New York City. His books include "Zen Spirit, Christian Spirit" and "Zen Gifts to Christians." Kennedy sits with his Zen students daily at the Morning Star Zendo in Jersey City, NJ.

How did you become involved in Zen?
I became involved in Zen through my work in Japan during the late 1950's and early 1960's. At that time, there were many Jesuits who were engaged in interfaith work with Zen Buddhists. It was through these Jesuits that I came upon the Buddhist ideal of the enlightened life.

What is an enlightened life?
"Enlightened life" is a Buddhist term for a life that is based upon wisdom and compassion. Specifically, it is a Jesuit ideal to bring gifts of greater worth to the church. This experience of wisdom and compassion is a great Buddhist gift that I thought could enrich the church in an interfaith manner.

What does it mean to "study Zen?" How does one go about it?
Zen must be understood as a verb. In other words, it is the act of doing. What you are doing when you study Zen is nothing other than practicing a compassionate life.

More specifically, the practice of Zen is the practice of paying attention in a way that is both sustained and communal. As we know from the work of Simone Weil, prayer is nothing other than paying attention.

The Buddhist practice of daily zazen, sitting meditation, encourages its practitioners to make attention a priority in their lives. Let me emphasize here the importance of training in Zen. Usually, there is nothing that can be done in life without sustained practice and training. There is no language learned, no art form mastered without effort and a competent teacher. In Zen, experienced teachers have themselves trained for many years. Their qualifications and ability to teach have been ratified time and time again over decades of their work with experienced masters.

Though we sit quietly when we sit zazen, it is not a period of time that we use to catch up on our sleep! It is, rather, a period of time in which our minds and bodies are employed fully at the highest level. Zen is an active effort to develop the unique and full-bodied contribution to life of which each of us is capable. What we attempt to move away from are the tired and repetitive responses to life that we may have carelessly accumulated throughout the years.

You were installed as a teacher of Zen in 1991. What has been your experience of teaching Zen since then?
The teaching of Zen is really the act of paying exquisite attention to the person who is sitting right in front of you. Through such attention, I try to empower students by helping them to realize their own unique gifts and qualities.

What do you emphasize in your interfaith teaching of Zen, particularly with those who accompany you on the weekend and weeklong Zen retreats that you conduct frequently throughout the year?
I ask students to trust in themselves and to develop their own self-reliance through the practice of Zen. Through self-reliance the student comes to see and to appreciate the many gifts that have been given to each. Is it not God's will that each of us comes to maturity and confidence in what we have been given? That we come to act like Christ through our daily work and relationships with others? We do so, I believe, when we learn to speak in our own voice.

Now having emphasized self-reliance and the expression of God's will through our own voice, I balance this emphasis by stressing, finally, the unknowability of God. Through Zen we are able to come to grips with the apophatic tradition, or the recognition of the utter mystery of God.

Certainly, in our Christian faith, we are familiar with the apophatic tradition, the tradition of prayer that is beyond words. That God is unknowable, that knowledge of God is beyond words, beyond discussion, was clearly taught by the Greek Fathers of the Church. Gregory of Nyssa, for example, writes, "The man who thinks that God can be known does not really have life; for he has been diverted from true being, to something devised by his own imagination."

The balance you strike between self-reliance and not knowing seems to help your students better appreciate two other gifts of Zen that you emphasize in your book, "Zen Gifts to Christians," the gift of impermanence and the gift of emptiness.
Yes, that balance may work well for us when we come up against what is inevitable in life, when the impermanence of life is brought fully home in sickness and death, for example. Self-reliance means that the student comes to realize that his true nature is within himself. To cite a fundamental insight of Zen: there is no thing but the self and this self contains the whole universe. Accordingly, this gift of self-reliance makes one stronger in the determination to live one's own true nature to the fullest extent possible.

There will be moments in our life, of course, when we must draw upon such strength. When the reality of sickness and death hits us full force, we have the opportunity either to sink or swim. Zen offers a way to swim within the currents of life. Content to walk along the path of not knowing and confident in her abilities, the Zen student is now ready to face the flux of impermanence and the reality of emptiness. To face the flux of impermanence means that the student appreciates the impossibility of clinging to things--all things must pass--and is encouraged to participate in the process of life.

Furthermore, in coming to terms with the reality of emptiness, the student realizes that "fundamentally, not one thing exists." In other words, there is no free standing universe but rather a universe that is one with the mind that co-creates it moment by moment.

When you speak and write about the Zen gift of emptiness, you exercise great care. Why is this?
I do so because out of all of the gifts of Zen, this one is perhaps the one that is most misunderstood in the West. By "emptiness of all things" the Zen Buddhists mean the co-origination of all things; that is, nothing is separate.

Let me emphasize that emptiness, as the Zen Buddhists understand it, is not a vacuum. Emptiness is all forms: men and women, mountains and rivers, moon and stars, but all seen as interdependent and integrated.

The great fear that we often experience in life derives from our misperception of emptiness as a vacuum. But in reality, therein may lie our greatest treasure. Our misperception of emptiness is that it means isolation; but in fact it is the revealer of our greatest intimacy, our connection with everything else.

Perhaps the Zen teaching of emptiness can help us understand that the command of Christ to deny our very self is not a harsh moral command but a compassionate invitation to experience that our true self can never be independent. Our true self is unthinkable apart from its union with the whole Christ.