His insights have inspired many other leading figures. Sometime gardener, lecturer and broadcaster, he is author of Invoking Ireland (Lilliput) which is a call for Ireland to rediscover its most ancient roots. It has been widely acclaimed, not only by reviewers, but scholars such as Declan Kiberd and poets such as Paul Durcan. John lives a hermetic existence down from the Horse's Glen at the foot of Mangerton Mountain in north Kerry and is currently fighting three forms of cancer.

WHEN the curtains are closed on you three times, when you get a triple diagnosis of cancer, you see death. I wasn't terribly shocked by cancer of the prostate, I wasn't terribly shocked by cancer of the bowel. But when I heard I had cancer of the liver, I thought: "This is it."

I felt like a wounded animal. Five to seven months to live. I heard the news in the Mater in Dublin, just after Christmas, and I thought to myself: I am going home now to Kerry to die.

I knew I would have to have an operation on the bowel, because it was nearly closed. But that would be purely palliative.

It came down to this: I have been given a death sentence. When the curtains were pulled around my bed three times, as they were for me, it is a wonderfully symbolic act. There are physical enormities and spiritual enormities to deal with.

I started dealing with them. In handling it I came to look at myself and my life. If I had had a girlfriend when I was sexually active and had to look back on a life where I had forced her to have an abortion, or if I had to deal with the cancer I have got, then I would rather, as a moral enormity, deal with the triple diagnosis of cancer.

I am treating this as the not so pleasant Eucharist of cancer and chemotherapy. I certainly believe that death isn't the end. It's a terminal lounge. The adventure goes on. I will lose my physical body but I can construct a mental body around me, to continue in the great moral and spiritual adventure of the hereafter.

This is not the first time I've fallen out of the boat. When I was 17 a Protestant library was broken up and someone gave me The Origin of Species to read. Up to then my world had been invented in 4004 BC. I fell out of the Biblical boat where you observed life by the 10 commandments and found your way to the end.

I was man overboard for years.

I had to think my way ashore. The places I found myself in, well I can say they were terrible enough for me to prefer having the cancer. It was rough crossing. I ceased to be Christian after I read Darwin, but the yearning for something was still there. I felt crushed by the world of modern science, where the world began in a big bang and ended in a big crunch. I came back to myself, on leaving university life.

I flourished at university because ideas were a passion to me. But then a time came when I didn't flourish and I left. Christ was in my mind the day I handed in my resignation. I had to ask myself the question: how am I going to live? I quoted to myself: seek you first the Kingdom of God? and all these things shall be added onto you. It struck me that that might be as true about the universe as Newton's Law of Gravity. And I got the courage.

The night before I came back to live in Connemara I wept, because I knew my time on the high street, of being a young man engaged in a young man's pursuits, was over and I was reaching solitary confinement, insecurity.

But like the seal coming up to the breathing hole I had to come up for air. I had to be myself. On a day when I felt I had no soul I went to a river which would give soul to you. I flourished again in a new way and I never forgot or regretted the leaving.

I have been forced to believe in reincarnation, because I couldn't explain the person I am otherwise, other than someone who has been around many, many times before.

The dreams that I dreamt as a boy could not be explained in terms of the life experience of a young boy growing up on a small farm in north Kerry. They were so vast. In those dreams I was in the savannahs when we were still only hominids.

I was taken down into the oldest, psychic seas, where the beast resides within.

There were stupendous encounters with vast karmic reservoirs in my psyche. A little lad walking up and down the road after 11 cows could not reach those places without dreams. I became unexplainable to myself in terms of the northern and western mind map of who we are.

My life seems to have fallen into two adventures - the love adventure and the death. I recall my time as a sexually active man on the high street. Then somewhere around 50 I encountered the death adventure. It can be an absurd accident, death, when one car crashes into another on the road, when young life is taken. But if you are given a run at a life at all, then somewhere into your 50s you face mortality.

When I did face mortality, thank God I had the courage not to become the oldest hippy in town and start chasing women in their 30s. I acted my age and graduated onto the adventurous road to death. When you integrate your dying, take it into your life as something acknowledged, you see your death as a ripening. You see the preparation for death as being as enriching as the search we have for love. They are the two great adventures - Eros and Panatos.

No matter how I die, no matter how many times I die, in the end the destination is re-emergence on divine ground. I have cancer in three places, one is cut out of me now at this moment, but I still go to bed believing in God and I still wake up believing in God.

Seals in the arctic in winter find holes in the ice in order to take a breath, before diving deep below the surface once more.

The sacraments - baptism, Eucharist, confirmation, last rites - to me are the seal's breathing holes. We need them to keep ourselves whole, alive. I need to breathe in grace as much as I need to take in air.

I do receive the Eucharist, even though I would have difficulty with it. I'm not a churchly person. My Christianity is very private, as I am. I have a little altar here in the house and Christ is at the heart of it. But there is a native American eagle feather as well, stuck into the rim of a perfectly formed thrush's nest. So that represents nature.

I am not often among crowds, I don't experience myself well in them. I don't go to matches or to the races. My religious practices are the religion of a loner. I'm just hoping that even though I don't go to church that often, that they will allow me back into it for my funeral when that happens. I would love a full requiem mass, it would be hugely important to me. So I suppose I am a loner who believes powerfully in community.

When I came home after surgery my old friend Eileen was there to meet me at the station. She stayed to look after me. She had to resign her job to do so, which I was not glad about, but I couldn't look after myself. Up until this I have been entirely on my own. She is a practising, devout Buddhist and her presence in the house is a beautiful one. We give each other space and at the same I am supported.

She is living the great Buddhist practices of friendship and great compassion.

When Eileen drove me home, after my surgery, it made me sad because my homecoming I felt to be a leavetaking. I had come home to take leave of the world around me. I looked around the mountains, my world, one I will leave. To me nature is eucharistic. I can inhale the scent of woodbine sacramentally. Putting my hand in the river, feeling it go cold, I feel the grace of nature, its redemption.

Eucharist is not just as it is prescribed by the church. You can receive redemption, in thanksgiving, you can do it walking the roads.

I have the great mystic works in my house; not only have I got them, I don't have to consult them anymore. I just have to consult my mind and heart. The Rhine of the 1400s is my Ganges. The greatest philosophers and religious thinkers lived on its banks. I understand Jesus fully working backwards from the Christian mystics, who we never fully integrated into the church, more than working forwards from the testaments.

I believe four things: who I am from conception to death is not the whole story. My life in the universe isn't the whole story. The universe itself isn't even the whole story. I put my Christian creed into the saying: the healing is finally greater than the illness.

In conversation with Suzanne Power