For Marion Carroll, miracles really do happen: the 50-year-old Athlone woman claims she was cured of Multiple Sclerosis after a pilgrimage to Knock.

And this week it was revealed that, for the first time in 131 years, the Mayo shrine is asking the Vatican to officially recognise the cure as a miracle.

But Marion is far from being the only pilgrim who believes that divine intervention played a part in her unlikely road to recovery.

Recently, while undertaking research for a book, I met a woman who described how a member of her family was cured at Knock. The story dates back to 1963 when the woman's brother, Gerard Clarke, was six years of age. He came home from school one day with a serious eye problem.

"When he came home, one of his eyes was turned in," Kay Healy from Bray, Co Wicklow, recalled.

"His eyes were crooked. My mother brought him to the Eye and Ear Hospital. They put him in glasses, with a black patch covering the bad eye. He was in and out of the hospital for about three months. They decided to operate.

"My mother had great belief in Our Lady of Knock. So before the operation she decided to take Gerard to Knock. The day after he returned, she brought him into the hospital for the operation. She hadn't noticed the condition of his eye because he was still wearing the glasses.

"But the doctor called her into his room and said, 'Mrs Clarke. I don't know what has happened but your son's eye is perfect. You can take him home'. My mother always maintained that Our Lady of Knock cured Gerard's eye."

It is tempting to dismiss claims such as this as fanciful or the product of chance. That's what scientists, with their emphasis on potent drugs and modern technology, argue. In the realms of medical science, everything must be explicable -- the direct consequence of a vast network of nerve cells and molecules behaving in predictable and well defined ways. To scientists, miracles are the equivalent of voodoo.

Many priests and church luminaries also bristle at the mention of miracles. In the course of years of research into miraculous phenomena and near-death experiences, I have encountered more hostile responses from men of the cloth, including one eminent theologian, than from any other social group or profession.

This is despite representing a faith based on Lazarus-like resurrections and the supernatural multiplication of loaves and fishes. Miracles, it would seem, make priests uncomfortable by highlighting their understandable inability to bring about supernatural recoveries.

In the light of my research, however, it is hard to escape the conclusion that what can only be described as miracles really do occur in defiance of medical science.

Terminal illnesses mysteriously go into remission. Tumours shrivel and die. The lame cast off their crutches and walk. The blind recover their sight. The chronically sick become well. I have encountered many such examples attributed not only to Our Lady but to saints including Padre Pio and Therese of Lisieux.

To this day, I am enthralled by the story once told to me by Padre Pio devotee Mona Hanafin, from Co Tipperary. Back in 1964 she developed cancer. Doctors scheduled the removal of her womb.

"I'm going to Padre Pio and he will cure me," she declared. During her visit to the Italian village of San Giovanni, where Padre Pio was living, she met with and was blessed by the future saint. On her return, the scans showed that the cancer was gone. "That's over 40 years ago," Mona told me. "I never got it back."

Also unforgettable is the story of young Jack Broderick, from Co Limerick. As a baby he suffered a series of mini-strokes and was written off as dead. The doctors said they were sorry but that there was nothing they could do.

Yet, after being blessed with a Padre Pio relic, he recovered. "Take your son home," one of the doctors told Jack's parents. "I don't know how he's alive. I have never known anyone with this much brain damage to live. He shouldn't be here."

Just as extraordinary is the story of Gemma, from Co Meath, whose leg was disabled for two years following the severing of a nerve during surgery. Immediately after a blessing in San Giovanni, she felt the leg's mobility returning.

On arriving back at her hotel, she found that she could walk up and down the room.

"We were wildly excited," she said of her Biblical revival. By the time she returned to Ireland, she no longer required crutches.

There is, in addition, the story of David Doherty, from Co Derry. Following a triple bypass operation, he became critically ill and plunged into a coma. He was, at one stage, given less than 12 hours to live. His family went home to prepare for his funeral.

Yet, once a Padre Pio mitten was brought to his hospital bed, he gradually got better. "I believe Padre Pio intervened," he said of his dramatic restoration to life.

"He went to Jesus or whoever. He said, 'There are people here praying for this man. They want him to have a second chance. Give it to him'."

What causes extraordinary revivals like these is a matter of controversy and debate.

These occurrences are often dismissed as being imaginary and unreal, the product of fertile imaginations or ill-conceived attempts to establish connections where none exist.

As Thomas Paine, the American intellectual and revolutionary, put it: "All the tales of miracles, with which the Old and New Testament are filled, are fit only for impostors to preach and fools to believe."

More recent studies stress the powerful role of thought, imagination and willpower in effecting cures. The importance of mind over matter is central. Intense belief can stimulate the mind and harness its powers. The use of positive imagery in the treatment of cancer patients has been shown to bring about dramatic improvements, ranging from tumour shrinkage to complete disappearance of the disease.

There is also the issue of chance. The eminent British mathematician John Littlewood argued that everyone can expect a miracle to happen to them at the rate of about one a month. He defined a miracle as something of significance that occurred with the odds of one in a million.

A miracle, in other words, is a function of probability, with certain coincidences happening from time to time. Some miracles, understandably, can be more profound and dramatic than others.

Then, of course, there is the matter of supernatural provenance. Since that wet Thursday evening in August 1879, when a vision of Our Lady reportedly appeared on the gable of the church at Knock, hundreds of cures have been noted among sick and disabled pilgrims.

Among those recorded by the parish priest of Knock in the immediate aftermath of the apparition were cures from heart disease, paralysis, epilepsy, blindness and even cancer.

As for Marion Carroll, what her chances were of recovering from Multiple Sclerosis after a visit to Knock two decades ago is anyone's guess. Without doubt, something remarkable happened. To recover, as she did, from being paralysed, blind in one eye and having lost control of her bladder was, in itself, extraordinary, unexpected and inexplicable.

But was it a miracle? Of course it was. To be symptom-free after what Marion Carroll had been through is nothing short of miraculous, no matter what the Vatican or anyone else decrees.

Colm Keane's new book, The Distant Shore -- More Irish Stories from the Edge of Death, will be published in October. Exclusive extracts will be featured in the Irish Independent

See Also John Boland's TV column on page 26

Irish Independent