Pontiff's book opens debate on his infallibility

Rome: Pope Benedict XVI has shocked theologians and opened a chink in the theory of papal infallibility by saying that people should feel free to disagree with what he has written in his latest book, a meditation on Jesus Christ.

Titled Jesus of Nazareth, the first book that Benedict XVI has written since his election as pope in 2003 will be published next spring. The first part describes Jesus's life from his baptism in the river Jordan until his transfiguration, when he reveals his divinity to his disciples.

Referencing hundreds of works of history, the pope writes that he believes Christ is a "historically convincing figure".

In the foreword, he states that the book is "absolutely not" a work of Catholic doctrine, but rather the "expression of my personal research". He adds: "Consequently, everyone is free to contradict me."

No pope has ever opened up his work and opinions to criticism before. Nor has any pope tried to separate his personal and public personas, according to Professor Giuseppe Alberigo, a professor of the history of the Catholic Church at Bologna University.

"I really believe this is the first time this has ever happened," he said. "It is an extraordinarily important gesture. What it means is that the pope is not totally infallible."

He added that Pope John Paul II "could never have made a distinction between 'official' pope and 'ordinary' pope".

Father Federico Lombardi, the Vatican's spokesman, said the pope had acted with his "usual simplicity and humility" in seeking to "freely allow discussion and criticism".

Some critics warned that the pope could not be both a free-thinking theologian and the leader of the Catholic church.

Luigi Lombardi Vallauri, a professor of philosophy at Florence University, said: "It seems a coquettish thing to pretend there is a freedom of theology while knowing well that this theology rests on the shoulders of a pope."