Pope Francis may not have made any specific changes to Catholic doctrine in his recent treatise, but the thoughts and pronouncements released on Friday should still be considered an important document that could lead to a significant cultural shift in the church, according to theologians.

"It's a seismic shift," says Gerard Mannion, a professor in Catholic studies at Georgetown University's department of theology. "A lot of people are saying he hasn't changed any doctrine, but that's not true actually because doctrine is a lot more than what's set in stone in rigid terms.

"He's changing the tone, he's changing the realism of the church and he's actually encouraging the church to put pastoral care ahead of particular rules and particular norms. It's a carefully crafted document once it gets into its flow. It's a real game changer in terms of church's teaching."

The 256-page The Joy of Love was two years in the making and the product of an unprecedented canvassing of ordinary Catholics and senior churchmen. In it, Francis suggests, for the first time, that divorced and civilly remarried Catholics could receive communion from bishops and priests on a case-by-case basis.

Church teaching holds that unless such Catholics receive an annulment, or a church decree that their first marriage was invalid, they are committing adultery and cannot receive the sacrament.

"The Pope [is] saying, I think in a coded way but in a clear way to those who read the Roman tea leaves, in certain circumstances, it's possible for a divorced and remarried person to turn to the sacraments," said Rev. James Bretzke, a Boston College theologian.

"But he's not giving blanket permission."

More revolutionary, says Bretzke, is Francis's note that church authority should help form moral consciences, but should not be a substitute for one's own informed conscience.

"We have been called to form consciences, not to replace them," Francis says in the document.

'Breathtaking quotable quote'

"That is a breathtaking quotable quote that would have been completely unimaginable in the pontificates of Pope Benedict and Pope John Paul II," Bretzke says.

It had been previously held that any good Catholic had to follow the current church teachings on issues because that teaching was authoritative, said Bretzke.

"What Pope Francis is doing here in this document, is he's changing the code a bit. He's saying you have to follow what you believe God is asking of you and we trust in God's grace."

Mannion says the Pope is also reversing the trend of the last 40 years that has seen some people stop taking the church seriously.

"All of a sudden, people are sitting, listening to what a Pope is saying about human sexuality and relationships. I think it's enormously significant and it will take some time before people realize just how much this is going to transform so much of what the church does."

Pope Francis's 256-page treatise was two years in the making and the product of an unprecedented canvassing of ordinary Catholics and senior churchmen. (Jason Lee/Reuters)

Gay Catholics had hoped for other changes. The treatise offered nothing significant beyond existing church teaching that gays are not to be discriminated against and are to be welcomed into the church with respect and dignity. It repeated the church's position that same-sex unions can in no way be equivalent to marriage between a man and woman.

"I think that if you're a gay person, you're largely disappointed in that there's really no shift," said David Deane, associate professor of theology at Halifax's Atlantic School of Theology.

Deane also says the document may not be as groundbreaking as others suggested. It doesn't have the same status as a papal encyclical, he says, meaning it may not be as binding.

'Moderate, middle-of-the-road'

He agrees that its purpose is not necessarily to change doctrine or teaching, but to change the culture.

"What this text is is a very moderate, middle-of-the-road text which is definitely not a liberal document but it's also not a conservative document," Deane said. "It's not changing the letter of the law but it's shifting the spirit of the law and the pastoral practice."

Bretzke says the Pope is quite aware of divisions in the church and is trying to avoid increasing polarization.

"He's not all of a suddenly going to say 'Hey, I'm totally undoing things people have been preaching and teaching in decades," added Mannion. "But he's moving things forward."