Tony Blair faith project's global warning
"It is difficult, but that's the whole point," says Ruth Turner, head of the Tony Blair Faith Foundation, an organisation which works to improve understanding between the world's religions.
Difficult might be an understatement.
Where do you begin with such a vast and open-ended project as building communication between different and often conflicting faiths?
Adding another layer is the complex figure of its founder, Tony Blair, a man of strong views who in turn provokes strong views.
But the foundation has been quietly gathering partners and setting up links, where ideas and ideals, beliefs and disbeliefs can be debated and shared.
Last month, the first African university signed up to the project, joining the likes of Yale in the US, Durham in the UK and Peking University in China.
A schools programme is operating in 15 countries, across Europe, North America, Asia, Africa and Australasia.
But what's it all for?
"It's not just about having endlessly fascinating debates between academics - it's about working out how their insights can be useful to the public," says chief executive Ruth Turner.
Ms Turner was the former Downing Street director of government relations - and the experience of this time in office has shaped the foundation's sense of purpose.
Globalisation means understanding a world in which religion plays a much bigger role in many places than it does in the secular West, she says.
It is not always a benevolent role - and she says the violence that comes with religious extremism means that we cannot ignore it.
"We under-estimate how much a motivating force religion is in many parts of the world.
"The vast majority of people might not like extremism - but they can't say that it isn't their business.
"The people who are trying to preach intolerance are well-organised, well-financed.
"If you look at the extreme and bigoted material - it uses compelling language, they understand how to use technology. We need to step up a gear."
The faith foundation is an attempt to increase understanding of religion and between religions - putting together networks of schools, universities and individuals.
In many parts of the world negotiating religious differences and identities is part of every day life, she says.
And regardless of whether someone has a belief themselves, she says the internet and a globalised world is going to bring religion to everyone's door.
She points to the story of the pastor of a small church in Florida who threatened to burn a copy of the Koran - and how this smalltown story became an international news event, drawing in the White House and the Vatican and prompting protests in Pakistan and Afghanistan.
"It would be foolish to ignore" the implications of such international chain reactions, she says.
The faith foundation is an unusual hybrid. On one hand it's an educational project - with video link-ups for schools and lectures in universities. There are fellowships that link students from different religious backgrounds. Film competitions have been run on the theme.
But it also feels like one of those high-powered, transatlantic lobbying groups, international and influential, but hard to pin down. What is it that they're trying to achieve?
A word that Ruth Turner keeps using is that it has to be "practical".
As an example, she says the foundation is running a health project in Africa, harnessing the grassroots reach of religious groups by using churches and mosques as bases from which to tackle malaria.
This is a way in which two of the world's major religions, Christianity and Islam, can work together against a common enemy.
But the foundation is also about trying to explore the tensions between religions and to build dialogue. It's a form of conflict resolution.
The project has set up conversations between schools in places as different as Ramallah and Long Island. "This can be fraught with sensitivities and suspicions. But it's about debating ideas, not confronting other people's views," she says.
There might be an ambition to understand religion better, but Ruth Turner says that a secular society such as Britain finds this difficult.
"We're not used to having an easy public discourse about religion," she says.
The big picture behind all this is Tony Blair's world view of the fundamental importance of religion, both for individuals and relations between communities, cultures and countries.
His years in office saw the terror of 9/11 and the rise of Islamic extremism, but also the optimism of the Northern Ireland peace process.
It raises the question as to whether religion will be a force for goodwill or a way of reinforcing negative images of each other.
Ruth Turner rejects the idea that this is any kind of vanity project for the former premier, saying there were much easier options for that kind of legacy. And she says that Mr Blair is committed to this for the long term.
It certainly won't be a project with any easy answers.