It was while studying religion at college, originally with the intention of becoming a minister, that Chris Stedman realised he was an atheist.
Mr Stedman, who was hosted in Canberra by the ANU League of Godlessness, the Canberra Atheist Church and the Canberra Atheist Meetup Group, yesterday addressed a crowd at the Australian National University.
The writer and Harvard University fellow, who is touring Australia, grew up in a non-religious home in America's mid-west but joined an evangelical church at the age of 11.
He spent years struggling with his sexuality and his place within his church community, but it wasn't until he began studying theology full-time that he discovered ''the idea of God never made sense to me''.
''I really wrestled with it and, for me, the existence of God was something I couldn't rationalise,'' he said.
''But I felt like if I wasn't religious then the only other option was to be opposed to religious expression.
''It was one of two extremes and I didn't know how to think about relationships with religious people.''
Mr Stedman went looking for ways to bridge what he describes as a ''chasm'' between religious and non-religious communities in the United States.
He spent time in seminaries, advanced his studies and worked with Chicago's Interfaith Youth Core, which brings young people of different faiths and traditions together to work on shared community projects.
He started a blog, NonProphet Status, and began sharing his hopes for better relationships between atheist and religious groups as a writer for The Washington Post and The Huffington Post.
Eighteen months ago, Mr Stedman was named the inaugural interfaith and community service fellow at Harvard University's Humanist Chaplaincy, where the 25-year-old co-ordinates programs that are ''intentionally designed for people of religious and non-religious backgrounds to come together to do shared work''.
One of his biggest projects so far took place in the American autumn, when volunteers of different faith, philosophical and generational backgrounds packaged 30,000 meals for children in need in the Boston area.
''People can see that, in spite of our differences, we have a shared value that's important to us,'' Mr Stedman said.
''I have a really strong desire to see reconciliation between communities that don't understand each other.''
Mr Stedman believes that misunderstanding between non-believers and people of various faiths is prevalent in the US, where ''very few'' people identify as atheist.
Mr Stedman said his goals were both pragmatic and personal. ''I think the people that I learn the most from are those who don't share the same beliefs as me,'' he said. ''Because they challenge me to think about them more deeply.''