"A professor in the United States claims one of the main roots of black gospel music is Scottish," says organiser Pete Heywood. "He says it comes from the Gaelic tradition in which the minister would chant a line and the congregation would sing harmonies around it."
"Common Ground on the Hill", now in its third year in Scotland, is a celebration of music, traditional arts, and cultural and racial diversity.
"It began with Walt Michael, who was involved in the civil rights movement in the Sixties," says Mr Heywood. "Later, as a professional musician playing to largely white, middle-class audiences, he had this idea that music can be the common ground, where people can respect and learn about each other."
Through mutual musical friends in Scotland - Walt Michael played on the first Singing Kettle album - the two men met, and Mr Heywood was invited to teach at a Common Ground event in Maryland. "It brought a wonderful mix of people together. In the summer of 2001, Pete Seeger took part and provided inspirational moments, but these were part of a wider experience that touched people in many ways."
As a musician and editor of a music magazine, Mr Heywood has attended hundreds of music festivals. But this was a revelation: "The inclusion of dialogue about racism and non-violence created an atmosphere that pervaded the event. People became open to talking about themselves, their music and society."
Although rooted in Scottish traditional music, "Common Ground on the Hill in Scotland" retains its American influences.
"The teachers in the non-violence sessions are well-qualified peace educators, some of whom worked with Martin Luther King. We are also developing our own agenda. Colin Sands is coming over from Northern Ireland. He was a musician there when carrying a fiddle-case put you on one side of the sectarian divide. We're bringing guys who've been involved in post-conflict resolution in Bosnia. Alastair Hulett is talking about Red Clydeside."
And there are some parallels between black people in the US and asylum seekers in Scotland, says Mr Heywood: "We often don't think about this. Few of us have been taught about non-violence or civil rights. We tend to assume that a man's a man for a' that is what Scotland is about."
Music has its own life and energy, however, and will always be much more than a vehicle for ideas. The heart of "Common Ground" remains playing, singing and learning about music, says Mr Heywood. "Around a third of participants are artists who can command the concert stage.
"Mornings are formal sessions with tuition in small groups - fiddle, guitar, banjo, concertina, mandolin. Afternoons are more relaxed, with musicians getting together, playing and interacting."
Early evening is when the gospel choir rehearse, which is very popular, says Mr Heywood. Then there are high quality concerts and informal music making - "slow jams", which allow beginners to participate. "We have a programme for the children of participants, and a number of teenagers have since gone on to higher education in traditional Scottish music."
According to non-violence teaching, if people are ever going to settle something they disagree upon, they first have to find something to agree upon - the common ground. "If you both love music you can't be all bad," says Mr Heywood.
www.commongroundscotland.comThe hill of the festival's title is Capitol Hill, where Martin Luther King gave his "I have a dream" speech