Earlier this week there was shock and outrage around the globe at the massacre of scores of women and children in Syria by forces loyal to President Bashar al-Assad.
Part of the tension causing the present conflict is the fact that Assad and his supporters belong to the minority Shia Alawite sect, about 10 per cent of the population, which lords it over the majority Sunni Muslims who make up 75 per cent of Syria's citizens.
Assad represents a very secularised stream of politicians now being challenged and overthrown in many Arab countries. His motivation is not religious, and is largely to do with a ruthless maintenance of political power which is at odds with the ideals of his religion.
Among Muslims worldwide, roughly 85 per cent are Sunni, and the remaining 15 per cent are Shia. Most Shia live in Iran and Iraq. The divide between these two 'denominations' of Islam is poorly understood by non-Muslims.
The scholar featured in this interview is a Shia Muslim who belongs to the Ismaili branch of Shi'ism. Dr Reza Shah-Kazemi typifies the blend of intellectual and spiritual approaches to faith that is a mark of progressive Shia Islam. He speaks about his vision for tolerance and dialogue with other faiths based on Quranic texts.
The divide between Sunni and Shia dates back to the early years following the death in 632 CE of the Prophet Mohammed. The dispute was over who could lead the Muslim community and had little to do with basic beliefs and practices. Sunni and Shia Muslims believe the same basic tenets, and worship and pray in the same way.
From the beginning the Sunni majority held sway, arguing that any close companion of the Prophet could be Caliph (leader). The Shia minority argued that only those of the Prophet's blood lineage could lead, and, like him, they would have special powers of inspiration and interpretation of the faith.
The first three Caliphs were not direct descendents of the Prophet, but the fourth, Ali, who came to power in 656, was the Prophet's cousin and son-in-law. Shia Muslims regard him as the first legitimate Caliph, or as they call it, as Imam. Their name comes from the Arabic, Shia-i Ali, which means followers or partisans of Imam Ali.
Imam Ali was assassinated in 661, and some 20 years later when Shia believers moved to have Ali's son, Husain, proclaimed as Caliph,