Between them the Arab Spring and Boko Haram of northern Nigeria are doing a good job of putting Sharia law on the map. These two extremes in fact show dramatically how Sharia interpretations can vary from destructive madness as in Nigeria to calm accommodation, even liberalism, as in Tunisia.

Sharia law is not only a legacy of Mohammed – he only devoted a handful of pages in the Koran to the dos and don’ts of moral life. Much comes from the Hadith, the collection of thoughts and sayings from the first couple of centuries after Mohammed’s death. Much of the Hadith is even more remote from the central text and Mohammed than some of the reflections of St Paul and the final chapter of the New Testament, the Apocalypse of John, are from Jesus and the Gospels.

Boko Haram, with its bombings, appears to be causing mayhem, drawing support in part from the poverty of the northern Muslim population that lags behind the accelerating progress of the Christian south. On Sunday President Goodluck Jonathan said in a speech that the security situation was more complex than the life-taking civil war of four decades ago. “During the civil war we knew and even could predict where the enemy was coming from, but the challenge we have today is more complicated.” Boko Haram insists it’s fighting for a rigorous interpretation of Sharia law – grisly punishments and effectively an abolition of many of the rights of women, as well as ending pervasive corruption.

At the opposite end of the pole is Tunisia, the country whose rebellion triggered the Arab Spring. An Islamist party won the election and has set up a government in coalition with secular parties. It is governing in a moderate way – no universal application of Sharia extremes. The religious tempo is balanced.

In Libya likewise, although a worrying recent speech by the prime minister suggested that women’s rights had gone too far. In Egypt, where the party of the Muslim Brotherhood has emerged victorious in the elections just completed, there are fears that it will push society in the direction of a vigorous interpretation of Sharia law in a country where for all the faults of the military-based government it has been a secular polity. But a majority of observers believe the Muslim Brotherhood will not roll back the social progress made before.

We should add that in two countries, Indonesia and India, the large Muslim populations, larger than anywhere else, are barely touched by the harsher versions of Sharia law.

In a new book ” Islam Without Extremes”, Mustafa Akyol, writes that we should go back to the sixteenth century when the Ottoman scholar Seyh-ul Islam Ebusuud supported reasonable interest rate charging and argued that singing, dancing, whirling, shaking hands – all banned by various Hadiths – were permissible. (Christian societies of that time also banned all sorts of reasonable behaviour, and horrendous punishment for small crimes was a matter of course.) Later, Islamic teachers argued that a wide-ranging number of things from coffee to railways broke the law, which no Muslim society believes makes sense today.

Aykol makes the good point that a vigorous version of Sharia law can be voluntarily adopted by those Muslims who wish to organize their lives according to it – just as Orthodox Jews live according to the rigorous fundamentalist Halakha code. But their extremes do not have to be imposed on society at large.

Ottoman rule long set the pace for Sharia reform, culminating in the revolution of the “Young Turks” in the 1920s and the rise to power of Ataturk. But long before him Ottoman scholars permitted alterations of the Sharia to cope with new issues and problems. The Ottoman system gave the state the right to enact secular laws. Under Sultan Mehmed 11, the conqueror of Constantinople in 1453, harsh punishments such as amputation and stoning were deemed obsolete.

Ataturk reformed Turkey, the truncated successor state of the Ottoman Empire. Women were granted full equality before the law and were given the vote in 1935, many years before many European nations had it. Islamic schools – madrassas – were abolished. The arts and sciences were encouraged and two hundred Jewish professors escaping the Nazis were welcomed. Religious symbols were outlawed. The US believed in freedom of religion but Ataturk’s government believed in freedom from religion.

This was excess the other way. In recent decades there has been a revival of Islamism. The wearing of the headscarf is one manifestation of it. Still young Turkish women wear the attractive clothes of their western counterparts, albeit the more modest variety.

The Islamist-orientated government now in power has distinguished itself for its moderate practices. Observers see it as practising “Islamic democracy”, similar to the idea of the European “Christian democracy”. Not surprisingly many in the Arab Spring think this is the way to go.