Another cracking In Our Time, yesterday, on sharia law. But did you notice something about the discussion? It stopped with events about 500 years ago, and was carefully titled The Origins of Islamic Law.

Sharia was this vibrant, contested, life-giving tradition in Islamic culture before the 16th century. Today, it's something as much to fear, and not always only in the western imaginary, I guess. (Melvyn tried valiantly to get his guests to talk about beheadings and stonings, and they insisted that it was a marginal concern, with not a single record that anyone was ever stoned for adultery, in the period under scrutiny.)

It's the same with discussions about Islamic science. In the attempt to appreciate Muslim culture we talk about its origins, its history, its golden age. There's Al Biruni who argued that planets could move in ellipses not circles way before Kepler. Or Al Ghazali who anticipated David Hume's concerns about causation by over half a millennium. There's the work on optics, mathematics and astronomy without which Copernicus and Galileo would have floundered. (They rarely acknowledged their Islamic predecessors, though that said, they routinely didn't mention their Christian predecessors either. I read that the fifteenth century cardinal, Nicholas of Cusa, knew the argument from inertia about why we don't feel the earth moving, for example. Galileo read Nicholas for sure, though, I think, claimed that argument as his own.)

Today? Science in the Islamic world is in a poor state. There's no university from a Muslim majority country in the top 400, though millions are being poured into academic and technical establishments in countries with the petrodollars to spare, so that will surely change in time - if the cash is coupled to a culture of free enquiry. Only a few, narrow scientific concerns are of lively interest in the broader populus, such as how you determine the timings for prayer and the start of the fast. They raise all sorts of concerns about the position of the sun and moon, especially at higher latitudes.

But the question is why did science decline? It's the biggy that seems largely unsettled amongst scholars of history - no doubt, in part, because it's a big political question too. The ideological theories - blaming Al Ghazali's undermining causation, say - don't stack up. Hume undermined causation too, and science in Europe carried on regardless, though it is true that Hume's response was to play backgammon not speculate on God's action in the world.

Social contingencies mattered too, such as the autonomy won by European medieval universities. If the powers-that-be in one town objected to what its university did, the members of the university could just up sticks. Hence, when a bunch of scholars didn't like what was going on in Oxford, they founded Cambridge.

Economic and political issues seem the likeliest major factors, particularly the sudden power gained by Europe from the wealth of the New World, which rendered activity in Muslim countries effectively obsolete. As economic wealth in the modern world shifts east, Europeans might feel warned - though it seems you do need this culture of free enquiry to stack up the patents and cited papers, and not just the BScs and PhDs. And further, by free enquiry, that means freedom from utilitarian driven research policies and the part nationalization of British universities by the governmental underwriting of student loans!

But if the aim is to celebrate Islam, the historical approach is inevitably limited. There is the spirit of curiosity, the pleasure of historical knowledge, and the value of driving out ignorance - of course. But the risk is that the historical approach comes across as a patronising wake. The science was great, once. Sharia was not a tool of reactionary Wahhabism, once.

Will radio programmes like Melvyn's, or TV series like those of Jim Al-Khalili, be much more commissioned? The brave producer will be the one who sympathetically addresses the decline. Europeans might learn a lesson or two from history as well.