Originally Posted by doctoremma
Nature published an issue dedicated to Islam and science, back in 2006. It might be interesting and is presented as a series of easily-digested short reports:
It seems that science does not usually flourish under totalitarian regimes, for example, Stalin got rid of scientists except those working towards his political aims. And it might be reasonable to describe *some* Islamic countries as totalitarian? Although where Iran (a relative big spender in science) comes into that, I don't know (unless, of course, their science budget is taken up by research that might fulfil their political aims....). It's not necessarily a function of wealth - Saudi Arabia can easily afford to fund world-leading scientific endeavour but chooses not to. Is science and discovery a threat to power, a path from faithful to secular society (scientifically-literate countries have higher proportions of atheists)?
The above is merely conversation, not an expert analysis
On your Iran point its seems they are doing quite well for themselves in terms of science and economics.
Iran for example,recently became 17th in the world for PPP (Purchasing power Parity), overtaking Poland and Australia. Due to heavy sanctions Iran has had to invest heavily in domestic manufacturing and scientific R+D. Its contribution to world science has increased at 11 times the world rate between 1980-2009. Combining the scientific output of Iran and Turkey (if you go by order it goes Turkey,Iran,Israel) you get a result bigger than the rest of the middle east put together, including Israel.
As you can see from the link below, in terms of scientific output other countries in the region such as Saudi Arabia are dwarfed by Iran Turkey and Israel. On top of this Iran is largely independent of other nations for much of it's manufacturing needs. Iran is also quite advanced in areas such as chemistry,nuclear physics and nanotechnology.
The main link I see between these 3 countries is they have all had relative stability for the last 30 years and are largely free of outside intervention.Yet the same can be said for Saudi and Jordan for example and the same results have not been produced there. Why? I don't know the answer, but their are several possibilities, two of which Ill mention now.
Is it too do with religion? Iran is a theocracy yet far surpasses Saudi Arabia and Jordan with their monarchies. It is well documented that at it's core the Quran encourages rational thought, and the accusation of ALL knowledge. Perhaps then it is the perversion of this message that lies at the heart of the problem, as with many of the problems in religions today. I have seen some evidence to suggest that Saudi Arabia suppresses a lot of scientific en-devours and education in general in some round about method of keeping the public under control, but still this isn't the full story.
Perhaps the main reason, is Saudi and Jordan have had a heavy reliance on Western nations to supply them with capital, workers, expertise, weapons and other equipment, with little effort to develop their own. Whereas in Iran and Turkey this reliance on foreign countries is temporary, only long enough for them to learn the tricks of the trade themselves before continuing on their own.
That's my take on it anyway, and I know the OP was talking about a historical decline, but I think the modern situation has a relevance too.
A short paper
on the above with the relevant info.