The astrophysicist Neil deGrasse Tyson has said that during the Islamic Golden Age, especially in Baghdad, science and discovery flourished for a few centuries. Then an Islamic scholar named al-Ghazali became prominent, whose ideas took root. Among these was something along the lines that mathematics was, to use Tyson's words "the work of the devil".
I've listened to many of Tyson's talks, and he's mentioned this many times. Today I came across the Wikipedia article for al-Ghazali and thought I'd spend some time reading about him. He was a rather influential Islamic scholar in many ways, but specific to the claim that his philosophy led to the decline of science within the Islamic world, I only found the following:
His reforms are widely seen as having initiated the decline of scientific research in the Islamic world.[by whom?] Against this view, Saliba (2007) has given a number of examples especially of astronomical research flourishing after the time of al-Ghazali
Here is a video of Tyson making this claim. Sorry about the disputatious annotations made by the poster, but this was the first result I got for "Tyson al-Ghazali".
Is there any evidence that al-Ghazali said something like manipulating numbers or math is the work of the devil, or maybe sinful, or immoral? And as corollary to that, did he damage the spirit of scientific inquiry in the Islamic world?
Here is a quote written from one of the versions, found in video link 2 below:
"And in that interpretation (al-Ghazali's) it included the perspective that the manipulation of numbers is the work of the Devil. This cuts the kneecaps out of any mathematical advances that would unfold."
Links to other occasions he's said this before, here are two:
Edit: OK, I'm pretty sure I know what happened. Steven Weinberg is a physics Nobel laureate and acquaintance of Neil Tyson. Steven Weinberg is critical of religion, and has written:
"Alas, Islam turned against science in the twelfth century. The most influential figure was the philosopher Abu Hamid al-Ghazali, who argued in The Incoherence of the Philosophers against the very idea of laws of nature, on the ground that any such laws would put God’s hands in chains. According to al-Ghazali, a piece of cotton placed in a flame does not darken and smoulder because of the heat, but because God wants it to darken and smoulder. After al-Ghazali, there was no more science worth mentioning in Islamic countries."
Here is a video of Weinberg explaining this, just before Neil deGrasse Tyson comes to the podium to do his talk. It's possible that Neil Tyson's explanation of al-Ghazali has come from what Weinberg has told him.