If they were the only force operating

It's about the ending of the golden age of Islam. Here I don't understand what is "force operating", always the problem to understand to what it imply and then I fail to understand the meaning so thanks for helping me with that

and so that's why it all ended" (Golden age of Islam). If they were the only force operating, then later when the Islamic culture rose, you would still see this tradition of scientific innovation, but it has not recovered! it has not come back at all! compared to what was going on in that three hundred years. And what you do, is you read the writings of Al-Ghazali, who is a Muslim cleric, and he was to Islam what St. Augustine was to Christianity.