Charles Doughty doubted the illumination of Islam
"Charles Montagu Doughty (August 19, 1843 – January 20, 1926) was an English poet, writer, and traveller born in Theberton Hall, Saxmundham, Suffolk. His book Travels in Arabia Deserta is a vast recounting of his treks through the Arabian deserts, and his discoveries there. It is written in a style, largely based on the King James Bible, but constantly surprising with verbal turns and odd inventiveness." Wiki
Looking at recent revolutions in the Mideast, Michael Knox writes -
A small number of Islamic intellectuals, many of them educated in the West, have during the last few decades attempted to open the Islamic mind and reconcile the teachings of the prophet with individual liberty, freedom of conscience, the rule of law, and wide and accurate learning. They have sought to disprove the pessimistic conclusion of Charles Doughty, who after living for some time among the Arabs complained, in Travels in Arabia Deserta, that “the Moslem religion ever makes numbness and death in some part of the human understanding.”
I have not read Doughty's book, but many Westerners have identified a conflict between a "golden age" of Islamic thought and present trends. We have commented on that conflict and its significance for Britain.