Western scholars equated Islamic morality with the possibility of Islamic self-critique

Evidence

At first he felt that the author must be Christian, but reflected that ‘whatsoever is here alledged and layd down, though never so good and Christianlike; or contrariwise absurd and monstrous; is nevertheless found and read in that their law’; moreover, he knew for a fact that Muslims compose ‘the like morall sayings and zealous exhortations unto vertue, and holinesse of life’. So he changed his mind; in other words, he thought that if they could be moral, they could be anti-Islamic. — Norman Daniel, Islam and the West, 2455