Failed conversion attempts led to labeling Muslims irrational rather than questioning Christianity

Evidence

Christian doctrine is rationally explained to them. Yet Muslims were no more apt than Jews to be converted by Christians’ supposedly rational arguments. Hence Martí (and other thirteenth-century authors) classify the Muslims as irrational: it is far easier to lambast one’s opponents as irrational, subhuman beasts than to call into question the rational basis of one’s own system of beliefs. — John V. Tolan, Saracens, 1215

Categorization

• XREF: Connects to the general pattern of how missionary failure reshapes rhetoric toward dehumanization of the target group. — connects to: Mediaeval critics mocked the Qur’an’s chapter names as irrational