Around the beginning of the 900s, most Sunni jurists argued that all major matters of religious law had been settled, allowing for
taqlid, "the established legal precedents and traditions," to take priority over
ijtihad. However, the
Shi'i Muslims recognized "human reasoning and intellect as a legal source that supplements the Quran and other revealed texts," thus continuing to acknowledge the importance of
ijtihad. Due to the Sunni movement towards
taqlid during this era, some Western scholars today argue that this period led to the notion of the "closure of the doors of ijtihad" in Islam.
Joseph Schacht, a well-known Western scholar argued, "closure of the door of
ijtihad" had occurred by the beginning of the 10th century CE: "hence a consensus gradually established itself to the effect that from that time onwards no one could be deemed to have the necessary qualifications for independent reasoning in religious law, and that all future activity would have to be confined to the explanation, application, and, at the most, interpretation of the doctrine as it had been laid down once and for all." (Other scholars believe that debates about the `closing of the gate of ijtihad` "were not apparent in legal literature until the end of the eleventh century, and even then only as a theoretical issue".