The classical process of ijtihad combined these generally recognized principles with other methods, which were not adopted by all legal schools, such as "istihsan" (juristic preference), "istislah" (consideration of public interest) and "istishab" (presumption of continuity). A jurist who is qualified to practice ijtihad is known as a "mujtahid". The use of independent reasoning to arrive at a ruling is contrasted with "taqlid" (imitation), which refers to following the rulings of a mujtahid. By the beginning of the 10th century, development of Sunni jurisprudence prompted leading jurists to state that the main legal questions had been addressed and the scope of ijtihad was gradually restricted. From the 18th century on, leading Muslim reformers began calling for abandonment of taqlid and renewed emphasis on ijtihad, which they saw as a return to the vitality of early Islamic jurisprudence.