|Istihsan as a way to limit the use of qiyas remained a major bone of contention during the period of formation of fiqhi schools. As a rule the Hanafites, as proponents, and the Shafi`ites, as opponents, were pitted against one another. The controversy spread to the works on usul whose compilation dated back to 4th/10th centuries. As regards the Malikites, their avoidance of analogical methods may be interpreted as an orientation towrad istihsan. In fact, the notion of al-masalih al-mursala, i.e. istihsan, as a means of avoiDing qiyas, was considered the distinctive characteristic of Malikite fiqh.
Khwarazmi has noted istihsan and istislah as the two disputed methods of reasoning in the 4th century AH. The two styles were advocated by the Hanafites and Shafii`tes, respectively (p. 7). During this period, a group of Hanafite usulis offered a new definition for istihsan, with a tilt toward ra’y. They considered istihsan as being any divergence from analogy prompted by a shar`i reason, even if it implied the application of a more precise analogy, or one based on a textual evidence. This was an approach which could not be easily refuted by usulis of other schools. This new Hanafite definition caused a softening of the position of other schools vis-à-vis istihsan, a fact that prompted the likes of Shafi`ite Ibn Sam`ani and the Malikite Ibn Hajib to conclude the dispute over the authority of istihsan as a mere disagreement about words.