Subsidiary Rational Sources (Istihsan, Istidlal, Istaslah, Istishab, Maslahah Mursalah)

These represent supplementary rational principles used in Islamic legal reasoning:

• Istihsan: Literally means to consider something good. Technically, it means the preference of stronger evidence over analogy or preference over Qiyas.
• Istadlal: Means inference and serves as a secondary source.
• Istaslah: Signifies the need of time.
• Maslaha Mursala: Refers to public benefits or interests which are accepted legally by the islamic law principle.
• Istishab: According to Al-Sarakshi, establishing a completely new rule using the presumption of Istishab is a grave mistake.