“Istihsan,” which literally means “betterment” or “seeing something as good,” is employed in Islamic law when a case cannot be resolved by the existing proofs (the Qur’an, Sunnah, consensus, analogical reasoning, etc.) or when the solution reached is judged unsuitable in terms of justice or maslahah (public benefit).

“Anyone who wishes to carry out long-lasting, solid, and enduring action that benefits people both in this world and the next must conduct every task according to clear criteria and within a definite plan and program.

For a believer these criteria are the primary proofs (al-adilla al-asliyya): the Book, the Sunnah, the consensus of the community, and juristic analogy.

In addition there are what we may call secondary or time-bound proofs such as maslahah, istihsan, and custom (urf). Ijtihad and deduction are carried out on the basis of these as well.

Yet it must be understood that all such ijtihad and deductions are made by evaluating the threads left in the primary sources; our noble mujtahids never issued rulings ‘from their own fancies.’ In the terminology of usul al-fiqh, they performed qiyas or exercised ijtihad on the basis of a “maqisu’n-alayh.” And we should add that those towering figures fulfilled this very difficult task with a sensitivity as fine as splitting a hair into forty strands.”¹⁾

“The fundamental sources in which we can read our feeling and thought are, first, the primary shar’i proofs—the Qur’an, Sunnah, consensus, and analogy—and, second, the subsidiary shar’i proofs such as custom, usage, maslahah, and istihsan. Venturing into other sources without first learning these and identifying their unambiguous rulings often leads to confusion.”²⁾

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