Istiṣḥāb is one of the principles that many secondary rules of Islamic jurisprudence are based on. Although there is nothing wrong with the application of this general principle in some cases, there is dispute concerning the manifestation of the mukhaṣṣiṣ (adverb or qualifying term restricting the meaning of a term) and its general applicability. Different sayings and proofs have been established by those who subscribe to its authoritativeness or non- authoritativeness. In this article, after examining their statements and the arguments presented by them in their works, the arguments of the opponents have been preferred and the arguments of proponents are considered complete, inasmuch as the authority of uṣūl-i principles such as the authority of literal meanings, common understanding and logical rules have been demonstrated. Hence, the principle of non-eternity does not apply to the general rule to include the doubted object. In fact, the problem should be solved with the application of principles such as the principle of exemption etc.