- ẓann (probable assumption): entertaining two possibilities while one of them preponderates over the other; that stronger side is called ẓann.
- shak (doubt): entertaining two possibilities when neither one outweighs the other.
- wahm (mere surmise): entertaining two possibilities when one of them is weaker than the other; that weaker side is wahm.
naẓar (reflective inquiry): the mind’s deliberation about the object under consideration. It is the path to knowing legal rulings, provided its conditions are met. Its primary condition is that the inquirer be fully equipped—that is, well-versed in a broad range of the revealed sciences, the principles of jurisprudence, and the Arabic disciplines, as will be detailed, Allah willing.
dalīl (evidence): that which guides to the desired conclusion, whether it yields certainty or only probability.
Nāṣib al-dalīl (the one who establishes the evidence): Allah, exalted is He, while the Messenger—may Allah bless him and grant him peace—conveys it on His behalf.
al-mustadil (the seeker of evidence): the one who searches for proof. This term applies to the questioner, for he seeks evidence from the one being asked, and it likewise applies to the respondent, for he seeks evidence from the foundational sources.
al-mustadall ʿalayh (the matter for which evidence is adduced): the ruling itself—be it permissibility, prohibition, dislike, or recommendation.
al-mustadall lah (the beneficiary of the evidence): this may refer to the ruling, because the evidence is sought on its behalf, and it may also refer to the questioner, because the evidence is sought for him.
istidlāl (the act of adducing evidence): the quest for proof, which may proceed from the questioner to the respondent or from the respondent to the foundational texts.