Is an exception (Istithna') valid in an acknowledgment when the exception is of a different genus than the acknowledged item?
General Chapter
Al-Mughni
Book of Acknowledgment of Rights
Primary text
An exception is not valid in an acknowledgment if it pertains to something of a different genus than the acknowledged item. This position is held by Zufar and Muhammad ibn al-Hasan. Abu Hanifa stated that if the exception is a measure or weight (makil or mawzun), it is permissible, but not if the exception is a slave or garment from a measure or weight. Malik and Ash-Shafi'i hold that exception from a different genus is absolutely valid, citing textual evidence from the Quran (e.g., Quran 18:50, Quran 56:25-26) and the language of the Arabs. The basis for non-validity is that an exception inherently withdraws part of what was included; an item of a different genus was never included in the initial statement, so the use of the exception particle acts merely as a rectification (Istidrak), which is only valid after a negation, not an affirmation like an acknowledgment.
Supporting text
If an exception is made after a complete, separate clause, such as 'I owe him one hundred dirhams, but I have a garment belonging to him,' the initial acknowledgment is accepted, and the subsequent claim (دعوى) is rejected, acting as if it were stated explicitly without the exception wording. Furthermore, the exception of Iblis in Quran 18:50 is argued to be an exception from the same genus, as Iblis was among the angels who were commanded to prostrate.