Is a settlement (Sulh) valid over an unknown quantity or object?
General Chapter
Al-Mughni
Book of Settlement
Primary text
A settlement concerning an unknown item or debt is valid, provided that its precise nature or measure cannot be known. Ahmad permitted settlement in cases where the object is entirely unknown. This is supported by the narration where the Prophet (peace be upon him) instructed two men disputing obscure inheritances to draw lots (istahma) and aim for certainty, allowing one to absolve the other. This act constitutes a settlement over the unknown. Furthermore, settlement is valid in the unknown because it involves the relinquishment (isqat) of a right, which is valid even when the right is unknown, similar to manumission (itaq) and divorce (talaq). If settlement is valid when the right is known and performable, it is more valid when it is unknown, as ignorance may prevent mutual resolution otherwise, leading to the loss of property. The basis of validity is the need to absolve liabilities and remove disputes.
Supporting text
Al-Shafi'i invalidates settlement over the unknown because it is secondary to sale (bay'), and sale over the unknown is invalid. However, even if accepted as a sale, it is valid in cases of necessity, evidenced by the sale of building foundations, capped wells, or the contents of an animal's stomach.