What is the ruling on selling an unspecified, non-shared portion of a structure (like land or a house) by measure, such as 'a cubit of the house'?
Chapter on Selling Assets and Fruits
Al-Mughni
Book of Sales
Primary text
Selling a specific, non-shared measure, such as 'a cubit of the house' or 'ten cubits of it,' is invalid. However, if the parties intend to sell a shared portion (like one-tenth) and they know the total number of cubits comprising the structure, the sale is valid. This view is held by Al-Shafi'i.
Supporting text
Abu Hanifa holds that this is invalid because a cubit refers to a specific location whose position is unknown. The counter-argument is that ten out of one hundred is a fraction, and similarly, ten units out of a known whole represents a defined fraction.