Are meat and fat two distinct categories for the purpose of exchange?
Chapter on Riba (Usury) and Exchange (Sarf)
Al-Mughni
Book of Sales
Primary text
Meat and fat are considered two distinct categories (*jinsan*). Similarly, the liver, spleen, heart, and brain are each considered distinct categories. The exchange of any one category for another category, with or without excess (*mutafadilan*), is permissible. This view is supported by Abu Hanifa and Al-Shafi'i, following the apparent position of the Madhhab. The evidence for permitting unequal exchange between them is that they are two distinct categories, analogous to gold and silver exchange.
Supporting text
Malik disliked the exchange unless the quantities were equal (*mutamathila*). The view that prohibits the exchange because meat is never devoid of fat is refuted because the inseparable fat is not the intended object of exchange and thus does not prevent the transaction. Furthermore, if this reason prohibited the sale, then selling meat for meat would also be invalid due to the mutual inclusion of non-identical components.