valid to sell it, as is the apparent position of al-Shāfiʿī’s school.

The second is that its sale is valid, whether or not it has been described, as in Abū Hanīfah’s school.

The third, which is Mālik’s position and the well-known position of Ahmad’s school, is that its sale is valid if it is described, but not otherwise.

If this item perishes through a natural calamity before the purchaser has had an opportunity to take possession of it, the sale is annulled, by agreement of the scholars. The purchaser cannot demand a replacement, because his entitlement was attached to that particular item.

As for an unspecified item sold as an obligation owed, an example is the obligation arising from an advance-payment sale (salam): the purchaser has paid in advance for something described in general terms, without specifying a particular item. This is comparable to an unspecified price and to other obligations established without specifying particular items, such as a bridal due, repayment of a loan, rent, and the like. Its counterpart among religious obligations is the obligation to free an unspecified slave, and similar duties.

Here, what is owed is something unspecified, not a particular item. The person who owes it may therefore provide any particular item that fulfils the intended purpose. If he provides a particular item and it perishes before the recipient has had an opportunity to take possession of it, the recipient is entitled to demand another.

The jurists make the same distinction between an unspecified sacrificial offering—such as the offerings for tamattuʿ (Umrah followed by Hajj) and qirān (Umrah and Hajj combined)—and a designated offering, as when someone vows to sacrifice a particular animal. If the designated animal perishes without negligence on his part, he is not obliged to replace it. This differs from an offering owed as an obligation: even if he designates a particular animal, he must replace it if it perishes.

Everything that exists externally is, in itself, particular. Yet knowledge of it may or may not include knowledge of its particular identity. When an item offered for sale is directly observed, the purchaser knows its particular identity. When it is absent, it remains particular in itself, but the purchaser does not know its particular identity; he knows only a general description of it. That description may apply exclusively to it, or it may apply both to it and to other things. For someone may sell him the slave or the plot of land whose