and deduct the remainder proportionately from the price. Thus, he has eaten two kilograms, while I sold him five kilograms for fifty riyals. Three kilograms therefore remain, so thirty riyals are deducted from the price. Is this permissible or not? According to the school, it is not permissible, for the amount to be eaten must be known at the time of the contract, and this is difficult to determine. The second view, however, is that it is permissible and unobjectionable, so long as it is known that the value of the five kilograms is fifty riyals—that is, that each kilogram is worth ten riyals. Whatever you eat is charged proportionately from the price, and whatever you leave is deducted proportionately from it. There is no uncertainty in this, because even if some uncertainty is assumed to exist at the time of the contract, it will ultimately become known.
From this we move to an issue that people have now begun to deal in: sale on a return basis. An example is where someone says: “Here are five cartons of milk or five baskets of bread,” which he supplies to the grocer on a return basis. This means that he comes to him at the end of the day and asks, “How much have you sold?” The grocer replies, “Such-and-such,” and he says, “That amount is due from you, and return the remainder, which will be deducted from the price.” According to the school, this is not permissible. But according to the view that we held to be unobjectionable in the case of dates eaten, we say that it is permissible, provided that he assigns a price to each item. But if he says, “According to what you sell,” without telling him, “Each carton is such-and-such,” or, “Each basket of bread is such-and-such,” this leads to uncertainty.
Thus, there are two ways of arranging sale on a return basis. One is for the person who brings the bread or milk to appoint the grocer as his agent, saying: “Take this, sell it, and you will receive such-and-such for each carton.” This is unquestionably permissible, because it is an agency arrangement for compensation, and there is no problem with it.