has designated it and the contract was concluded with respect to that particular coin, it becomes the seller’s property. The buyer therefore cannot substitute it, just as the seller cannot substitute the garment. But if we say that it is not specified, then he may substitute it: he may take another dirham from his pocket, other than the one he designated, and hand it over to the seller. This is one of the consequences of the disagreement. If we say that coins become specified through their designation in the contract, they may not be substituted; but if we say that they do not become specified, they may be substituted, because there is no difference between this dirham and that one.

The same applies to paper currency. If he says, “I bought this garment from you with this ten-note,” and then wishes to give him another ten-note in its place, may he substitute it? This depends on the disagreement. If we say that it becomes specified by designation, he has no right to substitute it; but if we say that it does not become specified, he may do so. The view closer to what people ordinarily intend is that it does not become specified, since the seller does not care whether it is this ten-note or another.

Moreover, there may also be a relevant difference between them. For example, if he produces the ten-note and it turns out to be a new note, then wishes to replace it with an old note that may soon become worn out, may he replace it? This depends on the disagreement. Yet even if we say that it does not become specified, in this case the seller has the right to say, “I do not want this.” There is a difference between a note likely soon to become worn out and a new note, for the relevant consideration differs here. Thus, the apparent view is that, even if we say that currency does not become specified, it does become specified in this particular case, because people’s preferences differ between one and the other. If you substitute it, then it is a new contract involving these new dirhams.