in substance is that its substance has become impure through acquiring the qualities of wine, just as it has thereby become forbidden. Do you not see that it was pure and lawful when it was juice, before acquiring the qualities of wine? Once it acquired those qualities, it became impure and forbidden. Since the presence of the qualities of wine in juice is the legal cause of its prohibition and impurity, when those qualities disappear, the ruling must cease with the disappearance of its cause. Those who employ analogical reasoning do not disagree that a ruling established on the basis of a legal cause ceases when that cause disappears, unless another cause takes its place and entails the same ruling.

I know of no disagreement among Muslims that wine is impure, or that, if it turns into vinegar on its own, it becomes pure and therefore lawful, apart from Ibn Lubābah’s contention that its impurity is disputed. He held that Mālik’s statement—may Allah have mercy on him—that it is lawful to consume it if it turns into vinegar, or if someone treats it until it becomes vinegar, indicates that Mālik did not consider it impure, even though drinking it is forbidden. Not everything forbidden is impure: examples include silk and gold for men, animals whose flesh may not be eaten, and other things. He also held that Mālik’s disapproval of wine treated with fish until it becomes murrī (a fermented condiment) indicates the contrary, and that, according to the view that wine is impure, it renders any water or food into which it enters impure, like other impurities.

His statement is plainly mistaken. There is no disagreement that wine is impure and renders clothing, water, and food impure, nor is there any disagreement that, if it turns into vinegar on its own, it becomes lawful and pure. They disagreed only over whether it may be consumed when deliberately turned into vinegar, depending on their disagreement over the grounds for prohibiting this process. It has been said that the prohibition on turning it into vinegar is a devotional injunction without an underlying rationale. It has also been said that the prohibition does have a rationale: the transgression and disobedience involved in keeping it. Another view is that the rationale is the suspicion that its keeper will not turn it into vinegar when he has it out of sight. On that account, he is ordered to pour it away and is not allowed to turn it into vinegar.

According to the view that the prohibition on turning it into vinegar is a devotional injunction without an underlying rationale, it may not be turned into vinegar under any circumstances. Whether it may be consumed once it has been turned into vinegar can be deduced in two ways, corresponding to the disagreement over whether a prohibition entails the invalidity of the prohibited act.

According to the view that the prohibition on turning it into vinegar rests on an underlying rationale, doing so is permissible when that rationale no longer applies. Thus, those who considered the rationale to be the transgression and disobedience involved in keeping it permitted someone whose juice had fermented into wine, without his having intended to produce wine, to turn it into vinegar. They held that if someone turns wine into vinegar after sinfully keeping it, he may not consume it, as a punishment. Those who considered the rationale to be the suspicion that its keeper will not turn it into vinegar when he is out of sight