Thus, both textual evidence and analogy establish their permissibility.

Moreover, they all agree that when wine turns into vinegar by the act of Allah Most High, it becomes lawful and wholesome. Yet the transformation of these substances is greater than that of wine. Those who distinguish between the two say: “Wine became impure through transformation, so it becomes pure through transformation, unlike blood, carrion, and pork.”

This distinction is weak, for all impure substances likewise became impure through transformation. Blood results from the transformation of pure substances, as do excrement and urine, and an impure animal results from the transformation of pure created matter. Furthermore, Allah Most High prohibited foul things because of their foulness, just as He permitted wholesome things because of their wholesomeness. These disputed substances possess none of the qualities of foulness; rather, they possess the qualities of wholesomeness.

Once this is understood, according to the more correct of the two views, smoke and vapour produced by the transformation of impure substances are pure, because they consist of particles of air, fire, and water, with no quality of foulness remaining in them. According to the other view, whatever of this is difficult to avoid must be excused, just as whatever is difficult to avoid is excused according to the more correct of the two views. As for anyone who declares the impurity of