of the most repulsive substances. People’s own feelings bear witness to this, as do their natural dispositions and temperaments: scarcely anyone places it on the same footing as an animal’s milk and offspring. We recognize only two categories: pure and impure. Once it falls outside the category of pure substances, it enters that of impurities. The treatment generally accorded to it—keeping it at a distance and avoiding it—is that accorded to impurities, so it cannot be pure. For when a substance resembles competing legal precedents, it is assigned to the one it most closely resembles. It stands between milk and other kinds of urine, and resembles the latter more closely.

This is reinforced by the words of Allah Most High:

“From between digested matter and blood, pure milk, palatable to those who drink it.”

It has been established that blood is impure; so too is digested matter, that His power and mercy may be manifest in bringing forth something wholesome from between two foul substances. All this is further clarified by the fact that it shares the physical characteristics, colour, smell, and taste of other urine. How, then, can a distinction be drawn between them despite these shared features, which almost make the essential nature of one identical to that of the other?

The first line of reasoning is analogy by comparison: attaching the ruling to the shared feature established by the evidence.

The second is causal analogy: refining the operative basis of the ruling and formulating a universal principle.

The third is to distinguish it from the category of pure substances, so that it cannot be included among them. These, then, are the forms of analogy: a foundation, a connection, and a distinction.

The first line of reasoning provides the foundation and links it with other impure substances.