1. That the Lawgiver has explicitly declared it impure—for example, domesticated donkeys.

2. Or that He has laid down a general criterion, such as: every beast with canine teeth and every bird with talons.

3. Or that its impurity is self-evident, like the mouse, the snake, and insects.

4. Or that the Lawgiver has either ordered its killing or forbidden its killing.

5. Or that it is known to live on carrion, such as vultures and the rakhm (Egyptian vulture) and their like.

6. Or that it is born from a lawful and an unlawful parent, in which case prohibition prevails, as with the mule.

7. Or that its impurity is incidental, such as a jallalah—an animal fattened on filth—or liquids that have become contaminated.

8. Or that it is prohibited because it causes bodily harm, like all kinds of poisons.

9. Or that it is prohibited because it harms the mind, such as wine and narcotics.

10. Or that it has been slaughtered in an unlawful manner, whether on account of the implement used, the person performing the slaughter, or the purpose behind it.

Whatever does not possess any of these causes of impurity remains lawful.