Clean and Unclean: The Origin of the Biblical Purity Laws

There are various theories about the origins of the biblical purification regulations. The purification laws are set out as, among other things:

Some see the biblical purity laws as hygiene or medical rules. Certain animals are unclean because of their behaviour: for instance, they have dirty habits, such as eating carrion or droppings. For that reason, perhaps it was forbidden to eat such animals out of considerations of hygiene.

Others emphasise that the purity laws are mainly concerned with the difference between life and death. Purity is on the side of life, impurity on the side of death. For that reason, one should not eat any animals that eat blood or other animals, and one must not touch their carcasses (Leviticus 11:24-28).

From an anthropological perspective, explanation of purity laws is sought in the way in which people view the natural order. Clean animals are perfect, complete, and represent the wholeness of God and his creation. Unclean animals deviate from the natural order by their behaviour or their appearance. Ruminants, for instance, have cloven hooves (Leviticus 11:2-8), like pigs, but they do not chew the cud. Hares and camels chew the cud, but on the other hand do not have cloven hooves. Hence pigs, hares and camels do not fit well in the order and so are impure. Ideas about purity and impurity protect the order and preserve the holiness of the whole.
Whatever explanation one follows, in any case the division between clean and unclean means that impurity distances the human being from holiness and alienates him from God.