Theories of Clean & Unclean Things

What, if any, are the critieria which decide when an object is clean and unclean? This is a question that has puzzled scholars of the Old Testament in general, and of the book of Leviticus in particular. It is not surprising, therefore, that a number of different theories have been proposed. We outline here the most common ones.

The Hygienic Theory argues that hygienic concerns lay behind the clean and unclean regulations. This can make good sense of a regulation like the one concerning leprosy and other skin diseases (Lev 13) and, by a stretch, the regulations concerning bodily discharges (Lev 15). But it is hardly sufficient to explain why some animals are considered clean and others unclean when there are no obvious critieria by which to distinguish them on such a basis. It also fails to explain why, after Pentecost, they were declared to no longer apply (Acts 10:10-16).

The Cultic Theory proposes that unclean things were unclean because they were used in Canaanite religious practices. But this can hardly be true, since the bull, so widely used in the Israelite sacrificial system, was also widely used by the Canaanites in their religious rites.

Symbolic Theory

It is obvious that much thoughts have been poured into the exercise to understand what makes for an object been clean or unclean, and that none of the explanations offered have been entirely satisfactory. The basic problem is none of them are consistent and comprehensive enough to encompass all the regulations in their explanations. The symbolic theory appears to be a promising candidate but even it is beset with the question, "What are they symbolic of?" To this too, no consistent and all-encompassing answer has been provided.