Abstract
Descriptions of social norms can be explanatory. The erotetic approach to explanation provides a useful framework. I describe one very broad kind of explanation-seeking why-question, a genus that is common to the special sciences, and argue that descriptions of norms can serve as an answer to such why-questions. I draw upon Woodwards recent discussion of the explanatory role of generalizations with a significant degree of invariance. Descriptions of norms provide what is, in effect, a generalization regarding the kind of historically contingent system a group or society, a generalization with a significant degree of invariance. Key Words: explanation invariance norms social sciences erotetic laws.