"These two different attitudes toward precedent reveal an important part of the terrain of inquiry into law’s use and construction of history. They remind us of the complex and contingent interpretive possibilities of a legal order dedicated to a faithful respect for its past. Reasoning by analogy, distinguishing cases, identifying rules and their exceptions provide, in one sense, the very substance of legal reasoning. But in another they provide the resources with which law can live within the prison of history and yet escape it as needed. They provide but one indication of the fact that law’s history is almost always the subject of contest and interpretive dispute, that its' is a purposive and politicized attitude toward history. They also suggest that the interpretive touchstone for such contestation in the question of legitimacy."