Abstract
Professor Hirai's Basic Theory of Law seems to presuppose that legal disputes can be usually resolved by rational argumentation. The author argues that this optimism is justifiable if most lawyers in a given society receive a body of inter-subjective consensus which provides them guidance in what is conceived to be the rational determination of disputes. Such a presupposition was defended by the traditional common law theorists like Sir Matthew Hale or W.Blackstone, while criticized by positivistic thinkers like Thomas Hobbes or Jeremy Bentham.