This article proposes that a general theory of assessment of historical testimony should do justice to the long tradition of adjudication in accordance with maxims of reliability and competence. I argue that an explanatory genealogical theory (along lines first adumbrated by Charles Seignobos) satisfies this condition, and that it has further notable virtues: respect for the strengths of rival theories, regard for the links between adjudication of testimony and other basic procedures of historical inquiry, and the promise of profitable lines (...) of investigation. (shrink)