Every man, according to Bacon, is a debtor to his profession. Although the historian pays his debt by devotion to truth, unless he has thought about truth as well as worshipped it he may — to adapt a figure from Bishop Berkeley — become a thriving earthworm but he will surely make a sorry historian. So vermiculate a metaphor need not prompt every disciple of Clio to compose a penetrating Idea of History, but it may properly incite him to give life to his facts by evoking the universal while documenting the specific, by preferring insights to formulas, and by recalling that historiographical clichés and historical facts — modern saws and ancient instances — go ill together. If the historian of the ancient world benefits from built-in ignorance, the historian of the modern world suffers from built-in knowledge, not merely because of the mountain of fact but because this very mountain permits him to let a tissue of fact do duty for history. Absence of metaphysics is too high a price for erudition.

For some years historians have been revolting against easy generalizations and after-mindedness. Their revolt does not find expression in systems, which carry farthest the very practices exciting revolt, but in analysis of assumptions. The critical historian explores his topic in its own terms, not in terms of later dogmas; he reconstructs ideas and institutions in their own context, not as the shape of things to come; he considers his characters in their own environment, not as ancestors; he replaces anonymous society and impersonal forces with living men and women.