Finally, when historians contest interpretations of the past among themselves, they’re liberating it in yet another sense: from the possibility that there can be only a single valid explanation of what happened.

Assuming stability is one of the ways ruins get made. Resilience accommodates the unexpected.

Lightness of being,” then, is the ability, if not to find the good in bad things, then at least to remain afloat among them, perhaps to swim or to sail through them, possibly even to take precautions that can keep you dry.

Despite the legacy of slavery, the near extermination of native Americans, and persistent racial, sexual, and social discrimination, the citizens of the United States could plausibly claim, in 1945, to live in the freest society on the face of the earth.

Learning about the past liberates the learner from oppressions earlier constructions of the past have imposed upon them.

These things did not happen simply because Reagan gave a speech or because Orwell wrote a book: the remainder of this book complicates the causation. It is worth starting with visions, though, because they establish hopes and fears. History then determines which prevail.

The most important one was the belief, which went back to Lenin, that capitalists would never be able to cooperate with one another for very long. Their inherent greediness – the irresistible urge to place profits above politics – would sooner or later prevail, leaving communists with the need only for patience as they awaited their adversaries’ self-destruction.

That’s why war – explicitly in Clausewitz, implicitly in Tolstoy – must reflect policy. For when policy reflects war, it’s because some high-level hedgehog – a Xerxes, or a Napoleon – has fallen in love with war, making it an end in itself. They’ll stop only when they’ve bled themselves bloodless. And so the culminating points of their offensives are self-defeat.

Reassuring withdrawals, Clausewitz writes in On War, “are very rare.” More often armies and nations fail to distinguish orderly disengagements from abject capitulations – or foresight from fear.

F. Scott Fitzgerald’s test, from 1936, for a first-rate intelligence: “the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.