“All rulers in all ages have tried to impose a false view of the world upon their followers, but they could not afford to encourage any illusion that tended to impair military efficiency. So long as defeat meant the loss of independence, or some other result generally held to be undesirable, the precautions against defeat had to be serious. Physical facts could not be ignored. In philosophy, or religion, or ethics, or politics, two and two might make five, but when one was designing a gun or an aeroplane they had to make four. Inefficient nations were always conquered sooner or later, and the struggle forefficiency was inimical to illusions.
Moreover, to be efficient it was necessary to be able to learn from the past, which meant having a fairly accurate idea of what had happened in the past. Newspapers and history books were, of course, always coloured and biased, but falsification of the kind that is practised today would have been impossible.”