“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.”

“In past ages, a war, almost by definition, was something that sooner or later came to an end, usually in unmistakable victory or defeat. In the past, also, war was one of the main instruments by which human societies were kept in touch with physical reality. 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 for efficiency 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 practiced today would have been impossible. War was a sure safeguard of sanity, and so far as the ruling classes were concerned it was probably the most important of all safeguards. While wars could be won or lost, no ruling class could be completely irresponsible.”

“Very well, I agree that two and two make four is an excellent thing; but...two and two make five is also a very fine thing too.”

“I agree that two times two makes four is an excellent thing; but if we are dispensing praise, then two times two makes five is sometimes a most charming little thing as well.”

“Twice two makes four seems to me simply a piece of insolence. Twice two makes four is a pert coxcomb who stands with arms akimbo barring your path and spitting. I admit that twice two makes four is an excellent thing, but if we are to give everything its due, twice two makes five is sometimes a very charming thing too.”

“But again and again there comes a time in history when the man who dares to say that two and two make four is punished with death. The schoolteacher is well aware of this. And the question is not one of knowing what punishment or reward attends the making of this calculation. The question is one of knowing whether two and two do make four”