For, after all, how do we know that two and two make four? Or that the force of gravity works? Or that the past is unchangeable? If both the past and the external world exist only in the mind, and if the mind itself is controllable – what then?
George OrwellIt was true that there was no such person as Comrade Oglivy, but a few lines of print and a couple of faked photographs would soon bring him into existence... Comrade Oglivy, who had never existed in the present, now existed in the past, and when once the act of forgery was forgotten, he would exist just as authentically, and upon the same evidence, as Charlemagne or Julius Caesar.
George Orwell