In the end the Party would announce that two and two made five, and you would have to believe it. It was inevitable that they should make that claim sooner or later: the logic of their position demanded it. Not merely the validity of experience, but the very existence of external reality was tacitly denied by their philosophy. The heresy of heresies was common sense.

George Orwell

1984. Part 1, Chapter 7. Winston. Orwell got inspiration from a real event in Russia where the community party celebrated achieving a production goal in four years instead of five by announcing the workers had made 2+2=5.