To be fair, he didn't come up with it, Freud (who would have a field day analyzing Orwell's books) had the concept of Verleugnung ("denial" or "disavow"). Scott Fitzgerald, of Great Gatsby fame, once wrote that "the test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function".
Heck, if we squint a little we could track back a lot of concepts of 1984 all the way back to Hobbes.