in what ways does the political alliance between oceania and eurasia involved double-think? what are other examples of doublethink?

Doublethink is a term from Orwell's 1984, which means the ability to hold two contradictory beliefs and believe in both of them. I's paradoxical. So, throughout the book the Party has claimed to be at war with either Eastasia or Eurasia. They flip flop back and forth. People simply agree with the Party's latest decree knowing that just an hour before they believed the opposite.