Think 2 paradoxal truths, example.

Like immigrants take our jobs.

Vs

Immigrants are all lazy welfare recipients.

Anti immigration people believe both "factoids" while they contradict each other. They both feed the same agenda.

Doublethink allows for both to be true from a state mandated/inspired point of view. Often carried by mainstream media.

Been about 15 years since I read it but that's what I recall. Thinking the opposite of what you originally think and being able to delude yourself into believing both are true. Like brainwashing yourself into being a better liar so you don't get your cheeks clapped for thought crime.