doublethink
The power of holding two contradictory beliefs in one's mind simultaneously and accepting both of them as true or correct; an instance of doing so.
uncountable
The stars can be near or distant, according as we need them. Do you suppose our mathematicians are unequal to that? Have you forgotten doublethink?
Where it comes from
From double + think. Coined by George Orwell in 1949 as part of the Newspeak in his novel Nineteen Eighty-Four.
Adapted from the Wiktionary entry doublethink (CC BY-SA 4.0).