In George Orwell's 1984, a great deal of space is devoted to explaining "Double-think," part of The Party's method of "reality control." Here's a particularly clear passage:
Doublethink means the power of holding two contradictory beliefs in one's mind simultaneously, and accepting both of them. The Party intellectual knows in which direction his memories must be altered; he therefore knows that he is playing tricks with reality; but by the exercise of doublethink he also satisfies himself that reality is not violated. The process has to be conscious, or it would not be carried out with sufficient precision, but it also has to be unconscious, or it would bring with it a feeling of falsity and hence of guilt. Doublethink lies at the very heart of Ingsoc, since the essential act of the Party is to use conscious deception while retaining the firmness of purpose that goes with complete honesty...
Another really good passage describes the practice of doublethink. O'Brien, a member of the inner party, produces a photograph of some people who are supposed to have never existed. But then he destroys it.
"It exists!" he [Winston, the protagonist] cried!
"No," said O'Brien... "Ashes," he said. "Not even identifiable ashes. Dust. It does not exist. It never existed."
"But it did exist! It does exist! It exists in memory. I remember it. You remember it."
"I do not remember it," said O'Brien.
It's interesting (and terrifying), but I suspect it isn't possible.
As I understand, in Freudian theory, repression is an unconscious process that happens to traumatic or unacceptable memories. That's clearly different from doublethink, even if it were possible (and there doesn't seem to be any evidence that it is.)
Is doublethink actually possible? Are there any documented examples of it? Is there anything similar to it, possible or otherwise?