http://en.wikipedia.org/wiki/DoublethinkDoublethink (known in Oldspeak but never used as reality control) is an integral concept in George Orwell's dystopian novel Nineteen Eighty-Four, and is the act of holding two contradictory beliefs simultaneously, fervently believing both, and being unaware of their incompatibility.
The power of holding two contradictory beliefs in one's mind simultaneously, and accepting both of them. ... To tell deliberate lies while genuinely believing in them, to forget any fact that has become inconvenient, and then, when it becomes necessary again, to draw it back from oblivion for just so long as it is needed, to deny the existence of objective reality and all the while to take account of the reality which one denies—all this is indispensably necessary. Even in using the word doublethink it is necessary to exercise doublethink. For by using the word one admits that one is tampering with reality; by a fresh act of doublethink one erases this knowledge; and so on indefinitely, with the lie always one leap ahead of the truth.
Some people think that doublethink is a concept unique to Nineteen Eighty-Four, and others think that it is a real psychological function. Among those who consider doublethink real, there are two conflicting definitions:
1. "believing contradictory beliefs for reasons of practicality, convenience, and/or emotional stability" or
2. "enjoying the malicious pleasure of the contrast between what one believes to be true and what one knows to be true."
Both of the above can be observed to exist.
The second definition explains the affinity for opposites (e.g. war is peace, freedom is slavery, etc.), because opposites maximize the contrast with the truth. It also explains Newspeak words that consist of two contradictory definitions, especially among words of fundamental importance such as 'truth / deception', 'good / evil', etc, as such malicious doublethink creates an affinity for making such deceptions deeply ingrained in one's thinking, and therefore very subtle. The main antangonist in Nineteen Eighty-Four, 'O'Brien', made explicit note of such maliciously deceptive subtlety when he told Winston that (paraphrased) 'in the future, the oppression will come in increasingly subtle forms'. That means that the second definition is closer to the doublethink of Nineteen Eighty-Four, but the similarity with the first definition is also notable.
on edit: Emphasis mine. Hope this does not count as more than 4 paragraphs.