Doublethink was described by George Orwell as simultaneously holding two conflicting beliefs. Orwell describes it thus:
“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.”
Orwell describes doublespeak as being a part of newspeak, which is the method for control of thought through subtle language. Doublethink adds control that eliminates uncertainty and so the whole belief system seems coherent.
Doublethink is not hypocrisy as the person actually believes in both things, even though they contradict.
A politician believes in general openness, yet the need for secrecy in certain things.
A person believes they will succeed, yet also they will learn from their mistakes.
A sales person convinces themself that their company products are the very best, yet they personally prefer a competitor’s product.
Belief systems often contain many beliefs and it is easy for any of these to contradict one another at different levels and in different contexts. People who want to believe in the whole system therefore have to find ways of handling the internal conflicts. They may do this simply by ignoring differences or by rationalizing these with fallacious argument. In arguing with others, a typically method is chunking up to a higher level question that defends the whole belief system (‘Are you doubting the word of God??’).
People also tend to have multiple belief systems which even more easily contradict, such as a person who is both a scientist and a committed Christian. The way such contradictions are often managed is by compartmentalization, thinking in one set or beliefs or another, but somehow having a ‘Chinese wall’ in the mind that holds two two apart.
To get people to believe in two contradictory beliefs, present them both as part of a larger belief system where it is more important to accept the whole system than question ‘minor’ inconsistencies within it.
If you want to succeed in your own life, try to hold two beliefs: one is that you will inevitably succeed and another is that you must work hard for that success.