Explain Doublethink in "1984". Why is it essential to the success of the party? part 1

Doublethink is one of the founding principles
of the Party and is essentially the technique of believing two contradicting ideas
simultaneously in one's mind.defines doublethink as "reality control." Thus, it is the
ability to "use logic against logic" in order to believe any information propagated by
the Party. The Party expects all of its members to maintain complete orthodoxy at all times and
to passively accept any idea delivered to them, regardless of whether it makes sense or not.
Using doublethink, one could believe that two plus two equals five. A Party member must be able
to accept and believe this illogical answer with doublethink.

The practice of
doublethink also allows the Party to maintain control of its populace and enables the government
to alter facts and history continually without being questioned. Throughout the novel, Oceania
continuously switches enemies with Eastasia and Eurasia and relies on Party members to alter
every past document to coincide with the regime's current status. For Party members to accept
Big Brother's agenda and believe that they've always been at war against one enemy, Party
members must utilize doublethink to accept the government's current
stance.