How is "ignorance strength" in Orwell's 1984 and what are the advantages of being ignorant in Orwell's novel?
In George Orwell's 1984, one of the slogans of the ruling party in Oceania is "Ignorance is Strength." Ordinarily, one would think that knowledge would be strength, but in the world in which Winston Smith lives, it is better not to know than to know.
In Smith's world, which is controlled by the Party, an individual is only supposed to think what the Party wants them to think. If The Party says that Oceania is at war with Eurasia, even though they are actually at war with Eastasia, it is in one's best interest to train one's main to engage in doublethink. Thus, in Smith's world, one must feign ignorance of the facts in order to stay alive.
Thinking something contrary to what the Party wants a person to think can cost a person his or her life. When Smith learns that Julia loves him, this puts his life at risk. When Smith finally reads Goldstein's book, this puts his life at risk.
Ultimately, after the Thought Police arrest Winston, reverting to a state of ignorance helps save his life. When Smith can accept that "two and two make five", then he has reverted to the state of ignorance in which the Party wishes him to exist. At the end of the novel, with tears streaming from his eyes, Winston can acknowledge that "He had won the victory over himself. He loved Big Brother."