The Party encourages, or rather simply allows, intimacy for the purpose of procreation. At one point, we are told it's also allowed for the pleasure of (only) men, but this just appears a temporary expedient, because O'Brien boasts that the Party currently has its neurologists working on how to "abolish the orgasm."
In other words, the Party is puritanical about sex in a way that makes traditional religions seem almost liberal. Why is this? It's the opposite of the dystopia of Huxley's Brave New World, in which complete sexual freedom is the norm and people are encouraged to operate according to the pleasure principle. Among early reviewers of 1984, C. S. Lewis considered this aspect unrealistic; in his view, an atheistic society would not be anti-sex as the Party is.
The explanation in Orwell 's narrative is that the Party considers intimacy between men and women as a counterforce to its power and therefore seeks to suppress it. If men and women feel strongly attached to each other, then that...
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