John the Savage says "O brave new world" at three different points in the novel, and each time the words have a different meaning. The phrase comes from Shakespeare's The Tempest, in which Miranda, who has grown up since babyhood on a deserted island, makes the exclamation "How beauteous mankind is! O Brave new world . . ." when she sees multiple young men from the shipwrecked vessel for the first time.
When John first quotes this phrase from The Tempest, he is speaking sincerely. He is on the Savage Reservation and is thrilled to be going to the World State, which his mother Linda has described to him for many years as a utopia. He also is in love with Lenina, so—as with Miranda—the phrase has sexual overtones. There's also humor and irony, however, in John thinking in the midst of all this of Lenina:
"How many goodly creatures are there here! How beauteous mankind is!" The flush suddenly deepened; he was thinking of Lenina, of an angel in bottle-green viscose, lustrous with youth and skin food, plump, benevolently smiling. His voice faltered. "O brave new world," he began . . .
The statement is an example of dramatic irony, for the reader already knows what life is like in the World State.
The second time John the Savage uses the quote, it is with bitter irony. He is watching, with some horror, the multitude of duplicate test-tube creatures at work:
Forty-seven snubs by forty-seven hooks; forty-seven receding by forty-seven prognathous chins. The completed mechanisms were inspected by eighteen identical curly auburn girls in Gamma green, packed in crates by thirty-four short-legged, left-handed male Delta-Minuses, and loaded into the waiting trucksand lorries by sixty-three blue-eyed, flaxen and freckled Epsilon Semi-Morons.
"O brave new world . . ." By some malice of his memory the Savage found himself repeating Miranda's words. "O brave new world that has such people in it."
As John experiences grief over his mother's death, the insensitivity and dehumanization of this world overcomes him:
He halted and, with bewildered and horrified eyes, stared round him at the khaki mob, in the midst of which, overtopping it by a full head, he stood. "How many goodly creatures are there here!" The singing words mocked him derisively. "How beauteous mankind is! O brave new world . . ."
. . . In his mind the singing words seemed to change their tone. They had mocked him through his misery and remorse, mocked him with how hideous a note of cynical derision! Fiendishly laughing, they had insisted on the low squalor, the nauseous ugliness of the nightmare.
In his final use of the words, right after the last quote, they are a call to action. He decides that at this point there is still hope. He wants to disrupt the soma distribution and try to get these people to feel some real emotions. We remember he is distraught with grief:
"O brave new world!" Miranda was proclaiming the possibility of loveliness, the possibility of transforming even the nightmare into something fine and noble. "O brave new world!" It was a challenge, a command.