"I shall begin at the beginning," said the D.H.C. and the more zealous students recorded his intention in their notebooks: Begin at the beginning. "These," he waved his hand, "are the incubators." And opening an insulated door he showed them racks upon racks of numbered test-tubes. "The week's supply of ova. Kept," he explained, "at blood heat; whereas the male gametes," and here he opened another door, "they have to be kept at thirty-five instead of thirty-seven. Full blood heat sterilizes." Rams wrapped in theremogene beget no lambs. (1.9)
Here begins a key feature of the way science is presented in Brave New World: horrifying precision. A mere two degrees of temperature separates male gametes from female ones, yet this difference is exact and crucial.
"They'll grow up with what the psychologists used to call an 'instinctive' hatred of books and flowers. Reflexes unalterably conditioned. They'll be safe from books and botany all their lives." The Director turned to his nurses. "Take them away again." (2.26)
"Nature" has no meaning in this new world; Mustapha Mond will later explicitly make the point that there is no such thing as "instinct," or if there is, it is no different from what citizens are programmed to believe.
"These early experimenters," the D.H.C. was saying, "were on the wrong track. They thought that hypnopædia could be made an instrument of intellectual education…"
[…]
"The - Nile - is - the - longest - river - in - Africa - and - the - second - in - length - of - all - the - rivers - of - the - globe…" The words come rushing out. "Although - falling - short - of…"
"Well now, which is the longest river in Africa?"
The eyes are blank. "I don't know."
[…]
"Whereas, if they'd only started on moral education," said the Director, leading the way towards the door. The students followed him, desperately scribbling as they walked and all the way up in the lift. "Moral education, which ought never, in any circumstances, to be rational." (2.54-60)
Science has its limits. It is interesting that science—an entirely rational subject—can be employed to indoctrinate irrational inclinations.