These are two very interesting examples of dystopian fiction at their best: although both have very different tones, both works of fiction posit potential futures that question what it is to be human and challenge notions today of society and governance. What is common to both of these tales is the way that society is supposedly "improved" by the changes brought in by two despotic regimes. In Brave New World, this is clearly indicated by the words of Mustapha Mond as he reflects on the imperfections of the present world:
What with mothers and lovers, what with the prohibitions they were not conditioned to obey, what with the temptations and the lonely remorses, what with all the diseases and the endless isolating pain, what with the uncertainties and the poverty—they were forced to feel strongly. And feeling strongly (and strongly, what was more, in solitude, in hopelessly individual isolation), how could they be stable?
In the future, conditioning and rigid social hierarchy has erased such "instability," and Mond believes that this has made the world a better place. However, as the text explores, others argue that this has only created humans who are less than human and that being able to face temptations and remorses and "feeling strongly" is what makes humans human. Remove that, and you only have preconditioned robots left over.
In 1984, the human capacity for reason and logical thought is removed once again, but this time through a society that makes every decision for its population and leaves them no opportunity to think for themselves. Note how this position is presented by Smith:
In the end the Party would announce that two and two made five, and you would have to believe it. It was inevitable that they should make that claim sooner or later: the logic of their position demanded it. Not merely the validity of experience, but the very existence of external reality was tacitly denied by their philosophy.
Just as Mond praised the way that society changed to remove the capacity for emotional feeling and free thought, so in this dystopian world Party members have become almost automatons in the way that they accept whatever "facts" and "truths" the Party presents, even though it contradicts the very basis of truth itself. Both texts therefore present dystopian societies that are based around making humans less than human through the removal of individual thought and creative intellectual discovery.