sexual selection as opposed to natural selection- evolution as spurred by mating preferences. for example, if everyone suddenly refused to have sex withi blondes, in a few generations there would be way fewer blondes. so, all else being equal, over the long haul humanity has been evolving itself to be more sexually appealing to itself. which doesn't mean we should all be alpha supermodels, because if people are more appealing then people can also be more selective. it doesn't matter if i'm better than a caveman -- am i better than the guy next to me? so theoretically, life is getting better and better by generations, but nobody can tell.
on a related note, i can't remember where i got this, but it's a point i've always been intrigued by -- the easiest way to cure hemophilia would be to let all the hemophiliacs bleed to death. species vs individuals. but who knows what that would cost us even if we were so cutthroat. in a sense, surviving natural selection means having a sufficient collection of useless attributes, for the next unexpected calamity. i wonder if anyone has ever tried to sue their parents for passing down bad genes.
in summary, whichever philosopher said he'd rather be an unhappy man than a happy pig was full of shit. the one thing i think brave new world reallyl got right was that succesful worlds along that line are only distopian to outsiders. you think ants are sad that they're ants?