A Disneyland with no children.

"It is conceivable that optimal efficiency would be attained by grouping capabilities in aggregates that roughly match the cognitive architecture of a human mind…But in the absence of any compelling reason for being confident that this so, we must countenance the possibility that human-like cognitive architectures are optimal only within the constraints of human neurology (or not at all). When it becomes possible to build architectures that could not be implemented well on biological neural networks, new design space opens up; and the global optima in this extended space need not resemble familiar types of mentality. Human-like cognitive organizations would then lack a niche in a competitive post-transition economy or ecosystem.

We could thus imagine, as an extreme case, a technologically highly advanced society, containing many complex structures, some of them far more intricate and intelligent than anything that exists on the planet today – a society which nevertheless lacks any type of being that is conscious or whose welfare has moral significance. In a sense, this would be an uninhabited society. It would be a society of economic miracles and technological awesomeness, with nobody there to benefit. A Disneyland with no children.

-- Philosopher Nick Bostrom, quoted by Scott Alexander in a thought-provoking essay. My own thoughts are AAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHH