Cannot upvote this enough.

Oops.

There was more to slavery than estimations of intelligence - the justifications varied wildly, were usually absurdly simple to disprove, and often contradicted each other ("they were designed by God to be enslaved by superior races" vs "they have weaker self-control and would kill/rape us if left unchecked", for example.)

However, the point that it was a failure of rationality, not ethics, is still valid. Unfortunately that was the OP's point as well.

I think Eliezer addressed that at one point (using a cake-making intelligence, I believe) - it would be more ethical, from a human perspective, to allow the paperclippers to make paperclips. However, it would be unethical to change the world from it's current state to one containing trillions of paperclippers, since the CEV of current people don't want that.

Stick it in a matrix.

Because a rabbit doesn't understand its continued existence, it's not wrong to kill it suddenly and painlessly, out of sight/smell/earshot of other rabbits.

That doesn't follow. I understand it's continued existence.

Great post, though. Well written, accurate and so on.

it only ever carries one message: annihilation.

Um, no.

[source]

what the hell do they use that horn for?

Stabbing lions. And ill-informed hunters.

Oh, you mean that humans might genuinely dislike homosexuality as a terminal value, because evo-psych.

... huh.