I think the major issue House Elves create has to do not with (1) first order reasoning over ethical behavior with other people, nor (2) second order character development aimed at other people (binding pre-commitments to do momentarily irrational things to create certain game theoretic incentive systems with pleasing global properties) but something like (3) "third order moral reasoning" over political processes that include people pre-committed to various irrational character regimes being subject to political speech exhorting people to make similar pre-commitments based on shared traits.
Suppose humans meet "radically different aliens". First contact stories are a staple of science fiction and they can play out in various ways. Some of the pleasant outcomes involve humans and aliens changing their mind about some stuff so as to recognize each other as "people" and get along.
Now imagine that humans create house elves to be capable of speech and eye contact and geometric verbal reasoning and laughter and so on. Only then does this two-species composite meet "radically different aliens".
From the alien's perspective, humans and house elves are nearly identical except for a small fudge, right? Since the humans were OK creating the house elves they must endorse that state as "theoretically acceptable". Therefore it wouldn't seem like that large of an imposition to ask the humans to modify themselves that way, right? Maybe the house elves are actually happier? And they're certainly cheaper to feed!
Suppose the aliens earnestly and naively explained that they would be horrified to have created "house aliens" but they don't want to judge us, and would like to participate in our culture to some degree. Since "alien shaped slaves" make them queasy, and house elves are too small to do useful jobs on their space ships they want some humans to explain how to modify full human brains to make them good servants. And could be maybe show them how this technology works and give them some prototype volunteer slave humans? Pretty please? What could possibly go wrong? And they pinky-to-tentacle promise not to abuse the technology... not that humans can yet read the way their mandibles and multi-facted eyes squirm around to distinguish between delight at the opportunity to make new friends or gleeful appreciation of having found a new already-half-tamed slave species to upgrade a little and then sell on the galactic market...
And then the people who have been complaining about house elves all this time freak out about the creation of more "intrinsically oppressed" sentient beings. And the people who insisted that house elves weren't problematic at all don't want to give those dumb liberals "I told you so" credits so they agree with the aliens that maybe some weird humans can be found somewhere to volunteer so that humans can get some pretty glass beads from the aliens.
And six different philosophers/priests/politicians come up with subtly different takes on the issue and argue amongst each other to make a name for themselves, creating bickering factions of supporters... which makes the jobs of the people currently negotiating with the aliens that much harder, because it obviously gives the aliens a BATNA to try waiting for a regime change and seeing if they can get cooperation from one of the currently-out-of-power factions who are squabbling in favor of full cooperation so that humans can get some of those pretty beads the aliens wear!
Maybe there will never be such aliens? Maybe the general sanity waterline is high enough that no one should worry about this stuff? But if you're unsure of the answers to those issues, do you really want to fudge the brightline definition of "human" that we got for free from evolution? If you've going to fudge it, do you really want to fudge it down instead of up? Maybe keeping the universe of "moral atoms" simple enough for 12 year old kids to understand is helpful to making sure everyone acts morally in the long run?
I think that when bioconservatives talk about disgust and purity in the context of transhumanism, these are some of the pragmatic political issues that are lurking behind their moral sentiments. I don't generally "side" with the bioconservatives, but this is a reasonably good zombie argument that I've been able to reconstruct from their position.
This is among the best political comments on LW.
Edit: This is old material. It may be out of date.
I'm talking about the fictional race of House Elves from the Harry Potter universe first written about by J. K. Rowling and then uplifted in a grand act of fan-fiction by Elizer Yudkowsky. Unless severely mistreated they enjoy servitude to their masters (or more accurately the current residents of the homes they are binded to), this is also enforced by magical means since they must follow the letter if not the spirit of their master's direct order.
Overall treating House Elves the way they would like to be treated appears more or less sensible and don't feel like debating this if people don't disagree. Changing agents without their consent or knowledge seems obviously wrong, so turning someone into a servant creatures seem intuitively wrong. I can also understand that many people would mind their descendants being modified in such a fashion, perhaps their dis-utility is enough to offset the utility of their modified descendants. However how true is this of distant descendants that only share passing resemblance? I think a helpful reminder of scale might be our own self domestication.
Assuming one created elf like creatures ex nihilo, not as slightly modified versions of a existing species why would one not want to bring a mind into existence that would value its own existence and benefits you, as long as the act of creation or their existence in itself does not represents huge enough dis-utility? This seems somewhat related to the argument Robin Hanson once made that any creatures that can pay for their own existance and would value their own existance should be created.
I didn't mention this in the many HP fan fiction threads because I want a more general debate on the treatment and creation of such a class of agents.
Edit: Clearly if the species or class contains exceptions there should be ways for them to pursue their differing values.