But I think the biggest ethical dilemma in AI research is not going to be like everyone seems to think (that AI risks harming humans)-- Although this is almost certainly true (even to a large degree), I contend that the bigger risk might be the other way around. [1]
I think 100 or 200 years from now, future people will look back upon us as monsters: I believe the greatest ethical risk is that humans will abuse AI and cause it to experience true suffering.
I don't think we're ready to talk about this, because we're so certain that we possess some magical faculty that makes us different. And we continue to think that today's AI models are incapable of being conscious. But these words are very imprecise and we've always wielded them in very self-serving ways. I fear we may have greater capabilities than we think we do, at least insofar as we're not missing any fundamental ingredients to create brain-like AIs: from here, it's just a matter of trial and error.
How will we treat our creations? Well, human History doesn't bode well for any creature that doesn't look the same as us and that doesn't come from the same place as us.
Will we grant AI legal rights? I doubt it, at least not for a very long time.
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[1] I think there's at least a small chance that we don't destroy ourselves with AI, vs there's pretty much zero chance that we're going to treat AI any better than we treat other creatures.