To my mind all such questions are related to arguments about solipcism, i.e. the notion that even other humans don't, or may not, have minds/consciousness/qualia. The basic argument is that I can only see behavior (not mind) in anyone other than myself. Most everyone rejects solipsism, but I don't know if there have actually many very good arguments against it, except that it is morally unappealing (if anyone know of any please point them out). I think the same questions hold regarding emulations, only even more so (at least with other humans we know they are physically similar, suggesting some possibility that they are mentally similar as well - not so with emulations*). Especially, I don't see how there can ever be empirical evidence that anything is conscious or experiences qualia (or that anything is not conscious!): behavior isn't strictly relevant, and other minds are non-perceptible. I think this is the most common objection to Turing-tests as a standard, as well.
*Maybe this is the logic of the biological position you mention - essentially, the more something seems like the one thing I know is conscious (me), the more likehood I assign to it also being conscious. Thus other humans > other complex animals > simple animals > other organisms > abiotics.
Arguments against solipsism? Well, the most obvious one would be that everyone else appears to be implemented on very nearly the same hardware I am, and so they should be conscious for the same reasons I am.
Admittedly I don't know what those reasons are.
It's possible that there are none, that the only reason I'm conscious is because I'm not implemented on a brain but in fact on some unknown thing by a Dark Lord of the Matrix, but although this recovers the solipsism option as not quite as impossible as it'd get if you buy the previous argument, it doesn't seem likely. Even in matrix scenarios.
- Eliezer Yudkowsky, "Value is Fragile"
I had meant to try to write a long post for LessWrong on consciousness, but I'm getting stuck on it, partly because I'm not sure how well I know my audience here. So instead, I'm writing a short post, with my main purpose being just to informally poll the LessWrong community on one question: how sure are you that whole brain emulations would be conscious?
There's actually a fair amount of philosophical literature about issues in this vicinity; David Chalmers' paper "The Singularity: A Philosophical Analysis" has a good introduction to the debate in section 9, including some relevant terminology:
So, on the functionalist view, emulations would be conscious, while on the biological view, they would not be.
Personally, I think there are good arguments for the functionalist view, and the biological view seems problematic: "biological" is a fuzzy, high-level category that doesn't seem like it could be of any fundamental importance. So probably emulations will be conscious--but I'm not too sure of that. Consciousness confuses me a great deal, and seems to confuse other people a great deal, and because of that I'd caution against being too sure of much of anything about consciousness. I'm worried not so much that the biological view will turn out to be right, but that the truth might be some third option no one has thought of, which might or might not entail emulations are conscious.
Uncertainty about whether emulations would be conscious is potentially of great practical concern. I don't think it's much of an argument against uploading-as-life-extension; better to probably survive as an up than do nothing and die for sure. But it's worrisome if you think about the possibility, say, of an intended-to-be-Friendly AI deciding we'd all be better off if we were forcibly uploaded (or persuaded, using its superhuman intelligence, to "voluntarily" upload...) Uncertainty about whether emulations would be conscious also makes Robin Hanson's "em revolution" scenario less appealing.
For a long time, I've vaguely hoped that advances in neuroscience and cognitive science would lead to unraveling the problem of consciousness. Perhaps working on creating the first emulations would do the trick. But this is only a vague hope, I have no clear idea of how that could possibly happen. Another hope would be that if we can get all the other problems in Friendly AI right, we'll be able to trust the AI to solve consciousness for us. But with our present understanding of consciousness, can we really be sure that would be the case?
That leads me to my second question for the LessWrong community: is there anything we can do now to to get clearer on consciousness? Any way to hack away at the edges?