My initial response to the question in the title, without reading the article or any other comments:
About as sure as I am that other humans are conscious, which is to say ~98% (I tend to flinch away from thinking I'm the only conscious person in existence, but all I have to go on is that so far as I know, we're all using extremely similar hardware and most people say they're conscious, so they probably are.).
The trouble is that this is an outside view; I haven't the faintest idea what the inside view would be like. If a small portion of my brain was replaced with an artificial component, I would have no idea how to predict what that would feel like from the inside, but expect that it'd look like I was still conscious from the outside. I'm personally concerned with the inside part, and that's a huge unknown.
But if we had emulations running around, I'd almost definitely think of them as people just as much as everyone else in the world, and I'd treat their reports on consciousness the same.
For part of that 2%, you may consider the possibility that brains do not produce consciousness/qualia, and your actual consciousness is implemented on a different sort of hardware, outside the matrix.
(Does telling you this fairly specific story in any way budge the 2% number?)
- 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?