Susan Schneider's beautifully clear TEDx talk on the future of robot consciousness has me thinking about the possibility of accidentally turning oneself into a zombie. (I mean "zombie" in the philosopher's sense: a being who outwardly resembles us but who has no stream of conscious experience.)
Suppose that AI continues to rely on silicon chips and that -- as Schneider thinks is possible -- silicon chips just aren't the right kind of material to host consciousness. (I'll weaken these assumptions below.) It's 2045 and you walk into the iBrain store, thinking about having your degenerating biological brain replaced with more durable silicon chips. Lots of people have done it already, and now the internet is full of programmed entities that claim to be happily uploaded people who have left their biological brains behind. Some of these uploaded entities control robotic or partly organic bodies; others exist entirely in virtual environments inside of computers. If Schneider is right that none of these silicon-chip-instantiated beings is actually conscious, then what has actually happened is that all of the biological people who "uploaded" actually committed suicide, and what exist are only non-conscious simulacra of them.
You've read some philosophy. You're worried about exactly that possibility. Maybe that's why you've been so slow to visit the local iBrain store. Fortunately, the iBrain company has discovered a way to upload you temporarily, so you can try it out -- so that you can determine introspectively for yourself whether the uploaded "you" really would be conscious. Federal regulations prohibit running an uploaded iBrain at the same time that the original source person is conscious, but the company can scan your brain non-destructively while you are sedated, run the iBrain for a while, then pause your iBrain and update your biological brain with memories of what you experienced. A trial run!
From the outside, it looks like this: You walk into the iBrain store, you are put to sleep, a virtual you wakes up in a robotic body and says "Yes, I really am conscious! Interesting how this feels!" and then does some jogging and jumping jacks to test out the the body. The robotic body then goes to sleep and the biological you wakes up and says, "Yes, I was conscious even in the robot. My philosophical doubts were misplaced. Upload me into iBrain!"
Here's the catch: After you wake, how do you know those memories are accurate memories of having actually been conscious? When the iBrain company tweaks your biological neurons to install the memories of what "you" did in the robotic body, it's hard to see how you could be sure that those memories aren't merely presently conscious seeming-memories of past events that weren't actually consciously experienced at the time they occurred. Maybe the robot "you" really was a zombie, though you don't realize that now.
You might have thought of this possibility in advance, and so you might remain skeptical. But it would take a lot of philosophical fortitude to sustain that skepticism across many "trial runs". If biological you has lots of seeming-memories of consciousness as a machine, and repeatedly notices no big disruptive change when the switch is flipped from iBrain to biological brain, it's going to be hard to resist the impression that you really are conscious as a machine, even if that impression is false -- and thus you might decide to go ahead and do the upload permanently, unintentionally transforming yourself into an experienceless zombie.
But maybe if a silicon-chip brain could really duplicate your cognitive processes well enough to drive a robot that acts just as you would act, then the silicon-chip brain really would have to be conscious? That's a plausible (though disputable) philosophical position. So let's weaken the philosophical and technological assumptions a little. We can still get a skeptical zombie scenario going.
Suppose that the iBrain company tires of all the "trial runs" that buyers foolishly insist on, so the company decides to save money by not actually having the robot bodies do any of those things that the the trial-run users think they do. Instead, when you walk in for a trial they sedate you and, based on what they know about your just-scanned biological brain, they predict what you would do if you were "uploaded" into a robotic body. They then give you false memories of having done those things. You never actually do any of those things or have any of those thoughts during the time your biological body is sedated, but there is no way to know that introspectively after waking. It would seem to you that the uploading worked and preserved your consciousness.
There can be less malicious versions of this mistake. Behavior and cognition during the trial might be insufficient for consciousness, or for full consciousness, while memory is nonetheless vivid enough to lead to retrospective attributions of full consciousness.
In her talk, Schneider suggests that we could tell whether silicon chips can really host consciousness by trying them out and then checking whether consciousness disappears when we do so; but I'm not sure this test would work. If nonconscious systems (whether silicon chip or otherwise) can produce both (a.) outwardly plausible behavior, and (b.) false memories of having really experienced consciousness, then we might falsely conclude in retrospect that consciousness is preserved. (This could be so whether we are replacing the whole brain at once or only one subsystem at a time, as long as "outward" means "outside of the subsystem, in terms of its influence on the rest of the brain".) We might then choose to replace conscious systems with nonconscious ones, accidentally transforming ourselves into zombies.
Update June 27:
Susan Schneider replies!