I disagree. Say we were Nazi's or something and we did not have to care about ethics. If such is the case, we could mess with people's brains (people only because they can talk about what their consciousness is like) until we figure out what the physical correlates of consciousness are. It would still be hard to accomplish this goal, but if at some point I can make a machine that causes you to see, hear, taste etc. what I want in some way, then I am sure many of the conversations about consciousness would change dramatically (and in a positive way as well).
This is the Scientific Method. At some point, I am sure we would then get down to how consciousness works. I know the last sentence has some faith in it. Oh well, I admit it, I have faith in the Scientific Method (until some better method comes along, not a likely event though is my guess!).