I don't think your comments really answer the questions that are being asked. The question, as far as I understand it, is why humans can't operate exactly as th

I don't think your comments really answer the questions that are being asked. The question, as far as I understand it, is why humans can't operate exactly as they do now, but without the sensation of consciousness. I don't think the question is "hard", I think it simply does not have a good solution. Science can explain how things work, but not why. One day, we may even be able to have an empirical theory of consciousness, e.g., how manipulating various parts of the brain affect how we are conscious, what physical structures are needed to generate consciousness (or at least, beings that act as if they are conscious), etc., but we can never explain why we are conscious, i.e., why we have experience.