one of the reasons I can think of why consciousness has alluded most research scientists (psychologists, neuroscientists and philosophers alike) and so insistently defy clear and simple definition and explanation is the fact that we have made wrong assumptions about our consciousness, and that has led us to look in the wrong direction.
I hate to do this, but very often trying to operationally define consciousness in the scientific sense almost always lead us back to the many fundamental philosophical questions: what is thought specifically in the physical sense? Less relevant, but even more extreme: je pense donc je suis? do I even really exist? Does the thoughts I have really belong to me? I shall go with the flow instead of defying it. Again, the question, what is thought. Saying it's just a bunch of conscious brain processes does not explain anything but just beg the question again.
You, whatever idea you have of yourself, no matter how alive you feel, are nevertheless a conglomerate of lifeless bunch of stuffs (which I believe we all agree, as far as our perception brings us). Senses are perception from stimulus. Ideas are perception without stimulus. Or rather, stimulus from the memory, and also the current thoughts/ideas that lead to it. Connections, we may call such things. They can be reliably replicated both in physical way and in an abstract sense. I can make a machine, or a computer program that does this. What then, distinguish them from us?
Perhaps it's high time we give up the seemingly undeniable idea that we are in CONTROL of our consciousness, of our thought processes, of our volition. Research evidence increasingly points to the conclusion that much of what one does is not entirely controlled by the person; yet, we are often led to think and feel and experience that our behavior is determined by ourself, by our volition. Well. Can you assume that volition belongs to you? Can it not be your behavior is determined by other things and you are made to feel that you are in control? That other thing, whatever it is, may very well be the thing that controls your thoughts. A projection of whatever you have in mind on your mind, and your mind attributes itself to the creation of such thoughts, and even this attribution is made by that projection of that thing. I shall call such a thing a mind runner. No matter what do I label it as, we have not come to a definite conclusion of what and how the mind and the consciousness works. This remains my speculation and I do not see it any time soon being proved to be the case.
Like-wise, if we generalize this idea to the whole world, can we say that the world is a virtual world, a fake world, a non-existing world in the physical sense, much like how we think of worlds in computer games? This analogy I give is a recurring idea in many literature, to the point of it becoming jaded. But we still have not have an answer. Will we ever do?