The nature of consciousness has often been touted as one of the primary "untouchable" cornerstones of the theological argument for a supreme being. Since science has yet to even come very close to explaining it, they declare, it is unexplainable and must have been brought about by the work of a "creator". How little they have learned from the history of science and religion. Do they realize how many times some aspect of the unknown has been used as "proof" only to have science explain it?
From the other side of the argument, we must realize that even a full explanation of sentience will not close the door on religion - just as proof that the earth is not flat, that it is not the center of the universe, that it has changed greatly over time through plate tectonics, that life has evolved via the process of natural selection, that humans share a common ancestry with every other life-form on earth as proven through DNA, has not ended faith in the supernatural.
Nevertheless, with each new piece of the puzzle, more and more people have moved to a naturalistic view of the universe. A comprehensive explanation of consciousness would be a huge such piece of knowledge to add. And while we are still a very long way from having a theory any where near as robust as the theory of evolution, progress is being made and great leaps are likely in the coming decades.
Many have heard about this recent study, in which scientists were able to recreate an out of body experience (known by aficionados as "OBE") for subjects in a study performed at University College London, UK, and the Swiss Federal Institute of Technology in Lausanne and described in a recent issue of the journal "Science". They believe they have clearly demonstrated that the OBE has a neurological explanation. They did it with an interesting use of virtual reality goggles, tricking the brains of subjects into thinking their bodies were somewhere different from where their minds were at. You can see a short video clip of the experiments here.
This is simply the latest assault on a previously "unknown" aspect of consciousness. An experiment from 2002 is described here. And, in 2005, another study in which, "we aim to take the theory a stage further, by looking at the way people see and experience their bodies, and how - through perfectly ordinary psychological processes - these images and experiences may create the impression of seeing their bodies from the outside."
Philosopher Paul Churchland says that all of this work on consciousness is not "reductionist", although he is somewhat sympathetic to those who feel threatened by it. In fact, he assures, the opposite is true and his reasoning on it is quite impressive. His wife (and partner in philosophy) Pat Churchland says that "The problem of consciousness is not going to be explained by any one experiment". You can find a highly enlightening video interview on this with the husband and wife philosopher team from the University of California, San Diego on this page, about half way down on the right.
All of this work on explaining OBE's is one of many areas of the study of consciousness in which science slowly but inexorably closes in on an understanding of the natural evolution of the unique sentience of Homo sapiens. The great news is that based on these successes, we can expect so much more in the next 20 to 30 years.