For anyone interested in this topic who hasn't come across the following book, you might find it worth picking up:

http://www.amazon.com/Mindful-Univer.../dp/3642180752

I think Stapp's theory is the closest we've got to an explanation which makes sense. To me, at least.

The fascinating thing about Stapp's theory (or one of them) is that he actually provides a mechanism whereby even though consciousness is not physical, the capacity for consciousness could have been acquired by animals via natural selection. There's a major problem for Darwinism here that doesn't exist for any other feature of living systems. The problem is this: the materialists don't want to accept that consciousness is causal over matter, because that looks to them like dualism and "dualism is bad". BUT...if consciousness is NOT causal over matter then it can't have been selected by natural selection, because it can't have made any difference to the actual behaviour of the first conscious animals. For the materialists, this is "rock and hard place" time, and the only way out is to deny there is any such thing as consciousness, or to claim it evolved "by accident" (i.e. it is a totally random feature of animals and serves no evolutionary purpose.)