One of the head-scratchers for me is simply this: Did the things which we now know exist, exist before we knew about them? If they did, then there is a material existence separate from consciousness. Unless, that is, you postulate some kind of unversal consciousness. At which point, we cycle back to theism and all the unfortunate baggage that brings with it.

Anyone who has encountered a cat, a dog, a dolphin or a Millwall supporter knows that there are degrees of consciousness among living beings. It follows that consciousness may be tied to levels of evolution and adaptation. This does not imply the merely physical - there is no proof that anything is entirely physical in its' makeup - but it implies that consciousness is in some way linked to and is acted upon by the same factors that guide or force evolution.. We have largely concentrated, as a species, on the material because it has helped us survive and made us more comfortable. We will sooner or later take a serious look at the non-material if only because some brarnches of physics are already heading in that direction.

I shall reserve judgement.