Sorry about Campbell's longwindedness and the large amount of time this takes...
Morphane, good point about the bacteria, it's just an analogy. Not a bad one either, I sometimes feel like a bacterium or an ant myself, popping up its head in hyperspace and catching a glimpse of totally impossible things. I just don't think I can imagine or 'hallucinate' these huge 100% coherent worlds and hypercomplex things with my stupid little brain
Also, there is plenty of well documented evidence that NDEs are real. People can have intense life-changing experiences without brain activity, being dead for 90 minutes or even more.
Subjective DMT experiences convinced me that my brain matter doesn't actually generate consciousness, it's rather like a receiver or antenna. I know I can't prove that to the outer world but that's not the point of firsthand experiences. But that doesn't mean it's invalid! Nobody can prove they dream, yet we accept dreaming is a real phenomenon because we experience them subjectively and tell each other about it.
Witnesses are teken seriously in court (at least, they should be), why not here.
Ken Wilber wrote some interesting stuff about this, his four quadrants. Sadly, he degenerated into another cult leader...
The physical world is just as mysterious and 'spiritual' as anything. Through science, we discovered the huge scale and complexity of the universe - much more interesting and terrifying than the old world views and religions with their simplistic 'snap with the fingers' omnipotent god. I love matter!
I dislike new age stuff too, but I think Campbell is a bit more solid. He was trained by Robert Monroe under lab conditions and went at great length getting reproducible results and retrieving information that would have been impossible to get otherwise. Being a practical nuts & bolts guy, he needed hard proof himself. Burnt, I hear you think 'they all say that'
What is so unscientific about the idea that matter is not all there is? Matter is not even solid, the idea of 'solid stuff' is an fabrication!