I haven't had a lot of success with this kind of question post before. But, here goes anyway.
Can you imagine a world like this in all ways except that its inhabitants are not conscious?
It's very fashionable for pro-science, apparent naturalists to claim that, though consciousness isn't a special kind of stuff (this is what Descartes thought),
it isn't a product of our material brains. There could be brains exactly like ours not accompanied by consciousness, this is enough to show that consciousness something separate from the natural world.
Does this sound reasonable to you?
I've been meaning to get round to writing my own post on this, but it's just so difficult, I'll get there in the end. If you feel like putting in loads of effort, this post is very pleasingly mind bending.