Listening with pleasure to this conversation between Sam Harris and Ross Douthat, I felt that they were often talking past each other and thus failing to identify the true nature of their disagreement. I can help with that!
Re: what human life might be like in a post-scarcity society, I’d recommend my essay on Iain M. Banks’s Culture novels. (I’d also recommend Banks’s novels, of course, but first things first.)
Re: demons, I’d recommend my outline of a demonology.