This conversation is split with one in the BvS, which is a bit irrational:(
The real problem here is that we are so very, very far from a decent explanation of consciousness. We are like primitive science, and sometimes it is best to accept two concepts for a while (centuries?) even though the eventual aim might be to unify them again (an example might be electricity and magnetism). I see more hope of progress on consciousness if we treat it as something apart - studying the way it behaves without insisting it is ultimately physical. Thus, since Ganzfeld experiments provide significant evidence that one mind can affect another without a physical connection, it would make more sense to accept that as a property of non-physical mind-stuff (subject to correction if ultimately the Ganzfeld and related experiments were shown to be false). If you want to get a feel for the real challenge that consciousness poses to physical explanations, you really should read Irreducible Mind.
At the moment, physicalists have no option other than to promise explanations for mental phenomena somewhere in the far future, and to scoff at any experiment that seems to show the mind escaping from the brain.
Given such a pragmatic split, your question, " Why can't the mind arise from brain function?", would sound more like what it really is - musing about a science that is a fair way off, and something that could be refuted by experimental observations (people who claim access to previous lives, reincarnation, etc.). My big beef is that we are discarding a lot of good scientific evidence just because we can't see how it could fit in to our world picture. Here is a neuroscientist who seems to think roughly the same:
David