The problem with any form of physicalism is that if consciousness arises from physical principles, then the vast majority of the universe consists of unobserved physical interactions. Does the universe really exist at that point? If it doesn't, how come I am here to experience it? If it does, it would be more likely that I am a disembodied boltzman brain than a human that evolved on earth, since there is no reason for the unobserved portion of the universe to not be infinitely large. You simply wouldn't know it.