I have two separate objections.
1) The first objection, which I hint at in my original post, is that the selection of a reference class of human beings seems to be selected specifically to make whatever point the anthropic reasoner is trying to make. Why don't I have an equal likelihood of being
Obviously each of these reference classes generate completely different answers. You would guess that, e.g. for each reference class,
In other words, there is no good reason to pretend that human consciousness works anything like a virtual-parallel-Earth device rather than being like any other conceivable reference class.
2) The second objection is, again, that the existence of "observers" in the first place is an illusion. You have a 100% likelihood of being you because you are identically you (minus some small increment allowing for insanity, etc.). We aren't souls injected into bodies from heaven. We are matter that thinks it has identity.
Let me start with the second question, since I think I have a little more of a clue how to answer it.
Anthropics doesn't really rely on you being you. You being you is just...I guess I could call it a convenient Schelling point. We've got to choose someone to do anthropics on. Suppose we chose Genghis Khan. We could say that Genghis was a conquering warlord, so therefore most people throughout history must be conquering warlords. But this would fail, because the only reason we selected Genghis Khan to begin with was that he was a conquering warlord.
But this...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.