Comment on Open Thread, March 1-15, 2012

Thu, 08 Mar 2012 00:25:55 GMT

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 selection bias is inherent in anything we try. If we were to deliberately select some random peasant from Khan's era to do anthropics on, so that we avoided that first bias, we would be biasing ourselves towards peasants, biasing ourselves toward people who weren't important, biasing ourselves towards people from the past, and biasing ourselves to Earthlings.

The fact that you are necessarily you is part of why anthropics works. If we were souls who chose bodies at the moment of birth, I couldn't condition on my own existence in 2012, because my soul might have been really excited at the prospect to go into one of those super-rare presingularity bodies. As it is, I know I have no selection bias in selecting myself with my specific characteristics, because I did not select myself or my personal characteristics. So I can look at those characteristics - white human male born in 1984 - and consider them a random sample of the characteristics of all people everywhere and everywhen, and do anthropics on them. The fact that the person who is a suitable random sample for anthropics also happens to be me is probably overemphasized, but I don't think it's that important.

And I think this also goes part of the way to solving your first objection. We can't do anthropics on my brain as a representative sample of all 1.4 kg lumps of matter, because it's getting selected specifically as a 1.4 kg lump of matter that is especially interesting to me - most 1.4 kg lumps of matter were disqualified before they even had a chance to be the one we're doing anthropics on.

I admit I am still quite confused on how this works in more complicated scenarios - see this post for the same argument in the opposite direction.

Discuss