John Collins writes:
> The fact that we're alive shows that as a species we've been historically
> very 'lucky', the biggest 'break' being in the finely tuned initial
> conditions for our universe. At least a level I many-worlds theory is
> needed to explain this.
Yes, more like level 2, I'd say. That's where you get variations on the
dimensionality of the universe and the values of physical constants.
I think those are the parameters which are said to be finely tuned in
order to allow the kinds of stability that would allow structure to form.
> But in a higher level MWT this good luck might
> have extended further. For instance, our planet might have experienced an
> unusually high number of 'near misses' with other astronomical bodies. Now
> that we're here to watch, the universe will be forced to obey the law
> of averages, so there could be a significantly higher probability of
> a deadly asteroid collision than would be indicated by the historical
> frequeny of said events. Perhaps we should carefully compare how often
> the other planets have been hit with how often we have: They certainly
> look more craterful....
Certainly an interesting direction to pursue. However I think the
anthropic prediction in such cases is that our history would have
been just barely good enough to allow life like us to form. If meteor
bombardment should have wiped us out, we would predict that we would
have experienced a history of heavy meteor strikes, not quite enough to
wipe us out, but enough to be very troublesome.
> Have there been any serious studies into this? It's not just idle
> philosophial musings, it affects the way our governments should be
> spending our money (or rather your money; I'm a non-earning student).
I've seen a few papers that look at the possibility that the evolution
of intelligent life is overwhelmingly unlikely. Robin Hanson has a
couple of papers on this, http://hanson.gmu.edu/greatfilter.html and a
more technical one at http://hanson.gmu.edu/hardstep.pdf.